ISOLATION OF Phaffia rhodozyma YEASTS MUTANTS UNDER INCREASED CAROTENOID CONTENT

The aim of the paper was the selection of the improved strains of Phaffia rhodozyma using chemical mutagenesis and the identification of individual carotenoids synthesized by isolated more pigmented mutants. Hyperpigmented mutants of P. rhodozyma NRRL Y-17268-1 and IMB Y-5021-15 were isolated from initial strains NRRL Y-17268 and IMB Y-5021 by nitrosoguanidine mutagenesis. Pigments were purified by TLC and identified using HPLC and liquid chromatography-mass spectrometry. It was shown that initial strains P. rhodozyma NRRL Y-17268 and IMB Y-5021 and obtained from them mutants NRRL Y-17268-1 and IMB Y-5021-15 produced torulene and torularhodin without illumination in shaking flasks at 20 оC. The content of torularhodin produced by the mutant strains Y-17268-1 (18.2 μg) and Y-5021-15 (16.5 μg) per 1.0 g of dry biomass was increased to 33.8 and 18.4%, respectively, in comparison with the content of this pigment in the initial parental strains. The obtained strains present interest for further selection of more active producers of carotenoids and examination of the action of reactive oxygen species as stimulators of carotenoid production in yeasts.