Changes in microbial community and methanogenesis during high-solid anaerobic digestion of ensiled corn stover

The stability of corn stover high-solid anaerobic digestion is affected by the low efficiency of solid-liquid mass transfer while the total volatile fatty acids accumulation often occurs during the process leading to acidification of the system and influencing the functional anaerobic microbial community of the system. Therefore, the problems of slow start and unstable process often occurred. In this study, the effects of different leachate spraying working conditions on total volatile fatty acids and microbial community structure were studied. Three batch tests of three 45 L leach bed reactors (LBRs) were conducted with continuously domesticated leachate and operated at different process (total solids of 15–30%, spray time of 2–6 min and spray interval of 3–8 h) to determine the relative influence of biotic and abiotic factors on microbial community structure and methanogenesis. Consequently, that within a certain range of parameter setting, biotic effects please an important role than abiotic effects, revealing microbiological mediation of methanogenesis. Higher methane yield of 188.2 mL/g VS was obtained under the conditions of 30%TS, spray time of 4 min in the first two weeks and 2 min in the third week, and spray interval of 6 h. The sludge reacting for two months was used as inoculum. After two months’ cultivation, the seeding sludge became stability and increased activity, and the microbial colony richness and diversity tend to be stable regardless of the operational parameters. This study enriches the understandings of biotic and abiotic factors of microbial community structure and methanogenesis in high-solid anaerobic digestion.