Analysis of the Changes in Physicochemical Properties and Microbial Communities During Fermentation of Sweet Fermented Rice

As a traditional rice wine, sweet fermented rice (SFR) is widely loved because of its unique flavor and high nutritional value. However, the physicochemical properties, microbial community composition, and metabolic pathway changes during the fermentation process of sweet wine have not been evaluated, and these changes can lead to unstable SFR quality. In this study, we used high-throughput sequencing technology to analyze and elucidate the dynamic changes in the microbial community, metabolic pathways, and carbohydrate enzyme functions in traditional SFR fermentation broth. The results revealed that Rhizopus abundance = 160,943.659 and Wickerhamomyces abundance = 241,660.954 were the predominant fungal genera in the fermentation process from the beginning (A0) to the end (A43) of SFR fermentation. The results of the diversity analysis revealed that the structure and composition of the microbial communities first increased but then decreased. Metabolic pathway analysis showed that energy production and conversion, carbohydrate transport, and amino acid transport were the most active metabolic pathways in fermentation. Moreover, the three primary functions of glycosyltransferases (GTs), glycoside hydrolases (GHs), and carbohydrate-binding modules (CBMs) in carbohydrate enzyme analysis were involved in the whole fermentation process. This study only provides some insight into the dynamic changes in the microbial population of SFR single samples prepared under fixed conditions. It provides a reference for optimizing the physicochemical properties of SFR fermentation broth, controlling the microbial community structure, optimizing fermentation conditions, and improving product quality.