[Glutathione plays an anti-oxidant role in Lactococcus lactis].

To assess the physiological function of GSH in resistance to oxidative stress in Lactococcus lactis ssp. cremoris NZ9000, the recombinant strain NZ9000 (pNZ3203) capable of producing GSH was used as the experiment materials. The anti-oxidant role of glutathione was observed under higher H2O2 dosage, i.e., 150 mmol/L H2O2 treatment for 15 min. The resistance of NZ9000 (pNZ3203) cells grown for 3 h, 5 h, and 7 h (nisin-induced for 1 h, 3 h and 5 h) were 1.8-fold, 2.6-fold, and 2.9-fold that of NZ9000 (pNZ8148) cells, respectively. In addition, the survival of NZ9000 (pNZ3203) cells grown for 5 h (nisin-induced for 3 h), upon treatment of 20 mmol/L menadione for 60 min, was 6.2-fold that of NZ9000 (pN8148) cells. Therefore, introduction a new biosynthetic pathway of glutathione could confer higher resistance to oxidative stress on L. lactis NZ9000.