Effects of heat shocks on microbial community structure and microbial activity of a methanogenic enrichment degrading benzoate

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• 作者：R. Mei ; T. Narihiro ; M.K. Nobu and W.-T. Liu
• 刊名：Letters in Applied Microbiology
• 出版年：2016
• 出版时间：November 2016
• 年：2016
• 卷：63
• 期：5
• 页码：356-362
• 全文大小：1154K
• ISSN：1472-765X

文摘

In anaerobic digesters, temperature fluctuation could lead to process instability and failure. It is still not well understood how digester microbiota as a whole respond to heat shock, and what specific organisms are vulnerable to perturbation or responsible for process recovery after perturbation. To address these questions, a mesophilic benzoate-degrading methanogenic culture enriched from digester was subjected to different levels of heat shock. Three types of methane production profiles after perturbation were observed in comparison to the control: uninhibited, inhibited with later recovery, and inhibited without recovery. These responses were correlated with the microbial community compositions based on the analyses of 16S rRNA and 16S rRNA gene. Specifically, the primary benzoate-degrading syntroph was highly affected by heat shock, and its abundance and activity were both crucial to the restoration of benzoate degradation after heat shock. In contrast, methanogens were stable regardless whether methane production was inhibited. Populations related to ‘Candidatus Cloacimonetes’ and Firmicutes showed stimulated growth. These observations indicated distinct physiological traits and ecological niches associated with individual microbial groups. The results obtained after exposure to heat shock can be critical to more comprehensive characterization of digester ecology under perturbations.