Reversible papain immobilization onto poly(AAm–MMA)-based cryogels

In the present work, new dye ligand affinity chromatographic support for papain adsorption was synthesized. For this purpose, poly(acrylamide–methyl methacrylate) [poly(AAm–MMA)] cryogels were synthesized by using the free radical cryopolymerization technique. These cryogels were then functionalized with Reactive Green 19 dye and were characterized with Fourier transform infrared, environmental scanning electron microscopy, macroporosity and energy-dispersive X-ray spectrometer analyses. Incorporation of the dye molecule onto cryogel structure was clearly demonstrated by these characterization techniques and pore diameter of the cryogel was found to be around 30–40μm. Effects of medium pH, initial papain concentration, medium temperature and ionic strength on the papain adsorption onto dye-attached cryogel were also investigated. Maximum papain adsorption was found to be 40.66 mg g−1 cryogel by using pH 5.5 acetate buffer at 25°C. Reusability profile of the cryogel was also investigated and it was found that the adsorption capacity of the cryogel decreased only about 2.13% at the end of the 10 reuses. Activity studies of papain in desorption medium were carried out and it was found that desorbed papain was active and showed 88.5% of its initial activity.