Metagenomics of Virus Diversities in Solid-State Brewing Process of Traditional Chinese Vinegar

Traditional Chinese vinegar offers an exceptional flavor and rich nutrients due to its unique solid-state fermentation process, which is a multiple microbial fermentation system including various bacteria, fungi and viruses. However, few studies on the virus diversities in traditional Chinese vinegar have been reported. In this paper, using Zhenjiang aromatic vinegar as a model system, we systemically explored the viral communities in the solid-state brewing process of traditional Chinese vinegar using bacterial and viral metagenomes. Results showed that the viral diversity in vinegar Pei was extensive and the virus communities varied along with the fermentation process. In addition, there existed some interactions between viral and bacterial communities. Moreover, abundant antibiotic resistance genes were found in viromes, indicating that viruses might protect fermentation bacteria strains from the stress of antibiotics in the fermentation environment. Remarkably, we identified abundant auxiliary carbohydrate metabolic genes (including alcohol oxidases, the key enzymes for acetic acid synthesis) from viromes, implying that viruses might participate in the acetic acid synthesis progress of the host through auxiliary metabolic genes. Taken together, our results indicated the potential roles of viruses in the vinegar brewing process and provided a new perspective for studying the fermentation mechanisms of traditional Chinese vinegar.