|
Chiral 2 - octanol is optically active intermediate, which can be synthesized by the liquid crystal material of the chiral agent, steroids, optically active drugs, insect sex hormone (biopesticides - green pesticides) and the like. To carry out the biocatalysis efficient preparation of optically pure 2 - octanol chiral alcohols dedicated biocatalyst screening and study the opponent biocatalysis has important practical significance and theoretical value. Including the large number of strains of bacteria, yeasts and molds from the laboratory preserved screened conversion of optically pure 2 - octanol better strains columnar Candida Candida cylindracea ATCC 14830. C. cylindracea ATCC 14830 transformed racemic 2 - octanol to give (R) -2 - octanol, an optical purity of 95.21% ee, in a yield of 45.38%. Intermediates of the conversion reaction is determined by mass spectrometry is 2 - octanone, the reaction process as C. cylindracea ATCC 14830 will be (S) -2 - octanol converted to intermediate 2 - octanone, reserved (R) -2 - octanol. Preparation of (R) -2 - octanol, to optimize the reaction system and the reaction conditions as follows: The organic solvent was n-octane, using whole cell catalyzed C. cylindracea ATCC 14830 buffer PE reaction pH6.5 two compared to 10:10, cell concentration of 10% (w / v), the reaction temperature is 30 ° C, reaction speed 150rpm/min. After optimization, the optical purity of the product is increased to 92.20% ee, and the conversion rate was increased to 46.84%. Investigated C. cylindracea ATCC 14830 and wine Leuconostoc Oenococcus oeni CECT 4730 Streptococcus redox coupled three ways, namely (1) while adding two microorganisms and substrate co-transformation; (2) order to add two microbial with the substrate reaction, the first strain of the end of the microbial reaction, without removing the first strains of microorganisms added directly to the second strain of microorganism reaction was continued for two microorganisms; (3) sequentially added with the substrate reaction, the end of the first strain of microbial reactions. Remove the first strains of microorganisms and then add a second microbial continue to react. The results show the effect of the conversion of the third coupling 2 - octanol. In TE buffer, pH 8.5, 10% of the amount of cells, the auxiliary substrate glucose 30g / L, the substrate concentration of up to 40g / L, ee GT; 99% yield gt; 90%. By O. oeni CECT 4730 medium and culture conditions to optimize O. oeni CECT 4730 optimized medium: yeast extract, 0.503%, 1% glucose, tryptone 1%, 0.5% of D-fructose, hydrochloric acid-L - cysteine ??0.05%, MgSO4 · 7H2O 0.02% of MnSO4 · 4H2O 0.005%, 0.458% diammonium hydrogen citrate, Tween 80 0.1%, 14.395% tomato juice. Optimization of culture conditions: inoculum 10%, initial pH5.5, incubation temperature 28 ° C, incubation time 42 hours. Optimization of media and culture conditions, O. oeni CECT 4730 incubation time shortened from 72 hours to 42 hours; cells amount increased from 4.32g / L to 6.87 g of / L; optical purity ee value of 98.86%; yield of 91.86 %.
|