Global transcriptomic analysis of subsp ATCC11842 reveals the role of in the post-acidification of yogurt.

During the storage of yogurt, acid-resistant bacteria continue to produce lactic acid (, post-acidification process), leading to undesirable taste and flavor. Many methods have been proposed to inhibit post-acidification. However, the specific genes involved during this biological process have not yet been systematically studied. Hence, herein, we assessed the culture starter subsp. ATCC11842 with regards to its transcriptomes under acid- and cold-culture conditions. Through differential gene expression analysis, we screened out 69 candidate genes that persistently responded to acid with or without cold stress. qPCR was then used to determine the expression levels of these candidate genes at different stages of yogurt fermentation and storage. Genes whose expression levels did not change much from the end of fermentation to the early stage of yogurt storage were more likely to be post-acidification genes, as such stability indicated that they were not affected by cold stress. was determined to be one such gene; the overexpression of this gene showed that the increase of gene expression could reduce the acid production of the strain without affecting normal growth. Therefore, the genetic manipulation techniques that increased the expression level of the gene might have the potential to inhibit the post-acidification of yogurt. Thus, plays an important role in the post-acidification process and would become a new target for regulating yogurt post-acidification.