郁李仁（R）-醇腈酶高效催化乙酰基三甲基硅烷与丙酮氰醇不对称转氰

Highly efficient asymmetric transcyanation of acetyltrimethylsilane with acetone cyanohydrin in an aqueous/organic biphasic system catalyzed with （R）-oxynitrilase from defatted Prunus Japonica seed meal for the preparation of optically active （R）-2-trimethylsilyl-2-hydroxyl-propionitrile was successfully carried out for the first time. For better understanding of the reaction, various influential variables were examined with respect to the initial reaction rate, the substrate conversion and the product enantiomeric excess （e.e.）. Diisopropyl ether was found to be the best organic phase for this reaction among all the organic solvents tested. The optimal concentrations of Prunus Japonica seed meal powder, acetyltrimethylsilane and acetone cyanohydrin, volume ratio of aqueous phase to organic phase, buffer pH value and the reaction temperature were 34.5g·L^-1 and 14mmol· L^-1, 28mmol· L^-1, 13% （by volume）, 5.0 and 30℃, respectively, while the initial reaction rate, the substrate conversion and the product enantiomeric excess were 1.34 mmol·L^-1·h^-1, 99.0% and 99.0%, respectively. The comparative study demonstrated that silicon atom in substrate showed great effect on the reaction and acetyltrimethylsilane was a much better substrate for （R）-hydroxynitrile lyase from Prunus Japonica seed than its carbon analogue 3,3-dimethyl-2-butanone.     

虾青素研究进展

虾青素是一种极具潜力的色素和抗氧化剂,在水产养殖、食品和医药化工行业具有广阔的应用前景。本文对虾青素的生物学功能、生物来源及应用等方面进行了论述     

基于酶促酯交换的速冻专用油脂制备及应用研究

利用脂肪酶Lipozyme TL IM催化质量比为7:3的棕榈硬脂与大豆油进行酯交换反应,混合油脂中的高熔点甘三酯三棕榈酸甘油酯(PPP)的含量从27.61%降至9.50%。以酯交换油为主体,设计了5种不同塑性范围和固体脂肪含量的基料油,并以此基料油为原料制备出5种速冻专用油脂,然后将之应用于制作速冻汤圆。结果表明,当基料油中的油脂配比为酯交换油:大豆油:棕榈硬脂=84:13:3(wt%)时,所制备的专用油脂具有最佳的抗冻性能,以之制作的速冻汤圆冻裂率最低,仅为5%,而应用市售速冻专用油脂、未酯交换油脂制备的速冻专用油脂、未添加速冻专用油脂制作的的汤圆冻裂率分别为30%、20%和50%;此外,所得速冻汤圆表面细腻,光洁,有弹性,口感好,感官评分最高,表明通过酶促酯交换反应可以制备出品质优良的速冻专用油脂。     

用盐析法分离低核酸酵母蛋白的研究

本文研究了用盐析法解离酵母核蛋白以获得低核酸酵母蛋白分离物的方法,系统地考察了盐的种类、浓度、温度等条件对酵母蛋白分离物(IYP)核酸含量的影响。结果表明,不同的盐对核蛋白解离的影响符合离子感胶序,在25℃下,用0.5M的NaClO_4处理2％的核蛋白溶液,可除去其中80％左右的核酸,与现有的碱法、酸法、酶法等方法相比,该法经济实用性较好。     

含水有机溶剂体系中固定化Acetobacter sp. CCTCC M209061细胞催化乙酰乙酸乙酯不对称还原反应

本论文报道了含微水有机溶剂体系中固定化Acetobacter sp.CCTCC M209061细胞催化乙酰乙酸乙酯不对称还原为(R)-3-羟基丁酸乙酯。研究表明,Acetobacter sp.CCTCC M209061细胞能遵循反Prelog规则高选择性地催化乙酰乙酸乙酯不对称还原。与单水相反应体系相比,含有机溶剂体系不仅可有效地解决底物和产物的抑制作用,而且可提高反应底物的浓度和产率。在所研究的不同有机溶剂中,正己烷为该反应的最适有机相,其能较好溶解底物且对Acetobacter sp.CCTCC M209061细胞的毒性较小,从而导致反应的初速度较快,产率较高。异丙醇为该反应的最佳辅底物,其最适浓度为60 mmol/L;该反应体系中的最适正己烷体积百分比、反应温度、底物浓度分别为约100.00%(水含量约为0.01 wt%),35℃,40 mmol/L。在此条件下,反应的初速率、产率和产物的e.e.值分别为0.72μmol/min,85.24%和99.00%以上,明显好于水单相反应体系进行该反应的结果。     

