The history of soy sauce started from 2000 years ago during the Western Han Dynasty of China. Nowadays, soy sauce becomes a popular food worldwide. Most sauce manufacturing processes share a common principle including four main steps: preparation of raw materials, koji-making, mash fermentation, and sauce extraction. The microbial community in soy sauce and the enzyme activities are considered to be important for soy sauce flavor, taste, and color. However, how the microbial community changes and influence soy sauce flavors during fermentation is still unclear. Here, soy sauce of black soybean was made simultaneously in laboratory and factory. Samples were taken and investigated by 16S Metagenomics to elucidate the difference of the microbial composition from soy sauce made in different environments. Also, the changes of soy sauce microbiome during 6-month fermentation were monitored. Various bacterial genera such as Bacillus, Staphylococcus, Enterococcus, Lactococcus and fungal genera Aspergillus, Rhizopus, Penicillium have discovered. The comparison between laboratory fermentation and factory fermentation in different time points suggested that microbial communities are not similar in different fermentation conditions. In factory samples, Bacillus was predominant during the fermentation process. All laboratory samples contained Enterococcus, Lactococcus (LAB) contributed 36.89% of the population through the fermentation process. In conclusions, during the fermentation process, microorganisms affect the quality of soy sauce by their enzyme activities, and these enzyme activities transform to volatile fatty acids and aromatic compounds, which is contributed to the favor of final product.

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