Dual role of multistage inoculation in manipulating bacterial community assembly patterns to improve degradation of lignocellulose during rice or corn straw composting

The degradation of lignocellulose in rice and corn straw during multistage inoculation composting was investigated, especially to reveal the strategies of functional bacterial interactions with indigenous bacteria driving lignocellulose degradation in different materials composting. Compared with the control, multistage inoculation significantly increased the degradation rate of lignocellulose, and corn straw (MS+) was preferred to rice straw (RS+) composting. The characterization and assembly mechanisms of bacterial communities were analyzed by sparse correlation networks and null models. Bacterial network stability and diversity were increased by inoculation in RS+, but the results were opposite in MS+. Inoculants via the increased dispersal limitation (DL, 41 % to 54 %) and decreased homogeneous selection (HoS, 39 % to 24 %) to impact complexity of community structure in MS+. This study revealed that inoculants in RS+ as regulators cooperated with indigenous bacteria to accelerate lignocellulose degradation. In contrast, inoculants in MS+ as competitors competed with indigenous bacteria for lignocellulose resources to enhance degradation. These findings contribute to the understanding of the assembly process and interactions between functional inoculants and indigenous bacteria in different straw composting, offering new insights into the microbial mode of action for lignocellulose degradation.