Roles of bacterial community in the transformation of dissolved organic matter for the stability and safety of material during sludge composting

This study was conducted to assess the roles of bacterial community in the dissolved organic matters (DOM) transformation during sludge composting. The relationship among the bacterial community, organic acids, diverse components of DOM as well as the indexes of the phytotoxin level and stability of materials was analyzed by regression and redundancy analysis. The results showed that there were significant correlations between the parameters for evaluating compost phytotoxicity and maturity including GI, C/N, SUVA(254), SUVA(280), E-253/203, and A(240-400), which led to a new index (PC1) by principal component analysis. PC1 was significantly affected by four components of DOM, acetic and tartaric acids that were correlated with the bacteria community shift, especially seven key bacteria. Based on structural equation modeling, the key bacteria with the ability to degrade tartaric acid exerted more important roles in regulating the transformation of DOM components, which was helpful for the stability and safety of compost.