Enzyme immobilization has attracted great attention for improving the performance of enzymes in industrial applications.This work was designed to create a new support for Candida rugosa lipase(CRL)immobilization.A por...Enzyme immobilization has attracted great attention for improving the performance of enzymes in industrial applications.This work was designed to create a new support for Candida rugosa lipase(CRL)immobilization.A porous poly(vinyl acetate–divinyl benzene)microsphere coated by a zwitterionic polymer,poly(maleic anhydride-alt-1-octadecene)and N,N-dimethylethylenediamine derivative,was developed for CRL immobilization via hydrophobic binding.The catalytic activity,reaction kinetics,stabilities and reusability of the immobilized CRL were investigated.It demonstrated the success of the zwitterionic polymer coating and subsequent CRL immobilization on the porous microsphere.The immobilized lipase(p2-MS-CRL)reached27.6 mg·g^-1 dry carrier and displayed a specific activity 1.5 times higher than free CRL.The increase of Vmax and decrease of Kmwere also observed,indicating the improvement of catalytic activity and enzyme-substrate affinity of the immobilized lipase.Besides,p2-MS-CRL exhibited significantly enhanced thermal stability and pH tolerance.The improved performance was considered due to the interfacial activation regulated by the hydrophobic interaction and stabilization effect arisen by the zwitterionic polymer coating.This study has thus proved the advantages of the zwitterionic polymer-coated porous carrier for lipase immobilization and its potential for further development in various enzyme immobilizations.展开更多
基金Supported by the National Natural Science Foundation of China(21621004,21878222).
文摘Enzyme immobilization has attracted great attention for improving the performance of enzymes in industrial applications.This work was designed to create a new support for Candida rugosa lipase(CRL)immobilization.A porous poly(vinyl acetate–divinyl benzene)microsphere coated by a zwitterionic polymer,poly(maleic anhydride-alt-1-octadecene)and N,N-dimethylethylenediamine derivative,was developed for CRL immobilization via hydrophobic binding.The catalytic activity,reaction kinetics,stabilities and reusability of the immobilized CRL were investigated.It demonstrated the success of the zwitterionic polymer coating and subsequent CRL immobilization on the porous microsphere.The immobilized lipase(p2-MS-CRL)reached27.6 mg·g^-1 dry carrier and displayed a specific activity 1.5 times higher than free CRL.The increase of Vmax and decrease of Kmwere also observed,indicating the improvement of catalytic activity and enzyme-substrate affinity of the immobilized lipase.Besides,p2-MS-CRL exhibited significantly enhanced thermal stability and pH tolerance.The improved performance was considered due to the interfacial activation regulated by the hydrophobic interaction and stabilization effect arisen by the zwitterionic polymer coating.This study has thus proved the advantages of the zwitterionic polymer-coated porous carrier for lipase immobilization and its potential for further development in various enzyme immobilizations.
文摘乌深1井是大港油田“1518”勘探工程的一口重点预探井,完钻井深5850m,其中φ311.1mm井眼的深度及φ244.5mm套管的下深(5456.9 m)创下了全国陆上油田已完钻井的最高记录,是一口高难度的超深井。针对该井的井身结构和地层情况确定了一套适应各井段的钻井液体系。上部地层(井深2300 m 以上)使用钾盐聚合物钻井液;下部地层(井深2300 m以下)使用硅基钻井液体系,进一步提高钻井液的防塌抗温效果。配合了一定的处理维护方法和防漏堵漏技术。结果表明,该钻井液体系抑制性和防塌性强,具有稳定井壁、携岩净化、抗高温、润滑防卡的能力,满足了深井大井眼钻井施工的要求。
