Bacterial Communities and Prediction of Microbial Metabolic Pathway in Rice Wine Koji From Different Regions in China.

Xinxin Zhao,Xinquan Yang,Zhuang Guo,Qiangchuan Hou,Wenchao Cai,Fengxian Tang,Wen Song,Chunhui Shan,Fanshu Xiang

doi:10.3389/fmicb.2021.748779

Xinxin Zhao, Xinquan Yang + Show 7 more

Open Access

https://doi.org/10.3389/fmicb.2021.748779

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Abstract

Rice wine koji, a traditional homemade starter culture in China, is nutritious and delicious. The final quality of rice wine koji is closely related to the structure of its microbial community. However, the diversity of natural microorganisms in rice wine koji from different regions has not been evaluated. In this study, the microbial population of 92 naturally fermented rice koji samples collected from Hubei, Guangxi, and Sichuan was systematically analyzed by high-throughput sequencing. From all the rice wine koji samples, 22 phyla and 479 bacterial genera were identified. Weissella, Pediococcus, Lactobacillus, Enterobacter, Lactococcus, Pantoea, Bacillus, Staphylococcus, and Leuconostoc were the dominant genera in rice wine koji. The bacterial community structure of rice wine koji samples from different regions was significantly different (p < 0.05). The bacterial community composition of the samples from Hubei and Guangxi was similar, but significantly different from that of SC samples (p < 0.05). These differences may be caused by variations in geography, environment, or manufacturing. In addition, the results of microbial phenotype prediction by BugBase and bacterial functional potential prediction by PICRUSt showed that eight of the nine predicted phenotypic functions of rice wine koji samples from different regions were significantly different (p < 0.05) and that vigorous bacterial metabolism occurred in rice wine koji samples.

Highlights

Koji is produced by solid-state anaerobic fermentation in a specific ecological environment, using mature koji as the parent strain, and contains many microorganisms, including bacteria and fungi, which play a decisive role in the quality of rice wine
To further identify the key groups of microorganisms in rice wine koji samples from the three regions, we investigated the differences in bacterial flora among the GX, HB, and SC samples at the genus level and in the operational taxonomic units (OTUs)
We found that the overexpression of clusters of orthologous groups (COG) [C, O, and T] involved in cell movement may indicate the strengthening of nutritionseeking activity driven by microorganisms in rice wine koji samples, which may increase the signal sensing ability of microorganisms and enable them to make better use of nutrients

Summary

Introduction

Koji is produced by solid-state anaerobic fermentation in a specific ecological environment, using mature koji as the parent strain, and contains many microorganisms, including bacteria and fungi, which play a decisive role in the quality of rice wine. As a traditional starter culture, rice wine koji offers an excellent model to study the diversity of Bacterial Community Structure and Prediction environmental microorganisms and the regional sources of beneficial microorganisms (El Sheikha, 2018). The LAB bacteria resources contained within rice wine koji may be unique and diverse, with a richer and more complex microbial community than previously thought (Ray et al, 2014). To perform an extensive study of the similarity and difference in microbial composition among regions, find the distribution diversity of microorganisms determined by geography, and further select and apply beneficial microorganisms, we performed a comprehensive and systematic analysis of rice wine koji samples collected from three major producing areas in China (Hubei, Sichuan, and Guangxi), as determined by previous experiments

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