ORCID Profile
0000-0002-4229-4348
Current Organisations
Universiti Teknologi PETRONAS
,
University of Novi Sad
,
University of South Australia
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Related Links
Publications
Enumeration of water-borne bacteria using viability assays and flow cytometry: A comparison to culture-based techniques
Publisher: Elsevier BV
Date: 12-2003
DOI: 10.1016/S0167-7012(03)00201-X
Abstract: Maintaining optimal conditions in catchments or distribution systems relies heavily on water authorities having access to rapid and accurate water quality data, including an indication of bacteriological quality. In this study, the BacLight bacterial viability kit and carboxyfluorescein diacetate (CFDA) were coupled with flow cytometry (FCM) for rapid detection of physiologically active bacteria from raw and potable waters taken from various locations around South Australia. Results were compared to the direct viable count (DVC) and quantitative DVC (qDVC), in addition to the culture-based methods of the heterotrophic plate count (HPC) and a commercial SimPlate technique. Raw and potable water analysis revealed that DVC and culture-based techniques reported significantly fewer viable bacteria compared to the number of physiologically active bacteria detected using the rapid FCM assays, where this difference appeared to be nonlinear across different s les. Inconclusive results were obtained using qDVC as a viability assay. In particular, HPC results were 2-4 log orders of magnitude below that reported by the FCM assays for raw waters. Few bacteria in potable waters examined were culturable by HPC, even though FCM assays reported between 5.56 x 10(2) and 3.94 x 10(4) active bacteria ml(-1). These differences may be attributed to the presence of nonheterotrophic bacteria, sublethal injury or the adoption of an active but nonculturable (ABNC) state.
Bacterial degradation of microcystin toxins within a biologically active sand filter
Publisher: Elsevier BV
Date: 02-2006
DOI: 10.1016/J.WATRES.2005.12.009
Abstract: Microcystin toxins are a problem for water authorities as they are recalcitrant to conventional water treatment. In this study, biological sand filtration was assessed in laboratory column experiments for its ability to remove two microcystin analogues, microcystin-LR and microcystin-LA. A lag period of 3 days was evident prior to the commencement of degradation. Contact times were varied during the experiment however, no microcystin was detected in the effluent after 4 days, even under conditions similar to those of a rapid sand filter. Removals of microcystin through the sand filters were shown to be primarily through biological degradation processes. Using polymerase chain reaction (PCR), biofilm, extracted from one of the sand filters that had effectively removed the microcystins, was shown to contain bacteria with the mlrA gene. Detection of this gene provided additional evidence that biological degradation of microcystin was the primary removal mechanism.
Profiling bacterial survival through a water treatment process and subsequent distribution system
Publisher: Oxford University Press (OUP)
Date: 07-2005
DOI: 10.1111/J.1365-2672.2005.02573.X
Abstract: To profile fractions of active bacteria and of bacteria culturable with routine heterotrophic plate count (HPC) methods through a typical water treatment process and subsequent distribution system. In doing so, investigate how water treatment affects both bacterial abundance and ersity, and reveal the identities of active bacteria not detected by traditional HPC culture. Profiling active fractions was performed by flow cytometric cell sorting of either membrane-intact (BacLight kit) or enzymatically active (carboxyfluorescein diacetate, CFDA) bacteria, followed by eubacterial 16S rDNA-directed PCR and denaturing gradient gel electrophoresis (DGGE). Water treatment significantly reduced active bacterial numbers detected by the BacLight kit and CFDA assay by 2.89 and 2.81 log respectively. Bacterial ersity was also reduced from > 20 DGGE bands in the active fractions of reservoir water to only two bands in the active fractions of finished water. These two bands represented Stenotrophomonas maltophila, initially culturable by HPC, and a Burkholderia-related species. Both species maintained measurable traits of physiological activity in distribution system bulk water but were undetected by HPC. Flow cytometric cell sorting with PCR-DGGE, to assess water treatment efficacy, identified active bacteria from a variety of major phylogenetic groups undetected by routine HPC. Following treatment S. maltophila and a Burkholderia-related species retained activity and entered distribution undetected by HPC. Methods used here demonstrate how water treatment operators can better monitor water treatment plant efficacy and assess distribution system instability by the detection and identification of active bacteria recalcitrant to routine HPC culture.
Bacterial degradation of microcystin toxins within a biologically active sand filter
Publisher: Elsevier BV
Date: 02-2006
DOI: 10.1016/J.WATRES.2005.12.009
Abstract: Microcystin toxins are a problem for water authorities as they are recalcitrant to conventional water treatment. In this study, biological sand filtration was assessed in laboratory column experiments for its ability to remove two microcystin analogues, microcystin-LR and microcystin-LA. A lag period of 3 days was evident prior to the commencement of degradation. Contact times were varied during the experiment however, no microcystin was detected in the effluent after 4 days, even under conditions similar to those of a rapid sand filter. Removals of microcystin through the sand filters were shown to be primarily through biological degradation processes. Using polymerase chain reaction (PCR), biofilm, extracted from one of the sand filters that had effectively removed the microcystins, was shown to contain bacteria with the mlrA gene. Detection of this gene provided additional evidence that biological degradation of microcystin was the primary removal mechanism.
Adsorption of congo red by three Australian kaolins
Publisher: Elsevier BV
Date: 03-2009
The role of methanol addition to water samples in reducing analyte adsorption and matrix effects in liquid chromatography–tandem mass spectrometry
Publisher: Elsevier BV
Date: 04-2015
DOI: 10.1016/J.CHROMA.2015.02.044
Abstract: Liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis coupled simply with water filtering before injection has proven to be a simple, economic and time-saving method for analyzing trace-level organic pollutants in aqueous environments. However, the linearity, precision and detection limits of such methods for late-eluting analytes were found to be much poorer than for early-eluting ones due to adsorption of the analytes in the operating system, such as s le vial, flow path and s le loop, creating problems in quantitative analysis. Addition of methanol (MeOH) into water s les as a modifier was shown to be effective in alleviating or even eliminating the negative effect on signal intensity for the late-eluting analytes and at the same time being able to reduce certain matrix effects for real water s les. Based on the maximum detection signal intensity obtained on desorption of the analytes with MeOH addition, the ratio of the detection signal intensity without addition of MeOH to the maximum intensity can be used to evaluate the effectiveness of methanol addition. Accordingly, the values of <50%, 50-80%, 80-120% could be used to indicate strong, medium and no effects, respectively. Based on this concept, an external matrix-matched calibration method with the addition of MeOH has been successfully established for analyzing fifteen pesticides with erse physico-chemical properties in surface and groundwater with good linearity (r(2): 0.9929-0.9996), precision (intra-day relative standard deviation (RSD): 1.4-10.7%, inter-day RSD: 1.5-9.4%), accuracy (76.9-126.7%) and low limits of detection (0.003-0.028μg/L).
Linearization of CMOS Broadband Power Amplifiers Through Combined Multigated Transistors and Capacitance Compensation
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 11-2007
Development and field testing of a real-time PCR assay for cylindrospermopsin-producing cyanobacteria
Publisher: Oxford University Press (OUP)
Date: 05-2008
DOI: 10.1111/J.1365-2672.2007.03676.X
Abstract: To develop and test a real-time PCR assay to detect and quantify genes specific to Cylindrospermopsis sp. and cylindrospermopsin-producing cyanobacteria. A duplex real-time PCR assay was developed that targets a cylindrospermopsin-specific and Cylindrospermopsis raciborskii-specific DNA sequence. The C. raciborskii-specific sequence was based on the rpoC1 DNA-dependent RNA polymerase gene, whilst the cylindrospermopsin-specific sequence was selected by surveying an extensive number of potential cylindrospermopsin-producing cyanobacterial strains for genes implicated in toxin production, aoaA, aoaB and aoaC. In toxic strains, sequences of each of these three genes were always present whilst in nontoxic strains the distribution of these sequences was patchy, resulting in what are likely to be natural deletion mutants. The real-time assay was optimized on a fixed and portable device, with results indicating that the reliable limit of detection for the assay was 100 copies per reaction or 1000 cells ml(-1) for both target sequences on both devices. In routine environmental s les enumerated by microscopy, the assay results were positive for all s les where C. raciborskii cells were observed at >1000 cells ml(-1) and negative in 15 s les where no C. raciborskii cells were observed. In field s les, the number of copies of the rpoC1 sequence more closely approximated the number of cells enumerated by microscopy, the number of copies of the pks sequence and detection of the toxin-specific sequence matched the results of toxin testing. The duplex real-time PCR assay was a sensitive and rapid method for detecting potential cylindrospermopsin-producing cyanobacteria in the laboratory or in the field. The observation of probable natural deletion mutants provides further evidence that the aoaA, aoaB and aoaC genes are involved in toxin production. This assay provides a new monitoring capability for tracking cylindrospermopsin-producing cyanobacteria that are an emerging threat to water quality.
An examination of the antibiotic effects of cylindrospermopsin on common gram-positive and gram-negative bacteria and the protozoanNaegleria lovaniensis
Publisher: Wiley
Date: 2008
DOI: 10.1002/TOX.20311
Abstract: The importance of the toxin cylindrospermopsin to the function and fitness of the cyanobacteria that produce it remains a matter of conjecture. Given that the structure of cylindrospermopsin has commonalities with other antibacterial protein synthesis inhibitors, such as streptomycin, authors tested the possibility that the toxin might act as an antibacterial compound that can kill competing microbes. Escherichia coli, Bacillus subtilis, Staphylococcus aureus, and Pseudomonas aeruginosa were tested by the minimal inhibitory concentration method and significant antibacterial activity was only observed at a cylindrospermopsin concentration of 300 microg mL(-1) after exposure for 5 days. No effect on log phase growth of E. coli was observed for this same toxin concentration. Protein synthesis was inhibited by cylindrospermopsin in E. coli 70S extracts, reduced by 25% compared with controls when treated with 41.5 microg mL(-1) of the toxin however, a much greater reduction of 97% was observed for chlor henicol in the same experiment. Naegleria lovaniensis, a phagotrophic protozoan, was more susceptible to cylindrospermopsin, with a decrease in the number of N. lovaniensis plaques after 24-h treatment with 5-50 microg mL(-1) of toxin and an LC(50) of approximately 60 microg mL(-1). Given these results, cylindrospermopsin is clearly not antibacterial at concentrations found in environmental waters, nor will it adversely affect N. lovaniensis at these concentrations. For organisms that are able to ingest cylindrospermopsin-producing cells, the response of N. lovaniensis to the toxin suggests that only a few ingested cells would be enough to kill predatory organisms with similar susceptibility.
