ORCID Profile
0000-0002-1387-6111
Current Organisation
E O Lawrence Berkeley National Laboratory
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Publisher: Proceedings of the National Academy of Sciences
Date: 19-07-2022
Abstract: Plants and microbes share common metabolic pathways for producing a range of bioproducts that are potentially foundational to the future bioeconomy. However, in planta accumulation and microbial production of bioproducts have never been systematically compared on an economic basis to identify optimal routes of production. A detailed technoeconomic analysis of four exemplar compounds (4-hydroxybenzoic acid [4-HBA], catechol, muconic acid, and 2-pyrone-4,6-dicarboxylic acid [PDC]) is conducted with the highest reported yields and accumulation rates to identify economically advantaged platforms and breakeven targets for plants and microbes. The results indicate that in planta mass accumulation ranging from 0.1 to 0.3 dry weight % (dwt%) can achieve costs comparable to microbial routes operating at 40 to 55% of maximum theoretical yields. These yields and accumulation rates are sufficient to be cost competitive if the products are sold at market prices consistent with specialty chemicals ($20 to $50/kg). Prices consistent with commodity chemicals will require an order-of-magnitude-greater accumulation rate for plants and/or yields nearing theoretical maxima for microbial production platforms. This comparative analysis revealed that the demonstrated accumulation rates of 4-HBA (3.2 dwt%) and PDC (3.0 dwt%) in engineered plants vastly outperform microbial routes, even if microbial platforms were to reach theoretical maximum yields. Their recovery and sale as part of a lignocellulosic biorefinery could enable biofuel prices to be competitive with petroleum. Muconic acid and catechol, in contrast, are currently more attractive when produced microbially using a sugar feedstock. Ultimately, both platforms can play an important role in replacing fossil-derived products.
Publisher: Springer Science and Business Media LLC
Date: 20-11-2021
DOI: 10.1186/S13068-021-02068-9
Abstract: The development of bioenergy crops with reduced recalcitrance to enzymatic degradation represents an important challenge to enable the sustainable production of advanced biofuels and bioproducts. Biomass recalcitrance is partly attributed to the complex structure of plant cell walls inside which cellulose microfibrils are protected by a network of hemicellulosic xylan chains that crosslink with each other or with lignin via ferulate (FA) bridges. Overexpression of the rice acyltransferase OsAT10 is an effective bioengineering strategy to lower the amount of FA involved in the formation of cell wall crosslinks and thereby reduce cell wall recalcitrance. The annual crop sorghum represents an attractive feedstock for bioenergy purposes considering its high biomass yields and low input requirements. Although we previously validated the OsAT10 engineering approach in the perennial bioenergy crop switchgrass, the effect of OsAT10 expression on biomass composition and digestibility in sorghum remains to be explored. We obtained eight independent sorghum ( Sorghum bicolor (L.) Moench) transgenic lines with a single copy of a construct designed for OsAT10 expression. Consistent with the proposed role of OsAT10 in acylating arabinosyl residues on xylan with p -coumarate ( p CA), a higher amount of p -coumaroyl-arabinose was released from the cell walls of these lines upon hydrolysis with trifluoroacetic acid. However, no major changes were observed regarding the total amount of p CA or FA esters released from cell walls upon mild alkaline hydrolysis. Certain diferulate (diFA) isomers identified in alkaline hydrolysates were increased in some transgenic lines. The amount of the main cell wall monosaccharides glucose, xylose, and arabinose was unaffected. The transgenic lines showed reduced lignin content and their biomass released higher yields of sugars after ionic liquid pretreatment followed by enzymatic saccharification. Expression of OsAT10 in sorghum leads to an increase of xylan-bound p CA without reducing the overall content of cell wall FA esters. Nevertheless, the amount of total cell wall p CA remains unchanged indicating that most p CA is ester-linked to lignin. Unlike other engineered plants overexpressing OsAT10 or a phylogenetically related acyltransferase with similar putative function, the improvements of biomass saccharification efficiency in sorghum OsAT10 lines are likely the result of lignin reductions rather than reductions of cell wall-bound FA. These results also suggest a relationship between xylan-bound p CA and lignification in cell walls.
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D3GC01481A
Abstract: Building a stronger bioeconomy requires production capabilities that can be generated through microbial genetic engineering. Engineered microbes can be paired with engineered feedstocks and compatible deconstruction methods to improve production.
Publisher: Elsevier BV
Date: 12-2022
Publisher: Oxford University Press (OUP)
Date: 16-07-2019
DOI: 10.1111/LAM.13190
Abstract: Clovamide and its analogues are N-hydroxycinnamoyl-L-amino acids (HAA) that exhibit antioxidant activities. For environmental and economic reasons, biological synthesis of these plant-derived metabolites has garnered interest. In this study, we exploited HDT1, a BAHD acyltransferase recently isolated from red clover, for the production of clovamide and derivatives in S. cerevisiae and L. lactis. HDT1 catalyses the transfer of hydroxycinnamoyl-coenzyme A (CoA) onto aromatic amino acids. Therefore, by heterologously co-expressing HDT1 with 4-coumarate:CoA ligase (4CL), we succeeded in the biological production of clovamide and more than 20 other HAA, including halogenated ones, upon feeding the engineered micro-organisms with various combinations of cinnamates and amino acids. To the best of our knowledge, this is the first report on the biological synthesis of HAA and, more generally, on the synthesis of plant-derived antioxidant phenolic compounds in L. lactis. The production of these health beneficial metabolites in Generally Recognized As Safe (GRAS) micro-organisms such as S. cerevisiae and L. lactis provides new options for their delivery as therapeutics. SIGNIFICANCE AND IMPACT OF THE STUDY: N-hydroxycinnamoyl-L-amino acids such as clovamide are bioactive plant-derived phenolic compounds with health beneficial effects. Relying on chemical synthesis or direct extraction from plant sources for the supply of these valuable molecules poses challenges to environmental sustainability. As an alternative route, this work demonstrates the potential for biological synthesis of N-hydroxycinnamoyl-L-amino acids using engineered microbial hosts such as Saccharomyces cerevisiae and Lactococcus lactis. Besides being more eco-friendly, this approach should also provide more structurally erse compounds and offer new methods for their delivery to the human body.
Location: United States of America
No related grants have been discovered for Aymerick Eudes.