Effects of microbial inoculum on microbial community and enzyme activity involved in nitrogen-sulfur metabolism during sewage sludge composting

The purpose of this study was to access the effects of thermotolerant nitrifying microorganisms and sulfur-oxidizing bacteria on microbial community and enzyme activity involved in nitrogen-sulfur metabolism during laboratory -scale sewage sludge (SS) composting,and to do a microbial-environmental factor association analysis to promote composting key species for nitrogen-sulfur transformation in the body. The microbial community structure and the ac-tivities variation of six key enzyme involved were detected. The microbial inocula added had little impact on the di-versity of the microbial community but changed its succession direction, and the abundance of Actinobacteria was decreased obviously of inoculation treatment (TR). The three dominant genera and indicator species in TR were signif-icantly correlated with the conversion of nitrogen and sulfur. The addition of microbial inocula promoted the conver-sion of nitrogen and sulfur in SS compost, and increased the activities of the key enzymes and the microbial genera involved in nitrogen-sulfur conversion. In other words, the nitrification and sulfur oxidation were enhanced simulta-neously in the later stage of composting in TR.

Automated summary

The purpose of this study was to assess the effects of thermotolerant nitrifying microorganisms and sulfur-oxidizing bacteria on the microbial community and enzyme activity involved in nitrogen-sulfur metabolism during sewage sludge composting. The results showed that the microbial inocula had little impact on the diversity of the microbial community but changed its succession direction, and decreased the abundance of Actinobacteria. The addition of microbial inocula promoted the conversion of nitrogen and sulfur in the compost and increased the activities of key enzymes and microbial genera involved in nitrogen-sulfur conversion.