Effect of Pretreatment by Freeze Vacuum Drying on Solid-State Anaerobic Digestion of Corn Straw

As a common agricultural waste, corn straw (CS) has refractory structure, which is not conducive to anaerobic digestion (AD). Appropriate pretreatment crucial for addressing this problem. Thus, freeze vacuum drying (FVD) was proposed. In study, fresh CS (F-CS) pretreated (5 h, ?40 °C) by FVD and naturally dried (D-CS) were compared. Differences in substrate surface structure nutrient composition first investigated. Results show that loose porous crystallinity, broken chemical bonds, as well higher proportions of VS, C, N, cellulose, hemicellulose, crude proteins F-CS potential methane production. Besides, process performance stability also examined both high (4, VS basis) low (1, S/I ratio AD. A degradation hemicellulose richer dissolved microbial metabolites, coenzymes, tyrosine-like proteins, hydrolysis rate particulate organic matter the system enhanced efficiency conversion. The cumulative yield increased from 169.66 209.97 mL/gVS (p = 0.02 < 0.05), 156.97 171.89 system. Additionally, 16S-rRNA-gene-based analysis performed. Interestingly, coordination key bacteria (Clostridium_sensu_stricto_1, Bacillus, Terrisporobacter, Clostridium_sensu_stricto_7, Thermoclostrium, UCG-012, HN-HF0106) more active. Poorer Methanosarcina Methanomassiliicoccus Methanobrevibacter Methanoculleus stimulated co-relationship archaea with diverse methanogenesis pathways. This study aims verify positive effect on AD CS, so provide reference applications waste management.