title: Effects of sludge retention time, carbon and initial biomass concentrations on selection process: From activated sludge to polyhydroxyalkanoate accumulating cultures.
abstract: Four sequence batch reactors (SBRs) fed by fermented sugar cane wastewater were continuously operated under the aerobic dynamic feeding (ADF) mode with different configurations of sludge retention time (SRT), carbon and initial biomass concentrations to enrich polyhydroxyalkanoate (PHA) accumulating mixed microbial cultures (MMCs) from municipal activated sludge. The stability of SBRs was investigated besides the enrichment performance. The microbial community structures of the enriched MMCs were analyzed using terminal restriction fragment length polymorphism (T-RFLP). The optimum operating conditions for the enrichment process were: SRT of 5days, carbon concentration of 2.52g COD/L and initial biomass concentration of 3.65g/L. The best enrichment performance in terms of both operating stability and PHA storage ability of enriched cultures (with the maximum PHA content and PHA storage yield (YPHA/S) of 61.26% and 0.68mg COD/mg COD, respectively) was achieved under this condition. Effects of the SRT, carbon concentration and initial biomass concentration on the PHA accumulating MMCs selection process were discussed respectively. A new model including the segmentation of the enrichment process and the effects of SRT on each phase was proposed.
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
authors.forename: Long
authors.initials: L
authors.lastname: Huang
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China. Electronic address: wqxshelly@263.net.
authors.forename: Qinxue
authors.initials: Q
authors.lastname: Wen
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
authors.forename: Huichao
authors.initials: H
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
authors.forename: Zirui
authors.initials: Z
authors.lastname: Guo
mesh_terms: D057919:Biological Oxygen Demand Analysis; D018533:Biomass; D019149:Bioreactors / Q000382:microbiology*; D054813:Polyhydroxyalkanoates / Q000378:metabolism*; D012722:Sewage; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D054813:Polyhydroxyalkanoates; D012722:Sewage
keywords: Carbon concentration; Initial biomass concentration; Mixed microbial cultures (MMCs); Polyhydroxyalkanoate (PHA); Sludge retention time (SRT)