title: Effect of pH on lactic acid production from acidogenic fermentation of food waste with different types of inocula.
abstract: Effect of acidic pH (4, 5, 6 and uncontrolled) on lactic acid (LA) fermentation from food waste was investigated by batch fermentation experiments using methanogenic sludge, fresh food waste and anaerobic activated sludge as inocula. Results showed that due to the increase of hydrolysis, substrate degradation rate and enzyme activity, the optimal LA concentration and yield were obtained at pH 5, regardless of the inoculum used. The highest LA concentration (28.4g/L) and yield (0.46g/g-TS) were obtained with fresh food waste as inoculum. Moreover, after the substrate was completely utilized, the lactic acid bacteria population sharply decreased, and the LA produced was converted to volatile fatty acids (VFAs) at pH 6 within a short period. The VFA components varied with the inoculum supplied. Microbial community analysis using high-throughput pyrosequencing revealed that diversity decreased and a high abundance of Lactobacillus (83.4-98.5%) accumulated during fermentation with all inocula.
authors.affiliation: School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Key Lab of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China; International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, Xi'an 710055, China.
authors.forename: Jialing
authors.initials: J
authors.lastname: Tang
authors.affiliation: School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Key Lab of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China; International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, Xi'an 710055, China. Electronic address: xcwang@xauat.edu.cn.
authors.forename: Xiaochang C
authors.initials: XC
authors.lastname: Wang
authors.affiliation: School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, Xi'an 710055, China.
authors.forename: Yisong
authors.initials: Y
authors.lastname: Hu
authors.affiliation: International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, Xi'an 710055, China; Taiyuan University of Technology, Shanxi Province, Taiyuan 030054, China.
authors.forename: Yongmei
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Civil and Environmental Engineering, Tohoku University, Sendai 9808579, Japan.
authors.forename: Yuyou
authors.initials: Y
authors.lastname: Li
mesh_terms: D000693:Anaerobiosis; D057919:Biological Oxygen Demand Analysis; D001709:Biotechnology / Q000379:methods; D004798:Enzymes / Q000378:metabolism; D005232:Fatty Acids, Volatile / Q000378:metabolism; D005285:Fermentation; D005502:Food; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D019344:Lactic Acid / Q000096:biosynthesis*; D059013:Microbial Consortia / Q000502:physiology*; D012722:Sewage / Q000382:microbiology; D018505:Waste Management / Q000379:methods*
chemical_list: D004798:Enzymes; D005232:Fatty Acids, Volatile; D012722:Sewage; D019344:Lactic Acid
keywords: Acidogenic fermentation; Food waste; Inoculum; Lactic acid; pH