Dissertation
Dissertation > Mathematical sciences and chemical > Chemistry > Organic Chemistry > Organic Chemistry general issues > Properties of organic compounds > Chemical properties of organic reactions

A Study on Asymmetric Reduction of 2-Acetyl Ethyl Heptanoate by Yeast Cells

Author SunLiQun
Tutor ZhouZiYan
School Yanbian University
Course Physical and chemical
Keywords Yeast Cells Asymmetric reduction 2 - acetyl heptanoate
CLC O621.25
Type Master's thesis
Year 2008
Downloads 14
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Chiral compounds in pharmaceuticals, pesticides and other fine chemicals has a very important value, Chiral Building Blocks synthesis of these products has become a hot research. Rich oxidoreductase baker's yeast and baker's yeast reduction of prochiral carbonyl compound is one of the important research method. 2 - acetyl heptanoate as substrate model investigated the catalytic its asymmetric reduction reaction characteristics of yeast cells in aqueous systems. First, we synthesized the substrate 2 - acetyl heptanoate separation and purification; chemical synthesis product of 2 - (1 - hydroxyethyl) - heptanoic acid ethyl ester and purified by chromatography as the standard product. Secondly, a gas chromatography analysis method for qualitative and quantitative analysis of substrates and products. The effects of the carrier gas flow rate, column temperature on the separation to determine a more optimal separation conditions, to create the conditions for research work smoothly. This paper focuses on yeast cells asymmetric reduction of 2 - acetyl heptanoate reaction characteristics of yeast cells can be used for the asymmetric reduction of ethyl 2 - acetyl Geng taken yeast Mauri Yeast reducing power preferably. Using orthogonal experiment the initial optimization of reaction conditions, and, on this basis, taking into account the reaction time - empty yield systematic study of the initial substrate concentration, the yeast cell concentration, reaction temperature, type of yeast, reaction time, pH value, the auxiliary substrate, culture conditions, the reaction conversion rate. The conversion rate of the substrate can be improved by increasing the concentration of yeast, the conversion rate of the substrate increases with the increase in the concentration of yeast cells, yeast cell concentration greater than 300g / L, the substrate conversion rate not; reaction time of 24h representing appropriate; optimum reaction temperature of 30 ° C; pH 7.0 when the reaction conversion rate higher; compare glucose, methanol, ethanol, isopropanol and glycerol Several auxiliary substrate, glucose is the best auxiliary substrate; the glucose concentration of 10g / The L conversion rate better. Aerobic culture; shock reduction reaction under the conditions of the substrate conversion rate is higher than the anaerobic culture can get a higher conversion rate than the stationary reaction. Portionwise adding the substrate of the results are better than the results added in one. Purification of the product structure after the judgment result indicates that yeast cells asymmetric reduction of 2 - acetyl-heptanoic acid ethyl ester product of the same structure of the reduction product with the chemical method, having an optical activity of a target product was determined.

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