How do fungal communities and their interaction with bacterial communities influence dissolved organic matter on the stability and safety of sludge compost?

This study was conducted to assess the effect of fungal communities and their interaction with bacterial communities on the dissolved organic matter (DOM) transformation for the stability and safety of sludge composting. The results showed that fungal community had strong shifts in diverse stages of sludge composting along with the changes of temperature. Correlation analysis demonstrated that fungal communities had significant connections with bacterial communities during composting but were not directly related to the indicators of phytotoxicity and maturity. Variance partitioning analysis suggested that the interactions of fungal and bacterial communities had the biggest contribution (49.75%) to composting stability and safety. Based on structural equation modeling, the possible way of fungal community participated in the transformation of DOM components and the formation of humic-like substances of DOM by interacting with bacterial community was proposed, which will provide important information for understanding the biotic interaction in composting and improving composting fermentation process.