核壳结构磁性树枝状纤维形有机硅固定化脂肪酶制备及其应用

Preparation and application of core-shell hydrophobic magnetic dendritic fibrous organosilica immobilized lipase

为了提升脂肪酶的稳定性并构建新型固定化酶催化体系,利用改进的WinsorⅢ微乳液双连续相体系合成了超顺磁性Fe_(3)O_(4)内核和树枝状纤维形氧化硅外壳的核壳结构磁性有机硅纳米粒子(MMOSNs),用于固定化南极假丝酵母脂肪酶B(CALB)。优化条件后CALB负载量为177.49 mg/g,比水解活性为27390 U/g。磁性有机硅通过与CLAB分子之间疏水相互作用及表面孔道结构,可有效激活CALB的界面活性并保护活性构象免受破坏,比游离酶和磁性无机硅固定化酶表现出更好的活性和稳定性。除此之外,将CALB@MMOSNs用于催化乙酰丙酸与十二醇的酯化反应最高转化率为85.05%,重复使用9次后仍保留68.94%转化率,而商业化N435只保留29.83%。证明疏水性磁性核壳结构有机硅是固定化CALB的良好载体,可有效扩展脂肪酶的工业应用。

In order to improve the stability of lipase and construct a new immobilized lipase catalytic system,the core-shell hydrophobic magnetic organosilica nanoparticles(MMOSNs)with superparamagnetic Fe_(3)O_(4) core and dendritic fibrous silica shell were synthesized through an improved WinsorⅢmicroemulsion dual continuous phase system,and the obtained MMOSNs were employed as support for the immobilization of Candida antarctica lipase B(CALB).After the optimized conditions,the CALB load was 177.49 mg/g,and the specific hydrolysis activity was 27390 U/g.The CALB@MMOSNs could effectively activate the interfacial activity of CALB and protect the active conformation from external environmental harm through hydrophobic interaction with CALB molecules and its surface pore structure,showing better activity and stability than free enzyme and magnetic inorganic silicon immobilized CALB.In addition,CALB@MMOSNs could catalyze the esterification of levulinic acid with lauryl alcohol,and the highest conversion rate reached 85.05%.After repeating the reaction for 9 cycles,the conversion rate remained 68.94%,while the commercial N435 retained only 29.83%.These results indicated that the core shell hydrophobic magnetic organosilicon is a good support for immobilized CALB,which can effectively expand the application of lipase in industry.