Abstract:Heyndrickxia coagulans characterized by low nutrient requirements, high titers of fermentation products, and thermal tolerance has become a major microbial species for lactic acid fermentation. We have demonstrated that phosphate stimulates the gene expression of l-lactate dehydrogenase in H. coagulans to increase l-lactic acid production, the mechanism of which, however, remains unknown. [Objective] To primarily investigated the mechanism of phosphate in stimulating the gene transcription of lactate dehydrogenase in H. coagulans. [Methods] RT-PCR was employed to analyze the transcriptional level changes of lactate dehydrogenase in H. coagulans after phosphate addition. The core promotor region responsive to phosphate stimulation was identified by conventional methods of molecular biology. [Results] The key element responsive to phosphate was located in the upstream promoter region of the l-lactate dehydrogenase gene. The core region of the promoter was responsible for phosphate stimulation. The identified promoter was employed to promote d-lactate production with diammonium phosphate addition. [Conclusion] This study reported a new phosphate-responsive gene element, providing a theoretical basis for improving the synthesis efficiency of other biochemicals.
