Research On Preparation Of Nanoscale Modified By Polymer And Its Application For Enzyme Immobilization

Composites is a new high-performance material,which has been widely used in field of enzyme immobilization.It combine the functions of two or more materials and increasing the enzyme loading,stability and reusability of immobilized enzyme by preparation and modification of composite materials.Nanomaterials have larger specific surface area and porosity than other materials,thus increase enzyme loading,stability and binding force between the enzyme and the carrier.It is beneficial to improve the catalytic efficiency of immobilized enzyme,and easy to recycle the immobilized enzyme from the reaction liquid so as to reuse it.Three kinds of carriers were selected to immobilize Candida antarctica lipase B,the immobilization performance was studied,the specific results are as follows:Using a combined electrospun membrane and biocompatible chitosan,we show that the chitosan-functionalized electrospun PMA-co-PAA fibrous membrane can provide effective anchoring sites for immobilization of the lipase,and the resulting membrane show enhanced stability in catalyzing Knoevenagel condensation reactions,potentially having implications for the design of "green" enzyme catalyst for sustainable organic synthesis.Polymethylmethacrylate-co-polyacrylic acid(PMMA-co-PAA)nanofibers were prepared by electrospining technique,followed by modification with chitosan(CTS),then grew polymer brush on the surface of CTS.The modified nanofibers were explored as the novel support for lipase immobilization,while the influence of enzymatic loading andstability was reached.The study shows that the hydrophilicity and diameter of the modified nanofibers were improved.The enzyme loading reached 165mg/g while the concentration of sodium methacrylate was 0.lmol/L.In addition,compared with free lipase,the immobilized lipase showed a better stability resistance to temperature and pH change at the lowest point.The relative activity of the immobilized lipase was 4.25 times and 5 times higher than that of the free lipase when the PH at 5-9 and temperature changes in the range of 20-60 ?.The relative activity of the immobilized enzyme compared with free enzyme up to 2.7 times after storage of 10h at 60 ?.3-D framework were preparation by carbonizing cheap melamine.The biocompatibility of carbon fiber were improved by compound with CTS.Using it as a carrier immobilized enzyme.Research shows that:the crystallinity of carbon fiber materials modified by CTS has been improved.The enzyme loading reached 185.3mg/g while the concentration of CTS was 2.5%.The effect of glutaraldehyde concentration on enzyme loading was positive,but it has decreased the activity of enzyme and the catalytic efficiency when glutaraldehyde concentration was too high.The stability of lipase has been improved after the immobilization process.