| Astaxanthin (3,3-dihidroxy-β-carotene-4,4-dione) is an unique carotenoid widely distributed in nature. Recently, there has been growing interest in nature astaxanthin produceing in consideration of its health benefits to human beings in light of its roles in cancer prevention, enhancement of immune response, and serving as a free radical quencher. As a result, astaxanthin possesses a high market value both to the pharmaceutical and food industries. Phaffia rhodozyma is an important source of natural astaxanthin, in this thesis, methods for analysis carotenoids and procedures for extracting astaxanthin from Phaffia rhodozyma were optimized, method of mutant genesis and model of astaxanthin accumulation were investigated, media components and conditions for Phaffia rhodozyma cultivation were studied and fermentation economics was evaluated.In mixed solution of acetone and dimethylsulphoxide in ratio of 2 to 1, The absorptive peaks in the spectra of astaxanthin was in range of 470 - 487 nm, and the absorptive peaks of β-carotene was in range of 450-465 nm. experiments carried out at 487nm with astaxanthin as standard showed that R~2 value of regressive model of calibration curve was in excess of 0.999, recoveries were in range of 98.85%~ 102.60%, RSD values ranged from 0.30% to 7.00%, which all indicated the proposed method was accurate and decisive for quantitative analyzing total carotenoids of Phaffia rhodozyma.Astaxanthin and β -carotene in extracts of Phaffia rhodozyma could be simultaneously analyzed by ratio spectrometric method, wavelength selected for determination astaxanthin and β -carotene by ratio spectrometric method were 466nm and 461nm, wavelength interval used for calculate ratio spectrometric values was 2nm, divisor was 2mg/l. Calibration graphs were established for p-carotene within 0 - 6.0 ug/ml and for astaxanthin within 0 - 5.0 μg/ml with their corresponding regressive equations in: y = -0.0082x-0.0002 and y = 0.0146x -0.0006, respectively. R square values in excess of 0.999 indicated the good linearity of the calibration graphs. Sample recovery rates were found satisfactory (99% - 101%) with therelative standard deviations (RSD) less than 5%. This method can be conveniently used to determine p-carotene and astaxanthin simultaneously in large sample analysis.There were several carotenoids contents in Phaffia rhodozyma; it is reasonable to analyze these different carotenoids composition simultaneously by chromatography method. Thin layer chromatography was a rapid microanalysis method, polarity suitable for analysis carotenoids of Phaffia rhodozyma on the silicon gel plate was so far 1.45, optimal solution for developing carotenoids of Phaffia rhodozyma on silicon gel plate was mixed with 7.7% ether, 17.7% chloroform, 16.4% dichloromethane, and 58.2% n-Hexane. The newly developed thin layer method was not so accurate and of precision to quantitatively determinate carotenoids of Phaffia rhodozyma, it was convenient to qualitatively analyze carotenoids of Phaffia rhodozyma.Optimal organic solvent components for isolating carotenoids of Phaffia rhodozyma on Novapak Cig reverse chromatography column were'composite with 33.33% methanol, 33.33%tetrahydrofuran and 33.33%acetonitrile. controlling developing phase flow at 1.2ml/min, column temperature at 40°C, column pressure at 0—3000psi,optimized gradient condition was that increasing ratio of organic phase ascended from 0 to 70% in the first 6 minutes, keeping 70% for 12 minutes, increasing the ratio of organic phase to 90% in 4 minutes, keeping the ratio for 12 minutes, then increased the ratio to 100% in 2minutes and followed by decreasing to 0% in 2 minutes. Under the optimal organic solvent and gradient procedure, 19 carotenoids were isolated, regressive equations were r=93768x-32214 for astaxanthin and r=39975x+2793.6 for P-carotene, respectively. R square values both in excess of 0.999 indicated the good linearity of the calibration graphs. Sample recovery rates were found satisfactory in range of 98.5%~ 105.6% for astaxanthin and 90.5%...
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