title: Lactic acid fermentation from food waste with indigenous microbiota: Effects of pH, temperature and high OLR.
abstract: The effects of pH, temperature and high organic loading rate (OLR) on lactic acid production from food waste without extra inoculum addition were investigated in this study. Using batch experiments, the results showed that although the hydrolysis rate increased with pH adjustment, the lactic acid concentration and productivity were highest at pH 6. High temperatures were suitable for solubilization but seriously restricted the acidification processes. The highest lactic acid yield (0.46g/g-TS) and productivity (278.1mg/Lh) were obtained at 37°C and pH 6. In addition, the lactic acid concentration gradually increased with the increase in OLR, and the semi-continuous reactor could be stably operated at an OLR of 18g-TS/Ld. However, system instability, low lactic acid yield and a decrease in VS removal were noticed at high OLRs (22g-TS/Ld). The concentrations of volatile fatty acids (VFAs) in the fermentation mixture were relatively low but slightly increased with OLR, and acetate was the predominant VFA component. Using high-throughput pyrosequencing, Lactobacillus from the raw food waste was found to selectively accumulate and become dominant in the semi-continuous reactor.
authors.affiliation: School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China. Electronic address: tangjialing88@126.com.
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. Electronic address: xcwang@xauat.edu.cn.
authors.forename: Xiaochang
authors.initials: X
authors.lastname: Wang
authors.affiliation: School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China.
authors.forename: Yisong
authors.initials: Y
authors.lastname: Hu
authors.affiliation: School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, 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: D019149:Bioreactors; D005232:Fatty Acids, Volatile; D005285:Fermentation; D005502:Food; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D019344:Lactic Acid / Q000378:metabolism*; D064307:Microbiota / Q000502:physiology*; D012037:Refuse Disposal / Q000379:methods*; D013696:Temperature; D014866:Waste Products
chemical_list: D005232:Fatty Acids, Volatile; D014866:Waste Products; D019344:Lactic Acid
keywords: Lactic acid fermentation; Lactobacillus; Organic loading rate (OLR); Temperature; pH adjustment