Effects of oxidative stress on the production of carotenoid pigments byPhaffia rhodozyma (Xanthophyllomyces dendrorhous).
The resistance to killing by free radicals of two mutants ofPhaffia rhodozyma was determined. Mutant 5-7 did not produce astaxanthin but produced beta-carotene, while mutant 3-4 did not produce any carotenoid pigments. The resistance of mutant 5-7 was the same as that of the wild type but mutant 3-4 was rapidly killed. Carotenoid pigments increased the resistance to killing by free radicals. We investigated the effects of free radicals, generated by H(2)O(2) and Fe(2+) added to the medium, on wild-type cells and mutants ofP. rhodozyma. Unpigmented mutants of basidiomycetous yeasts (Rhodotorula spp. and others) are more susceptible to killing by UV-irradiation than the pigmented, wild-type strains. Therefore, we investigated the effect of free radicals on a similar basidiomycetous yeast,P. rhodozyma, a species of economic importance, in the biological production of astaxanthin.
Santopietro
L M
LM
Planta Piloto de Procesos Industriales Microbiologicos, Avda Belgrano y Pje. Caseros, 4000, San Miguel de Tucumán, Argentina, iducrey@proimi.edu.ar.
Spencer
J F
JF
Spencer
D M
DM
Siñeriz
F
F