A new strategy to enhance glutathione production by multiple H 2O 2-induced oxidative stresses in Candida utilis

Abstract

Effect of H 2O 2-induced oxidative stress on glutathione (GSH) production in Candida utilis was investigated. Based on the results that H 2O 2 can effectively stimulate GSH accumulation but inhibit cell growth simultaneously, a novel strategy of multiple H 2O 2 stresses with different concentrations (1 mmol/L at 4 h, 2 mmol/L at 8 h, and 4 mmol/L at 12 h) were developed to maximize GSH production. As a result, a maximal GSH yield of 218 mg/L was achieved and a corresponding intracellular GSH content was 2.15%, which were 54.6% and 58.1% higher than the control. By further applying this strategy to 7 L fermentor, GSH yield and intracellular GSH content were 328 mg/L and 2.30%. Moreover, increased activities of catalase (CAT) and GSH reductase (GR) indicated that GSH and CAT were directly involved in protecting cell against oxidative stress by H 2O 2.