Improved Gamma-Decalactone Synthesis by Yarrowia lipolytica Yeast Using Taguchi Robust Design Method

Abstract

The production of gamma-decalactone (GDL) by Yarrowia lipolytica is mainly based on the biotransformation of ricinoleic acid, derived from castor oil triglycerides. The main difficulty in this process is the multitude of factors that determine the growth rate of microorganisms, and thus affect the efficiency of lactone synthesis. In order to improve the technological aspects of GDL biosynthesis in batch culture, the influence of three factors was determined: substrate concentration, medium mixing intensity, and its pH, using the Taguchi solid design method (based on orthogonal array design). On the basis of four bioreactor batch cultures, the most favorable culture conditions in terms of GDL synthesis were selected using the statistical Taguchi method. The statistical method of experimental planning has shown that the optimal parameters of lactone biosynthesis are a constant pH at the level of 7, a variable mixing speed in the range of 200–500 rpm, and a substrate concentration at the level of 75 g/L. Using these parameters, about 2.93 ± 0.33 g/L of aroma was obtained. The intensity of mixing turned out to be the most important factor influencing the increase in GDL concentration in the medium.