earticle

영어

Leuconostoc is a major lactic acid bacterium that produces D-lactate in fermented foods. Excessive dietary intake of D-lactate may cause metabolic stress in both infants and patients. Introduction of ldhL gene from Lb. plantarum into Leuconostoc citreum did not significantly shift D-lactate to L-lactate due to low L-LDH activity. To elevate the expression level of ldhL so that significantly alter D-/L-lactate ratio, nucleotides for pyruvate kinase promoter were fused to ldhL and cloned with pLeuCM42 to construct pLC42pkL. Introduction of pLC42pkL in L. mesenteroides subsp. mesenteroides ATCC8293 significantly improved both L-LDH activity and L-lactate productivity during MRS fermentation so that D-/L-lactate ratio was altered significantly. These results indicated that the enhanced L-LDH activity and L-lactate synthesis contributed to the active promoter of native pyruvate kinase and appropriate delivery vector of pLeuCM42. The resulting construct of actively expressing ldhL will further effectively applied in fermented foods. Furthermore, this work provides evidence that expression of other heterologous genes may facilitate the production of useful proteins in these economically important bacteria.