title: Microbial community structures in an integrated two-phase anaerobic bioreactor fed by fruit vegetable wastes and wheat straw.
abstract: The microbial community structures in an integrated two-phase anaerobic reactor (ITPAR) were investigated by 16S rDNA clone library technology. The 75L reactor was designed with a 25L rotating acidogenic unit at the top and a 50L conventional upflow methanogenic unit at the bottom, with a recirculation connected to the two units. The reactor had been operated for 21 stages to co-digest fruit/vegetable wastes and wheat straw, which showed a very good biogas production and decomposition of cellulosic materials. The results showed that many kinds of cellulose and glycan decomposition bacteria related with Bacteroidales, Clostridiales and Syntrophobacterales were dominated in the reactor, with more bacteria community diversities in the acidogenic unit. The methanogens were mostly related with Methanosaeta, Methanosarcina, Methanoculleus, Methanospirillum and Methanobacterium; the predominating genus Methanosaeta, accounting for 40.5%, 54.2%, 73.6% and 78.7% in four samples from top to bottom, indicated a major methanogenesis pathway by acetoclastic methanogenesis in the methanogenic unit. The beta diversity indexes illustrated a more similar distribution of bacterial communities than that of methanogens between acidogenic unit and methanogenic unit. The differentiation of methanogenic community composition in two phases, as well as pH values and volatile fatty acid (VFA) concentrations confirmed the phase separation of the ITPAR. Overall, the results of this study demonstrated that the special designing of ITPAR maintained a sufficient number of methanogens, more diverse communities and stronger syntrophic associations among microorganisms, which made two phase anaerobic digestion of cellulosic materials more efficient.
authors.affiliation: College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha 410128, China; State Key Joint Laboratory of Environment Simulation and Pollution Control (SKLESPC), School of Environment, Tsinghua University, Beijing 100084, China. Electronic address: chongwang06@126.com.
authors.forename: Chong
authors.initials: C
authors.lastname: Wang
authors.affiliation: State Key Joint Laboratory of Environment Simulation and Pollution Control (SKLESPC), School of Environment, Tsinghua University, Beijing 100084, China. Electronic address: jiane.zuo@mail.tsinghua.edu.cn.
authors.forename: Jiane
authors.initials: J
authors.lastname: Zuo
authors.affiliation: State Key Joint Laboratory of Environment Simulation and Pollution Control (SKLESPC), School of Environment, Tsinghua University, Beijing 100084, China.
authors.forename: Xiaojie
authors.initials: X
authors.lastname: Chen
authors.affiliation: State Key Joint Laboratory of Environment Simulation and Pollution Control (SKLESPC), School of Environment, Tsinghua University, Beijing 100084, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Xing
authors.affiliation: State Key Joint Laboratory of Environment Simulation and Pollution Control (SKLESPC), School of Environment, Tsinghua University, Beijing 100084, China.
authors.forename: Linan
authors.initials: L
authors.lastname: Xing
authors.affiliation: State Key Joint Laboratory of Environment Simulation and Pollution Control (SKLESPC), School of Environment, Tsinghua University, Beijing 100084, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Li
authors.affiliation: College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha 410128, China. Electronic address: xiangyangcn@163.com.
authors.forename: Xiangyang
authors.initials: X
authors.lastname: Lu
authors.affiliation: College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha 410128, China; Bioprocess control (Sweden) Co., Ltd., Beijing Representative Office, Beijing 100027, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Li
mesh_terms: D019149:Bioreactors / Q000382:microbiology*; D005735:Garbage; D059013:Microbial Consortia; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000737:chemistry*
chemical_list: D012336:RNA, Ribosomal, 16S
keywords: 16S rDNA clone library; Co-digestion; Fruit/vegetable waste; Integrated two-phase anaerobic digestion; Wheat straw