Abstract:In order to explore the microbial diversity and sugar metabolism process in pit mud of Chenggu Baijiu, traditional culture-dependent and high-throughput sequencing technology were used for analysis. The results showed that the bacteria in pit mud could be divided into 68 genera, and the core-microbiome were Petrimonas, Bacillus, Septinibacter and Clostridium. The fungi could be divided into 149 genera and the core-microbiome included Issatchenkia, Debaryomyces, Pichia and Aureobasidium. A total of 236 022 unigenes were annotated in KEGG database, with carbohydrate metabolism as the main metabolic activity and pyruvate metabolism as the most important process. The CAzY and COG databases annotated 23 functional categories and 210 major carbohydrate-active enzymes, respectively, among which the number of predicted proteins with unknown functions was the highest, followed by glycoside hydrolase and glycosyltransferase, accounting for 31% of the predicted protein sequence and 74% of the carbohydrate-active enzymes. In the sugar metabolism pathway, there were three different sugar transport protein systems with the key enzyme genes of phosphorylated sugars which could be converted sugars into intermediate products of glycolysis. Among them, there were 477 genes controlled by mannose transporter system, indicating the strongest ability to transport mannose. This study identified the dominant microbial community and related sugar metabolism pathway in pit mud of Chengguo Baijiu, providing a theoretical basis for improving the quality of Chenggu Baijiu.
