Syntrophic Butyrate-Oxidizing Consortium Mitigates Acetate Inhibition through a Shift from Acetoclastic to Hydrogenotrophic Methanogenesis and Alleviates VFA Stress in Thermophilic Anaerobic Digestion

In anaerobic digestion (AD), butyrate is degraded by syntrophic consortium, but can accumulate in highly loaded AD systems. The effect of on the process attracts much less attention than propionate or acetate. this work, an enrichment culture thermophilic butyrate-oxidizing consortium was obtained gradually increasing initial concentration from 20 to 170 mM. Surprisingly, even highest did not significantly inhibit methanogenic community, and stage acetate degradation limiting overall rate process. At mM butyrate, bacterial community changed towards dominance acetate-oxidizing (SAO) bacteria related Syntrophaceticus (42.9%), Syntrophomonas (26.2%) Firmicutes (26.2%), while archaeal experienced a sharp decrease abundance Methanosarcina thermophila (from 86.0 25.0%) increase Methanothermobacter thermautotrophicus 3.2 53.1%) Methanomassiliicoccus 21.9%). Thus, shift acetoclastic methanogenesis SAO coupled hydrogenotrophic occurred as adaptive strategy overcome high (~200 mM) build-up. Bioaugmentation with effective mitigating butyrate-dominated VFA build-up during readily biodegradable waste, methane production rate, yield volatile solids removal more 3.5, 6.2 2.9 times, respectively. Our study revealed that consortia bioaugmented could be potential alleviate organic load stress AD.