FACS enrichment and identification of floc-associated alphaproteobacterial tetrad-forming organisms in an activated sludge community
Publisher: Oxford University Press (OUP)
Date: 08-2008
DOI: 10.1111/J.1574-6968.2008.01230.X
Abstract: A precise phylogenetic identity of the Defluviicoccus-related glycogen-accumulating organisms (GAO) observed after FISH probing in a novel activated sludge process removing phosphorus was sought with the aim of exploring the phylogenetic ersity of this important group. These organisms, whose sequences were not revealed in previously generated community wide 16S rRNA gene clone libraries, were identified using flow cytometry cell sorting of FISH-positive cells. Sequencing of a 16S rRNA gene clone library created from this sorted population identified the Defluviicoccus-related GAO as being highly related to previous identified GAO from enhanced biological phosphorus removal systems, despite a marked environmental difference between the two systems.
Fluorescence Excitation-Emission Spectroscopy: An Analytical Technique to Monitor Drugs of Addiction in Wastewater
Publisher: MDPI AG
Date: 22-02-2019
DOI: 10.3390/W11020377
Abstract: Emerging contaminants of concern have become a serious issue for the scientific community and society more broadly in recent years due to their increasingly widespread environmental distribution and largely unknown environmental and human health impacts. This study aimed to explore the use of fluorescence excitation-emission (F-EEM) spectroscopy as an alternative analytical method to evaluate the presence of key drugs of addiction (benzoylecgonine, meth hetamine, MDMA, codeine and morphine) in wastewater treatment plants. The chemicals of interest from wastewater were extracted by mixed-mode solid phase extraction and quantified using liquid chromatography tandem mass spectrometry. The same wastewater s les were also analysed by a fluorescence spectrophotometer for fluorescence spectra at wavelengths 280–600 nm (emission) and 200–600 nm (excitation). The study also investigated the relevance of different methods for interpreting F-EEM matrices data including parallel factor analysis (PARAFAC) modelling and fluorescence regional integration technique. PARAFAC identified four components, and among them, component C2, identified at the λex/λem = 275/340 nm wavelength associated with proteinaceous compounds most likely related to tryptophan amino acid, showed significant correlation with codeine removal. MDMA and morphine were not correlated to any of the fluorescence regions. The fluorescence regions related to aromatic protein-like fluorescence were correlated significantly with drug concentration and so may offer a suitable alternative approach for monitoring drugs including benzoylecgonine, meth hetamine and codeine.
Bacterial inactivation kinetics of a photo-disinfection system using novel titania-impregnated kaolinite photocatalyst
Publisher: Elsevier BV
Date: 06-2011
Comparison of SYTO9 and SYBR Green I for real-time polymerase chain reaction and investigation of the effect of dye concentration on amplification and DNA melting curve analysis
Publisher: Elsevier BV
Date: 05-2005
Abstract: Following the initial report of the use of SYBR Green I for real-time polymerase chain reaction (PCR) in 1997, little attention has been given to the development of alternative intercalating dyes for this application. This is surprising considering the reported limitations of SYBR Green I, which include limited dye stability, dye-dependent PCR inhibition, and selective detection of licons during DNA melting curve analysis of multiplex PCRs. We have tested an alternative to SYBR Green I and report the first detailed evaluation of the intercalating dye SYTO9. Our findings demonstrate that SYTO9 produces highly reproducible DNA melting curves over a broader range of dye concentrations than does SYBR Green I, is far less inhibitory to PCR than SYBR Green I, and does not appear to selectively detect particular licons. The low inhibition and high melting curve reproducibility of SYTO9 means that it can be readily incorporated into a conventional PCR at a broad range of concentrations, allowing closed tube analysis by DNA melting curve analysis. These features simplify the use of intercalating dyes in real-time PCR and the improved reproducibility of DNA melting curve analysis will make SYTO9 useful in a diagnostic context.
Investigations into the biodegradation of microcystin-LR in wastewaters
Publisher: Elsevier BV
Date: 15-08-2010
DOI: 10.1016/J.JHAZMAT.2010.04.081
Abstract: Microcystins are potent hepatotoxins that can be produced by cyanobacteria. These organisms can proliferate in wastewaters due to a number of factors including high concentrations of nutrients for growth. As treated wastewaters are now being considered as supplementary drinking water sources, in addition to their frequent use for irrigated agriculture, it is imperative that these wastewaters are free of toxins such as microcystins. This study investigated the potential for biodegradation of microcystin-LR (MCLR) in wastewaters through a biological sand filtration experiment and in static batch reactor experiments. MCLR was effectively removed at a range of concentrations and at various temperatures, with degradation attributed to the action of microorganisms indigenous to the wastewaters. No hepatotoxic by-products were detected following the degradation of MCLR as determined by a protein phosphatase inhibition assay. Using TaqMan polymerase chain reaction, the first gene involved in bacterial degradation of MCLR (mlrA) was detected and the responsible bacteria shown to increase with the amount of MCLR being degraded. This finding suggested that the degradation of MCLR was dependent upon the abundance of MCLR-degrading organisms present within the wastewater, and that MCLR may provide bacteria with a significant carbon source for proliferation in turn increasing MCLR removal.
Environmental temperature controls Cryptosporidium oocyst metabolic rate and associated retention of infectivity
Publisher: American Society for Microbiology
Date: 07-2005
DOI: 10.1128/AEM.71.7.3848-3857.2005
Abstract: Cryptosporidium is a significant cause of water-borne enteric disease throughout the world and represents a challenge to the water industry and a threat to public health. In this study we report the use of a cell culture-TaqMan PCR assay to measure oocyst inactivation rates in reagent-grade and environmental waters over a range of temperatures. While oocysts incubated at 4°C and 15°C remained infective over the 12-week holding period, we observed a 4 log 10 reduction in infectivity for both 20 and 25°C incubation treatments at 12 and 8 weeks, respectively, for all water types examined, a faster rate of inactivation for oocysts than previously reported. This temperature-dependent inactivation was further investigated using a simple and rapid ATP assay described herein. Time course experiments performed in reagent-grade water at incubation temperatures of 4, 15, 20, 25, 30, and 37°C identified a close relationship between oocyst infectivity and oocyst ATP content, demonstrating that temperature inactivation at higher temperatures is a function of increased oocyst metabolic activity. While water quality did not affect oocyst inactivation, biological antagonism appears to be a key factor affecting oocyst removal from environmental waters. Both the cell culture-TaqMan PCR assay and the ATP assay provide a sensitive and quantitative method for the determination of environmental oocyst inactivation, providing an alternative to the more costly and time-consuming mouse infection assay. The findings presented here relating temperature to oocyst inactivation provide valuable information for determining the relative risks associated with Cryptosporidium oocysts in water.
Occurrence, removal and environmental risk of markers of five drugs of abuse in urban wastewater systems in South Australia
Publisher: Springer Science and Business Media LLC
Date: 09-06-2018
DOI: 10.1007/S11356-018-2464-6
Abstract: The occurrence and fate of five drugs of abuse in raw influent and treated effluent wastewater were investigated over a period of 1 year in the Adelaide region of South Australia. Four wastewater treatment plants were chosen for this study and monitored for five drugs which included cocaine in the form of its metabolite benzoylecgonine (BE), meth hetamine, 3,4-methylenedioxymeth hetamine (MDMA) and two opioids (codeine and morphine) during the period April 2016 to February 2017. Alongside concentrations in raw sewage, the levels of drugs in the treated effluent were assessed and removal efficiencies were calculated. Drug concentrations were measured by mixed-mode solid phase extraction and liquid chromatography coupled to a quadrupole mass spectrometer. Drug concentrations detected in the raw wastewater ranged from 7 to 6510 ng/L and meth hetamine > morphine > MDMA > BE. Results showed that all the targeted drugs were on average incompletely removed by wastewater treatment, with removal performance highest for morphine (94%) and lowest for MDMA (58%). A screening-level environmental risk assessment was subsequently performed for the drugs based on effluent wastewater concentrations. Based on calculated risk quotients, overall environmental risk for these compounds appears low, with codeine and meth hetamine likely to pose the greatest potential risk to receiving environments. Given the recognised limitations of current ecotoxicological models and risk assessment methods for these and other pharmaceutical drugs, the potential for environmental impacts associated with the continuous discharge of these compounds in wastewater effluents should not be overlooked.
Degradation of Microcystin-LR through Biological Sand Filters
Publisher: American Society of Civil Engineers (ASCE)
Date: 07-2007
Molecular Phylogeny of Anabaena circinalis and Its Identification in Environmental Samples by PCR
Publisher: American Society for Microbiology
Date: 09-2000
DOI: 10.1128/AEM.66.9.4145-4148.2000
Abstract: Although the cyanobacterium Anabaena circinalis occurs worldwide, Australian isolates are believed to exclusively possess the saxitoxin group neurotoxins (paralytic shellfish poisons). Identification of A. circinalis in a mixed population is complicated due to limited morphological differences between Anabaena species. Sequence analysis of the DNA-dependent RNA polymerase ( rpoC1 ) gene from 24 Anabaena isolates, including 12 designated A. circinalis , permitted a phylogenetic analysis to be performed. In addition, an A. circinalis -specific PCR was developed and tested successfully on environmental s les.
Multiplex PCR assay forCylindrospermopsis raciborskii and cylindrospermopsin-producing cyanobacteria
Publisher: Wiley
Date: 2003
DOI: 10.1002/TOX.10108
Abstract: Water bodies are routinely monitored for the presence of potentially toxic cyanobacteria however, the methodology for confirming toxicity is currently complex and expensive. Here we describe the application of gene-based technology to rapidly identify cylindrospermopsin-producing cyanobacteria, specifically, Cylindrospermopsis raciborskii. A multiplex polymerase chain reaction (PCR) test was developed that simultaneously identified polyketide synthase (pks) and peptide synthetase (ps) determinants associated with cylindrospermopsin production and distinguished C. raciborskii from other cylindrospermopsin-producing cyanobacteria of the species Anabaena bergii and Aphanizomenon ovalisporum, by targeting the rpoC1 gene. Twenty-one C. raciborskii, 5 A. bergii, 10 Aph. ovalisporum isolates and 3 environmental s les all yielded PCR results consistent with their toxicological status, as assessed by high-performance liquid chromatography coupled to mass spectrometry or matrix-assisted laser desorption ionization-time-of-flight mass spectrometry, and C. raciborskii was always correctly identified. The PCR test is a rapid, reliable, and economical way of assessing the toxic potential of cyanobacterial blooms formed by these organisms.
