Biochar facilitating methanogens evolution by enhancing extracellular electron transfer to boost anaerobic digestion of swine manure under ammonia stress - Raw data of bacteria

This study explored the mechanisms of biochar mitigating ammonia inhibition onanaerobic digestion (AD) of swine manure. 2-8g/L exogeneous ammonia dosagesgradually inhibited AD, which resulting in the efficiencies of hydrolysis, acidogenesisand methanogenesis declined by 3.4-70.8%, 6.0-82.0%, and 4.9-93.8%. Addingbiochar mitigated the inhibition, especially fulfilled methane production under 8g/Lexogenous ammonia addition. With biochar assistance, the microbial activities ofelectron transport system and extracellular electron transfer were enhanced, and themethanogen of Methanosarcina was primarily enriched. Meanwhile, biocharupregulated the genes encoding formylmethanofuran dehydrogenase andmethenyltetrahydromethanopterin cyclohydrolase for CO2-reducing methanogenesispathway by 26.9-40.8%. It was believed that biochar mediated direct interspecieselectron transfer between syntrophic partners to trigger methane production underammonia stress. Interestingly, as the acclimated microbial community established,removal biochar hardly depressed AD performances, addressing the key role ofbiochar for methanogen evolution to resist ammonia stress rather than anindispensable function when the evolution completed.