Novel syntrophic bacteria in full-scale anaerobic digesters revealed by genome-centric metatranscriptomics

摘要: Short-chain fatty acid (SCFA) degradation is an important process in methanogenic ecosystems, and usually catalyzed by SCFA-oxidizing bacteria syntrophy with methanogens. Current knowledge of this functional guild mainly based on isolates or enrichment cultures, but these may not reflect the true diversity situ activities syntrophs predominating full-scale systems. Here we obtained 182 medium to high quality metagenome-assembled genomes (MAGs) from microbiome two anaerobic digesters. The transcriptomic response individual MAG was studied after stimulation low concentrations acetate, propionate, butyrate, separately. most pronounced butyrate observed for MAGs recently described genus Candidatus Phosphitivorax (phylum Desulfobacterota), expressing a beta-oxidation pathway. For largest novel family Pelotomaculaceae, transcribing methylmalonyl-CoA All three species were common digesters at Danish wastewater treatment plants as shown amplicon analysis, first time their syntrophic features involved SCFA oxidation revealed evidence. Further, they also possessed unique genomic undescribed well-characterized syntrophs, including metabolic pathways phosphite oxidation, nitrite sulfate reduction.