Moderate acid stress improves the performance of selenium-enriched Candida utilis and its related mechanism

The capacities of selenium enrichment and glutathione biosynthesis as well as antioxidant properties of a sodium selenite-resisting Candida utilis Se-1301 were investigated in this study. The results illustrated that the highest intracellular organic selenium and glutathione contents of 1.08 mg/g and 18.48 mg/g,respectively,were obtained under a moderate acid stress environment(p H3.5). After assaying the activities of intracellularγ-glutamylcysteine synthetase,catalase and superoxide dismutase,together with determining the intracellular malondialdehyde content,the moderate acid stress was found to be not only favored to improve the ability of glutathione biosynthesis,but also helped to increase the antioxidant capacity of the yeast. The results provided a feasible route for efficient preparation of selenium-enriched Candida utilis with high performance.