Jarudilokkul S, Poppenborg L H, Stuckey D C
Department of Chemical Engineering and Chemical Technology, Imperial College of Science, Technology and Medicine, Prince Consort Road, London SW7 2BY, UK.
Biotechnol Bioeng. 1999 Mar 5;62(5):593-601.
The back-extraction of proteins encapsulated in AOT reverse micelles was performed by adding a counterionic surfactant, either TOMAC or DTAB. This novel backward transfer method gave higher backward extraction yields compared to the conventional method with high salt and high pH of the aqueous stripping solution. The protein activity was maintained in the resulting aqueous phase, which in this case had a near neutral pH and low salt concentration. A sharp decrease of the water content was observed in the organic phase corresponding to protein back-extraction using TOMAC. The backward transfer mechanism was postulated to be caused by electrostatic interaction between oppositely charged surfactant molecules, which lead to the collapse of the reverse micelles. The back-extraction process with TOMAC was found to be very fast; more than 100 times faster than back-extraction with the conventional method, and as much as 3 times faster than forward extraction. The formation of 1:1 complexes of AOT and TOMAC in the solvent phase was observed, and these hydrophobic complexes could be efficiently removed from the solvent using adsorption onto Montmorillonite in order for the organic solvent to be reused. A second cationic surfactant, DTAB, confirmed the general applicability of counterionic surfactants for the backward transfer of proteins.
通过添加反离子表面活性剂TOMAC或DTAB，对包裹在AOT反胶束中的蛋白质进行反萃取。与使用高盐和高pH值的水相剥离溶液的传统方法相比，这种新型的反向转移方法具有更高的反萃取产率。蛋白质活性在所得水相中得以保持，此时水相的pH值接近中性且盐浓度较低。使用TOMAC进行蛋白质反萃取时，观察到有机相中含水量急剧下降。推测反向转移机制是由带相反电荷的表面活性剂分子之间的静电相互作用引起的，这导致反胶束的崩溃。发现使用TOMAC的反萃取过程非常快；比传统方法的反萃取快100多倍，比正向萃取快3倍之多。观察到在溶剂相中形成了AOT和TOMAC的1:1配合物，这些疏水配合物可以通过吸附到蒙脱石上而有效地从溶剂中去除，以便有机溶剂能够重复使用。第二种阳离子表面活性剂DTAB证实了反离子表面活性剂对蛋白质反向转移的普遍适用性。
