Glutathione improves the cold resistance of Lactobacillus sanfranciscensis by physiological regulation

The microenvironmental manipulation of glutathione (GSH) on improving cold resistance of Lactobacillus sanfranciscensis DSM 20451(T) was investigated in this study. It was proved that GSH relieves the metabolic disorder of cells under cold stress, and prevents the decreased activities of related key enzymes such as pyruvate kinase (PK), glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and lactate dehydrogenase (LDH) upon cold challenges. Higher intracellular ATP level was also found in cells with GSH under cold stress. Moreover, cells with imported GSH had significantly higher intracellular than the control during cold treatment. In addition, proteomics analysis showed more exciting findings that the protective function of GSH under cold stress was related to metabolic regulation and the multi-control against induced cross-stresses. These results broaden the knowledge about the physiological function of GSH, and suggest a practicable approach to improve the cold resistance of L. sanfranciscensis, a starter culture for sourdough, by the addition of GSH.