The effect of pH on glutathione production was investigated in batch culture of Candida utilis SZU 07-01 in this study

pH3.5 and pH1.5 were determined as mild acid stress and severe acid stress conditions

respectively

based on analyzing and comparing the process parameters. Optimal time of 6 h and 2 h for mild acid stress of pH3. 5 and severe acid stress of pH1. 5 were then chosen for glutathione overproduction

respectively

during continuous culture of C.utilis SZU 07-01 in a chemostat.  Furthermore

C.utilis SZU 07-01 was cultured under batch culture with glucose feeding and acid stress

it was found that mild acid stress for 6 h was more advantageous to glutathione overproduction than severe acid stress for 2 h and no acid stress. In the end

the mechanisms of glutathione overproduction by mild acid stress were quantitatively interpreted by comparison of parameters obtained from batch fermentation kinetics

intracellular cofactors as NADH and ATP

together with the distribution of flux on key metabolites within glutathione biosynthesis.