Abstract: In order to explore the effects of adding Ureibacillus suwonensis E11 on the performance of methane production during thermophilic (55 ℃) anaerobic digestion of food waste, and optimize the experimental conditions for bioaugmentation. A 5 L continuous stirring anaerobic reactor was used in this study with kitchen waste as substrate long-term acclimated high-temperature anaerobic sludge as inoculum. By changing the microbial addition amount (0, 5%, 10%, 15%, 20%), the methanogenic performance of high-temperature anaerobic digestion was compared, the enhancement effect was evaluated, the optimal addition dose was determined, and the mechanism of bioenhancement was revealed by combining metagenomic data. The results showed that compared to the control group without the addition of functional microorganisms, all bioaugmentation groups exhibited a significant increase in methane production. The optimal addition rate of functional microorganisms was 15%, and under this condition, the cumulative methane production (measured as VS) in the bioaugmentation group (575.14 mL/g) was 27.00% higher than that in the control group (452.86 mL/g). Bioaugmentation could improve the utilization efficiency of acetic acid to a certain extent. Analysis of the microbial community structure revealed that bioaugmentation promoted the methane production during thermophilic anaerobic digestion of food waste by increasing the relative abundance of several key hydrolytic bacteria and the hydrogenotrophic methanogen Methanoculleus.

Key words: food waste, thermophilic anaerobic digestion, bioaugmentation, metagenome