title: Effect of carbon sources on the aggregation of photo fermentative bacteria induced by L-cysteine for enhancing hydrogen production.
abstract: Poor flocculation of photo fermentative bacteria resulting in continuous biomass washout from photobioreactor is a critical challenge to achieve rapid and stable hydrogen production. In this work, the aggregation of Rhodopseudomonas faecalis RLD-53 was successfully developed in a photobioreactor and the effects of different carbon sources on hydrogen production and aggregation ability were investigated. Extracellular polymeric substances (EPS) production by R. faecalis RLD-53 cultivated using different carbon sources were stimulated by addition of L-cysteine. The absolute ζ potentials of R. faecalis RLD-53 were considerably decreased with addition of L-cysteine, and aggregation barriers based on DLVO dropped to 15-43 % of that in control groups. Thus, R. faecalis RLD-53 flocculated effectively, and aggregation abilities of strain RLD-53 cultivated with acetate, propionate, lactate and malate reached 29.35, 32.34, 26.07 and 24.86 %, respectively. In the continuous test, hydrogen-producing activity was also promoted and reached 2.45 mol H2/mol lactate, 3.87 mol H2/mol propionate and 5.10 mol H2/mol malate, respectively. Therefore, the aggregation of R. faecalis RLD-53 induced by L-cysteine is independent on the substrate types, which ensures the wide application of this technology to enhance hydrogen recovery from wastewater dominated by different organic substrates.
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, China.|Advanced Water Management Centre, The University of Queensland, St Lucia, QLD, 4072, Australia.
authors.forename: Guo-Jun
authors.initials: GJ
authors.lastname: Xie
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, China. lbf@hit.edu.cn.
authors.forename: Bing-Feng
authors.initials: BF
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Ding
authors.affiliation: Advanced Water Management Centre, The University of Queensland, St Lucia, QLD, 4072, Australia.
authors.forename: Qilin
authors.initials: Q
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Ma
authors.affiliation: Harbin Institute of Technology Shenzhen Graduate School, Shenzhen, 518055, China.
authors.forename: Xu
authors.initials: X
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, China. rnq@hit.edu.cn.
authors.forename: Nan-Qi
authors.initials: NQ
authors.lastname: Ren
mesh_terms: D000085:Acetates; D018533:Biomass; D002244:Carbon / Q000737:chemistry* / Q000378:metabolism*; D003545:Cysteine / Q000494:pharmacology*; D005285:Fermentation; D005427:Flocculation; D006859:Hydrogen / Q000378:metabolism*; D058433:Photobioreactors; D012241:Rhodopseudomonas / Q000187:drug effects* / Q000378:metabolism
chemical_list: D000085:Acetates; D002244:Carbon; D006859:Hydrogen; D003545:Cysteine
keywords: Bioaggregate; Carbon source; Hydrogen production; L-cysteine; Rhodopseudomonas faecalis RLD-53