Functionalized microfiltration (MF) membranes are becoming increasingly popular in biotechnology and pharmaceutical industries. Affinity based separation using functionalized MF membranes are emerging as a potential alternative to conventional bead-based column chromatography. Functionalization of MF membranes offer choices of attaching the active groups or moieties on different types of materials (hydrophilic, hydrophobic), environments (external surface, internal pore surface) and dimensions (pore size varying from 0.05 to 10 ƒÝm).This study deals with functionalization of microfiltration (MF) membranes within the pore structures and their applications in the field of bio-separations. Pore surface possesses the advantage of attaching more number of active groups or moieties on a single membrane as compared to the external surface of the membrane. Wide pore structure of MF membranes allows easy access of the active groups/moieties to the target molecules, under convective flow condition. Therefore, the mass transfer resistance, and hence the processing time per unit volume of feed is less.

This study describes different pathways to functionalize MF membranes with various active groups. Different functionalization techniques and experimental conditions are adopted for different situations. Once the pore surface of the membrane is activated, further attachments of groups, moieties or molecules are carried out depending on the area of application. For example, in this research work, avidin is attached to separate a biotin-tagged protein from mixture. Also, an enzyme is separated from mixture, and then enzyme-substrate reaction is studied within the membrane phase. Effect of spacer molecule on the efficiency of the process is studied. Characterizations of the functionalized membranes are also presented in this study. Characteristic fouling of the membrane matrix associated with bio-separations is also analyzed critically.