Temperature affects microbial abundance, activity and interactions in anaerobic digestion

Temperature is a major factor determining the performance of the anaerobic digestion process. The microbial abundance, activity and interactional networks were investigated under a temperature gradient from 25 °C to 55 °C through amplicon sequencing, using 16S ribosomal RNA and 16S rRNA gene-based approaches. Comparative analysis of past accumulative elements presented by 16S rRNA gene-based analysis, and the in-situ conditions presented by 16S rRNA-based analysis, provided new insights concerning the identification of microbial functional roles and interactions. The daily methane production and total biogas production increased with temperature up to 50 °C, but decreased at 55 °C. Increased methanogenesis and hydrolysis at 50 °C were main factors causing higher methane production which was also closely related with more well-defined methanogenic and/or related modules with comprehensive interactions and increased functional orderliness referred to more microorganisms participating in interactions. This research demonstrated the importance of evaluating functional roles and interactions of microbial community.