Multi-omics reveal the structure and function of microbial community in co-digestion of corn straw and pig manure

Metagenomic sequencing, basing on whole genomic analysis, was carried out to explain the taxonomic and functional patterns of microbial communities in co-digestion and mono-digestions with corn straw and pig manure. Bacteroides graminisolvens and Clostridium stercorarium, the dominant species for corn straw degradation, and Proteiniphilum acetatigenes, emphasizing on protein decomposition, performed the optimum abundance during the co-digestion to improve efficiency of substrate decomposition. Methanosaeta concilii was the richest species during the process of bio-methane production, whose quantity and status in co-digestion were better than in mono-digestion. Analysis of functional patterns indicated that the carbohydrate-active enzymes in co-digestion were sustained abundant resulting short lag time, and the abundance of enzymes involving in methanogenesis were extremely high in co-digestion indicating the active methane metabolism. An adequate understanding of taxonomic and functional patterns further revealed the mechanism of rapid startup and superb methane production in co-digestion.