Effective in-situ chemical surface modification of forward osmosis membranes with polydopamine-induced graphene oxide for biofouling mitigation
Publisher: Elsevier BV
Date: 05-2016
Phosphorus recovery and reuse from waste streams
Publisher: Elsevier
Date: 2015
pTIM3, a Plasmid Delivery Vector for a Transposon-Based Inducible Marker Gene System in Gram-Negative Bacteria
Publisher: Elsevier BV
Date: 11-1995
Abstract: pTIM3 is a suicide plasmid vector for the delivery of a transposition defective derivative of Tn5, expressing inducible mercury resistance (HgR) and catechol 2,3-dioxygenase (C23O) activity, to a range of gram-negative microorganisms. pTIM3 was constructed by a four-stage process from pNMM1, a derivative of pSUP5011 containing a modified Tn5 where antibiotic-resistance determinants have been replaced by the mer operon of Tn501 and tdnC (encoding a C23O). In pTIM3, tdnC is fused to merD, to bring C23O expression under the control of the mer operon. pTIM3 was introduced into Acinetobacter calcoaceticus, Pseudomonas putida, Burkholderia cepacia, and Alcaligenes sp., and isolates were examined for loss of the vector, which is not stably maintained outside the Enterobacteriaceae, but retention of the Tn5 derivative. Transposition results from the action of a vector-encoded Tn5 transposase (Tnp) on the ends of IS50L and IS50R retained in the Tn5 construct. Between 10 and 20% of the isolates contained a single copy of the defective transposon in the chromosome. A single-copy isolate of each species was assayed for inducibility of C23O activity using HgCl2 as inducer. The increase in C230 activity was linear with increasing HgCl2 concentration and ranged between 10- and 20-fold at 20 micrograms/ml. HgR and C23O+ phenotypes were found to be stably maintained in each of the isolates following 40 generations of nonselective growth. A novel aspect of this marker gene system is that isolates can be recovered on nonselective medium and then sprayed with a catechol/HgCl2 mixture for rapid colorimetric detection. The system can be applied to the tracking of genetically modified microorganisms in the environment and has the advantage that their detection may be achieved cheaply and without the use of sophisticated equipment.
Synthesis and characterisation of novel titania impregnated kaolinite nano-photocatalyst
Publisher: Elsevier BV
Date: 2009
Reclaimed Water Systems: Biodiversity Friend or Foe?
Publisher: American Chemical Society
Date: 2015
An adsorption–photocatalysis hybrid process using multi-functional-nanoporous materials for wastewater reclamation
Publisher: Elsevier BV
Date: 10-2010
DOI: 10.1016/J.WATRES.2010.06.033
Abstract: In this study, two of our recently developed laboratory scale wastewater treatment systems, fluidized-bed reactor (FBR) using formulated clay mixture absorbents (clay-FBR adsorption) and an annular slurry photoreactor (ASP) using TiO(2) impregnated kaolin catalysts (TiO(2)-K-ASP) were integrated as an adsorption-photocatalysis hybrid process to treat municipal wastewater as alternative secondary and tertiary treatment for wastewater reclamation. Primary effluent from sewage and secondary effluent from a membrane bioreactor treatment process were used to assess chemical removal capabilities of the FBR and ASP systems, and the hybrid process. The formulated clays-FBR system demonstrated the prevailing removal efficiency toward PO(4)(3-), NO(3)(-) and suspended solids. The TiO(2)-K-ASP showed superior degradation of dissolved organic content while the presence of inorganic ions caused a detrimental effect on its performance. The integration of the adsorption and degradation system as a hybrid treatment process resulted in a synergetic enhancement for the chemical removal efficiency. Complete elimination of PO(4)(3-) content was obtained in the adsorption stage while 30% and 65% NO(3)(-) removal were obtained from the hybrid treatment of the primary and secondary effluents, respectively. The corresponding COD reduction during the photodegradation was further investigated by the high-performance size exclusion chromatography technique, where it revealed the shift of apparent molecular weight of the dissolved organic contaminants toward the smaller region. This present study demonstrated that this adsorption-photocatalysis hybrid technology can be used as a feasible alternative treatment process for wastewater reclamation.
Overlooked effects of organic solvents from sample preparation on reaction constants of micropollutants in UV-based advanced oxidation processes
Publisher: Elsevier BV
Date: 04-2017
Fine-Tuning the Surface of Forward Osmosis Membranes via Grafting Graphene Oxide: Performance Patterns and Biofouling Propensity
Publisher: American Chemical Society (ACS)
Date: 06-08-2015
Abstract: Graphene oxide (GO) nanosheets were attached to the polyamide selective layer of thin film composite (TFC) forward osmosis (FO) membranes through a poly L-Lysine (PLL) intermediary using either layer-by-layer or hybrid (H) grafting strategies. Fourier transform infrared spectroscopy, zeta potential, and thermogravimetric analysis confirmed the successful attachment of GO/PLL, the surface modification enhancing both the hydrophilicity and smoothness of the membrane's surface demonstrated by water contact angle, atomic force microscopy, and transmission electron microscopy. The biofouling resistance of the FO membranes determined using an adenosine triphosphate bioluminescence test showed a 99% reduction in surviving bacteria for GO/PLL-H modified membranes compared to pristine membrane. This antibiofouling property of the GO/PLL-H modified membrane was reflected in reduced flux decline compared to all other s les when filtering brackish water under biofouling conditions. Further, the high density and tightly bound GO nanosheets using the hybrid modification reduced the reverse solute flux compared to the pristine, which reflects improved membrane selectivity. These results illustrate that the GO/PLL-H modification is a valuable addition to improve the performance of FO TFC membranes.
Biodegradation of geosmin by a novel Gram-negative bacterium; isolation, phylogenetic characterisation and degradation rate determination
Publisher: Elsevier BV
Date: 06-2009
DOI: 10.1016/J.WATRES.2009.04.005
Abstract: Biologically active sand filters within water treatment plants (WTPs) are now recognised as an effective barrier for the removal of geosmin. However, little is known regarding the actual microbiological processes occurring or the bacteria capable of degrading geosmin. This study reports the enrichment and isolation of a Gram-negative bacterium, Geo48, from the biofilm of a WTP sand filter where the isolate was shown to effectively degrade geosmin in idually. Experiments revealed that Geo48 degraded geosmin in a planktonic state by a pseudo-first-order mechanism. Initial geosmin concentrations ranging from 100 to 1000ng/l were shown to directly influence geosmin degradation in reservoir water by Geo48, with rate constants increasing from 0.010h(-1) (R(2)=0.93) to 0.029h(-1) (R(2)=0.97) respectively. Water temperature also influenced degradation of geosmin by Geo48 where temperatures of 11, 22 and 30 degrees C resulted in rate constants of 0.017h(-1) (R(2)=0.98), 0.023h(-1) (R(2)=0.91) and 0.019h(-1) (R(2)=0.85) respectively. Phylogenetic analysis using the 16S rRNA gene of Geo48 revealed it was a member of the Alphaproteobacteria and clustered with 99% bootstrap support with an isolate designated Geo24, a Sphingopyxis sp. previously described as degrading geosmin but only as a member of a bacterial consortium. Of the previously described bacteria, Geo48 was most similar to Sphingopyxis alaskensis (97.2% sequence similarity to a 1454bp fragment of the 16S rRNA gene). To date, this is the only study to report the isolation and characterisation of a Gram-negative bacterium from a biologically active sand filter capable of the sole degradation of geosmin.
Biological filtration for the removal of algal metabolites from drinking water
Publisher: IWA Publishing
Date: 03-2006
DOI: 10.2166/WS.2006.064
Abstract: Biological sand filters were assessed for their ability to remove geosmin, 2-methylisoborneol (MIB) and microcystin-LR. Microcystin-LR was the most readily degradable metabolite with a maximum lag period of only 5 days before it was undetected in the filter effluent. Geosmin and MIB were difficult to degrade, with a period in excess of 75 days before greater than 95% removal was achieved. A microcystin-degrading gene was detected in the biofilm from one of the filters, confirming that the biofilm possessed the ability to degrade microcystin. A Sphingomonas sp. was identified as a potential geosmin degrader based on denaturing gradient gel electrophoresis (DGGE) analysis. DGGE analysis revealed a more complex bacterial community during the degradation of MIB, suggesting that more than one bacterium may be responsible for its degradation.
Molecular biology techniques in parasite ecology
Publisher: Elsevier BV
Date: 05-2002
DOI: 10.1016/S0020-7519(01)00352-6
Abstract: Molecular techniques are increasingly being used to study the ecology of a variety of organisms. These techniques represent important tools for the study of the systematics, population genetics, biogeography and ecology of parasites. Here, we review the techniques that have been employed to study the ecology and systematics of parasites (including bacteria and viruses). Particular emphasis is placed on the techniques of isoenzyme electrophoresis, in situ hybridisation and nucleic acid lification to characterise parasite/microbial communities. The application of these techniques will be exemplified using ticks, bacterial endosymbionts and parasitic protozoa.
Removal of cyanobacterial metabolites through wastewater treatment plant filters
Publisher: IWA Publishing
Date: 04-2012
DOI: 10.2166/WST.2012.002
Abstract: Wastewaters have the potential to proliferate excessive numbers of cyanobacteria due to high nutrient levels. This could translate to the production of metabolites, such as the saxitoxins, geosmin and 2-methylisoborneol (MIB), which can impair the quality of wastewater destined for re-use. Biological sand filtration was assessed for its ability to remove these metabolites from a wastewater. Results indicated that the sand filter was incapable of effectively removing the saxitoxins and in some instances, the effluent of the sand filter displayed greater toxicity than the influent. Conversely, the sand filter was able to effectively remove geosmin and MIB, with removal attributed to biodegradation. Granular activated carbon was employed as an alternative filter medium to remove the saxitoxins. Results showed similar removals to previous drinking water studies, where efficient removals were initially observed, followed by a decrease in the removal a consequence of the presence of competing organics which reduced adsorption of the saxitoxins.
Bathroom greywater recycling using polyelectrolyte-complex bilayer membrane: Advanced study of membrane structure and treatment efficiency
Publisher: Elsevier BV
Date: 09-2016
DOI: 10.1016/J.CARBPOL.2016.04.039
Abstract: Polyelectrolyte-complex bilayer membrane (PCBM) was fabricated using biodegradable chitosan and alginate polymers for subsequent application in the treatment of bathroom greywater. In this study, the properties of PCBMs were studied and it was found that the formation of polyelectrolyte network reduced the molecular weight cut-off (MWCO) from 242kDa in chitosan membrane to 2.71kDa in PCBM. The decrease in MWCO of PCBM results in better greywater treatment efficiency, subsequently demonstrated in a greywater filtration study where treated greywater effluent met the household reclaimed water standard of <2 NTU turbidity and <30ppm total suspended solids (TSS). In addition, a further 20% improvement in chemical oxygen demand (COD) removal was achieved as compared to a single layer chitosan membrane. Results from this study show that the biodegradable PCBM is a potential membrane material in producing clean treated greywater for non-potable applications.
