Inoculating with the microbial agents to start up the aerobic composting of mushroom residue and wood chips at low temperature

Abstract

Aerobic composting of cellulosic biomass is difficult to start at low temperatures. Especially, the effect of microbial inoculants on the initiation of aerobic composting of cellulosic material at low temperature and the succession of microbial community is still poorly defined. In this study, the aerobic composting of mushroom residue and wood chips successfully started at 3–11 °C by inoculating the microbial agents (including bacteria and fungi) for cellulose degradation and low temperature adaptation. It was found that the inoculum was beneficial for the heating of the compost pile, starting of the aerobic composting process and the degradation of cellulose. The thermophilic stage of inoculation group lasted for 13 days and 8 days longer than that of control group. The degradation efficiencies of hemicellulose and cellulose in inoculation group and control group were 37.50% and 27.30%, while the degradation efficiencies of cellulose were 21.29% and 16.18%, respectively. Furthermore, the results of high-throughput sequencing revealed that inoculation of microbial agents was beneficial to the optimization of community structure and the conversion of cellulose substrate. In addition, the inoculated strains of Aspergillus, Penicillium, Bacillus and Streptomyces might play active roles in the composting process, especially in the set-up and thermophilic stage of the composting.