Reetz Manfred T
Max-Planck-Institut fur Kohlenforschung, Mulheim an der Ruhr, Germany.
Methods Mol Biol. 2013;1051:241-54. doi: 10.1007/978-1-62703-550-7_16.
Lipases can be efficiently entrapped in the pores of hydrophobic silicates by a simple and cheap sol-gel process in which a mixture of a hydrophobic alkylsilane RSi(OCH3)3 and Si(OCH3)4 is hydrolyzed under basic conditions in the presence of the enzyme. Additives such as isopropanol, polyvinyl alcohol, cyclodextrins, ionic liquids or surfactants enhance the efficiency of this type of lipase-immobilization. The main area of application of these heterogeneous biocatalysts concerns esterification or transesterification in organic solvents, ionic liquids, or supercritical carbon dioxide. Rate enhancements (relative to the traditional use of lipase powders) of several orders of magnitude have been observed, in addition to higher thermal stability. The lipase-immobilizates are particularly useful in the kinetic resolution of chiral esters, enantioselectivity often being higher than what is observed when using the commercial forms of these lipases (powder or classical immobilizates). Thus, due to the low price of sol-gel entrapment, the excellent performance of the lipase-immobilizates, and the ready recyclability, the method is industrially viable.
通过一种简单且廉价的溶胶 - 凝胶法，脂肪酶能够有效地被包埋在疏水硅酸盐的孔隙中。在该方法中，疏水烷基硅烷RSi(OCH₃)₃和Si(OCH₃)₄的混合物在碱性条件下于酶的存在下进行水解。诸如异丙醇、聚乙烯醇、环糊精、离子液体或表面活性剂等添加剂可提高此类脂肪酶固定化的效率。这些非均相生物催化剂的主要应用领域涉及在有机溶剂、离子液体或超临界二氧化碳中的酯化或酯交换反应。除了具有更高的热稳定性外，还观察到反应速率提高了几个数量级（相对于传统使用脂肪酶粉末而言）。脂肪酶固定化物在手性酯的动力学拆分中特别有用，其对映选择性通常高于使用这些脂肪酶的商业形式（粉末或经典固定化物）时所观察到的对映选择性。因此，由于溶胶 - 凝胶包埋成本低廉、脂肪酶固定化物性能优异且易于回收利用，该方法在工业上是可行的。
