title: Long-term successional dynamics of microbial association networks in anaerobic digestion processes.
abstract: It is of great interest to elucidate underlying mechanisms to maintain stability of anaerobic digestion, an important process in waste treatment. By operating triplicate anaerobic digesters continuously for two years, we found that microbial community composition shifted over time despite stable process performance. Using an association network analysis to evaluate microbial interactions, we detected a clear successional pattern, which exhibited increasing modularity but decreasing connectivity among microbial populations. Phylogenetic diversity was the most important factor associated with network topology, showing positive correlations with modularity but negative correlations with network complexity, suggesting induced niche differentiation over time. Positive, but not negative, correlation strength was significantly related (p < 0.05) to phylogeny. Furthermore, among populations exhibiting consistent positive correlations across networks, close phylogenetic linkages were evident (e.g. Clostridiales organisms). Clostridiales organisms were also identified as keystone populations in the networks (i.e., they had large effects on other species), suggestive of an important role in maintaining process stability. We conclude that microbial interaction dynamics of anaerobic digesters evolves over time during stable process performance.
authors: State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China.
authors: Linwei
authors: L
authors: Wu
authors: State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China. Electronic address: yangyf@tsinghua.edu.cn.
authors: Yunfeng
authors: Y
authors: Yang
authors: Department of Civil and Environmental Engineering, The University of Tennessee, Knoxville, TN 37996, USA.
authors: Si
authors: S
authors: Chen
authors: State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China.
authors: Mengxin
authors: M
authors: Zhao
authors: Department of Civil and Environmental Engineering, The University of Tennessee, Knoxville, TN 37996, USA.
authors: Zhenwei
authors: Z
authors: Zhu
authors: State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China.
authors: Sihang
authors: S
authors: Yang
authors: Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China.
authors: Yuanyuan
authors: Y
authors: Qu
authors: Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China.
authors: Qiao
authors: Q
authors: Ma
authors: Institute for Environmental Genomics and Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK 73019, USA.
authors: Zhili
authors: Z
authors: He
authors: State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China; Institute for Environmental Genomics and Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK 73019, USA; Earth Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA. Electronic address: jzhou@ou.edu.
authors: Jizhong
authors: J
authors: Zhou
authors: Department of Civil and Environmental Engineering, The University of Tennessee, Knoxville, TN 37996, USA; Institute for a Secure and Sustainable Environment, The University of Tennessee, Knoxville, TN 37996, USA. Electronic address: qianghe@utk.edu.
authors: Qiang
authors: Q
authors: He
mesh_terms: D000693:Anaerobiosis; D019149:Bioreactors; D059013:Microbial Consortia; D056265:Microbial Interactions; D010802:Phylogeny
keywords: Anaerobic digestion; Microbial interactions; Process stability