Determination of Optimum Conditions for Ergosterol Production by Saccharomyces cerevisiae

Ergosterol is an important provitamin in the present-day of industrial biotechnology. Seven yeast strains were obtained from the market of Basrah city and subjected to screening for their ergosterol production ability using liquid-state fermentation, the cultural conditions, and nutritional requirements for optimal production of ergosterol by Saccharomyces cerevisiae under laboratory conditions were determined. Y.6 is the best isolate of the yeast that produced ergosterol. It was identified as S. cerevisiae, with a similarity rate of 97% by using the Vitek2 device, this S. cerevisiae (Y.6) was further subjected to optimization conditions. The results showed that the best medium for production was yeast extract peptone dextrose broth. The effect of two cheaper carbon sources, molasses and date juice were investigated. Maximum ergosterol (0.55% ) was produced using a medium containing date juice, with a replacement ratio of 75%, an incubation time of 72 hours, pH 5, at a temperature of 30 °C, and an inoculation volume of 4 ml. The percentage of ergosterol was (0.47, 0.55, 0.74, 0.66, 0.68 and 0.78 %), respectively.