Improving Catalytic Performance of Burkholderiacepacia Lipase by Chemical Modification with Functional Ionic Liquids

Various imidazolium and choline-based functional ionic liquids（Ks） comprising different cations and anions were grafted onto Burkholderiacepacia lipase（BCL） through surface amino acids coupling. The catalytic activity, thermostability, organic solvent tolerance and adaptability to temperature and pH changes of the modified BCL were then evaluated in olive oil hydrolysis reaction. The results showed that different combinations of cations and anions in ILs had important influence on the catalytic performance of the modified lipases. BCL modified with IL [Choline][H2PO4] was the most improved lipase, in which increases by 1.2 folds in relative activity, 2.5 folds in typi- cal proton solvent（10% methanol, volume fraction）, and 1.4 folds in thermostability（after incubation at 70℃ for 2 h） were achieved in relative toits native form. BCL modified with [HOOCEPEG350[M][BF4] had higher optimal tempe- rature and pH, and better thermosability compared with the native and other modified BCLs. The conformational changes of BCLs were also confirmed by fluorescence spectroscopy and circular dichroism spectroscopy.

产脂肪酶海洋微生物的筛选、鉴定及酶学性质研究

目的：从海洋来源样品中筛选脂肪酶产生菌，并对其进行鉴定和酶学性质研究。方法：以橄榄油为唯一碳源，采用固体平板变色圈观察法筛选脂肪酶产生菌。利用16SrDNA序列分析对其进行鉴定，并对脂肪酶酶学性质进行研究。结果：从海鳗和鲍鱼肠道内容物以及平潭海域、北极和盐湖泥样5个样品中共分离筛选出22株脂肪酶产生菌，其中ZF一16菌株产酶能力较强，根据其形态特征及16SrDNA序列分析鉴定为洋葱伯克霍尔德菌。其酶学性质研究表明，该脂肪酶最适反应pH为9．0，在pH5．0～10．0范围稳定；最适反应温度75℃，当温度小于40℃时较稳定；低浓度（1mmol／L）的Na＋和K＋对脂肪酶的活性有激活作用。Zn2＋对脂肪酶有强烈的抑制作用；对C4－C18均有降解作用，尤其对中长链的三辛酸甘油酯（C8）具有较强的降解能力。结论：从海洋来源的样品中筛选到产脂肪酶能力较强的细菌ZF-16菌株，经鉴定为洋葱伯克霍尔德菌。其所产脂肪酶为碱性高温脂肪酶，对C14-C18底物有降解作用，可用于食品烘焙、废纸脱墨和造纸脱胶工业。

洋葱伯克霍尔德菌的耐药性分析

目的:了解我院近两年分离的洋葱伯克霍尔德菌的临床分布和耐药性。方法:采用梅里埃VITEK-2全自动细菌鉴定药敏系统及纸片扩散法(K-B法)测定洋葱伯克霍尔德菌对13种抗菌药物的敏感性。结果:近两年共分离出洋葱伯克霍尔德菌127株,其中77.2%(98/127)分离于痰液,10.2%(13/127)分离于血液。药敏结果显示,多数药物耐药率均大于80%,复方新诺明、米诺环素耐药率最低,小于10%。哌拉西林/他唑巴坦、头孢哌酮/舒巴坦、头孢他定耐药率介于20%与30%之间。结论:洋葱伯克霍尔德菌耐药性较严重,临床抗感染治疗应根据药物敏感试验结果选用敏感药物。