Lactate-based chain elongation : Poduction and separation of medium-chain carboxylates from complex organic residues

Medium-chain fatty acids (MCFAs) have a variety of uses in the production of industrial chemicals, food, and personal care products. These compounds are often produced through palm refining, but recent work has demonstrated that MCFAs can also be produced through the fermentation of complex organic substrates, including organic waste streams. While “chain elongation” offers a renewable platform for producing MCFAs, there are several limitations that need to be addressed before full-scale implementation becomes widespread. Here, we review the history of work on MCFA production by both pure and mixed cultures of fermenting organisms, and the unique metabolic features that lead to MCFA production. We also offer approaches to address the remaining challenges and increase MCFA production from renewable feedstocks.

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Metabolic cascade of complex organic wastes to medium-chain carboxylic acids: A review on the state-of-the-art multi-omics analysis for anaerobic chain elongation pathways

Bioresource Technology ◽

10.1016/j.biortech.2021.126211 ◽

2021 ◽

pp. 126211

Author(s):

Hyunjin Kim ◽

Seongcheol Kang ◽

Byoung-In Sang

Keyword(s):

Carboxylic Acids ◽

State Of The Art ◽

Organic Wastes ◽

The State ◽

Chain Elongation ◽

Medium Chain ◽

Omics Analysis ◽

Complex Organic

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Medium Chain Carboxylic Acids from Complex Organic Feedstocks by Mixed Culture Fermentation

Molecules ◽

10.3390/molecules24030398 ◽

2019 ◽

Vol 24 (3) ◽

pp. 398 ◽

Cited By ~ 27

Author(s):

Vicky De Groof ◽

Marta Coma ◽

Tom Arnot ◽

David J Leak ◽

Ana B Lanham

Keyword(s):

Carboxylic Acids ◽

Organic Waste ◽

Chain Elongation ◽

Operational Parameters ◽

Critical Research ◽

Environmental Pressures ◽

Mixed Culture Fermentation ◽

Renewable Chemicals ◽

Medium Chain ◽

Complex Organic

Environmental pressures caused by population growth and consumerism require the development of resource recovery from waste, hence a circular economy approach. The production of chemicals and fuels from organic waste using mixed microbial cultures (MMC) has become promising. MMC use the synergy of bio-catalytic activities from different microorganisms to transform complex organic feedstock, such as by-products from food production and food waste. In the absence of oxygen, the feedstock can be converted into biogas through the established anaerobic digestion (AD) approach. The potential of MMC has shifted to production of intermediate AD compounds as precursors for renewable chemicals. A particular set of anaerobic pathways in MMC fermentation, known as chain elongation, can occur under specific conditions producing medium chain carboxylic acids (MCCAs) with higher value than biogas and broader applicability. This review introduces the chain elongation pathway and other bio-reactions occurring during MMC fermentation. We present an overview of the complex feedstocks used, and pinpoint the main operational parameters for MCCAs production such as temperature, pH, loading rates, inoculum, head space composition, and reactor design. The review evaluates the key findings of MCCA production using MMC, and concludes by identifying critical research targets to drive forward this promising technology as a valorisation method for complex organic waste.

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Biological production of medium-chain carboxylates through chain elongation: An overview

Biotechnology Advances ◽

10.1016/j.biotechadv.2021.107882 ◽

2022 ◽

Vol 55 ◽

pp. 107882

Author(s):

Jianlong Wang ◽

Yanan Yin

Keyword(s):

Chain Elongation ◽

Biological Production ◽

Medium Chain

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Aldehydes and sugars from evolved precometary ice analogs: Importance of ices in astrochemical and prebiotic evolution

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1418602112 ◽

2015 ◽

Vol 112 (4) ◽

pp. 965-970 ◽

Cited By ~ 76

Author(s):

Pierre de Marcellus ◽

Cornelia Meinert ◽

Iuliia Myrgorodska ◽

Laurent Nahon ◽

Thomas Buhse ◽

...

Keyword(s):

Gas Phase ◽

Molecular Clouds ◽

Room Temperature ◽

Laboratory Experiments ◽

Organic Residue ◽

Organic Residues ◽

Flight Mass Spectrometry ◽

The Earth ◽

Planetary Environment ◽

Complex Organic

Evolved interstellar ices observed in dense protostellar molecular clouds may arguably be considered as part of precometary materials that will later fall on primitive telluric planets, bringing a wealth of complex organic compounds. In our laboratory, experiments reproducing the photo/thermochemical evolution of these ices are routinely performed. Following previous amino acid identifications in the resulting room temperature organic residues, we have searched for a different family of molecules of potential prebiotic interest. Using multidimensional gas chromatography coupled to time-of-flight mass spectrometry, we have detected 10 aldehydes, including the sugar-related glycolaldehyde and glyceraldehyde—two species considered as key prebiotic intermediates in the first steps toward the synthesis of ribonucleotides in a planetary environment. The presence of ammonia in water and methanol ice mixtures appears essential for the recovery of these aldehydes in the refractory organic residue at room temperature, although these products are free of nitrogen. We finally point out the importance of detecting aldehydes and sugars in extraterrestrial environments, in the gas phase of hot molecular clouds, and, more importantly, in comets and in primitive meteorites that have most probably seeded the Earth with organic material as early as 4.2 billion years ago.

