Abstract: This study aimed to analyze the effect of Issatchenkia orientalis on the microbial community structure and volatile flavor substance synthesis in Nongxiangxing Baijiu Jiupei in order to explore its effect on the microbial interaction and metabolism in the Jiupei. Under laboratory conditions, the microbial system for Nongxiangxing Baijiu brewing consisting of the Jiupei and Huangshui, a by-product of Baijiu brewing, was fermented directly (control group) or after inoculation with a strain of I. orientalis isolated from the Jiupei (experimental group). The composition of microbial communities, microbial interactions, and volatile flavor substances in the 2 groups were analyzed. The results showed that the microbial abundance of Jiupei changed after inoculation with I. orientalis; the relative abundance of Lactobacillus and Issatchenkia increased, and the relative abundance of Paenibacillus and Aspergillus decreased. Moreover, the microbial interaction was strengthened, making the microbial network structure more complex and compact. Compared with the control group, the volatile flavor substances in the experimental group increased significantly, 20 significantly differential volatile flavor substances were identified, and the contents of isopropanol, isoamylol and isobutanol increased significantly. The results of this study disclose the influences of inoculating I. orientalis on the microbial community structure and volatile flavor substances in Nongxiangxing Baijiu Jiupei and help to understand the impact of functional microorganisms on the microbial perturbation and metabolite synthesis in Jiupei.

Key words: Jiupei; Issatchenkia orientalis; microbial community; volatile flavor substances; correlation analysis