Optimization of methionol bioproduction by Saccharomyces cerevisiae using response surface methodology

Methionol (3-methylthio-1-propanol) is an important volatile sulphur-containing alcohol that may significantly impact food flavour. The purpose of this research is to investigate the bioproduction of methionol from L-methionine catabolism by Saccharomyces cerevisiae EC-1118. The biotransformation was carried out in coconut cream supplemented with L-methionine. Response surface methodology was applied for the optimization of fermentation conditions to achieve a high yield of methionol. A second-order polynomial model (R2 = 0.912) was established based on the experimental data obtained in this study using multiple regression analysis. To obtain more accurate prediction results, a reduced quadratic model was obtained through backward elimination. Based on the reduced model, the optimal conditions for maximum methionol production were determined to be 0.30 % (w/v) of L-methionine, 0.10 % (w/v) of yeast extract and zero level of diammonium phosphate. Under these optimal conditions, a methionol concentration of 240.7 ± 17.4 μg/mL was achieved. This experimental result was in close agreement with the predicted value of 243.5 μg/mL, indicating that this model was adequate. These results indicate that fermentation by S. cerevisiae in L-methionine-supplemented coconut cream medium is an effective method for the production of methionol. Large-scale fermentation trials are needed to provide valuable information for industrial production.