Substrate variations triggered the emergent of different active bacterial and archaeal assemblages during biomethane production. bioreactor metagenome

Biomethane has been regarded as one of the promising renewable energy supplies. However, the microbial communities involved in methane synthesis have not been fully characterized. By examining the bacterial and archaeal 16S rRNA genes in the DNA and RNA using barcoded 454 pyrosequencing, the composition of a methane-generating microbial community and the corresponding active members during the transformation of three target substrates (food waste, cellulose, xylan) were determined. By assigning sequences to their respective taxonomies, substrate-dependent variations in the composition and relative abundance of the active microbial community members were detected. Results from this study suggest that the vast diversity of the microbial community enabled adaptation and transformation of multiple amended substrates, and a subset of the populations became active and altered in relative abundance during methane production. Overall, insights gained from high-throughput sequencing of the metabolically-active populations under different conditions should facilitate the optimization of biomethane systems.