Promoting chain elongation in mixed culture acidification reactors by addition of ethanol

Carboxylic acid production from brewer’s spent grain via mixed culture fermentation

“…2b), due to the reaction of acetic acid with ethanol for longer chain VFAs production. This phenomenon was also observed from the mixed culture fermentation using organic fraction of municipal solid waste or acetic acid as a substrate (Grootscholten et al, 2013a;Steinbusch et al, 2011). Propionic acid and butyric acid production almost remained unchanged with ethanol addition (data not shown).…”

“…The above results indicated that the pH 7 favored the VFA production and chain elongation to some extent. Levels of undissociated fatty acids at the pH 7 could partially lead to enhanced VFAs production (Grootscholten et al, 2013a). Although the VFAs were largely produced by the acidogenic and acetogenic fermentation of carbohydrates in the BSG, the rapid disappearance of ethanol and lactic acid at the early stage of fermentation could also contribute to the C2+ VFAs production via reverse b oxidation (Agler et al, 2012;Spirito et al, 2014).…”

Enhancing Biomass Utilization for Bioenergy — Crop Rotation Systems and Alternative Conversion Processes

“…In addition they found that supplementing the mixture with ruminal derived Clostridiumum kluyveri an ethanol-utilizing bacteria resulted in production levels of 4.9-6.1 g/L of caproate in 48-72 hours using either switchgrass or alfalfa stems as the substrate. The level of caproate production seen by the Weimer group is similar to what others have achieved [34,40], but in a 10 to 30 times less time frame for incubation. Being able to generate longer VFAs increases the energy density in each molecule increasing the value of the material for liquid fuels.…”

Complete genome sequence of Ruminococcaceae bacterium CPB6: A newly isolated culture for efficient n -caproic acid production from lactate

“…It has been extensively reported that ethanol is an efficient electron donor for CA production (Barker et al, 1945;Grootscholten et al, 2013;Spirito et al, 2014). The oxidation of ethanol can provide energy (Acetyl-CoA) for the subsequent sequential elongation of the carbon chain of carboxylic acids (e.g., acetic acid to butyric acid, and further to CA etc.).…”

“…Both ethanol and lactate are important intermediates in primary anaerobic fermentation of carbohydrates. Ethanol has been proved to be the efficient reducing substrate for CA synthesis (Agler et al, 2012;Barker and Taha, 1942;Grootscholten et al, 2013). Lactate, as an energy-rich reducing compound, has generally been reported to be used to produce butyrate (Prabhu et al, 2012;Tao et al, 2016;Weimer and Moen, 2013).…”