Remediation of metalliferous mines, revegetation challenges and emerging prospects in semi-arid and arid conditions
Publisher: Springer Science and Business Media LLC
Date: 19-08-2016
DOI: 10.1007/S11356-016-7372-Z
Abstract: Understanding plant behaviour in polluted soils is critical for the sustainable remediation of metal-polluted sites including abandoned mines. Post-operational and abandoned metal mines particularly in semi-arid and arid zones are one of the major sources of pollution by soil erosion or plant hyperaccumulation bringing ecological impacts. We have selected from the literature 157 species belonging to 50 families to present a global overview of 'plants under action' against heavy metal pollution. Generally, all species of plants that are drought, salt and metal tolerant are candidates of interest to deal with harsh environmental conditions, particularly at semi-arid and arid mine sites. Pioneer metallophytes namely Atriplex nummularia, Atriplex semibaccata, Salsola kali, Phragmites australis and Medicago sativa, representing the taxonomic orders Caryophyllales, Poales and Fabales are evaluated in terms of phytoremediation in this review. Phytoremediation processes, microbial and algal bioremediation, the use and implication of tissue culture and biotechnology are critically examined. Overall, an integration of available remediation plant-based technologies, referred to here as 'integrated remediation technology,' is proposed to be one of the possible ways ahead to effectively address problems of toxic heavy metal pollution. Graphical abstract Integrated remediation technology (IRT) in metal-contaminated semi-arid and arid conditions. The hexagonal red line represents an IRT concept based on remediation decisions by combination of plants and microbial processes.
Isolation and characterization of the gene associated with geosmin production in cyanobacteria
Publisher: American Chemical Society (ACS)
Date: 30-09-2008
DOI: 10.1021/ES801465W
Optimising diet decisions and urban agriculture using linear programming
Publisher: Springer Science and Business Media LLC
Date: 27-08-2014
The isolation and microbial community analysis of hydrogen producing bacteria from activated sludge
Publisher: Oxford University Press (OUP)
Date: 19-06-2007
DOI: 10.1111/J.1365-2672.2007.03370.X
Abstract: To profile the fractions of bacteria in heat-treated activated sludge capable of producing hydrogen and subsequently to isolate those organisms and confirm their ability to produce hydrogen. Profiling the community composition of the microflora in activated sludge using 16S rRNA gene-directed polymerase chain reaction-denaturing gradient gel electrophoresis suggested that a majority of bacteria were various Clostridium species. This was confirmed by clone library analysis, where 80% of the cloned inserts were Clostridium sp. A total of five isolates were established on solid media. Three of them, designated as W1, W4 and W5, harboured the hydrogenase gene as determined by PCR and DNA sequence analysis (99% similarity). These isolates were similar to Clostridium butyricum and Clostridium diolis as determined by 16S rRNA gene sequence. A maximum hydrogen production yield of 220 ml H(2) g(-1) glucose was achieved by W5, which was grown on improved mineral medium by batch fermentation without pH adjustment and nitrogen sparging during fermentation. Accumulation of malic acid and fumaric acid during hydrogen fermentation might lead to higher hydrogen yields for W4 and W5. W1 is the first reported Clostridium species that can tolerate microaerobic conditions for producing hydrogen. Clostridium species in heat-treated activated sludge were the most commonly identified bacteria responsible for hydrogen production. Specific genetic markers for strains W1, W4 and W5 would be of great utility in investigating hydrogen production at the molecular level. Two previously described primer sets targeting hydrogenase genes were shown not to be specific, lifying other genes from nonhydrogen producers. Clostridium species isolated from heat-treated activated sludge were confirmed as hydrogen producers during dark hydrogen fermentation. The isolates will be useful for studying hydrogen production from wastewater, including the process of gene regulation and hydrogenase activity.
Occurrence of illicit drugs in water and wastewater and their removal during wastewater treatment
Publisher: Elsevier BV
Date: 11-2017
DOI: 10.1016/J.WATRES.2017.07.068
Abstract: This review critically evaluates the types and concentrations of key illicit drugs (cocaine, hetamines, cannabinoids, opioids and their metabolites) found in wastewater, surface water and drinking water sources worldwide and what is known on the effectiveness of wastewater treatment in removing such compounds. It is also important to amass information on the trends in specific drug use as well as the sources of such compounds that enter the environment and we review current international knowledge on this. There are regional differences in the types and quantities of illicit drug consumption and this is reflected in the quantities detected in water. Generally, the levels of illicit drugs in wastewater effluents are lower than in raw influent, indicating that the majority of compounds can be at least partially removed by conventional treatment processes such as activated sludge or trickling filters. However, the literature also indicates that it is too simplistic to assume non-detection equates to drug removal and/or mitigation of associated risks, as there is evidence that some compounds may avoid detection via inadequate s ling and/or analysis protocols, or through conversion to transformation products. Partitioning of drugs from the water to the solids fraction (sludge/biosolids) may also simply shift the potential risk burden to a different environmental compartment and the review found no information on drug stability and persistence in biosolids. Generally speaking, activated sludge-type processes appear to offer better removal efficacy across a range of substances, but the lack of detail in many studies makes it difficult to comment on the most effective process configurations and operations. There is also a paucity of information on the removal effectiveness of alternative treatment processes. Research is also required on natural removal processes in both water and sediments that may over time facilitate further removal of these compounds in receiving environments.
Porous silicon membrane-modified electrodes for label-free voltammetric detection of MS2 bacteriophage
Publisher: Elsevier BV
Date: 06-2016
Cooperative biodegradation of geosmin by a consortium comprising three gram-negative bacteria isolated from the biofilm of a sand filter column
Publisher: Oxford University Press (OUP)
Date: 10-2006
A new approach to optimise an annular slurry photoreactor system for the degradation of Congo Red: Statistical analysis and modelling
Publisher: Elsevier BV
Date: 10-2009
A genetic and metabolic approach to redirection of biochemical pathways of Clostridium butyricum for enhancing hydrogen production
Publisher: Wiley
Date: 18-07-2013
DOI: 10.1002/BIT.24596
Abstract: Clostridium butyricum, a well known H(2) producing bacterium, produces lactate, butyrate, acetate, ethanol, and CO(2) as its main by-products from glucose. The conversion of pyruvate to lactate, butyrate and ethanol involves oxidation of NADH. It was hypothesized that the NADH could be increased if the formation of these by-products could be eliminated, resulting in enhancing H(2) yield. Herein, this study aimed to establish a genetic and metabolic approach for enhancing H(2) yield via redirection of metabolic pathways of a C. butyricum strain. The ethanol formation pathway was blocked by disruption of aad (encoding aldehyde-alcohol dehydrogenase) using a ClosTron plasmid. Although elimination of ethanol formation alone did not increase hydrogen production, the resulting aad-deficient mutant showed approximately 20% enhanced performance in hydrogen production with the addition of sodium acetate. This work demonstrated the possibility of improving hydrogen yield by eliminating the unfavorable by-products ethanol and lactate.
Determination of Volatile Disinfection Byproducts in Water by Gas Chromatography–Triple Quadrupole Mass Spectrometry
Publisher: Informa UK Limited
Date: 07-10-2014
Development of a nested-PCR assay for the detection of cryptosporidium parvum in finished water
Publisher: Elsevier BV
Date: 05-2001
DOI: 10.1016/S0043-1354(00)00426-7
Abstract: A nested-PCR assay, incorporating an internal positive control, was developed for Cryptosporidium monitoring in finished water. This assay was capable of reproducibly detecting 8 oocysts in spiked-filtered water s les collected from 5 South Australian water treatment plants. The RT-PCR assay of Kaucner and Stinear (Appl. Environ. Microbiol. 64(5) (1998) 1743) was also evaluated for the detection of Cryptosporidium parvum. Initially, under our experimental conditions, a detection level of 27 oocysts was achieved for spiked reagent water s les. This level was improved to 5 oocysts by modification of the method. Untreated South Australian source waters concentrated by calcium carbonate flocculation were found to be highly inhibitory to the RT-PCR assay. Concentration of similar s les using Envirochek filters appeared to eliminate PCR inhibition. While both methods possessed similar sensitivities the nested-PCR assay was more reproducible, more cost effective, simpler to perform and could detect both viable and non-viable intact Cryptosporidium parvum oocysts, which is an important consideration for plant operators. These factors make the nested-PCR assay the method of choice for screening large numbers of potable water s les, where a reliable low level of detection is essential.
Development of a pilot fluidised bed reactor system with a formulated clay–lime mixture for continuous removal of chemical pollutants from wastewater
Publisher: Elsevier BV
Date: 04-2010
Root Iron Plaque on Wetland Plants as a Dynamic Pool of Nutrients and Contaminants
Publisher: Elsevier
Date: 2016
Applications of graphene in microbial fuel cells: The gap between promise and reality
Publisher: Elsevier BV
Date: 05-2017
Using H-titanate nanofiber catalysts for water disinfection: Understanding and modelling of the inactivation kinetics and mechanisms
Publisher: Elsevier BV
Date: 12-2011
Self-leadership: a cognitive resource for entrepreneurs
Publisher: Informa UK Limited
Date: 09-2013
Aquatic Phytotoxicity to Lemna minor of Three Commonly Used Drugs of Addiction in Australia
Publisher: Springer Science and Business Media LLC
Date: 03-09-2019
DOI: 10.1007/S00128-019-02708-9
Abstract: The manufacturing and consumption of drugs of addiction has increased globally and their widespread occurrence in the environment is an emerging concern. This study evaluated the phytotoxicity of three compounds: meth hetamine, codeine and morphine commonly reported in Australian urban water, to the aquatic plant Lemna minor under controlled conditions. L. minor was sensitive to lower drug concentrations when administered in multi-compound mixtures (100-500 µg L
Electrochemical biosensors featuring oriented antibody immobilization via electrografted and self-assembled hydrazide chemistry
Publisher: American Chemical Society (ACS)
Date: 13-01-2014
DOI: 10.1021/AC401747J
Abstract: Appropriate site-directed chemistry is essential to maximize the performance of immunosensors. We present two new functionalization strategies that preserve proper folding and binding potential of antibodies by forcing their oriented immobilization. Both strategies are based on the formation of hydrazone bonds between aldehyde groups on the Fc moieties of periodate-oxidized antibodies and hydrazide groups on functionalized gold electrodes. Those hydrazide groups are introduced by electrografting of diazonium salts or by self assembly of mono- and dithiolated hydrazide linkers, resulting in films with tailored functional groups and, thus, antibody distribution and spacing. Their barrier properties and permeability toward electroactive species are evaluated. To demonstrate the potential of these new functionalization strategies, detection of bacteriophage MS2 is performed through either a direct assay using electrochemical impedance spectroscopy (EIS) or through a sandwich assay using differential pulse voltammetry (DPV). Diazonium and monothiolated self-assembled monolayer-modified electrodes enable the detection of less than 1 plaque forming unit (pfu)/mL in a direct EIS assay. However, nonspecific adsorption renders measurements in river water s les difficult. In contrast, sandwich-assays on electrodes with electrografted diazonium salts and monothiolated self-assembled monolayers do not show significant matrix effects using river water s les, but the limits of detection are 10(8) times higher than those of the direct assay. Best results are achieved for immunosensors based on mixed monolayers of hydrazide and hydroxyl diothiolated linkers (15 pfu/mL). These new functionalization techniques are facile to implement. They afford the possibility to tune the surface composition and tailor the electrochemical properties of electrochemical sensors. These advantages should translate into broad interest in this type of surface chemistry for biosensor development.
