Solid-State Co-digestion of NaOH-Pretreated Corn Straw and Chicken Manure Under Mesophilic Condition

Abstract

Solid-state anaerobic digestion is an attractive way to convert corn straw and chicken manure into bioenergy. This study investigated the performance of solid-state co-digestion of NaOH-pretreated corn straw and chicken manure at mixing ratios of 1:0, 3:1, 1:1, 1:3, and 0:1 under mesophilic (37 °C) condition. Additionally, high-throughput sequencing was used to analyze the microbial diversity and community structure. Results showed that synergistic effect was found when corn straw and chicken manure was mixed at 3:1, regardless pretreat or not. However, NaOH pretreatment showed no benefit for co-digestion of corn straw and chicken manure. The analysis of pH, total ammonia–nitrogen, total alkalinity, and volatile fatty acid also proved that NaOH pretreatment worked against the co-digestion. Through the analysis by high-throughput sequencing, the major microorganisms in co-digestion process were found to be Euryarchaeota, Bacteroidete, and Firmicutes. Co-digestion of corn straw and chicken manure could improve the microbial richness, while NaOH pretreatment worked against it. These results suggested that NaOH pretreatment was inappropriate for co-digestion of corn straw and chicken manure at 37 °C, while co-digestion was behaved like a good way to change the microbial community structure and improve anaerobic digestion efficiency.