Astaxanthin Synthesis by Xanthophyllomyces dendrorhous DSM 5626 and Its Mutants on Carrot Extract Medium Under Different Illumination Intensity

The effect of illumination intensity on astaxanthin synthesis by yeast Xanthophyllomyces dendrorhous DSM 5626 and its 4 mutants grown in cultures on carrot extract medium was investigated. Cell concentration, total carotenoid and astaxanthin yields were assessed in obtained cultures. Collected data were used to construct regression models describing the effect of illumination intensity on controlled parameters. Maximum cellular (0.44-0.46 g/kg of dry cell weight) and volumetric yields (2.3-2.4 mg/L) of the pigment were observed for mutants 10BE and 34B at 600 lx, as well as for mutant 26UV at 1000 lx. The highest yield of astaxanthin for the parental strain was obtained in culture at illumination of 1000 lx (0.29 g/kg of dry cell weight and 1.51 mg/L). The values of illumination determined on the basis of constructed regression models for individual yeast strains, at which astaxanthin synthesis should be the most efficient, remained within the range of 660-1000 lx.