Isolation and characterization of Xanthophyllomyces dendrorhous mutants with altered carotenoid content

Cells of the astaxanthin-producing yeast Xanthophyllomyces dendrorhous were subjected to successive 60 Co and UV irradiation. Colonies exhibiting increased pigmentation were recovered from different non-selective plates. Mutant strains were subcultured to ensure their genetic homogeneity and their pigment production was characterized. Analysis of the metabolic patterns of 7 pigment-overproducing mutants (derived from 3 wild-type parental isolates) revealed different patterns of carotenoid production: the greatest increase in astaxanthin production (6.7-fold) was found for X. dendrorhous strain ATCC 24229/S119 (274 μ g g−1 dry weight). Mutant strains with increased total carotenoid content, but without significant change in astaxanthin production, were also isolated