Changes in structure and function of bacterial and fungal communities in open composting of Chinese herb residues

In this study, dynamic changes in bacterial and fungal communities, metabolic characteristics, and trophic modes in Chinese herb residues open composting for 30 days were analyzed by using high-throughput sequencing, PICRUSt, and FUNGuild, respectively. Bacillaceae and Basidiomycota predominated at the early composting stage, while Proteobacteria and Ascomycota became the dominant phyla during the active phase. Aerobic composting had a significant effect on bacterial metabolic characteristics and fungal trophic modes over the composting time. The function of the bacterial communities changed from environmental information processing to metabolism. Fungal communities changed as well, with the pathogenic fungi decreasing and wood saprotrophs increasing. These results indicated that open composting of Chinese herb residues not only influenced microbial community structure but also changed metabolic characteristics and trophic modes, which became the internal dynamics of composting.