title: Impact of undissociated volatile fatty acids on acidogenesis in a two-phase anaerobic system.
abstract: This study investigated the degradation and production of volatile fatty acids (VFAs) in the acidogenic phase reactor of a two-phase anaerobic system. 20 mmol/L bromoethanesulfonic acid (BESA) was used to inhibit acidogenic methanogens (which were present in the acidogenic phase reactor) from degrading VFAs. The impact of undissociated volatile fatty acids (unVFAs) on "net" VFAs production in the acidogenic phase reactor was then evaluated, with the exclusion of concurrent VFAs degradation. "Net" VFAs production from glucose degradation was partially inhibited at high unVFAs concentrations, with 59%, 37% and 60% reduction in production rates at 2190 mg chemical oxygen demand (COD)/L undissociated acetic acid (unHAc), 2130 mg COD/L undissociated propionic acid (unHPr) and 2280 mg COD/L undissociated n-butyric acid (unHBu), respectively. The profile of VFAs produced further indicated that while an unVFA can primarily affect its own formation, there were also unVFAs that affected the formation of other VFAs.
authors.affiliation: Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, Singapore 637141, Singapore; School of Civil and Environmental Engineering, Nanyang Technological University, Singapore 639798, Singapore. Electronic address: xiaokeke19890524@163.com.
authors.forename: Keke
authors.initials: K
authors.lastname: Xiao
authors.affiliation: Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, Singapore 637141, Singapore; School of Civil and Environmental Engineering, Nanyang Technological University, Singapore 639798, Singapore.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, Singapore 637141, Singapore; School of Civil and Environmental Engineering, Nanyang Technological University, Singapore 639798, Singapore. Electronic address: CHGUO@ntu.edu.sg.
authors.forename: Chenghong
authors.initials: C
authors.lastname: Guo
authors.affiliation: Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, Singapore 637141, Singapore; School of Civil and Environmental Engineering, Nanyang Technological University, Singapore 639798, Singapore.
authors.forename: Yogananda
authors.initials: Y
authors.lastname: Maspolim
authors.affiliation: Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, Singapore 637141, Singapore; School of Civil and Environmental Engineering, Nanyang Technological University, Singapore 639798, Singapore. Electronic address: WJNg@ntu.edu.sg.
authors.forename: Wun Jern
authors.initials: WJ
authors.lastname: Ng
mesh_terms: D000693:Anaerobiosis; D001673:Biodegradation, Environmental; D019149:Bioreactors; D005232:Fatty Acids, Volatile
chemical_list: D005232:Fatty Acids, Volatile
keywords: Acidogenesis; Anaerobic process; Substrate inhibition; Undissociated volatile fatty acids; Waste treatment