Detecting source of p-cresol in strong flavor Chinese liquor by high throughput sequencing

Abstract:

[Objective] The aims of this study were to detect the source of p-cresol in strong flavor Chinese liquor; analyze the microbial community structure in pit mud, and separate strains producing p-cresol. [Methods] p-Cresol concentration in Daqu, pit mud and saccharogenic grains was detected by GC-MS. Microbial communities of different parts of pit muds were detected by highthroughput sequencing technology. Then strains that could produce p-cresol were separated. [Results] p-Cresol was only detected in pit mud, not in Daqu or saccharogenic grains. The concentration was 24.24 μg/g in bottom part of pit mud. The microbes mainly belonged to 8 classes in pit mud. Among them, Bacteroidia, Clostridia and Methanobacteria were all higher than 8%. The microbes mainly belonged to 11 genus, Clostridium, Aminobacterium, Methanobacterium, Methanobrevibacter, etc. After strains separation and volatile compounds detection, Clostridium aminovalericum, Clostridium ultunense and Clostridium purinilyticum could produce p-cresol, and were all higher than 0.20% in pit mud. [Conclusion] Clostridium was the primary microbial source of p-cresol.

Key words:p-cresol, pit mud, Clostridium, flavor, Chinese liquor