A Review of Enzyme Induced Carbonate Precipitation (EICP): The Role of Enzyme Kinetics
Publisher: MDPI AG
Date: 22-02-2021
Abstract: Enzyme-induced carbonate precipitation (EICP) is a relatively new bio-cementation technique for ground improvement. In EICP, calcium carbonate (CaCO3) precipitation occurs via urea hydrolysis catalysed by the urease enzyme sourced from plants. EICP offers significant potential for innovative and sustainable engineering applications, including strengthening of soils, remediation of contaminants, enhancement of oil recovery through bio-plugging and other in situ field applications. Given the numerous potential applications of EICP, theoretical understanding of the rate and quantity of CaCO3 precipitation via the ureolytic chemical reaction is vital for optimising the process. For instance, in a typical EICP process, the rate and quantity of CaCO3 precipitation can depend significantly on the concentration, activity and kinetic properties of the enzyme used along with the reaction environment such as pH and temperature. This paper reviews the research and development of enzyme-catalysed reactions and its applications for enhancing CaCO3 precipitation in EICP. The paper also presents the assessment and estimation of kinetic parameters, such as the maximal reaction velocity (Vmax) and the Michaelis constant (Km), that are associated with applications in civil and geotechnical engineering. Various models for evaluating the kinetic reactions in EICP are presented and discussed, taking into account the influence of pH, temperature and inhibitors. It is shown that a good understanding of the kinetic properties of the urease enzyme can be useful in the development, optimisation and prediction of the rate of CaCO3 precipitation in EICP.
Electrochemical detection of N‐nitrosodimethylamine using a molecular imprinted polymer
Publisher: Elsevier BV
Date: 12-2016
Development of an mlrA Gene-Directed TaqMan PCR Assay for Quantitative Assessment of Microcystin-Degrading Bacteria within Water Treatment Plant Sand Filter Biofilms
Publisher: American Society for Microbiology
Date: 08-2009
DOI: 10.1128/AEM.00036-09
Abstract: We report for the first time a quantitative mlrA gene-directed TaqMan PCR assay for the rapid detection of microcystin-degrading bacteria. This was applied, in combination with 16S ribosomal DNA-directed quantitative PCR and denaturing gradient gel electrophoresis, to study virgin sand filter column biofilm development and to correlate mlr A gene abundance with microcystin removal efficiency.
Cell culture-Taqman PCR assay for evaluation of Cryptosporidium parvum disinfection
Publisher: American Society for Microbiology
Date: 05-2003
DOI: 10.1128/AEM.69.5.2505-2511.2003
Abstract: Cryptosporidium parvum represents a challenge to the water industry and a threat to public health. In this study, we developed a cell culture-quantitative PCR assay to evaluate the inactivation of C. parvum with disinfectants. The assay was validated by using a range of disinfectants in common use in the water industry, including low-pressure UV light (LP-UV), ozone, mixed oxidants (MIOX), and chlorine. The assay was demonstrated to be reliable and sensitive, with a lower detection limit of a single infectious oocyst. Effective oocyst inactivation was achieved ( log 10 units) with LP-UV (20 mJ/cm 2 ) or 2 mg of ozone/liter (for 10 min). MIOX and chlorine treatments of oocysts resulted in minimal effective disinfection, with .1 log 10 unit being inactivated. These results demonstrate the inability of MIOX to inactivate Cryptosporidium . The assay is a valuable tool for the evaluation of disinfection systems for drinking water and recycled water.
Evaluation of Methylated Silica Solid-Phase Extraction Sorbent to Retain a Surfactant in the Detection of Pesticides in Water Using Ultra-Performance Liquid Chromatography–Tandem Mass Spectrometry
Publisher: Springer Science and Business Media LLC
Date: 09-01-2017
Assessing granular media filtration for the removal of chemical contaminants from wastewater
Publisher: Elsevier BV
Date: 05-2011
DOI: 10.1016/J.WATRES.2011.04.005
Abstract: Granular media filtration was evaluated for the removal of a suite of chemical contaminants that can be found in wastewater. Laboratory- and pilot-scale sand and granular activated carbon (GAC) filters were trialled for their ability to remove atrazine, estrone (E1), 17α-ethynylestradiol (EE2), N-nitrosodimethylamine (NDMA), N-nitrosomorpholine (NMOR) and N-nitrosodiethylamine (NDEA). In general, sand filtration was ineffective in removing the contaminants from a tertiary treated wastewater, with the exception of E1 and EE2, where efficient removals were observed after approximately 150 d. Batch degradation experiments confirmed that the removal of E1 was through biological activity, with a pseudo-first-order degradation rate constant of 7.4 × 10(-3) h(-1). GAC filtration was initially able to effectively remove all contaminants although removals decreased over time due to competition with other organics present in the water. The only exception was atrazine where removal remained consistently high throughout the experiment. Previously unreported differences were observed in the adsorption of the three nitrosamines, with the ease of removal following the trend, NDEA > NMOR > NDMA, consistent with their hydrophobic character. In most instances the removals from the pilot-scale filters were generally in agreement with the laboratory-scale filter, suggesting that there is potential in using laboratory-scale filters as monitoring tools to evaluate the performance of pilot- and possibly full-scale sand and GAC filters at wastewater treatment plants.
Rapid Confirmation of Clostridium perfringens by Using Chromogenic and Fluorogenic Substrates
Publisher: American Society for Microbiology
Date: 09-2001
DOI: 10.1128/AEM.67.9.4382-4384.2001
Abstract: The use of 4-methylumbelliferyl phosphate (MUP) and ortho -nitrophenyl-β- d -galactopyranoside (ONPG) for the identification of Clostridium perfringens was investigated. A liquid assay containing both MUP and ONPG was a highly specific alternative method for C. perfringens confirmation, reducing incubation time from 48 to only 4 h. The assay solution is easy to prepare, does not require anaerobic conditions for use, and has an extended shelf life.
Can integrated aquaculture-agriculture (IAA) produce “more crop per drop”?
Publisher: Springer Science and Business Media LLC
Date: 21-10-2014
Isolation and identification of a novel microcystin-degrading bacterium from a biological sand filter
Publisher: Elsevier BV
Date: 12-2007
DOI: 10.1016/J.WATRES.2007.06.057
Abstract: A novel bacterium capable of degrading two microcystin analogues, microcystin-LR and -LA (MCLR and MCLA), was isolated from a biological sand filter which was previously shown to effectively remove these toxins from source waters. Based on phylogenetic analysis of the 16S rRNA gene sequence, the isolated organism, LH21, most likely belonged to the genus Sphingopyxis and of the previously cultured species clustered with Sphingopyxis witflariensis. Using polymerase chain reaction (PCR), isolate LH21 was shown to contain homologues to each of the four genes, mlrA, mlrB, mlrC and mlrD previously associated with the degradation of MCLR by Sphingomonas sp. ACM-3962. Isolate LH21 was able to effectively degrade MCLR and MCLA in batch experiments under environmentally relevant conditions, with complete removal observed within 5h after re-exposure of the toxins.
Metabolic flux analysis of hydrogen production network by Clostridium butyricum W5: Effect of pH and glucose concentrations
Publisher: Elsevier BV
Date: 07-2010
Development of a buried bag technique to study biochars incorporated in a compost or composting medium
Publisher: Springer Science and Business Media LLC
Date: 29-01-2016
Deletion of creB in Aspergillus oryzae Increases Secreted Hydrolytic Enzyme Activity
Publisher: American Society for Microbiology
Date: 15-09-2013
DOI: 10.1128/AEM.01406-13
Abstract: Aspergillus oryzae has been used in the food and beverage industry for centuries, and industrial strains have been produced by multiple rounds of selection. Targeted gene deletion technology is particularly useful for strain improvement in such strains, particularly when they do not have a well-characterized meiotic cycle. Phenotypes of an Aspergillus nidulans strain null for the CreB deubiquitinating enzyme include effects on growth and repression, including increased activity levels of various enzymes. We show that Aspergillus oryzae contains a functional homologue of the CreB deubiquitinating enzyme and that a null strain shows increased activity levels of industrially important secreted enzymes, including cellulases, xylanases, amylases, and proteases, as well as alleviated inhibition of spore germination on glucose medium. Reverse transcription-quantitative PCR (RT-qPCR) analysis showed that the increased levels of enzyme activity in both Aspergillus nidulans and Aspergillus oryzae are mirrored at the transcript level, indicating transcriptional regulation. We report that Aspergillus oryzae DAR3699, originally isolated from soy fermentation, has a similar phenotype to that of a creB deletion mutant of the RIB40 strain, and it contains a mutation in the creB gene. Collectively, the results for Aspergillus oryzae , Aspergillus nidulans , Trichoderma reesei , and Penicillium decumbens show that deletion of creB may be broadly useful in erse fungi for increasing production of a variety of enzymes.
