DEVELOPMENT OF COMPOSITE OF CHITOSAN AND DEXTRAN FOR SEPARATION OF PROTEINS AND ITS APPLICATION FOR INDUSTRIAL LARGE SCALE PROTEIN SEPARATION

离子交换色谱法用于大规模工业分离蛋白质。许多离子交换剂已被研制出来。葡聚糖-DEAE如DEAE Sephadex a -50 （Pharmacia LKB Biotechnology）是一种非常好的蛋白质分离剂。然而，由于它非常柔软，即使在非常慢的流速下，它也会被压缩在一个柱中，因此它不能用于工业规模的蛋白质分离。在本工作中，我们开发了一种壳聚糖与葡聚糖- deae的复合材料，使葡聚糖- deae具有较强的硬度。葡聚糖- deae的载体是壳聚糖珠壳珠2501 (Ch-2501, Fuji Spinning Co.)，它是一种坚硬的凝胶，本身就是蛋白质的吸附剂。我们通过与葡聚糖溶液接触，使葡聚糖渗透到Ch-2501的大孔中。然后，将大孔中的葡聚糖交联，在葡聚糖网络上引入DEAE。成品（以下称为Ch-Dx-DEAE-2）是硬的，根本没有压缩在一个柱。pH值对BSA的平衡吸附热有较大影响。这意味着Ch-Dx-DEAE-2可以用于蛋白质的分离。等温线与Langmuir方程有很好的关联。Ch-Dx-DEAE-2吸附BSA的饱和容量分别是DEAE Sepharose Fast Flow （Pharmacia LKB Biotechnology）、Ch-2501和DEAE Sephadex A-50的4.5倍、2.5倍和1.3倍。实验突破曲线与考虑颗粒内扩散、液膜扩散和床层轴向扩散的理论突破曲线吻合较好。通过对实验突破曲线与理论突破曲线的匹配，确定了BSA的粒子内有效扩散系数。Ch-Dx-DEAE-2的扩散系数在上述离子交换剂中最大。它比Ch-2501大十倍。吸附在Ch-Dx-DEAE-2上的牛血清白蛋白易于NaCl水溶液解吸。床层中BSA的洗脱曲线非常清晰。峰值为吸附过程中BSA饲料浓度峰值的870倍。这是使用世界上常用的最好的商业离子交换器所获得的4倍大。少

Ion exchange chromatography is useful for large industrial-scale separation of proteins. A number of ion exchangers have been developed. Dextran-DEAE such as DEAE Sephadex A-50 (Pharmacia LKB Biotechnology) is a very good protein separator. However since it is very soft, it is compressed in a column even in very slow flow rate and therefore it can not be used in industrial-scale protein separation.In the present work, we have developed a composite of chitosan and dextran-DEAE to make the dextran-DEAE hard. The supporter of the dextran-DEAE was a chitosan bead, Chitopearl 2501 (Ch-2501, Fuji Spinning Co.), which was a hard gel and an adsorber of protein in itself. We let dextran penetrate into the macropores of Ch-2501 by contacting with dextran solution. Thereafter, the dextran in the macropore was cross-linked and then DEAE was introduced on the dextran network. The finished product (hereafter called Ch-Dx-DEAE-2) was hard and was not compressed in a column at all. The equilibrium iso … More therm for adsorption of BSA was affected by pH considerably. This means that Ch-Dx-DEAE-2 is feasible for separation of proteins. The isotherms were correlated well by the Langmuir equation. The saturation capacity for adsorption of BSA on Ch-Dx-DEAE-2 was 4.5,2.5, and 1.3 times larger than those of DEAE Sepharose Fast Flow (Pharmacia LKB Biotechnology), Ch-2501, and DEAE Sephadex A-50, respectively. The experimental breakthrough curve agreed well with the theoretical breakthrough curve obtained by considering the intraparticle diffusion, liquid film diffusion, and axial dispersion in the bed. The intraparticle effective diffusivities of BSA were determined by matching the experimental breakthrough curves with the theoretical ones. The diffusivity in Ch-Dx-DEAE-2 was the largest in the above ion exchangers. It was ten times larger than that in Ch-2501. BSA adsorbed on Ch-Dx-DEAE-2 could be desorbed using NaCl aqueous solution easily. The elution curve of BSA from the bed was very sharp.The value of the peak was 870 times larger than that of feed concentration of BSA in adsorption process. This is 4 times larger than that obtained using the best commercial ion exchanger which is used commonly in the world. Less