Influence of different fermentation parameters on glutathione volumetric productivity by Saccharomyces cerevisiae

A full factorial experimental design was carried out, with the aim of combining the best fermentation conditions for S. cerevisiae cell growth, with the most important parameters affecting glutathione GSH intracellular accumulation. Conditions favouring cell growth (max. 10.5 g dw/l) were identified as (g/l) beet molasses 80, ammonium sulphate 1, magnesium sulphate 0.2, and temperature 30 °C. These results were in contrast to what found to enhance GSH intracellular levels (max. 1.85% dw), identified as (g/l) molasses 20, ammonium sulphate 5, magnesium sulphate 1.2, temperature 24 °C. By calculating GSH volumetric productivity (mg/l day), it was possible to evidence the best conditions (GSH max. 81 mg/l day) allowing cell growth to be maximised, 80 g/l (high level) molasses and 1 g/l (low level) ammonium sulphate, and GSH accumulation, employing a magnesium sulphate concentration set at 1.2 g/l (high level). The possibility of obtaining S. cerevisiae cells with a high GSH intracellular content (up to 1.85% dw) can be considered an interesting opportunity of furthering the range of application and utilization of this molecule.