中国生物工程杂志

The zinc chloride and cystine resistant strain of S. cerevisiae YZM-14(ZnCL2r, Cysr) was screened with the mutant processing of the protoplast of S. cerevisiae by combinative mutagens of ultraviolet and nitrite. The glutathione (GSH) production (84.72 mg/L), dry cell weight (7.63 g/L) and the intracellular GSH content (11.10 mg/g) of the mutant strain were about 2.79, 1.63 and 1.71 times than that of the initial strain. The biosynthetic process of GSH was divided into three phases according to the time course of the specific cell growth rate and GSH yielding coefficient. In the second phase, the metabolic flux of the pentose phosphate pathway and the GSH precursors biosynthetic pathway of the mutant strain increased by 8.1%, compared with that of the initial strain. Furthermore, the metabolic flux of the organic acids secretion of the mutant strain decreased. Through these mechanisms, the utilization efficiency of the carbon sources was enhanced and high production of GSH was obtained.