辐射聚合离子性水凝胶固定化酵母细胞

IMMOBILIZATION OF YEAST CELLS WITH IONIC HYDROGEL PRODUCED BY RADIATION POLYMERIZATION

在低温(-78℃)下,通过辐照使2-丙烯酰胺2-甲基丙磺酸(TBAS)和聚乙二醇二甲基丙烯酸醇系列单体聚合,获得了具有离子性的水凝胶载体。用这些载体固定化酵母细胞的乙醇生产力均比游离细胞高,其中用poly TBAS-14G固定化细胞的乙醇生产力是游离细胞的4.5倍,每小时糖的转化率达50％。固定化酵母的活性随聚乙二醇二甲基丙烯酸分子中乙二醇数目的增加而增加。固定化酵母具有较高活性的原因是这些高分子载体具有一定的多孔性、膨胀性,载体带有电荷并具有一定的机械强度,固定化细胞能较好地繁殖,使载体内具有较高的细胞密度。

The mixture of an ionic monomer of 2-acrylamido 2-methylpropane-sulfonic acid and a series of polyethylene glycol dimethacrylate monomer were polymerized at -78℃ with 60Coγ-rays and were used for immobilization of yeast cells. The immobilized yeast cells with these carriers had higher ethanol productivity than that without any carriers. The yield of ethanol with polyTBAS-14G carrier was the highest,and increased by 3.5 times compared with the free yeast cells.It was found that the ethanol yield increased with the increase of the glycol number in polyethylene glycol dimethacrylate.The state of the immobilized cells was observed with microscope and it was found that the difference in the ethanol productivity was mainly due to the difference in the internal structure and the properties of polymer carrier. It was considered that the polymer carrier had a proper hydrophilicity, swelling ability,cation in the surface and porousi-ty in the internal structure for immobilizing yeast cells.