Enhancing anaerobic methane production from corn straw: Promoting lignocellulosic biomass biodegradation via aeration in liquid fraction of digestate for green and efficient pretreatment

The recalcitrant lignocellulosic structure of corn straw severely limits its anaerobic bioconversion efficiency, despite its potential as a renewable carbon source for biogas production. In this study, a green, efficient, and cost-effective tactic was creatively proposed so that the aerated liquid fraction of digestate (aerated-LFD) could be employed to pretreat corn straw. The influence of aerated-LFD post different aeration intervals (10 min, 60 min, 120 min) and aerated-LFD without aeration on the biomethane production of corn straw were compared. The results show that the lignocellulosic array structure was disrupted, promoting microbial attachment and releasing soluble organic matter crucial for methane production. Methane production performance was better in all aerated-LFD groups than in the liquid fraction of digestate (LFD) and control group. The methane production of corn straw pretreated by 120 min aerated-LFD was the highest, which was 198.23 mL/g_VS, 40.05 % higher than the untreated corn straw, together with a 67 % lag time reduction. The coupling model could well explain the kinetic behavior during anaerobic digestion of corn straw. These findings highlight the potential of aerated-LFD pretreatment as a sustainable bioenergy production strategy, offering insights into meeting energy needs while mitigating environmental impacts.