Optimization of L-methionine Bioconversion to Aroma-active Methionol by Kluyveromyces lactis Using the Taguchi Method

The bioproduction of methionol through fermentation was performed by Kluyveromyces lactis KL71 in coconut cream supplemented with L-methionine (Met). This bioprocess was successfully optimized with the Taguchi method applying the L27 (313) orthogonal array. Among these studied factors, shaking speed was found to be the most significant factor that affected the bioproduction of methionol, followed by incubation time, pH level and Met concentration. The optimum fermentation conditions were determined as follows: 0.45% (w/v) of Met, 48 h of incubation, shaking speed of 160 rpm, 0.05% (w/v) of yeast extract (YE), 0 mg/L of diammonium phosphate (DAP) and pH of 6.3. Under the optimum conditions, the signal to noise (S/N) ratio achieved was 59.9 decibels (dB), which was in good agreement with the predicted S/N ratio of 58.2 dB. The average yield of methionol obtained under the optimum fermentation conditions was 990.1 ± 49.7 µg/mL. This indicates that the Taguchi method was effective for the optimization of bioproduction of methionol by K. lactis.