Effect of POX genotype and Lip2p overexpression on lactone production and reconsumption by Yarrowia lipolytica using castor oil as substrate

Abstract

γ-Decalactone production from ricinoleic acid biotransformation by Yarrowia lipolytica has drawn the attention of many authors and, in the last years, molecular and physiological developments were made through the use of engineered strains in novel culture conditions.

The purpose of this work was to monitor the performance of modified Y. lipolytica strains in their lipid metabolism specifically at the β-oxidation pathway (MTLY40-2P strain, disrupted in the native genes POX2-5 and expressing an ectopic Aox2p-encoding gene) or at the triglyceride hydrolysis (JMY3010 strain, Lip2p overexpressed) using castor oil as substrate, in a lab-scale bioreactor. Using step-wise fed-batch cultures of MTLY40-2P strain, a γ-decalactone concentration of 7 g L−1 was reached. γ-Decalactone reconsumption was prevented and hydroxylactone production was reduced by Y. lipolytica MTLY40-2P strain. Moreover, substantial increase in the initial rate of aroma production was obtained with strain overexpressing LIP2 gene due to the fast hydrolysis of castor oil.