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Medium Chain Fatty Acid (MCFA) Production in a Lignocellulosic Biorefinery

International Chain Elongation Conference 2020 ◽

10.18174/icec2020.18012 ◽

2020 ◽

Author(s):

Daniel R. Noguera

Keyword(s):

Fatty Acid ◽

Chain Fatty Acid ◽

Medium Chain Fatty Acid ◽

Chain Elongation ◽

Medium Chain

Contribution to the International Chain Elongation Conference 2020 | ICEC 2020.

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Multi-omic analysis of medium-chain fatty acid synthesis by Candidatus Weimerbacter bifidus, gen. nov., sp. nov., and Candidatus Pseudoramibacter fermentans, sp. nov.

10.1101/726943 ◽

2019 ◽

Cited By ~ 1

Author(s):

Matthew J. Scarborough ◽

Kevin S. Myers ◽

Timothy J. Donohue ◽

Daniel R. Noguera

Keyword(s):

Fatty Acids ◽

Acid Synthesis ◽

Chain Elongation ◽

Industrial Chemicals ◽

Culture Studies ◽

Medium Chain ◽

Medium Chain Fatty Acids ◽

Metabolic Functions ◽

Energy Conserving ◽

Chain Fatty Acids

ABSTRACTChain elongation is emerging as a bioprocess to produce valuable medium-chain fatty acids (MCFA; 6 to 8 carbons in length) from organic waste streams by harnessing the metabolism of anaerobic microbiomes. Although our understanding of chain elongation physiology is still evolving, the reverse β-oxidation pathway has been identified as a key metabolic function to elongate the intermediate products of fermentation to MCFA. Here, we describe two chain-elongating microorganisms that were enriched in an anaerobic microbiome transforming the residues from a lignocellulosic biorefining process to short- and medium-chain fatty acids. Based on a multi-omic analysis of this microbiome, we predict that Candidatus Weimerbacter bifidus, gen. nov., sp. nov. used xylose to produce MCFA, whereas Candidatus Pseudoramibacter fermentans, sp. nov., used glycerol and lactate as substrates for chain elongation. Both organisms are predicted to use an energy conserving hydrogenase to improve the overall bioenergetics of MCFA production.IMPORTANCEMicrobiomes are vital to human health, agriculture, environmental processes, and are receiving attention as biological catalysts for production of renewable industrial chemicals. Chain elongation by MCFA-producing microbiomes offer an opportunity to produce valuable chemicals from organic streams that otherwise would be considered waste. However, the physiology and energetics of chain elongation is only beginning to be studied, and we are analyzing MCFA production by self-assembled communities to complement the knowledge that has been acquired from pure culture studies. Through a multi-omic analysis of an MCFA-producing microbiome, we characterized metabolic functions of two chain elongating bacteria and predict previously unreported features of this process.

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Developing Clostridia as Cell Factories for Short- and Medium-Chain Ester Production

Frontiers in Bioengineering and Biotechnology ◽

10.3389/fbioe.2021.661694 ◽

2021 ◽

Vol 9 ◽

Author(s):

Qingzhuo Wang ◽

Naief H. Al Makishah ◽

Qi Li ◽

Yanan Li ◽

Wenzheng Liu ◽

...

Keyword(s):

Organic Acids ◽

Value Added ◽

Carbon Chain ◽

Chain Elongation ◽

Medium Chain ◽

Cell Factories ◽

Alcohol Acyltransferase ◽

Volatile Esters

Short- and medium-chain volatile esters with flavors and fruity fragrances, such as ethyl acetate, butyl acetate, and butyl butyrate, are usually value-added in brewing, food, and pharmacy. The esters can be naturally produced by some microorganisms. As ester-forming reactions are increasingly deeply understood, it is possible to produce esters in non-natural but more potential hosts. Clostridia are a group of important industrial microorganisms since they can produce a variety of volatile organic acids and alcohols with high titers, especially butanol and butyric acid through the CoA-dependent carbon chain elongation pathway. This implies sufficient supplies of acyl-CoA, organic acids, and alcohols in cells, which are precursors for ester production. Besides, some Clostridia could utilize lignocellulosic biomass, industrial off-gas, or crude glycerol to produce other branched or straight-chain alcohols and acids. Therefore, Clostridia offer great potential to be engineered to produce short- and medium-chain volatile esters. In the review, the efforts to produce esters from Clostridia via in vitro lipase-mediated catalysis and in vivo alcohol acyltransferase (AAT)-mediated reaction are comprehensively revisited. Besides, the advantageous characteristics of several Clostridia and clostridial consortia for bio-ester production and the driving force of synthetic biology to clostridial chassis development are also discussed. It is believed that synthetic biotechnology should enable the future development of more effective Clostridia for ester production.

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