Enrichment and description of novel bacteria performing syntrophic propionate oxidation at high ammonia level.

摘要: Inefficient syntrophic propionate degradation causes severe operating disturbances and reduces biogas productivity in many high-ammonia anaerobic digesters, but propionate-degrading microorganisms these systems remain unknown. Here, we identified candidate ammonia-tolerant propionate-oxidising bacteria using enrichment at high ammonia levels (0.7-0.8 g NH3 L-1 ) continuously-fed reactors. We reconstructed 30 high-quality metagenome-assembled genomes (MAGs) from the propionate-fed reactors, which revealed two novel species families Peptococcaceae Desulfobulbaceae as candidates. Both MAGs possess genomic potential for oxidation electron transfer required energy conservation and, similar to acetate degrading syntrophs, both contain genes predicted link pH tolerance. Based on relative abundance, a sp. appeared be main degrader has been given provisional name "Candidatus Syntrophopropionicum ammoniitolerans". This bacterium was also found quantitative PCR. Acetate degraded by acetate-oxidising hydrogenotrophic methanogenic community consisted of Methanoculleus bourgensis yet characterised work provides knowledge cooperating reveals that populations share common features, diverge genomically taxonomically known species.