Responses of anaerobic microorganisms to different culture conditions and corresponding effects on biogas production and solid digestate quality

Microbial communities of anaerobic digestion have been intensively investigated in the past decades. Majority of these studies focused on correlating microbial diversity with biogas production. The relationship between microbial communities and compositional changes of the solid digestate (AD fiber) has not been comprehensively studied to date. Therefore, the objective of this study was to understand the responses of microbial communities to different operational conditions of anaerobic co-digestion and their influences on biogas production and solid digestate quality. Two temperatures and three manure-to-food waste ratios were investigated by a completely randomized design. Molecular analyses demonstrate that both temperature and manure-to-food waste ratio greatly influenced the bacterial communities, while archaeal communities were mainly influenced by temperature. The digestion performance showed that biogas productivity increased with the increase of supplemental food wastes, and there were no significant differences on carbohydrate contents among different digestions. The statistical analyses conclude that microbes changed their community configuration under different conditions to enhance digestion performance for biogas and homogenized solid digestate production.