Production Of Astaxanthin By Red Yeast Phaffia Rhodozyma

Red yeast Phaffia rhodozyma is researched by production of astaxanthin, an orange-pink pigment that has potential applications in aquaculture, food and. pharma(?)utical industry. This paper researched characteristics of growth, culture parameters, the effects of components of medium on growth and astaxanthin formation, optimization of culture medium, modulation and control of astaxanthin synthesis, culture in bioreactor and mutagenesis of Phaffia rhodozyma.The research on characteristic of growth and synthesis showed: The astaxanthin synthesis of P.rhodozyma is growth-associated and mainly in exponential phase and stationary phase. The optimum temperature for growth and astaxanthin synthesis is 20℃. The optimum pH for growth is 5.9 and the optimum pH for astaxanthin synthesis is 5.0. The culture time of inoculum is 54 hours. Inoculum concentration is 10%. The culture cycle is 72 hours.The research on culture medium showed: Molasses is the best one of 11 carbon sources for growth. Xylose is the best one of 11 carbon sources for astaxanthin synthesis. When glucose concentration is in the range of 0¹00g/L, the specific growth rate increased proportion to increasing glucose concentration. However, astaxanthin content and yield of biomass to glucose decreased proportion to increasing glucose concentration. The optimum initial glucose concentration for flask culture is 30g/L. Yeast extract is the best nitrogen source for growth and astaxanthin synthesis. P.rhodozyma As2.1557 can also use urea, ammonium sulphate, peptone and potassium nitrate. Urea and ammonium sulphate are more easily used than potassium nitrate by P.rhodozyma. The mixture of urea and potassium in ratio of 1: 4 can increase astaxanthin production. The optimum C/N for production of astaxanthin is 5. MgSO₄ is indispensible nutrient for growth and astaxanthin synthesis. A mathematical model was developed by second-order rotatable central composite design. An simple and inexpensive medium components was developed by optimizing the mathematical model: glucose, 30g/L; urea, 0.5g/L; potassium nitrate, 5.5g/L; KH₂PO₄, 2.5g/L; Na₂HPO₄, 5.5g/L; MgSO₄,1.5g/L; CaCl₂: 0.1 g/L.