Gabrovska Katya, Georgieva Aneliya, Godjevargova Tzonka, Stoilova Olya, Manolova Nevena
University Prof Dr A Zlatarov, Department of Biotechnology, Bourgas, Bulgaria.
J Biotechnol. 2007 May 10;129(4):674-80. doi: 10.1016/j.jbiotec.2007.01.014. Epub 2007 Jan 30.
(Poly)acrylonitrile/chitosan (PANCHI) composite membranes were prepared. The chitosan layer was deposited on the surface as well as on the pore walls of the base membrane. This resulted in the reduction of the pore size of the membrane and in an increase of their hydrophilicity. The pore structure of PAN and PANCHI membranes were determined by TEM and SEM analyses. It was found that the average size of the pore under a selective layer base PAN membrane is 7 microm, while the membrane coated with 0.25% chitosan shows a reduced pore size--small or equal to 5 microm and with 0.35% chitosan--about 4 microm. The amounts of the functional groups, the degree of hydrophilicity and transport characteristics of PAN/Chitosan composite membranes were determined. Urease was covalently immobilized onto all kinds of PAN/chitosan composite membranes using glutaraldehyde. Both the amount of bound protein and relative activity of immobilized urease were measured. The highest activity (94%) was measured for urease bound to PANCHI2 membranes (0.25% chitosan). The basic characteristics (pH(opt), pH(stability), T(opt), T(stability), heat inactivation and storage stability) of immobilized urease were determined. The obtained results show that the poly(acrylonitrile)chitosan composite membranes are suitable for enzyme immobilization.
制备了（聚）丙烯腈/壳聚糖（PANCHI）复合膜。壳聚糖层沉积在基膜的表面以及孔壁上。这导致膜的孔径减小且亲水性增加。通过透射电子显微镜（TEM）和扫描电子显微镜（SEM）分析确定了PAN和PANCHI膜的孔结构。结果发现，选择性层基PAN膜下孔的平均尺寸为7微米，而涂覆0.25%壳聚糖的膜孔径减小——小于或等于5微米，涂覆0.35%壳聚糖的膜孔径约为4微米。测定了PAN/壳聚糖复合膜的官能团数量、亲水性程度和传输特性。使用戊二醛将脲酶共价固定在各种PAN/壳聚糖复合膜上。测定了固定化脲酶的结合蛋白量和相对活性。与PANCHI2膜（0.25%壳聚糖）结合的脲酶活性最高（94%）。测定了固定化脲酶的基本特性（最适pH、pH稳定性、最适温度、温度稳定性、热失活和储存稳定性）。所得结果表明，聚（丙烯腈）壳聚糖复合膜适用于酶固定化。
