Studie Of Astaxathin Production By The Fermentation Of Red Yeast Phaffia Rhodozyma

The paper researched extraction and determination method of intracellular astaxanthin of phaffia rhodozyma, optimization of culture medium, culture in bioreactor and mutagenesis of phaffia rhodozyma.Disruptive method of the red yeast phqffia rhodozyma and the condition of astaxanthin being extracted were obtained as below: hydrochloric acid of 3mol/L 4mL, cell wall disruption at 100℃ and for 4min, acetone 6ml, astaxanthin being extracted under 20℃ and for 30min. The chromatography conditions of HPLC were found: methanol-acetonitrile(9:1) as mobile phase at 1.4ml/min, detection wavelength 478nm, room temperature.The research on optimization of culture medium and culture conditions showed: the optimum nitrogen for growth is peptone and yeast extract for astaxanthin synthesis, the optimal proportion of yeast extract is 40% in mixed nitrogen.The optimum temperature for growth and astaxanthin synthesis is 20℃ and pH is 7, the optimum medium volume is 50mL (in 500mL flask). In orthogonal test, the yeast biomass, astaxanthin content and yield could reach 11.16g/L, 0.70mg/kg dry cell weight and 7.83mg/L, respectively increased 57%, 66%and 160%.High cell density culture was studied with fed-batch culture in bioreactor. Fed-batch culture in 5L bioreactor got the following results: the cell biomass is 29.68g/L, astaxanthin content is 0.35mg/kg dry cell weight and the production of astaxanthin reached 10.24mg/LAn astaxanthin high-producing mutant Puv-24 and the thermotolerant mutant Tuv-4 was obtained by ultraviolet mutagenesis. Astaxanlhin production of mutant Puv-24 are reached 4.71mg/L, increased 46%. The topmost temperature of mutant Tuv-4 increased 5℃, its characteristics of growth and astaxanthin production at 25℃ went near to that of As2.1557.