Influence of culture conditions on glutathione production by Saccharomyces cerevisiae.

A strategy of experimental design using a fractional factorial design (FFD) and a central composite rotatable design (CCRD) were carried out with the aim to obtain the best conditions of temperature (20-30 degrees C), agitation rate (100-300 rpm), initial pH (5.0-7.0), inoculum concentration (5-15%), and glucose concentration (30-70 g/l) for glutathione (GSH) production in shake-flask culture by Saccharomyces cerevisiae ATCC 7754. By a FFD (2(5-2)), the agitation rate, temperature, and pH were found to be significant factors for GSH production. In CCRD (2(2)) was obtained a second-order model equation, and the percent of variation explained by the model was 95%. The results showed that the optimal culture conditions were agitation rate, 300 rpm; temperature, 20 degrees C; initial pH, 5; glucose, 54 g/l; and inoculum concentration, 5%. The highest GSH concentration (154.5 mg/l) was obtained after 72 h of fermentation.