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.

Seasonal soil microbial responses are limited to changes in functionality at two Alpine forest sites differing in altitude and vegetation

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The spatial scale dependence of diazotrophic and bacterial community assembly in paddy soil

“…Primers of PolF/PolR (5′‐TGCGAYCCSAARGCBGACTC‐3′/5′‐ATSGCCATCATYTCRCCGGA‐3′) were used for amplifying nifH genes (Poly, Monrozier, & Bally, ), and primers of 515F/806R (5′‐GTGCCAGCMGCCGCGGTAA‐3′/5′‐GGACTACHVGGGTWTCTAAT‐3′) were used for amplifying 16S rRNA genes (Caporaso et al, ). Two‐step PCR experiments were used to prepare amplicon libraries of both nifH genes and 16S rRNA genes as described previously (Wu et al, ). Specifically, 10 cycles were used in the first step and 20 cycles in the second step for 16S rRNA genes; 12 cycles were used in the first step and 23 cycles in the second step for nifH genes.…”

Bacteriophage–prokaryote dynamics and interaction within anaerobic digestion processes across time and space

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