Production of yeast biomass with elevated content of glutathione

Abstract

Research on biosynthesis of glutathione (GSH) by yeast Saccharomyces cerevisiae was undertaken with the aim of achieving high content of this compound intracellularly. The effect of GSH-amino-acids free and GSH-amino-acids enriched media added alone or in combination at different concentrations were examined. Furthermore, the combined effect of carbon and sulphur were also investigated. Cultivations were performed in shake-flasks at 28°C for 24-48 h in a synthetic medium with saccharose and ammonium sulphate as the sources of carbon and sulphur. The strain Saccharomyces cerevisiae cultured in GSH-amino-acids enriched media accumulated about 11-20 mg GSH/g d:ry biomass and the content of biomass was 6.5-12.5 g dry biomass/dm3 after 24 h of cultivation. Cysteine added alone to the medium was confirmed as the key amino-acid responsible for the increased biosynthesis of GSH in the yeast cell. In addition, increase in the sulphur content exerted a marked positive effect on its biosynthesis