Evaluation of Glutathione Production Method using Saccharomyces cerevisiae

Abstract

Industrial interest of glutathione, as a pure substance or accumulated in yeast, has been prominent as a result of various applications of glutathione in food and pharmaceutical industries. Glutathione production by fermentation process is easier and more economical compare to production by chemical and enzymatic reaction. This study aims to evaluate environmental condition to the fermentation process producing glutathione in three different strategies. In the following work, stress conditions and cysteine addition coupled with fed-batch fermentation of Saccharomyces cerevisiae ITBCC R58 for glutathione accumulation have been investigated. Stress conditions applied on this study included temperature shift from 30 to 50°C and 27°C, pH shift from 5 to 1.2 and 8.8, and osmotic stress by addition NaCl to the solution. Another strategy was to add cysteine as one of glutathione precursors into the fermentation medium. Later, the oxidative state of glutathione harvested was also checked. Osmotic stress showed the best result amongst stress variations applied on this work, however combined cysteine addition with fed-batch fermentation stood out as the best strategy in this study. In all experiments, oxidized-state glutathione was identified, indicating the need of a specific method development to harvest glutathione in reduced state.