ORCID Profile
0000-0002-4804-6687
Current Organisation
Instituto de Biotecnología, Universidad Nacional Autónoma de México
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.
Publisher: Elsevier BV
Date: 09-2012
DOI: 10.1016/J.YMBEN.2012.07.007
Abstract: Despite the abundance of xylose in nature, the production of chemicals from C5 sugars remains challenging in metabolic engineering. By deleting xylFGH genes and using adaptive evolution, an efficient E. coli strain capable of producing D-lactate from xylose was engineered. Quantitative proteomics and genome sequencing were used to understand the new phenotype and the metabolic limitations of xylose conversion to D-lactate. Proteomics identified major changes in enzyme concentration in the glycolytic and tricarboxylic acid pathways. Whole genome sequencing of the evolved strain identified a point mutation in the gatC gene, which resulted in a change from serine to leucine at position 184 of the GatC protein. The knockout of gatC in a number of strains and the insertion of the mutation in the non-evolved strain confirmed its activity as a xylose transporter and demonstrated that the mutation is responsible for the high xylose consumption phenotype in the evolved strain. The newly found xylose transporter is a candidate for future strain engineering for converting C5-C6 syrups into valuable chemicals.
Publisher: Springer Science and Business Media LLC
Date: 03-01-2017
Publisher: Oxford University Press (OUP)
Date: 08-11-2017
DOI: 10.1104/PP.16.01240
Publisher: S. Karger AG
Date: 18-10-2013
DOI: 10.1159/000355264
Abstract: The glycolytic intermediate phosphoenolpyruvate (PEP) is a precursor of several cellular components, including various aromatic compounds. Modifications to the PEP node such as PEP:sugar phosphotransferase system (PTS) or pyruvate kinase inactivation have been shown to have a positive effect on aromatics production capacity in i Escherichia coli /i and i Bacillus subtilis /i . In this study, pyruvate kinase and PTS-deficient i B. subtilis /i strains were employed for the construction of derivatives lacking shikimate kinase activity that accumulate two industrially valuable chemicals, the intermediates of the common aromatic pathway, shikimic and dehydroshikimic acids. The pyruvate kinase-deficient strain (CLC6-PYKA) showed the best production parameters under resting-cell conditions. Compared to the PTS-deficient strain, the shikimic and dehydroshikimic acids specific production rates for CLC6-PYKA were 1.8- and 1.7-fold higher, respectively. A batch fermentor culture using complex media supplemented with 83 g/l of glucose was developed with strain CLC6-PYKA, where final titers of 4.67 g/l (shikimic acid) and 6.2 g/l (dehydroshikimic acid) were produced after 42 h.
Publisher: Elsevier BV
Date: 02-2017
DOI: 10.1016/J.BIORTECH.2016.11.064
Abstract: Agave bagasse (AGB) has gained recognition as a drought-tolerant biofuel feedstock with high productivity in semiarid regions. A comparative analysis of ionic liquid (IL) and organosolv (OV) pretreatment technologies in AGB was performed using a sequential enzymatic saccharification and fermentation (SESF) strategy with cellulolytic enzymes and the ethanologenic Escherichia coli strain MS04. After pretreatment, 86% of xylan and 45% of lignin were removed from OV-AGB, whereas IL-AGB reduced lignin content by 28% and xylan by 50% when compared to the untreated biomass. High glucan (>90%) and xylan (>83%) conversion was obtained with both pretreated s les. During the fermentation stage (48h), 12.1 and 12.7kg of ethanol were produced per 100kg of untreated AGB for IL and OV, respectively. These comparative analyses showed the advantages of SESF using IL and OV in a biorefinery configuration where a better understanding of AGB recalcitrance is key for future applications.
Location: Mexico
No related grants have been discovered for Alfredo Martinez.