Composite matrices based on macroporous silica modified by N vinylcaprolactam copoly mers with diallyldimethylammonium chloride and with 2 hydroxyethyl methacrylate were obtained. Lipase from Pseudomonas fluorescens was immobilized on the obtained materials. The temperature dependence of the hydrolytic activity of the immobilized lipase preparations in the triacetin hydrolysis was investigated. The hydrolytic activity of lipase immobilized on the matrix modified by the N vinylcaprolactam copolymer with 2 hydroxyethyl methacrylate can be regulated by varying the temperature of the reaction medium. The temperature dependence of the hydrolytic activity of the immobilized enzyme has a maximum at 40 °C, the activity of the immobilized lipase being ∼3.5 times higher compared to that at 20 °C. After immobilization on these composite materials, lipase retained the activity in the acetylation of 1 (RS) phenyl ethanol with vinyl acetate in Bu t OMe.In recent decades, rapt attention of researchers is at tracted by synthetic polymers able to change their confor mation and properties in response to minor changes in the environment, in particular, temperature. 1 These smart polymers are used for enzyme and cell immobilization, 2 controlled delivery of drugs, 3 preconcentration of metal ions, 4 affinity precipitation, 5 and so on.By using thermo and/or pH sensitive polymeric ma terials, one can prepare systems ensuring the retention of functional properties of the biomolecules incorporated into it and control the preparation activity by measuring the temperature and/or pH. A series of biocatalysts ob tained by enzyme immobilization into gels based on thermosensitive polymers are currently known. These are, in particular, urease and alkaline phosphatase incorpo rated into poly(N isopropylacrylamide), 6,7 trypsin in the poly(N isopropylacrylamide)-methacrylic acid cоpoly mer gel, 8 asparaginase and β galactosidase incorporated into gels of poly(N isopropylacrylamide) copolymer with acrylic acid, 9,10 and trypsin, В carboxypeptidase, 11 α chy motrypsin 12 incorporated in the poly(N vinylcapro lactam) Ca alginate gel. It was shown in the above men tioned studies that enzymes immobilized in composite gels retain the catalytic activity in both aqueous and mixed water-organic media, as they are stabilized by the smart polymers incorporated in gels. In some cases, the enzy matic activity can also be regulated in these systems by varying the temperature. However, the accessibility of the active sites of the enzymes incorporated in the gel bulk usually decreases due to the diffusion restrictions for the transport of the substrate and the enzymatic reaction prod ucts. Apparently, immobilization of the enzymes on solid surfaces modified by thin layers of thermally sensitive polymers would increase the efficiency of the biocatalysts obtained, in particular, by increasing their mechanical strength, high sorption capacity and the lack of diffusion restrictions for substrate transport toward the enzyme. Thus it has been shown 13 that the adsor...
