IIn this study two types of membranes were modified to selectively bind protein; polysulfone membranes were used to purify Green Fluorescent Protein (GFP) from a complex mixture of proteins, whereas cellulose membranes were selected to bind the enzyme laccase, which was examined for the breakdown of the anti-inflammatory drug Diclofenac. Chloromethylated polysulfone (CMPS) ultrafiltration membrane adsorbers grafted with polyacrylic acid polymer brushes for binding of green fluorescent protein were fabricated using the non-solvent induced phase separation (NIPS) method. Polysulfone (PS) was chloromethylated using chlorotrimethylsilane and paraformaldehyde to obtain chloromethylated polysulfone, indicated by a peak at 4.5 ppm using 1H-NMR spectroscopy. The introduction of chloromethyl groups to the membrane surface acted as an initiator for surface polymerization of tert-butyl acrylate (tBA) monomer via surface initiated atom transfer radical polymerization (SI-ATRP) to poly-tert butyl acrylate (poltBA). Selective acid hydrolysis of the pol-tBA brushes for deprotection of the tert-butyl groups yielded polyacrylic acid (PAA) brushes, with effective binding sites for immobilization of protein, confirmed using attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy identified by decrease in transmittance at 1640 cm-1 corresponding to a decrease in hydrogen bonding interactions due to the presence of poly(AA). Increasing the length of time for ATRP led to an increase in polymer grafting, which led to an increase in hydrophilicity, demonstrated from water contact angle studies. Adsorption and flux studies were carried out to further examine the anti-fouling properties of the membranes. Scanning electronic microscope (SEM) images reveal that the grafted membranes exhibit typical features of ultrafiltration membranes, with a dense skin layer and well defined finger-like macrovoid sublayer. Green Fluorescent Protein (GFP) was successfully bound to the grafted brushes. Fluorescent microscopy identified the stable 8 binding of GFP. The produced membranes have strong potential for the selective separation of proteins in downstream processing. The second part of this project used surface initiated atom transfer radical polymerization (SI-ATRP) to successfully graft hydrophilic polymer brushes onto commercial cellulose membrane surfaces, which were capable of immobilizing laccase enzyme. Initiator immobilisation was achieved through esterification of the hydroxyl groups present on the membrane surface with α-bromoisobutyryl bromide (BIBB). As above, SI-ATRP was used to introduce the poly tBA brushes and acid hydrolysis carried out to create poly (AA) brushes. Their presence on the surfaces of the hydrolysed membranes was confirmed through FTIR analysis. The stability of the bound enzymes were challenged at a range of pHs, temperatures and ionic strengths. It was found that the stability of immobilised laccase was enhanced at pH 4 and pH 5 in comparison to the free form at 10oC and at pH 5 at 22 oC. There was no significant difference in activity between the two enzyme forms at pH 6 and pH 7 at 22oC and pH 5 at 30oC. These results suggest that the association of laccase with a support surface may not affect its structural integrity and make it suitable for use in a wide range of conditions. The enzyme bound membranes (EBMs) were capable of breaking down 96% of the anti-inflammatory drug Diclofenac (DCF) after 2 hrs without the addition of any mediator at 22oC and pH 7; conditions similar to drinking water treatment, indicating their strong potential for industrial use.