The Role of ING2-E5A in Mesophilic Biogas Reactor Systems as Deduced from Multiomics Analyses.

Members of the genera and were speculated to represent indicators reflecting process instability within anaerobic digestion (AD) microbiomes. Therefore, ING2-E5A was isolated from a biogas reactor sample and sequenced on the PacBio and Illumina MiSeq sequencers. Phylogenetic classification positioned the strain ING2-E5A in close proximity to and species (family Dysgonomonadaceae). ING2-E5A encodes a number of genes for glycosyl-hydrolyses (GH) which are organized in Polysaccharide Utilization Loci (PUL) comprising tandem CD-like genes for a TonB-dependent outer-membrane transporter and a cell surface glycan-binding protein. Different GHs encoded in PUL are involved in pectin degradation, reflecting a pronounced specialization of the ING2-E5A PUL systems regarding the decomposition of this polysaccharide. Genes encoding enzymes participating in amino acids fermentation were also identified. Fragment recruitments with the ING2-E5A genome as a template and publicly available metagenomes of AD microbiomes revealed that species are present in 146 out of 257 datasets supporting their importance in AD microbiomes. Metatranscriptome analyses of AD microbiomes uncovered active sugar and amino acid fermentation pathways for species. Likewise, screening of metaproteome datasets demonstrated expression of the PUL-specific component SusC providing further evidence that PUL play a central role for the lifestyle of species.