[Using transporter to enhance the acid tolerance of DSM1].

As the precursor of polylactic acid (PLA), optically pure l-lactic acid production is attracting increasing attention. The accumulation of lactic acid during fermentation inhibits strain growth. Therefore, it is necessary to improve the acid tolerance of lactic acid producers. In this study, comparative transcriptomic analysis was performed to investigate the effects of transporters on lactic acid tolerance of DSM1, which is an l-lactic acid producer. The genes with more than two-fold up-regulation in transcriptional profile were further verified using real-time PCR. The transcriptional levels of , , , , , and were enhanced during lactic acid fermentation. Strain overexpressing exhibited a retarded cell growth and low lactic acid production at pH 6.0, but an improved lactic acid production at pH 4.6. This study may facilitate the investigation of the acid tolerance mechanism in DSM1, as well as the construction of efficient lactic acid producers.