Carotenogenesis induction with hydrogen peroxide in xanthophyllomyces dendrorhous colored mutants

Xanthophyllomyces dendrorhous synthesizes astaxanthin as the most representative xanthophyll derivative. This compound displays antioxidant properties and its production has been stimulated via reactive oxygen species (ROS). Detailed mechanisms for carotenogenesis in X. dendrorhous have not been elucidated. Carotenoid production was stimulated with H₂O₂ in X. dendrorhous wild type (Wt), mutants R4 (red, astaxanthin hyperproducer); W10 (white, accumulates phytoene); Y21 (yellow, accumulates β-carotene) and P26 (pink, accumulates monocyclic carotenoids), to identify important biosynthetic steps in this microorganism. Addition of H₂O₂ prolonged the lag phase in all strains but reached similar growth at the stationary phase as that observed for their own control culture. The addition of H₂O₂ increased the carotenoid contents in 16 % for Wt and R4, 60 % in W10 and Y21 mutants, while in P26 this parameter remained constant. The results reported herein suggest that carotenogenesis induction by H₂O₂ may occur before the β-carotene step formation and its oxygenation is a limiting step in the astaxanthin formation pathway in X. dendrorhous.