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Chiral (Chirality) of the basic properties of nature, whether it is composed of living macromolecules such as proteins, nucleic acids, etc., or the nature of the planetary rotation, almost all atmospheric phenomena cyclones chiral characteristics. Chiral compounds in the pharmaceutical, pesticide and other fields have an important role, because of the same compound not only between both enantiomers physicochemical and pharmacological aspects are very different, the two enantiomers also show biological activity between a significant difference. Chiral alcohols in the synthesis of chiral drugs, chiral pesticides and other aspects of high-performance liquid crystal material has important application value, so synthesis of chiral alcohols single study has important theoretical and practical significance. Lipases as biocatalysts for chiral alcohols with good stereoselectivity, and its catalytic reaction conditions are mild, environmentally friendly, has been widely used in the field of chiral separation. However, due to the free lipase as a catalyst there are still some deficiencies, such as poor stability, difficult recovery, etc., which greatly limits the lipase industrial applications. The use of immobilized enzyme technology can be a good solution to this problem, so the research enzyme immobilization enzyme engineering technology has always been the research focus. Sol - gel (sol-gel) is a physical method of immobilized enzyme technology embedding process, organic or inorganic compounds (typically alkoxy compounds such as tetraethyl ester TMOS or TEOS TEOS) as precursor. in the liquid phase under the front body and the biological macromolecules uniformly mixed, by hydrolysis, polycondensation reaction system to form a stable transparent sol, the sol state gradually solidified to form three-dimensional network structure of the gel process. Sol - gel method is divided into hydrolysis and polymerization, gelation, aging and drying steps. Sol - gel method with fixed biomolecules immobilization process efficiency, good reproducibility and the carrier can be modified and other characteristics. Firstly, the present laboratory has acquired LipA engineering bacteria were cultured to obtain a large number of LipA crude enzyme, and by sonication, ammonium sulfate precipitation, Hitrap Sepharose column ion exchange chromatography purified lipase LipA the purified lipase LipA used for immobilization. In this paper, different silane precursor, and found that trimethoxysilane and TEOS as silane precursor lipase LipA be embedded, showed the highest specific activity. Wherein propyl trimethoxy silane and TEOS molar ratio, the amount of enzyme solution, the crosslinking agent is added in an amount such as the activity of the immobilized enzyme affect important parameters of the experimental study of these factors alone, C trimethoxysilane and TEOS molar ratio 4/1, the amount of enzyme added 300ul, the crosslinking agent is added in an amount 200ul, the precursor silane hydrolysis time was 30min, the above conditions are fixed lipase LipA of its specific activity is free lipase LipA of 1.5 times. Second, this paper immobilized LipA structure of three representative chiral alcohols split reactions. By examining the structure and substrate molecules immobilized enzyme catalytic performance relationship and find a suitable immobilized lipase LipA split substrate. It was found that the immobilized enzyme pair 2 - methyl-1 - butanol has a high catalytic activity and stereoselectivity is also improved compared with the free enzyme. Also investigated the various chain length acyl donor, temperature, pH, water activity, etc. Enzymatic 2 - methyl-1 - butanol transesterification reaction of the important factors, the acyl donor is vinyl butyrate ester , the reaction temperature was 50 ℃, pH 9.5, the optimal water activity of 0.54 under the experimental conditions, the highest stereoselectivity immobilized enzyme E is 13.05, when the reaction conversion rate reached 64.13%, Only 2 - methyl-1 - Alcohol optical purity can reach 97%. The paper also immobilized LipA reuse were studied, reused eight times immobilized enzymes LipA still has a very high energy, and its relative activity was 70% of the initial activity. This good reusability of immobilized lipase LipA production in industrialized continuous use of the foundation.
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