UTILIZATION OF AN AUXOTROPHIC STRAIN OF THE YEAST YARROWIA-LIPOLYTICATO IMPROVE GAMMA-DECALACTONE PRODUCTION YIELDS

gamma-Decalactone is an aroma compound with a pleasant peachy odour. M ost industrial processes use the bioconversion of ricinoleic acid by y easts to produce gamma-decalactone. Peroxisomal beta-oxidation activit y is responsible for the bioconversion. Some yeasts, Yarrowia lipolyti ca in particular, grow during the bioconversion, yielding a low biocon version rate, Auxotrophy for uracil of a genetically engineered Y. lip olytica strain was used to prevent growth in the bioconversion medium. beta-Oxidation activities and gamma-decalactone production of the aux otrophic strain were measured and compared with a wild-type strain in media supplemented or not. Induction of beta-oxidation was observed in the non-supplemented medium, although to a lesser extent than in supp lemented medium. Aroma productivity of the auxotrophic strain in the s upplemented medium was similar to that observed for the wild-type stra in in both media. However, in the non-supplemented medium the producti vity of the auxotrophic strain was 10-20-fold higher.