Supermacroporous hydrophobic affinity sorbents for penicillin acylase purification

Penicillin acylase (PA, EC 3.5.1.11) is used as a raw material in the production of semi-synthetic penicillins. Although there are many methods for PA purification, affinity chromatography is advantageous as it provides efficient one step purification. In this study, poly(2-hydroxyethyl methacrylate) based cryogel column containing hydrophobic N-methacryloyl-L-tryptophan (MATrp) functional monomer as a ligand was prepared. Interaction of MATrp with amino acids in PA structure is the basis of hydrophobic interaction chromatography in this study. PHEMA and PHEMATrp cryogel columns were characterized by surface area measurements, infrared spectroscopy, swelling tests, elemental analysis and scanning electron microscopy (SEM). Initial PA concentration, pH, effect of temperature, amount of ligand, flow rate, ionic strength and time on PA adsorption on PHEMATrp cryogel were investigated. Optimum pH was determined as 5.0 for PA adsorption and maximum adsorption capacity was obtained as 6.40 mg/g. It was observed that adsorption capacity increased with the increasing of temperature. Also, PA adsorption increased up to 0.25 M salt concentration and decreased in higher salt concentrations. Data obtained in this affinity system suggests that hydrophobic interactions are dominant. In the last stage of the study, PA was purified from Penicillium chrysogenum with 76.3% yield and 332.3 purification factor.