Catalytic condition optimization in the conversion of nootkatone from valencene byYarrowia lipolytica

Abstract

Yarrowia lipolytica was a widespread and promising object in biotechnology, which was used to increase the biotransformation of valencene into nootkatone in shake flasks in this study. The main objective of this work is to determine the optimum combination of transformation conditions in shake flasks on the basis of single factor process optimization experiment. The results showed that Y. lipolytica was cultured in medium for 36 hr (exponential phase) and the amount of added Y. lipolytica was 5% (v/v). The concentration of substrate valencene was 920 mg·L−1, and the transformation time was 36 hr after adding substrates. Dimethyl sulfoxide, a water-soluble organic solvent, was used as a co-solvent with a concentration of 0.8% (v/v). The maximum production of nootkatone was 628.41 ± 18.60 mg·L−1 and the conversion rate was 68.30 ± 2.02% at cultivation conditions of 32°C, 150 rpm, and PH 5.30. The results showed that optimizing the catalytic conditions can significantly increase the yield of nootkatone by Y. lipolytica. Practical applications Recently, natural nootkatone is increasingly important due to its flavoring and physiological effects, but the amount of nootkatone in plants is low and cannot meet the demand. Also, there were few studies about microbial transformation of valencene by Yarrowia lipolytica under certain catalytic conditions. We demonstrated that optimizing the catalytic conditions can significantly increase the yield of nootkatone. Therefore, it provides a basis for the subsequent use of genetic engineering to transform Y. lipolytica to produce nootkatone.