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γ-CGTase突变体制备及其产γ-CD条件优化
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Preparation of γ-CGTase Mutant and Optimization of the Production of γ-CD
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DOI:10.3969/j.issn.1673-1689.2018.10.002
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中文关键词: CGTase γ-CD 定点突变 产物专一性
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英文关键词: Keyword: CGTase,γ-CD,site-directed mutagenesis,product specificity
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基金项目:
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摘要点击次数: 330
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全文下载次数: 213
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中文摘要:
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采用定点突变法将来自Bacillussp.G-825-6的γ-CGTase的211位的酪氨酸突变为亮氨酸,并利用突变体Y211L催化淀粉制备γ-CD,分别研究了底物种类、底物质量分数、反应时间、反应温度、加酶量对γ-CD产率的影响,并在单因素的基础上进行了正交优化,优化后的反应条件为:木薯淀粉质量分数为6%,加酶量为4 U/g,反应温度50 ℃,反应时间为24 h,在此条件下催化产生γ-CD的产率可达到14%,以总环糊精质量分数为100%计,催化产γ-CD的比率为97%。
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英文摘要:
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In this thesis,tyrosine 211 of γ-CGTase from Bacillus sp. G-825-6 changed into leucine based on site-directed mutagenesis. The influences of substrate type,concentration,time,temperature,and enzyme concentration on the mutant Y211L catalyticed starch to produced γ-CD were evaluated. On the basis of single of factor experiments,orthogonal design method was used to optimize the condition for production of γ-CD. As a result,the best condition was:cassava starch 6%,enzyme concentration 4 u/g,temperature 50 ℃,time 24 h. Under thses conditions,the production of γ-CD can reach 14%. If the total cyclodextrin content is 100%,the catalytic production ratio of γ-CD is 97%.
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