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

Molecules ◽  
2019 ◽  
Vol 24 (3) ◽  
pp. 398 ◽  
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.

scholarly journals Fermentation of Organic Residues to Beneficial Chemicals: A Review of Medium-Chain Fatty Acid Production

Processes ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 1571
Author(s):  
Panagiota Stamatopoulou ◽  
Juliet Malkowski ◽  
Leandro Conrado ◽  
Kennedy Brown ◽  
Matthew Scarborough
Keyword(s):  
Organic Waste ◽  
Chain Elongation ◽  
Organic Substrates ◽  
Industrial Chemicals ◽  
Waste Streams ◽  
Fatty Acid Production ◽  
Medium Chain ◽  
Renewable Feedstocks ◽  
History Of ◽  
Complex Organic

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.

Multi-omics study on chain elongation processes for medium chain carboxylic acids

2020 ◽  
Author(s):  
Byoung-In Sang
Keyword(s):  
Carboxylic Acids ◽  
Chain Elongation ◽  
Medium Chain ◽  
The Right

Contribution to the International Chain Elongation Conference 2020 | ICEC 2020. An abstract can be found in the right column.

scholarly journals Medium-chain carboxylic acids production using consortia from winery wastewater, ruminal fluid and granular sludge

2020 ◽  
Author(s):  
Sharon B. Villegas-Rodríguez
Keyword(s):  
Carboxylic Acids ◽  
Granular Sludge ◽  
Chain Elongation ◽  
Ruminal Fluid ◽  
Medium Chain ◽  
Winery Wastewater ◽  
The Right

Contribution to the International Chain Elongation Conference 2020 | ICEC 2020. An abstract can be found in the right column.

scholarly journals Bio-electro CO2 recycling to medium chain carboxylic acids in two steps

2020 ◽  
Author(s):  
Meritxell Romans-Casas
Keyword(s):  
Carboxylic Acids ◽  
Chain Elongation ◽  
Medium Chain ◽  
Co2 Recycling ◽  
The Right

Contribution to the International Chain Elongation Conference 2020 | ICEC 2020. An abstract can be found in the right column.

scholarly journals Long-Term Continuous Extraction of Medium-Chain Carboxylates by Pertraction With Submerged Hollow-Fiber Membranes

2021 ◽  
Vol 9 ◽  
Author(s):  
Jiajie Xu ◽  
Bin Bian ◽  
Largus T. Angenent ◽  
Pascal E. Saikaly
Keyword(s):  
Partial Pressure ◽  
Carboxylic Acids ◽  
Hollow Fiber ◽  
Operating Conditions ◽  
Extraction Rate ◽  
Chain Elongation ◽  
Hollow Fiber Membranes ◽  
Small Surface ◽  
Medium Chain ◽  
Fiber Membranes

Medium-chain carboxylic acids (MCCAs), which can be generated from organic waste and agro-industrial side streams through microbial chain elongation, are valuable chemicals with numerous industrial applications. Membrane-based liquid-liquid extraction (pertraction) as a downstream separation process to extract MCCAs has been applied successfully. Here, a novel pertraction system with submerged hollow-fiber membranes in the fermentation bioreactor was applied to increase the MCCA extraction rate and reduce the footprint. The highest average surface-corrected MCCA extraction rate of 655.2 ± 86.4 mmol C m−2 d−1 was obtained, which was higher than any other previous reports, albeit the relatively small surface area removed only 11.6% of the introduced carbon via pertraction. This submerged extraction system was able to continuously extract MCCAs with a high extraction rate for more than 8 months. The average extraction rate of MCCA by internal membrane was 3.0- to 4.7-fold higher than the external pertraction (traditional pertraction) in the same bioreactor. A broth upflow velocity of 7.6 m h−1 was more efficient to extract MCCAs when compared to periodic biogas recirculation operation as a means to prevent membrane fouling. An even higher broth upflow velocity of 40.5 m h−1 resulted in a significant increase in methane production, losing more than 30% of carbon conversion to methane due to a loss of H2, and a subsequent drop in the H2 partial pressure. This resulted in the shift from a microbial community with chain elongators as the key functional group to methanogens, because the drop in H2 partial pressure led to thermodynamic conditions that oxidizes ethanol and carboxylic acids to acetate and H2 with methanogens as the syntrophic partner. Thus, operators of chain elongating systems should monitor the H2 partial pressure when changes in operating conditions are made.

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