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Natural freezing-thawing pretreatment of corn stalk for enhancing anaerobic digestion performance

Li, Juan, Wachemo, Akiber Chufo, Yuan, Hairong, Zuo, Xiaoyu, Li, Xiujin
Bioresource technology 2019 v.288 pp. 121518
Methanobacterium, anaerobic digestion, biogas, biotransformation, corn stover, energy, freeze-thaw cycles, methane, winter
Natural freezing-thawing (NFT) was proposed as a low energy input and alternative pretreatment method for high biomethane production from corn stalk (CS) by anaerobic digestion (AD). The CS was pretreated by freezing-thawing in winter season using different pretreatment time periods (7d, 14d, 21d and 28d) and solid-to-liquid ratios (1:2, 1:4, 1:6, 1:8 and 1:10). The results showed that CS pretreated for 21d coupled with a solid-to-liquid ratio of 1:6 achieved the best result among all pretreatment conditions. In this case, the biomethane yield and VS removal rate of CS reached the highest values of 253 mL·gvs−1 and 58.6%, respectively, which were 40.5% and 27.4% higher than that of the untreated. It was also found that the predominant bacterial and archaeal at genus level in AD were Clostridium_sensu_stricto_1 (36.1%) and Methanobacterium (54.0%), respectively. This study provided that NFT is a simple pretreatment strategy for efficient AD bioconversion of CS to biomethane.