Long-term successional dynamics of microbial association networks in anaerobic digestion processes

Linwei Wu; Yunfeng Yang; Si Chen; Mengxin Zhao; Zhenwei Zhu; Sihang Yang; Yuanyuan Qu; Qiao Ma; Zhili He; Jizhong Zhou; Qiang He

doi:10.1016/j.watres.2016.07.072

Long-term successional dynamics of microbial association networks in anaerobic digestion processes

Water Res. 2016 Nov 1:104:1-10. doi: 10.1016/j.watres.2016.07.072. Epub 2016 Aug 2.

Authors

Linwei Wu¹, Yunfeng Yang², Si Chen³, Mengxin Zhao¹, Zhenwei Zhu³, Sihang Yang¹, Yuanyuan Qu⁴, Qiao Ma⁴, Zhili He⁵, Jizhong Zhou⁶, Qiang He⁷

Affiliations

¹ State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China.
² State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China. Electronic address: yangyf@tsinghua.edu.cn.
³ Department of Civil and Environmental Engineering, The University of Tennessee, Knoxville, TN 37996, USA.
⁴ Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China.
⁵ Institute for Environmental Genomics and Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK 73019, USA.
⁶ 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.
⁷ 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.

PMID: 27497626
DOI: 10.1016/j.watres.2016.07.072

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.

Keywords: Anaerobic digestion; Microbial interactions; Process stability.

MeSH terms

Anaerobiosis
Bioreactors*
Microbial Consortia
Microbial Interactions
Phylogeny*