Effect of one step temperature increment from mesophilic to thermophilic anaerobic digestion on the linked pattern between bacterial and methanogenic communities.

• δ13CH 4 reflected the methanogenic pathway changes during temperature increase. • The decline link was found in Methanomicrobiaceae and Firmicutes affiliated families. • Microbial redundancy was the main reason to ensure the δ13CO 2 stability. Process fluctuation caused by temperature modification of anaerobic digestion is routinely monitored via operational parameters, such as pH and gas production, but these parameters are lagging on microbial community performance. In this study, 13C isotope fractionation in CH 4 and CO 2 of biogas together with microbial community dynamics were applied to evaluate process stability in response to temperature increment. Results showed that the weakening correlated links between Firmicutes affiliated families and Methanomicrobiaceae were found regarding temperature increase. In contrast, Methanosarcinaceae and Methanobacteriaceae strengthened their links with multiple bacterial groups. This suggests that the 13C isotope fractionation in CH 4 can predict the collapse of certain microbial interconnections and process instability, the new reinforced microbial links directly reflect the microbial community redundancy for maintaining function of syntrophic populations. [ABSTRACT FROM AUTHOR]