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 degrees C to 55 degrees 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 degrees C, but decreased at 55 degrees C. Increased methanogenesis and hydrolysis at 50 degrees 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. (C) 2016 Elsevier Ltd. All rights reserved.