Metagenomic analysis of key methanogenic pathways in solid-state anaerobic co-fermentation of weathered coal and cattle manure

This research leveraged metagenomic sequencing to assess microbial diversity and functional activity structures during solid-state anaerobic co-fermentation of cattle manure with weathered coal, aiming to evaluate key metabolic pathways. Results demonstrated that anaerobic co-fermentation significantly enhanced biomethane production, concomitant with substantial upregulation of carbohydrate-active enzymes including cellobiose phosphorylase (GH94), glycosyltransferase (GT4), and glycoside hydrolase (GH18). The process reinforced microbial interspecies electron transfer through enrichment of 2-oxoglutarate/2-oxoacid ferredoxin oxidoreductase subunit α, pyruvate ferredoxin oxidoreductase α subunit, and methyl-coenzyme M reductase β subunit, while glucose-6-phosphate isomerase and fructose-1,6-bisphosphatase II played pivotal roles in cellulose degradation within mixed substrates. Combined Solid-state anaerobic co-fermentation was dominated by methane production from the acetyl fragmentation pathway, and that the two synergistically promoted the CO₂ reduction pathway. This study provides a mechanistic study for the treatment of weathered coal and cattle manure, which provides new ideas for solid waste treatment and clean energy.