Abstract：This study aimed to explore the potential of vermicomposts used as microbial fertilizer by analyzing their microbial communities using metagenomics. For this, the metagenomic sequences of 16S rDNA from three common vermicomposts of dewatered sludge, cow dung, and vegetable waste were annotated to distinguish bacterial species and function. The scaftigs of 117505, 81182, and 81104 were obtained in the vermicomposts of sludge, cow dung and vegetable waste, respectively. The dominant bacterial phyla in three vermicomposts were Proteobacteria, Bacteroidetes, Verruca, and Actinobacteria. The analysis of the metabolism pathway for nitrogen and phosphorus showed that Rhizobium, Mesorhizobium, Bradyrizobium, and Azospirillum were dominated as nitrogen fixing bacteria and Nitrosomonas, Nitrosospira, Nitrosoccus, and Nitrospira were predominated as nitrifying bacteria in the vermicomposts. Moreover, phosphate solubilizing bacteria were dominated by Flavobacterium, Pseudomonas, Arthrobacter, and Streptomyces. In contrast, the vermicompost of vegetable waste exhibited a higher potential as a microbial fertilizer. Compared with vegetable waste vermicompost (371Unigenes), the greater numbers of human pathogenic bacteria were detected in vermicomposts of sludge (2461Unigenes) and cow dung (965Unigenes). In addition, the relative abundances of antibiotic resistance genes from sludge, cow dung, and vegetable wastes were 0.93×10-3, 0.32×10-3, and 0.32×10-3, respectively, with the main types of antibiotic resistance belonging to β-lactams, aminoglycosides, macrolides, and tetracyclines. This study suggests that a great number of beneficial and harmful microorganisms are simultaneously inhabited in the vermicomposts, and thus the environmental risks of their biological pollutants deserve attention.
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