离子液介质中生物催化与生物转化的研究进展

Ionic liquids have negligibly low vapor pressure, high stability and polarity. They are regarded as green solvents. Enzymes, especially lipases, as well as whole-cell of microbe, are catalytically active in ionic liquids or aqueous-ionic liquid biphasic systems. Up to date, there have been many reports on enzyme-exhibited features and enzyme-mediated reactions in ionic liquids. In many cases, remarkable results with respect to yield, catalytic activity, stability and (enantio-, regio-) selectivity were obtained in ionic liquids in comparison with those observed in conventional media. Accordingly, ionic liquids provide new possibilities for the application of new type of solvent in biocatalytic reactions.     

郁李仁(R)-醇腈酶高效催化乙酰基三甲基硅烷与丙酮氰醇不对称转氰

Highly efficient asymmetric transcyanation of acetyltrimethylsilane with acetone cyanohydrin in an aqueous/organic biphasic system catalyzed with(R)-oxynitrilase from defatted Prunus Japonica seed meal for the preparation of optically active(R)-2-trimethylsilyl-2-hydroxyl-propionitrile was successfully carried out for the first time.For better understanding of the reaction,various influential variables were examined with respect to the initial reaction rate,the substrate conversion and the product enantiomeric excess(e.e.).Diisopropyl ether was found to be the best organic phase for this reaction among all the organic solvents tested.The optimal concentrations of Prunus Japonica seed meal powder,acetyltrimethylsilane and acetone cyanohydrin,volume ratio of aqueous phase to organic phase,buffer pH value and the reaction temperature were 34. 5 g.L~(-1) and 14 mmol·L~(-1) ,28 mmol.L~(-1) , 13%(by volume),5. 0 and 30℃,respectively,while the initial reaction rate,the substrate conversion and the product enantiomeric excess were 1. 34 mmol.L~(-1) .h~(-1) ,99. 0% and 99. 0%,respectively.The comparative study demonstrated that silicon atom in substrate showed great effect on the reaction and acetyltrimethylsilane was a much better substrate for(R)-hydroxynitrile lyase from Prunus Japonica seed than its carbon analogue 3,3-dimethyl-2-butanone.     

区带毛细管电泳法同时分离检测6种喹诺酮类抗生素

采用区带毛细管电泳法建立6种喹诺酮类抗生素同时分离检测的方法,考察了缓冲液种类、离子浓度、pH以及分离电压,温度等因素对电泳分离的影响.优化后的分离检测条件为:缓冲液为30mmol/L硼酸钠-10mmol/L磷酸二氢钠(pH8.5)、分离电压和温度分别为18kV和25℃、紫外检测波长278mm.结果表明,6种药物在10min内完全达到基线分离,且各组分浓度与峰面积呈良好的线性关系(R2>0.9929),检出限为29-51μg/L,回收率为98.05%-104.30%,相对标准偏差(RSD)小于4%.     

用离子交换法改性KY分子筛吸附剂

用离子交换法将 KY 分子筛改性成为一种能同时吸附分离出高纯度的间二甲苯(MX)和乙基苯(EB)的吸附剂,并初步探讨了其吸附分离特性与 Y 型分子筛某些物化性能之间的关系。     

琥珀酸二辛酯磺酸钠对海星皂苷在超临界CO2中的增溶作用

利用琥珀酸二辛酯磺酸钠(AOT)/混合醇/水溶液为助溶剂,以乙醇助溶剂为参照,考察了表面活性剂对海星皂苷在超临界CO2介质中的增溶作用。探讨了表面活性剂浓度、助表面活性剂组成、复合表面活性剂配比等因素对海星皂苷增溶的影响,结果表明:摩尔比为4∶1、浓度为0.05 moL/L的AOT/辛基酚聚氧乙烯醚(OP-10)复配表面活性剂,对海星皂苷具有良好的选择性增溶作用,海星皂苷的萃取率为2.40%,提取物中海星皂苷质量分数为58.99%,分别是使用乙醇助溶剂的4.08、2.18倍。