Enhancement of anaerobic digestion performance of corn straw via combined sodium hydroxide-cellulase pretreatment

Effective pretreatment of corn straw is essential to improve its anaerobic digestion (AD), NaOH-cellulase pretreatment of corn straw may be effective in enhancing its AD at the theoretical level. In this study, the effects of NaOH-cellulase treatment on corn straw degradation rate and sugar yield were investigated. Moreover, the microstructure analysis of corn straw was performed to determine the treatment mechanism. Gas production, methane content, kinetic fitting, and stability of AD of corn straw were compared before and after pretreatment to determine the efficacy of NaOH-cellulase pretreatment. The results showed the highest straw degradation rate (230% higher than that of the control group) when hydrolyzed by 6.0% of NaOH as 0.10 g.g(-1) dry matter cellulase, and the biomethane content in corn straw pretreated with 6.0% of NaOH-elution-cellulase reached 70.1%. The biomethane yields of the corn straw after NaOH-elution-enzymatic hydrolysis using 4% of NaOH was 317 +/- 11 mL.g(-1) VS. The efficiency of AD after 4.0% of NaOH pretreatment was better than that after 6.0%-NaOH pretreatment, where the anaerobic system was more stable. In this study, NaOH-cellulase was used for the first time to pretreat corn straw, which effectively improved its AD.