Effects of earthworms on physicochemical properties and microbial profiles during vermicomposting of fresh fruit and vegetable wastes

• The investigation of fresh FVW decomposed by earthworms was carried out.
• Vermicomposting resulted in rapid losses of total carbon and nitrogen of fresh FVW.
• A greater volume of leachate was collected from earthworms’ reactors.
• Earthworms promoted changes of bacterial and fungal densities and communities.

This study aimed to investigate the effect of earthworms on physicochemical and microbial properties during vermicomposting of fresh fruit and vegetable wastes (FVW) by contrasting two decomposing systems of FVW with and without earthworms for 5 weeks. Compared to control treatment (without earthworms), vermicomposting treatment resulted in a rapid decrease of electrical conductivity and losses of total carbon and nitrogen from the 2nd week. Quantitative PCR displayed that earthworms markedly enhanced bacterial and fungal densities, showing the higher values than control, during the whole decomposition process. In addition, denaturing gradient gel electrophoresis combined with sequencing analysis revealed that earthworms pronouncedly modified bacterial and fungal community structures, through broadening the community diversities of Actinobacteria, Bacteroidetes, Proteobacteria, and Ascomycotina. These results suggest that the presence of earthworms promoted the activity and population of bacteria and fungi, and modified their communities, thus altering the decomposition pathway of fresh FVW.