Application of H-titanate nanofibers for degradation of Congo Red in an annular slurry photoreactor
Publisher: Elsevier BV
Date: 07-2009
Biodegradation rates of 2-methylisoborneol (MIB) and geosmin through sand filters and in bioreactors
Publisher: Elsevier BV
Date: 02-2007
DOI: 10.1016/J.CHEMOSPHERE.2006.08.016
Abstract: Taste and odour (T&O) causing compounds, in particular, 2-methylisoborneol (MIB) and geosmin, are a problem for water authorities as they are recalcitrant to conventional water treatment. In this study, biological sand filtration was shown to be an effective process for the complete removal of MIB and geosmin, with removal shown to be predominantly through biodegradation. In addition, MIB and geosmin were also effectively degraded in batch bioreactor experiments using biofilm sourced from one of the sand filters as the microbial inoculum. The biodegradation of MIB and geosmin was determined to be a pseudo-first-order reaction with rate constants ranging between 0.10 and 0.58 d(-1) in the bioreactor experiments. Rate constants were shown to be dependent upon the initial concentration of the microbial inoculum but not the initial concentration of MIB and geosmin when target concentrations of 200 and 50 ng l(-1) were used. Furthermore, rate constants were shown to increase upon re-exposure of the biofilm to both T&O compounds. Enrichment cultures with subsequent community profile analysis using 16S rRNA-directed PCR-DGGE identified four bacteria most likely involved in the biodegradation of geosmin within the sand filters and bioreactors. These included a Pseudomonas sp., Alphaproteobacterium, Sphingomonas sp. and an Acidobacteriaceae member.
Effect of water treatment processes on Cryptosporidium infectivity
Publisher: Elsevier BV
Date: 03-2008
DOI: 10.1016/J.WATRES.2007.11.008
Abstract: Conventional water treatment processes have the ability to remove Cryptosporidium oocysts through coagulation, flocculation, sedimentation and filtration, provided there is efficient management of plant performance. The potential exists for the breakthrough of oocysts through the treatment train. The effect of the water treatment chemical aluminium sulphate (alum) on Cryptosporidium oocyst infectivity has been assessed using an assay that combines cell culture and real-time polymerase chain reaction techniques. The infectivity of fresh and temperature-aged oocysts (stored up to 6 months at 4 or 15 degrees C) was unaffected by exposure to a range of doses of alum in standard jar test procedures and dissolved air flotation processes and subsequent exposure to chlorine or chloramine. Removal efficiencies and infectivity measures are important in determining risk to public health and will reflect the ability of water treatment plants to act as a barrier to these pathogens.
Tailored carbon nanotube immunosensors for the detection of microbial contamination
Publisher: Elsevier BV
Date: 05-2015
DOI: 10.1016/J.BIOS.2014.09.089
Abstract: The use of carbon nanotubes (CNTs) as building blocks in the design of electrochemical biosensors has been attracting attention over the last few years, mainly due to their high electrical conductivity and large surface area. Here, we present two approaches based on tailored single-walled CNTs (SWCNTs) architectures to develop immunosensors for the bacteriophage MS2, a virus often detected in sewage-impacted water supplies. In the first approach, SWCNTs were used in the bottom-up design of sensors as antibody immobilization support. Carboxy-functionalised SWCNTs were covalently tethered onto gold electrodes via carbodiimide coupling to cysteamine-modified gold electrodes. These SWCNTs were hydrazide functionalized by electrochemical grafting of diazonium salts. Site-oriented immobilization of antibodies was then carried out through hydrazone bond formation. Results showed microarray electrode behavior, greatly improving the signal-to-noise ratio. Excellent sensitivity and limit of detection (9.3 pfu/mL and 9.8 pfu/mL in buffer and in river water, respectively) were achieved, due to the combination of the SWCNTs' ability to promote electron transfer reactions with electroactive species at low overpotentials and their high surface-to-volume ratio providing a favorable environment to immobilize biomolecules. In the second approach, SWCNTs were decorated with iron oxide nanoparticles. Diazonium salts were electrochemically grafted on iron-oxide-nanoparticle-decorated SWCNTs to functionalize them with hydrazide groups that facilitate site-directed immobilization of antibodies via hydrazone coupling. These magnetic immunocarriers facilitated MS2 separation and concentration on an electrode surface. This approach minimized non-specific adsorptions and matrix effects and allowed low limits of detection (12 pfu/mL and 39 pfu/mL in buffer and in river water, respectively) that could be further decreased by incubating the magnetic immunocarriers with larger volumes of s le. Significantly, both approaches permitted the detection of MS2 to levels regularly encountered in sewage-impacted environments.
Isolates of ‘Candidatus Nostocoida limicola’ Blackall et al. 2000 should be described as three novel species of the genus Tetrasphaera, as Tetrasphaera jenkinsii sp. nov., Tetrasphaera vanveenii sp. n
Publisher: Microbiology Society
Date: 10-2006
Abstract: Despite differences in their morphologies, comparative analyses of 16S rRNA gene sequences revealed high levels of similarity ( %) between strains of the filamentous bacterium ‘ Candidatus Nostocoida limicola’ and the cocci Tetrasphaera australiensis and Tetrasphaera japonica and the rod Tetrasphaera elongata , all isolated from activated sludge. These sequence data and their chemotaxonomic characters, including cell wall, menaquinone and lipid compositions and fingerprints of their 16S–23S rRNA intergenic regions, support the proposition that these isolates should be combined into a single genus containing six species, in the family Intrasporangiaceae in the Actinobacteria . This suggestion receives additional support from DNA–DNA hybridization data and when partial sequences of the rpoC1 gene are compared between these strains. Even though few phenotypic characterization data were obtained for these slowly growing isolates, it is proposed, on the basis of the extensive chemotaxonomic and molecular evidence presented here, that ‘ Candidatus N. limicola’ strains Ben 17, Ben 18, Ben 67, Ben 68 and Ben 74 all be placed into the species Tetrasphaera jenkinsii sp. nov. (type strain Ben 74 T =DSM 17519 T =NCIMB 14128 T ), ‘ Candidatus N. limicola’ strain Ben 70 into Tetrasphaera vanveenii sp. nov. (type strain Ben 70 T =DSM 17518 T =NCIMB 14127 T ) and ‘ Candidatus N. limicola’ strains Ver 1 and Ver 2 into Tetrasphaera veronensis sp. nov. (type strain Ver 1 T =DSM 17520 T =NCIMB 14129 T ).
Bacterial inactivation kinetics, regrowth and synergistic competition in a photocatalytic disinfection system using anatase titanate nanofiber catalyst
Publisher: Elsevier BV
Date: 07-2010
Legionella confirmation using real-time PCR and SYTO9 is an alternative to current methodology
Publisher: American Society for Microbiology
Date: 12-2005
DOI: 10.1128/AEM.71.12.8944-8948.2005
Abstract: The currently accepted culture techniques for the detection of Legionella spp. in water s les (AS/NZS 3896:1998 and ISO 11731 standard methods) are slow and laborious, requiring from 7 to 14 days for a result. We describe a fully validated rapid confirmation technique that uses real-time PCR incorporating the intercalating dye SYTO9 for the direct identification of primary cultures, significantly decreasing turnaround time and allowing faster remedial action to be taken by the industry.
Genetic manipulation of butyrate formation pathways in Clostridium butyricum
Publisher: Elsevier BV
Date: 09-2011
DOI: 10.1016/J.JBIOTEC.2011.07.004
Abstract: Clostridium butyricum is one of the commonly used species for fermentative hydrogen production. While producing H₂, it can produce acids (lactic, acetic and butyric acids) and CO₂, as well as a small amount of ethanol. It has been proposed that elimination of competing pathways, such as the butyrate formation pathway, should increase H₂ yields in Clostridium species. However, the application of this strategy has been hindered by the unavailability of genetic tools for these organisms. In this study, we successfully transferred a plasmid (pMTL007) to C. butyricum by inter-specific conjugation with Escherichia coli and disrupted hbd, the gene encoding β-hydroxybutyryl-CoA dehydrogenase in C. butyricum. Fermentation data showed that inactivation of hbd in C. butyricum eliminated the butyrate formation pathway, resulting in a significant increase in ethanol production and an obvious decrease in H₂ yield compared with the wild type strain. However, under low partial pressure of H₂, the hbd-deficient strain showed increased H₂ production with the simultaneous decrease of ethanol production, indicating that H₂ production by C. butyricum may compete for NADH with the ethanol formation pathway. Together with the discovery of a potential bifurcating hydrogenase, this study extends our understanding of the mechanism of H₂ production by C. butyricum.
Biochemical kinetics of fermentative hydrogen production by Clostridium butyricum W5
Publisher: Elsevier BV
Date: 2009
Identification of genes implicated in toxin production in the cyanobacterium Cylindrospermosis raciborskii
Publisher: Wiley
Date: 10-2001
DOI: 10.1002/TOX.1051
Abstract: Cylindrospermopsis raciborskii is a bloom-forming cyanobacterium found in both tropical and temperate climates which produces cylindrospermopsin, a potent hepatotoxic secondary metabolite. This organism is notorious for its association with a significant human poisoning incident on Palm Island, Australia, which resulted in the hospitalization of 148 people. We have screened 13 C. raciborskii isolates from various regions of Australia and shown that both toxic and nontoxic strains exist within this species. No association was observed between geographical origin and toxin production. Polyketide synthases (PKSs) and peptide synthetases (PSs) are enzymes involved in secondary metabolite biosynthesis in cyanobacteria. Putative PKS and PS genes from C. raciborskii strains AWT205 and CYP020B were identified by PCR using degenerate primers based on conserved regions within each gene. Examination of the strain-specific distribution of the PKS and PS genes in C. raciborskii isolates demonstrated a direct link between the presence of these two genes and the ability to produce cylindrospermopsin. Interestingly, the possession of these two genes was also linked. They were also identified in an Anabaena bergii isolate that was demonstrated to produce cylindrospermopsin. Taken together, these data suggest a likely role for these determinants in secondary metabolite and toxin production by C. raciborskii.
Boron-Doped Reduced Graphene Oxide with Tunable Bandgap and Enhanced Surface Plasmon Resonance
Publisher: MDPI AG
Date: 11-08-2020
DOI: 10.3390/MOLECULES25163646
Abstract: Graphene and its hybrids are being employed as potential materials in light-sensing devices due to their high optical and electronic properties. However, the absence of a bandgap in graphene limits the realization of devices with high performance. In this work, a boron-doped reduced graphene oxide (B-rGO) is proposed to overcome the above problems. Boron doping enhances the conductivity of graphene oxide and creates several defect sites during the reduction process, which can play a vital role in achieving high-sensing performance of light-sensing devices. Initially, the B-rGO is synthesized using a modified microwave-assisted hydrothermal method and later analyzed using standard FESEM, FTIR, XPS, Raman, and XRD techniques. The content of boron in doped rGO was found to be 6.51 at.%. The B-rGO showed a tunable optical bandgap from 2.91 to 3.05 eV in the visible spectrum with an electrical conductivity of 0.816 S/cm. The optical constants obtained from UV-Vis absorption spectra suggested an enhanced surface plasmon resonance (SPR) response for B-rGO in the theoretical study, which was further verified by experimental investigations. The B-rGO with tunable bandgap and enhanced SPR could open up the solution for future high-performance optoelectronic and sensing applications.
