INIBIOMA   20415
INSTITUTO DE INVESTIGACIONES EN BIODIVERSIDAD Y MEDIOAMBIENTE
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Effect of oxidative stress on the survival of Phaffia rhodozyma and in the production of carotenoid pigments and mycosporine-glutaminol-glucoside
Autor/es:
PAJAROLA, LUCIA; DE GARCÍA, VIRGINIA; LIBKIND, DIEGO; CIFUENTES, VICTOR; MOLINÉ, MARTÍN
Lugar:
Perugia
Reunión:
Congreso; ISSY 32nd, International Specialized Symposium on Yeasts; 2015
Resumen:
Phaffia rhodozyma is a basidiomycetous yeast capable of synthesizing two compounds of biotechnological value: carotenoid pigments (astaxanthin) and mycosporine-glutaminol-glucoside (MGG, UV sunscreen). Both metabolites exert protection against UV radiation and probably against reactive oxygen species (ROS). In this work, we studied for the first time the effect of ROS on the accumulation of carotenoids and MGG in Phaffia rhodozyma and evaluated the role of both compounds in the survival of this yeast against oxidative stress.Six strains including an hyperproducer mutant of MGG and carotenoids, two wild type strains, and 3 mutants deficient for the production of one of the two compounds were exposed to hydrogen peroxide, superoxide anion (generated with duroquinone) and singlet oxygen (generated with rose bengal). The survival of the strains was estimated by CFU. The effect of ROS on the production of MGG and carotenoids was assessed by adding sub-inhibitory concentrations of each ROS at the beginning of the cultures, and the accumulation of each metabolite was determined after 5 days exposure. The results obtained in this work demonstrated that both, carotenoids and MGG, exerts a protecting role in P. rhodozyma against hydrogen peroxide. The hyperproducer strain was more resistant to stress induced by H2O2 (81% survival after 90 minutes) than the parental strains and the strains deficient for the production of these metabolites (less than 2% survival). On the other hand, no differences in survival could be detected for strains exposed to superoxide anion, suggesting that these compounds do not protect against this radical. On the contrary when exposed to singlet oxygen the strains producing high concentrations of MGG presented the lowest survival suggesting that the presence of this compound was detrimental. Only exposure to singlet oxygen induced the accumulation of MGG while the accumulation of carotenoid pigments was stimulated by the three ROS studied.