We report a method for suppression of lactate production by lactic acid bacteria (LAB) in culture. LAB produce lactate to regenerate NAD⁺ that is consumed during glycolysis. Glucose suppresses NAD⁺ regeneration pathways other than lactate dehydrogenase and non-glycolytic ATP production pathways. Therefore, the carbon source was changed to sucrose, and fed-batch culture was performed to limit the glycolytic flux and thus suppress lactate production. As a result, lactate productivity (i.e., the amount of lactate produced per amount of grown cell) in the sucrose/fed-batch culture was decreased compared to that in glucose/batch culture, in all five LAB strains examined. The productivity level decreased to 24% and 46% in Lactobacillus reuteri JCM 1112 and Lactococcus lactis JCM 7638, respectively. Metabolic flux analysis of Lactobacillus reuteri JCM 1112 revealed increased contributions of the mannitol production pathway to NAD⁺ regeneration and the arginine deiminase pathway to ATP production in the sucrose/fed-batch culture.

我们报告了一种抑制乳酸菌（LAB）在培养物中产生乳酸的方法。LAB产生乳酸以再生糖酵解过程中消耗的NAD ⁺。葡萄糖除了抑制乳酸脱氢酶和非糖酵解ATP产生途径外，还抑制NAD ⁺再生途径。因此，将碳源改变为蔗糖，并进行分批补料培养以限制糖酵解通量，从而抑制乳酸的产生。结果，在所有所检查的五个LAB菌株中，与葡萄糖/分批培养相比，蔗糖/分批培养中的乳酸生产率（即，每生长的细胞产生的乳酸量）降低。生产力水平降低至24％和46％在罗伊氏乳杆菌JCM 1112和乳酸乳球菌分别为JCM 7638。罗伊氏乳杆菌JCM 1112的代谢通量分析显示，蔗糖/分批培养中甘露醇生产途径对NAD ⁺再生的贡献增加，精氨酸脱亚氨酶途径对ATP产生的贡献增加。