Effects of stirring time on anaerobic digestion of cattle manure-corn stover: Microbial diversity and metabolic pathways

This study optimized the stirring time of cattle manure (CM)-corn stover (CS) co-digestion to improve Anaerobic digestion (AD) performance. The results showed that the experimental (T2) with the optimum stirring time (15 min/h) determined by computational fluid dynamics (CFD) simulation achieved the highest cumulative methane yield of 224.17 mL/g. Compared to continuous stirring (T1, 60 min/h) and intermittent stirring (T3, 5 min/h), T2 increased the cumulative methane yield by 18.65 % and 7.11 %, respectively. Additionally, microbial community analysis indicated that the relative abundance of the predominant methanogen Methanosarcina in T2 was increased by 9.56 % and 26.14 % compared to T1 and T3, respectively. Functional prediction by PICRUSt2 revealed that T2 enhanced the hydrogenotrophic methanogenesis pathway, which played a major role in the methanogenesis pathway. In summary, this study provides insights for optimizing the stirring time of AD and plays an important role in improving the methane yield efficiency and reducing energy consumption of biogas projects.