Single-Step Assembly of Multifunctional Poly(tannic acid)-Graphene Oxide Coating to Reduce Biofouling of Forward Osmosis Membranes
Publisher: American Chemical Society (ACS)
Date: 29-06-2016
Abstract: Graphene oxide (GO) nanosheets have antibacterial properties that have been exploited as a biocidal agent used on desalination membrane surfaces in recent research. Nonetheless, improved strategies for efficient and stable attachment of GO nanosheets onto the membrane surface are still required for this idea to be commercially viable. To address this challenge, we adopted a novel, single-step surface modification approach using tannic acid cross-linked with polyethylene imine as a versatile platform to immobilize GO nanosheets to the surface of polyamide thin film composite forward osmosis (FO) membranes. An experimental design based on Taguchi's statistical method was applied to optimize the FO processing conditions in terms of water and reverse solute fluxes. Modified membranes were analyzed using water contact angle, adenosine triphosphate bioluminescence, total organic carbon, Fourier transform infrared spectroscopy, ζ potential, X-ray photoelectron spectroscopy, transmission electron microscopy, and atomic force microscopy. These results show that membranes were modified with a nanoscale (<10 nm), smooth, hydrophilic coating that, compared to pristine membranes, improved filtration and significantly mitigated biofouling by 33% due to its extraordinary, synergistic antibacterial properties (99.9%).
A comparative study of carboxyfluorescein diacetate and carboxyfluorescein diacetate succinimidyl ester as indicators of bacterial activity
Publisher: Elsevier BV
Date: 03-2003
DOI: 10.1016/S0167-7012(02)00207-5
Abstract: Staining bacteria with esterified fluorogenic substrates followed by flow cytometric analysis offers a means for rapid detection of metabolically active bacteria. Flow cytometry (FCM) was used to assess carboxyfluorescein diacetate (CFDA) and carboxyfluorescein diacetate succinimidyl ester (CFDA/SE) as indicators of bacterial activity for cultured bacteria, including Aeromonas hydrophila, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus epidermidis and bacteria from environmental waters. In theory, CFDA/SE should be a better indicator of metabolic bacterial activity compared to CFDA due to greater intracellular retention of the fluorescent product. Qualitative and quantitative analysis of exponential phase cultures, mixtures of active and inactive cells and bacteria from environmental waters revealed CFDA was successful in detecting active bacteria, whereas CFDA/SE was not. CFDA/SE labelled inactive cells with intensities equal to that of the active population and could not even discriminate between bacteria in exponential phase growth and a fixed cell preparation. We propose that the specific mode of action of the succinimidyl ester (SE) group in combination with the nonenzymatic aqueous hydrolysis of the CFDA moiety results in the nonspecific labelling of all cells, irrespective of their metabolic state. This study shows that CFDA/SE is a poor marker of bacterial activity.
Feasibility study on the application of advanced oxidation technologies for decentralised wastewater treatment
Publisher: Elsevier BV
Date: 11-2012
Use of DNA melting simulation software for in silico diagnostic assay design: Targeting regions with complex melting curves and confirmation by real-time PCR using intercalating dyes
Publisher: Springer Science and Business Media LLC
Date: 29-03-2007
Abstract: DNA melting curve analysis using double-stranded DNA-specific dyes such as SYTO9 produce complex and reproducible melting profiles, resulting in the detection of multiple melting peaks from a single licon and allowing the discrimination of different species. We compare the melting curves of several Naegleria and Cryptosporidium licons generated in vitro with in silico DNA melting simulations using the programs POLAND and MELTSIM., then test the utility of these programs for assay design using a genetic marker for toxin production in cyanobacteria. The SYTO9 melting curve profiles of three species of Naegleria and two species of Cryptosporidium were similar to POLAND and MELTSIM melting simulations, excepting some differences in the relative peak heights and the absolute melting temperatures of these peaks. MELTSIM and POLAND were used to screen sequences from a putative toxin gene in two different species of cyanobacteria and identify regions exhibiting diagnostic melting profiles. For one of these diagnostic regions the POLAND and MELTSIM melting simulations were observed to be different, with POLAND more accurately predicting the melting curve generated in vitro . Upon further investigation of this region with MELTSIM, inconsistencies between the melting simulation for forward and reverse complement sequences were observed. The assay was used to accurately type twenty seven cyanobacterial DNA extracts in vitro . Whilst neither POLAND nor MELTSIM simulation programs were capable of exactly predicting DNA dissociation in the presence of an intercalating dye, the programs were successfully used as tools to identify regions where melting curve differences could be exploited for diagnostic melting curve assay design. Refinements in the simulation parameters would be required to account for the effect of the intercalating dye and salt concentrations used in real-time PCR. The agreement between the melting curve simulations for different species of Naegleria and Cryptosporidium and the complex melting profiles generated in vitro using SYTO9 verified that the complex melting profile of PCR licons was solely the result of DNA dissociation. Other data outputs from these simulations were also used to identify the melting domains that contributed to the observed melting peaks for each of the different PCR licons.
Kinetic study and equilibrium isotherm analysis of Congo Red adsorption by clay materials
Publisher: Elsevier BV
Date: 15-05-2009
Development of glucosidase agar for the confirmation of water-borne Enterococcus
Publisher: Elsevier BV
Date: 12-2001
DOI: 10.1016/S0043-1354(01)00125-7
Abstract: Analysis of 56 river water s les by the Enterolert defined substrate technique, and standard m-Enterococcus agar isolation followed by confirmation, indicated that after 24 h incubation. Enterolert significantly underestimated the true numbers of enterococci. Extending Enterolert incubatioin to 36 h improved detection but also revealed false positives. These findings prompted the development of a novel confirmation medium we have termed glucosidase agar, which was prepared by dissolving Enterolert substrate in 2% (w/v) bacteriological agar. Analysis of 1,043 colonies arising on m-Enterococcus agar from 280 freshwater, marine and sewage effluent s les, demonstrated that 2-4 h incubation on glucosidase agar was a rapid and accurate means of confirming presumptive enterococci, when compared to standard confirmation procedures that take 48 h. The combination of primary isolation on m-Enterococcus agar followed by confirmation on glucosidase agar permits maximum recovery of Enteroccus whilst effectively eliminating false positives/negatives and provides a reliable alternative use of the Enterolert defined substrate technology.
A Novel and Rapid Legionella Detection System for Water Analysis
Publisher: ASM Press
Date: 09-04-2014
Metal bioavailability to Eisenia fetida through copper mine dwelling animal and plant litter, a new challenge on contaminated environment remediation
Publisher: Elsevier BV
Date: 09-2016
Recent developments in photocatalytic water treatment technology: A review
Publisher: Elsevier BV
Date: 05-2010
DOI: 10.1016/J.WATRES.2010.02.039
Abstract: In recent years, semiconductor photocatalytic process has shown a great potential as a low-cost, environmental friendly and sustainable treatment technology to align with the "zero" waste scheme in the water/wastewater industry. The ability of this advanced oxidation technology has been widely demonstrated to remove persistent organic compounds and microorganisms in water. At present, the main technical barriers that impede its commercialisation remained on the post-recovery of the catalyst particles after water treatment. This paper reviews the recent R&D progresses of engineered-photocatalysts, photoreactor systems, and the process optimizations and modellings of the photooxidation processes for water treatment. A number of potential and commercial photocatalytic reactor configurations are discussed, in particular the photocatalytic membrane reactors. The effects of key photoreactor operation parameters and water quality on the photo-process performances in terms of the mineralization and disinfection are assessed. For the first time, we describe how to utilize a multi-variables optimization approach to determine the optimum operation parameters so as to enhance process performance and photooxidation efficiency. Both photomineralization and photo-disinfection kinetics and their modellings associated with the photocatalytic water treatment process are detailed. A brief discussion on the life cycle assessment for retrofitting the photocatalytic technology as an alternative waste treatment process is presented. This paper will deliver a scientific and technical overview and useful information to scientists and engineers who work in this field.
Stress responses and specific metal exclusion on mine soils based on germination and growth studies by Australian golden wattle
Publisher: Elsevier BV
Date: 12-2016
The Use of Cell Culture and Real-time PCR to Assess Disinfection of Cryptosporidium Parvum
Publisher: Elsevier
Date: 2003
A PCR test for the identification and discrimination of Legionella longbeachae serogroups 1 and 2
Publisher: Elsevier BV
Date: 09-1999
DOI: 10.1016/S0167-7012(99)00070-6
Abstract: A PCR test has been developed for the specific identification of Legionella longbeachae. The test targeted sequence unique to both L. longbeachae serogroups 1 and 2 within the mip gene and permitted both species and serogroup identification. The test was trialed on a range of closely related species and 20 clinical isolates originating from Australia, the USA and Israel. Results were consistent with previous identification analyses. From 20 water s les known to contain Legionella spp. one s le yielded isolates which consistently tested positive by L. longbeachae serogroup 1 PCR. DNA sequencing of the PCR product, 5S rRNA gene sequence and hybridisation analysis with a specific oligonucleotide probe definitively identified one isolate as L. longbeachae serogroup 1. PCR testing was demonstrated as a superior method of identification to traditional seroagglutination reactions, which were ambiguous and could explain the previous failure to identify the presence of this microorganism in water.
Optimisation of an annular photoreactor process for degradation of Congo Red using a newly synthesized titania impregnated kaolinite nano-photocatalyst
Publisher: Elsevier BV
Date: 06-2009
Utilization of Biowaste for Mine Spoil Rehabilitation
Publisher: Elsevier
Date: 2016
Enhancing removal efficiency of anionic dye by combination and calcination of clay materials and calcium hydroxide
Publisher: Elsevier BV
Date: 11-2009
DOI: 10.1016/J.JHAZMAT.2009.06.094
Abstract: We explored a feasible approach to enhance removal capacity of three natural clays for removing anionic dye from aqueous solution. Optimal mixing proportions of the clay materials and temperature range for the calcination were investigated. We found that the removal efficiency can be improved significantly when the clay materials were mixed at certain ratio with the addition of lime and the mixed clay materials were calcined 100-300 degrees C. Batch experiments were conducted to study the effects of initial concentration, material dosage, contact time and pH on dye elimination. Kinetic study showed that more than 80% dye removal took place in 5 min. A high removal capacity (>575 mg g(-1)) of the mixed clay materials can be achieved at a low adsorbent dose. The mixed clay materials can be easily recovered by thermal treatment. The recovered mixtures demonstrated an enhanced removal capability after a few cycles of removal and regeneration. The results revealed that use of these clay materials could develop a low-cost treatment process for industrial wastewater.
