离子交换与吸附

右旋糖酐发酵液酶解制备的右旋糖酐40经过离子交换柱层析分离纯化后，相关产品指标达到国际最高标准。右旋糖酐发酵液酶解制备的右旋糖酐40，产率可达31.70 g/L，产品的重均分子量(M_w)为36125、10%大分子M_w为106805、10%小分子M_w为7272，达到欧洲标准；阳-阴-阳-阴不连续离子交换柱层析右旋糖酐40产品的炽灼残渣、重金属和氮含量分别为0.01%、0.000643%和0.004%，炽灼残渣和氮含量达到国际最高标准，重金属含量达国家标准，电导率降至70μS/cm以下；阳-阴-阳-阴-阳-阴不连续离子交换柱层析右旋糖酐40的炽灼残渣、重金属和氮含量分别为0.01%、0.0001%和0.005%，均达到国际最高标准，电导率降至10μs/cm以下；3次阳-阴连续离子交换柱层析右旋糖酐40的炽灼残渣、重金属和氮含量分别为0.01%、0.0001%和0.004%，均达到国际最高标准，重均分子量和分子量分布达到欧洲标准，收率超过85%，电导率降至5μS/cm以下。

Dextran 40 prepared by enzymatic hydrolysis of dextran fermentation broth was separated and purified by ion exchange column chromatography, achieving the highest international standards for product indexes.Dextran 40 was prepared by enzymatic hydrolysis of dextran fermentation broth, with a yield of 31.70 g/L of fermentation broth. The weight average molecular weight and molecular weight distribution of product were M_w 36125, 10% macromolecular M_w 106805, and 10% small molecular M_w 7272, meeting European standards. The contents of ignition residue, heavy metals, and nitrogen in the dextran 40 product obtained by cation – anion-cation-anion discontinuous ion exchange column chromatography were 0.01%, 0.000643%, and 0.004%,respectively. The contents of ignition residue and nitrogen met the highest international standards, while the heavy metal content met the national standard. The conductivity dropped below 70 μS/cm. The contents of ignition residue, heavy metals, and nitrogen in the Dextran 40 product by cation-anion-cation-anion-cation-anion discontinuous ion exchange column chromatography were 0.01%, 0.0001%, and 0.005%, respectively, meeting the highest international standards. The conductivity dropped below 10 μS/cm. The ignition residue, heavy metals, and nitrogen contents of dextran 40 obtained from three consecutive cation – anion ion exchange column chromatographies were 0.01%, 0.0001%, and 0.004%, respectively, meeting the highest international standards.The weight average molecular weight and molecular weight distribution met European standards. The yield exceeded 85%. The conductivity dropped below 5 μS/cm.