Bioaugmentation strategies for methane production from digestate-alkali pretreated biomass via anaerobic digestion

Sustainable management of agricultural and livestock wastes remains a major challenge in promoting the circular economy. In this study, a bioaugmentation strategy was applied to enhance methane production during the anaerobic digestion of lignocellulosic biomass. Under optimized conditions-including total solids content, pretreatment type, and inoculum source-the biogas yield and methane content reached 425 mL and 3.30%, respectively. Microbial community analysis indicated that Bacteroidota, Firmicutes, and Proteobacteria were the dominant phyla during anaerobic digestion, while the relative abundance of Methanocorpusculum increased steadily throughout the process. The anaerobic digestion performance of corn stover was further improved through the combined application of biostimulation and bioaugmentation, resulting in a methane content of 5.37%. Moreover, exogenous inoculation with genetically modified Trichoderma reesei SEU-7 and the methanogen Methanosarcina barkeri increased the biogas yield and methane content to 970 mL and 8.95%, respectively. Overall, these results demonstrate that rational optimization of anaerobic digestion parameters and microbial consortia can substantially enhance biomass degradation and bioconversion efficiency.