中空纤维膜组件在生物分子反应萃取中的应用

摘要

纯化从发酵培养液和其它天然来源的生物分子,分离步骤较多,会造成一定的损失.通过待分离的"靶"分子与载体分子反应,形成复合物,可选择性地纯化"靶"分子.反应形成的复合物由于在有机相中的溶解性提高,从而使"靶"分子从复杂的培养液混合物中分离出来的方法称为"反应萃取".该方法克服了常规分离技术的许多缺点.在降低分离过程中产品的损失方面很有潜力.本文报道了该方法在一些药物,包括氨基酸和二肽分离中的应用.实验系统是一套允许两种溶液分别流过管层和壳层的,具有列管式结构的中空纤维膜组件.料液和有机溶剂分别流过管层和壳层.靶溶质分子扩散到水-有机相界面与载体形成复合物;载体-溶质复合物被转运到壳层而被重新回收得到.该项研究的目的有以下三方面:1.应用商品化的膜组件,研究在不同条件(如料液的pH和有机相浓度)下,溶质的萃取百分率:2.直接应用实验数据推导出模式方程以确定总传质系数:3.尝试从"工业的"样品中分离掉杂质(如多肽).%Separation and purification of biomolecules from a fermentation broth or from a natural media involve many steps. Each step contributes to the product cost and product loss. The selective separation of any "target" product from the complex mixture can be accomplished by allowing a reaction between the molecule and a carrier. The carrier is dissolved in an organic phase that preferentially dissolves the reactant-carrier complex and this method is known as "reactive extraction". This method has the potential to overcome many disadvantages of the conventional separation techniques and could minimize the product cost and loss. In this report, the application of this method for the separation of some pharmaceutical products including amino acids and dipeptides is presented. The experimental system involves a hollow-fibre membrane module which has a shell-and-tube configuration and allows flow of two solutions in the fibre and shell sides. The feed and organic solutions are circulated on the fibre side and shell side, respectively. The target solute molecules diffuse to the aqueous-organic interface, forms a complex with the carrier; the carrier-solute complex is transported to the shell side, where it can be recovered. The results of extraction into the organic phase are presented for a variety of process conditions. The stability of the reactive extraction process in long-term operation is mentioned.The aim of this study was threefold:(i) To examine the extraction percentage of the solutes at various process conditions (e. g. feed pH and organic phase concentration) with a commercially available membrane module;(ii) To derive simple modelling equations for the determination of the overall mass transfer coefficient from straightforward use of the experimental data;(iii) To test an "industrial" sample for removing undesirable solutes (e. g. peptides etc. ).