Culture-independent techniques for rapid detection of bacteria associated with loss of chloramine residual in a drinking water system
Publisher: American Society for Microbiology
Date: 11-2005
DOI: 10.1128/AEM.71.11.6479-6488.2005
Abstract: Chloramination is often the disinfection regimen of choice for extended drinking water systems. However, this process is prone to instability due to the growth of nitrifying bacteria. This is the first study to use alternative approaches for rapid investigation of chloraminated drinking water system instability in which flow cytometric cell sorting of bacteria with intact membranes (membrane-intact fraction) (BacLight kit) or with active esterases (esterase-active fraction) (carboxyfluorescein diacetate) was combined with 16S rRNA gene-directed PCR and denaturing gradient gel electrophoresis (DGGE). No active bacteria were detected when water left the water treatment plant (WTP), but 12 km downstream the chloramine residual had diminished and the level of active bacteria in the bulk water had increased to more than 1 × 10 5 bacteria ml −1 . The bacterial ersity in the system was represented by six major DGGE bands for the membrane-intact fraction and 10 major DGGE bands for the esterase-active fraction. PCR targeting of the 16S rRNA gene of chemolithotrophic ammonia-oxidizing bacteria (AOB) and subsequent DGGE and DNA sequence analysis revealed the presence of an active Nitrosospira -related species and Nitrosomonas cryotolerans in the system, but no AOB were detected in the associated WTP. The abundance of active AOB was then determined by quantitative real-time PCR (qPCR) targeting the amoA gene 3.43 × 10 3 active AOB ml −1 were detected in the membrane-intact fraction, and 1.40 × 10 4 active AOB ml −1 were detected in the esterase-active fraction. These values were several orders of magnitude greater than the 2.5 AOB ml −1 detected using a routine liquid most-probable-number assay. Culture-independent techniques described here, in combination with existing chemical indicators, should allow the water industry to obtain more comprehensive data with which to make informed decisions regarding remedial action that may be required either prior to or during an instability event.
Self-leadership: a cognitive resource for entrepreneurs
Publisher: Informa UK Limited
Date: 09-2013
A Novel and Rapid Legionella Detection System for Water Analysis
Publisher: ASM Press
Date: 09-04-2014
A colony based confirmation assay for Legionella and Legionella pneumophila employing the EnviroAmp ™ <
Publisher: Oxford University Press (OUP)
Date: 05-1998
DOI: 10.1046/J.1472-765X.1998.00354.X
Abstract: Modifications to the EnviroAmp Legionella detection system are described which permit the rapid analysis of bacterial colonies taken from Legionella selective media. Capillary PCR permitted twice the number of s les to be analysed with a single kit. When PCR was positive for Leg. pneumophila, this result was confirmed by seroagglutination. The reverse dot blot hybridization assay was only used where PCR indicated a Legionella sp. other than Leg. pneumophila, permitting further savings on detection system components. This technique and standard confirmation procedures were applied to 133 isolates arising from 63 water s les plated to Legionella isolation media. Results agreed except for two isolates which gave a positive result for Legionella spp. by PCR and hybridization but were negative using standard procedures. Raising the annealing/extension temperature of the PCR by 2 degrees C eliminated the false positive result with these two isolates but did not adversely effect the sensitivity of the assay, as determined by re-testing of 68 environmental isolates and testing of 69 new environmental isolates and 12 Legionella reference species. The modified technique provides a convenient and cost effective alternative to standard confirmation procedures.
Impact of prechlorination on organophosphorus pesticides during drinking water treatment: Removal and transformation to toxic oxon byproducts
Publisher: Elsevier BV
Date: 11-2016
DOI: 10.1016/J.WATRES.2016.08.052
Abstract: Prechlorination is commonly used to minimize operational problems associated with biological growth as well as taste and odor control during drinking water treatment. However, prechlorination can also oxidise micropollutants into intermediate byproducts. This could impose profound effects on the safety of the finished water if the transformed byproducts are more toxic and less removable. This study investigated the effect of prechlorination on decomposition and subsequent removal of the four organophosphorus pesticides (OPPs): chlorpyrifos, diazinon, malathion and tolclofos-methyl using a simulated conventional water treatment process of powdered activated carbon assisted coagulation-sedimentation-filtration (PAC-CSF) and postchlorination. It was found that, following prechlorination, not only did the percentage of OPPs oxidation vary significantly, but also the concentration of transformed oxons, which are more toxic than their parent compounds, increased as the major identified oxidation byproducts in water. Removal of these oxons proved to be more difficult by the PAC-CSF than their parent OPPs, because they are more water soluble and more hydrophilic. Both the OPP oxidation and oxon formation increased with chlorine dose during prechlorination. Meanwhile, the continuing chlorination of OPPs by residual free chlorine during PAC-CSF further complicated the pesticide removal processes, generally resulting in a gradually increased formation of oxons. Moreover, in the final treatment stage of postchlorination, the more chlorine-reactive pesticides, malathion and diazinon, were completely oxidised and the formation of corresponding oxons was increased with the prechlorine dose. In contrast, a certain amount of the less chlorine-reactive pesticide tolclofos-methyl still remained in solution after postchlorination, accompanied by an increased formation of tolclofos-methyl oxon with prechlorine dose. Since the oxons are resistant to further oxidation and less adsorbable during the PAC-CSF process, the gross removal of these pesticides and their oxons decreased with increase of the prechlorine dose. This led to an accumulation of the more toxic oxons in the finished water, especially at higher chlorine doses during prechlorination. The significance of this work is the demonstration that, under circumstances where prechlorination is used and source water contains traces of OPPs, alternative practices should be prioritized to avoid the potential risks involved in consumption of the treated water.
The controversial antibacterial activity of graphene-based materials
Publisher: Elsevier BV
Date: 08-2016
Enhancing the biofiltration of geosmin by seeding sand filter columns with a consortium of geosmin-degrading bacteria
Publisher: Elsevier BV
Date: 02-2009
DOI: 10.1016/J.WATRES.2008.10.044
Abstract: Geosmin is a secondary metabolite that can be produced by many species of cyanobacteria and Actinomycetes. It imparts a musty/earthy taste and odour to drinking water which can result in consumer complaints and a general perception that there is a problem with the water quality. As geosmin is recalcitrant to conventional water treatment, processes are sought to ensure effective removal of this compound from potable water. Biological filtration (biofiltration) is an attractive option for geosmin removal as this compound has been shown to be biodegradable. However, effective biofiltration of geosmin can be site specific as it is highly dependent upon the types of organism present and there is often an extended acclimation period before efficient removals are achieved. We report here, a novel approach to enhance the biofiltration of geosmin by seeding sand filter columns with a bacterial consortium previously shown to be capable of effectively degrading geosmin. Geosmin removals of up to 75% were evident through sand columns which had been inoculated with the geosmin-degrading bacteria, when compared with non-inoculated sand columns where geosmin removals were as low as 25%. These low geosmin removals through the non-inoculated sand columns are consistent with previous studies and were attributed to physical/abiotic losses. The presence of an existing biofilm was shown to influence geosmin removal, as the biofilm allowed for greater attachment of the geosmin-degrading consortium (as determined by an ATP assay), and enhanced removals of geosmin. Minimal difference in geosmin removal was observed when the geosmin-degrading bacteria were inoculated into the sand columns containing either an active or inactive biofilm.
Rapid preparation of cyanobacterial DNA for real-time PCR analysis
Publisher: Oxford University Press (OUP)
Date: 13-12-2007
Evaluation of Oocyst DNA Extraction Methods Using Real-time PCR
Publisher: Elsevier
Date: 2003
Chemical impact of catholytes on Bacillus subtilis-catalysed microbial fuel cell performance for degrading 2,4-dichlorophenol
Publisher: Elsevier BV
Date: 10-2016
Expression of the geosmin synthase gene in the cyanobacterium anabaena circinalis AWQC318
Publisher: Wiley
Date: 23-09-2011
DOI: 10.1111/J.1529-8817.2011.01061.X
Abstract: The occurrence of taste and odor episodes attributed to geosmin continues to trouble water utilities worldwide, and only recently have advances been made in our fundamental understanding of the biochemical and genetic mechanisms responsible for the production of geosmin in microorganisms. For the first time, we have examined the expression of the geosmin synthase gene and corresponding geosmin production by Anabaena circinalis Rabenh. ex Bornet et Flahault AWQC318 under conditions of continuous light illumination and the removal of light as a stimulus and demonstrate that the expression of geosmin synthase appears to be constitutive under these conditions. The decrease in geosmin synthase transcription post maximum cell numbers and stationary phase suggests that a decrease in isoprenoid synthesis may occur before a decrease in the transcription of ribosomal units as the process of cell death is initiated.
BIOSOLIDS ENHANCE MINE SITE REHABILITATION AND REVEGETATION
Publisher: Elsevier
Date: 2016
Metabolic flux network and analysis of fermentative hydrogen production
Publisher: Elsevier BV
Date: 07-2011
DOI: 10.1016/J.BIOTECHADV.2011.02.001
Abstract: Fermentative hydrogen production (FHP) has received a great R & D interest in recent decades, as it offers a potential means of producing H₂ from a variety of renewable resources, even wastewater via a low energy continuous process. Various extracellular metabolites including ethanol, acetate, butyrate and lactate can be produced during the fermentation, building a complex metabolic network of the FHP. Except for the recognition of its complexity, the metabolic flux network has not been well understood. Studies on biochemical reactions and metabolic flux network associated with the FHP in anaerobic fermentation system have only been drawn attention in recent years. This review summarizes the biochemical reactions taking place in the metabolic network of FHP. We discuss how the key operation factors influence metabolism in the FHP process. Recently developed and applied technologies for metabolic flux analysis have been described. Future studies on the metabolic network to enhance fermentative hydrogen production by strict anaerobes are recommended. It is expected that this review can provide useful information in terms of fundamental knowledge and update technology for scientists and research engineers in the field of biological hydrogen production.
Evaluation of physicochemical methods in enhancing the adsorption performance of natural zeolite as low-cost adsorbent of methylene blue dye from wastewater
Publisher: Elsevier BV
Date: 04-2016
UV and UV/H2 O2 treatment of diazinon and its influence on disinfection byproduct formation following chlorination
Publisher: Elsevier BV
Date: 08-2015
Leading the Circular Future: South Australia’s Potential Influence on Circular Economy Development in Asia-Pacific Region
Publisher: MDPI AG
Date: 15-09-2023
DOI: 10.3390/SU151813756
Related Organisations
Related Funding Activities
No related grants have been discovered for Christopher Saint.