中文摘要：

利用静电纺丝法制备含LiCl的聚氨酯（PU）纳米纤维,用牛血清白蛋白（BSA）对纤维亲水改性,于其上固定β-D-半乳糖苷酶,提高酶在油水两相介质中催化转糖苷反应的活力.结果表明,以PU浓度26%（ω）的电纺液制备的直径240～300 nm的PU纤维膜在LiCl辅助作用下吸附BSA高达222 mg/g,使纤维膜的水接触角由103.7o降至77.3o.改性PU膜固定化酶比活力为1.59 U/mg,而未改性PU膜仅为其79.2%.改性膜固定化酶55℃下的活力半衰期高达游离酶的14倍,在4℃下储存45 d活力仍保持80%,而游离酶活力仅剩余16.3%;改性膜固定化酶重复催化42次转糖苷反应活力仍能保持31%.

英文摘要：

Polyurethane（PU） nanofiber with the diameter of 240～300 nm was prepared by electrospinning from 26%（ω） PU solution containing LiCl. In order to increase the catalytic efficiency of β-D-galactosidase immobilized on PU nanofibrous membrane, suitable microenvironment on the membrane was pre-created by hydrophilic modification. BSA was adsorbed with LiCl on PU nanofibrous membrane at the high loading of 222 mg/g. The contact angle of modified PU nanofibrous membrane with water was thus reduced from 103.7o to 77.3o. Then β-D-galactosidase was immobilized on the modified membrane and catalyzed the transgalactosylation reaction in hexanol-water biphasic system. The specific activity of β-D-galactosidase immobilized on PU nanofiber membrane was 1.59 U/mg, while the activity of β-D-galactosidase adsorbed on unmodified PU nanofibrous membrane was its 79.2%. Compared with native enzyme, the half-life of β-D-galactosidase immobilized on PU nanofiber membrane incubated at 55℃ was increased 14 times. The storage stability of β-D-galactosidase immobilized on the membrane at 4℃ was also increased obviously, after storage for 45 d, the activity retained over 80%, whereas the activity of native β-D-galactosidase only 16.3%. The activity of β-D-galactosidase immobilized on PU nanofiber membrane was retained 31% after reuse in 42 times.