The gene expression profile of Bacillus subtilis response to the high-temperature fermentation

High-temperature fermentation of the Bacillus subtilis isolated from the black part of maotai Daqu. Studying on the gene expression profile using microarray for analyzing the connection between metabolites and the maotai flavor substances. 84 differential expressed genes were obtained, including 40 up-regulated genes and 44 down-regulated genes.The differentially expressed genes involved in the metabolic pathways were just only KBL (glycine C - acetyltransferase) and ripA (bifunctional 3, 4 - dihydroxy - 4-2 - butanone phosphate synthase), up-regulated 2.9 and 2.9 times respectively, and their catalytic reaction prodction of aminobutyric acid and dihydroxy ethyl ketone phosphate, respectively. They may be further derived into alcohol and ketone flavoring substances. However, a large number of differential expressed genes was related to sporulation, such as ybaN (polysaccharide deacetylase) and rapA (aspartic acid phosphatase), they were up-regulated 17.5 times and down-regulated 112.5 times. YbaN is closely related to the formation of spore cortex and high temperature group spore cortex obvious thickening by TEM. RapA is signaling molecules to restrain spore formation, its lower expression can promote the sporulation in group A. Formation and release of peptidoglycan and the DPA (2, 6 - Pyridinedicarboxylic acid) of spore cortex during theseveral rounds of low temperature to high temperature circulation fermentation may be the main source of furan and pyranand nitrogen heterocyclic compounds in maotai flavor substances . In this paper, the formation of high-temperature fermentation Bacillus subtilis spores is closely related to the generation of maotai flavor substances. There are total of eight samples. It divided two groups, set as group A (High temperature fermentation) and B (normal temperature fermentation, continuous 37C). There are four replicates for each group.