The temporal profile of GH 1 gene abundance and the shift in GH 1 cellulase-producing microbial communities during vermicomposting of corn stover and cow dung

Vermicomposting is a promising method for corn stover management to achieve bioresource recovery and environmental protection. Most β-glucosidases, which limit the cellulose degradation rate during vermicomposting of corn stover, belong to glycoside hydrolase family 1 (GH 1 ). This study was conducted with different earthworm densities to quantify the GH 1 gene abundance and investigate the evolution of GH 1 cellulase-producing microbial communities using qPCR and pyrosequencing. The results showed that β-glucosidase activity, GH 1 gene abundance, TOC, and microbial communities carrying the GH 1 gene were affected by processing time and earthworm density. After introducing earthworms, β-glucosidase activity increased to 1.90–2.13 U/g from 0.54 U/g. The GH 1 gene abundance of treatments with earthworms (5.82E+09–6.70E+09 copies/g) was significantly higher than that of treatments without earthworms (2.48E+09 copies/g) on Day 45. Earthworms increased the richness of microbial communities. The relative abundances of Sphingobium and Dyadobacter , which are dominant genera harboring the GH 1 gene, were increased by earthworms to peak values of 23.90% and 11.20%, respectively. Correlation analysis showed that Sphingobium , Dyadobacter , Trichoderma , and Starkeya were positively associated with β-glucosidases. This work sheds new light on the mechanism of cellulose degradation during vermicomposting at the molecular level.