title: Carboxylic acid production from brewer's spent grain via mixed culture fermentation.
abstract: This study aimed at investigating carboxylic acid production from brewer's spent grain (BSG) via mixed culture fermentation. The results showed that the distribution of fermentation products was significantly affected by pH conditions and the addition of electron donors. Lactic acid was the dominant component under acidic and alkaline conditions while volatile fatty acids (VFAs) became dominant under the neutral condition. Furthermore, the neutral condition favored the chain elongation of carboxylic acids, especially with ethanol as the electron donor. Ethanol addition enhanced valeric acid and caproic acid production by 44% and 167%, respectively. Lactic acid addition also had positive effects on VFAs production under the neutral condition but limited to C2-C4 products. As a result, propionic acid and butyric acid production was increased by 109% and 152%, respectively. These findings provide substantial evidence for regulating carboxylic acid production during mixed culture fermentation of BSG by controlling pH and adding electron donors.
authors.affiliation: Department of Bioengineering, University of Missouri, Columbia, MO 65211, USA.
authors.forename: Shaobo
authors.initials: S
authors.lastname: Liang
authors.affiliation: Department of Bioengineering, University of Missouri, Columbia, MO 65211, USA. Electronic address: wanca@missouri.edu.
authors.forename: Caixia
authors.initials: C
authors.lastname: Wan
mesh_terms: D001709:Biotechnology / Q000379:methods*; D002208:Caproates / Q000378:metabolism; D002264:Carboxylic Acids / Q000378:metabolism*; D002523:Edible Grain / Q000378:metabolism*; D000431:Ethanol / Q000378:metabolism; D005232:Fatty Acids, Volatile / Q000378:metabolism; D005285:Fermentation; D019649:Food Industry; D006863:Hydrogen-Ion Concentration; D007220:Industrial Waste; D019344:Lactic Acid / Q000378:metabolism; D010421:Pentanoic Acids / Q000378:metabolism
chemical_list: D002208:Caproates; D002264:Carboxylic Acids; D005232:Fatty Acids, Volatile; D007220:Industrial Waste; D010421:Pentanoic Acids; C037652:hexanoic acid; D019344:Lactic Acid; D000431:Ethanol; C038780:n-pentanoic acid
keywords: Brewer’s spent grain; Carboxylic acids; Chain elongation; Lactic acid; Mixed culture