Technology Optimization Of Astaxanthin Production By Phaffia Rhodozyma JMU-MVP14

Astaxanthin is a lipid soluble carotenoid of powerful physiological functions. Because ofthe property of antioxidation, antitumor and enhancing immunity, astaxanthin has beenextensively used in food, feed, cosmetic and pharmaceutical. Phaffia rhodozyma is an importantnatural resource for astaxanthin production, but it can’t meet the increasing industrial deamandas astaxanthin productivity is low in wild strains of Phaffia rhodozyma. In our previus work, ahigh astaxanthin-producing Phaffia strain was obtained which was named as Phaffia rhodozymaJMU-MVP14. In order to improve its astaxanthin production, the fermentation technology wasstudied and culture parameters were optimized as follows:Firstly, astaxanthin production was investigated by single factor in Phaffia rhodozymaJMU-MVP14fermentation. The optimal culture medium for astaxanthin production was glucose30g/L, yeast extract6g/L,(NH4)2SO41.015g/L, MgSO4·7H2O1g/L, KH2PO413.6g/L, CaCl20.2g/L, and the optimal culture conditions were initial pH7.0, inoculum size5%, volume ofliquid30mL and culture temperature20°C. Under optimal condition, the biomass andastaxanthin production reached13.13g/L and67.07mg/L, respectively. Compared with theinitial condition, the biomass and astaxanthin production increased85.8%and15.8%,respectively.Secondly, the effects of five metabolic regulation and control agents (Soybean oil, H2O2,NaClO3, pinene and pyruvic acid) to Phaffia strains were studied on microorganism growth andastaxanthin production. When1g/L pyruvic acid was added in the culture medium, biomass andastaxanthin production of Phaffia rhodozyma JMU-VDL668increased29.6%and64%, and atthe meantime, biomass and astaxanthin production of Phaffia rhodozyma JMU-MVP14increased120%and74.2%. Couple agents added into medium could enhance asxanthinaccumulation much more than single agent did. Astaxanthin production of Phaffia rhodozymaJMU-VDL668increased82.4%when1g/L ethanol and2g/L citric acid was added, as well asthe production of Phaffia rhodozyma JMU-MVP14increased69.7%when1g/L pyruvic acidand1g/L glycerol was added. Furthermore, trio combination (pyruvic acid1g/L, ethanol1g/Land citric acid2g/L) lead to an increase of88.8%astaxanthin production to Phaffia rhodozymaJMU-VDL668.Nextly, the effects of glucose concentration and rotational speed on astaxanthin productionby Phaffia rhodozyma were investigated in shaking flask. For Phaffia rhodozyma JMU-VDL668, the biomass at low speed was higher than that at high speed when glucose concentration was10g/L. A second-synthesis of astaxanthin appeared at low speed during Phaffia fermentation. Thelow speed process on the production of astaxanthin by Phaffia rhodozyma was furtherinvestigated in7L bioreactor. It was shown that low speed process was feasible for Phaffiarhodozyma JMU-VDL668fermentation, and not for Phaffia rhodozyma JMU-MVP14fermentation.Finally, several sugar-feeding strategies were investigated in7L bioreactor with twoPhaffia rhodozyma strains. A significant increase (126%) in biomass was achieved in a DO-statprocess compared with a batch process for Phaffia rhodozyma JMU-VDL668, while a significantincrease (57%) in production of astaxanthin was achieved in a pH-stat process compared with abatch process.414.12mg/L astaxanthin and32.47g/L dry cell weight was obtained in the pulsefed-batch process with Phaffia rhodozyma JMU-MVP14, which increased79%and258%compared with the batch process.