Preparation of composite carriers for tyrosine purification

Tyrosine is an amino acid that is non-essential for the human body and can be produced by the body using L-phenylalanine. Tyrosine contributes to the production of important brain chemicals, regulation of mood, reduction of stress level, production of melanin pigment, regulation of thyroid functions, and other critical metabolic activities. Therefore, high purity synthesis of it has a commercial importance. Molecular printing is a cost effective, easy to prepare and highly reproducible method for obtaining the desired molecule with high purity and specificity. This technology is used frequently and successfully in the purification studies carried out today. Cryogels are super macroporous polymeric gels which are prepared by radicalic polymerization below freezing temperature and have high flexibility and durability. Therefore, the use of biomolecules in purification studies is quite high. In this study, tyrosine imprinted magnetic silica microspheres were synthesized and these microspheres were embedded in poly(2-hydroxyethyl methacrylate) based cryogels to prepare a composite carrier that has high selectivity and high chemical/mechanical resistance after characterization by SEM, FTIR, ESR and EDX. The prepared composite carrier was first characterized by SEM, FTIR, ESR and EDX methods. Then, optimum conditions for tyrosine adsorption were determined in the batch system by a rotator. Maximum tyrosine adsorption capacity was found as 62.27 mg/g in pH 8.0 buffer solution prepared at room temperature in aqueous solution. The tyrosine adsorbed by the prepared composite carrier was desorbed using 0.1 M NaCl after each analysis and the usability of the composite carrier was examined. In addition, the selectivity of the composite carrier aganist the competitive agents was investigated. Finally, with the mathematical calculations, the adsorption isotherm model which is compatible for the interaction between tyrosine and composite carrier was determined. It has been found that the developed composite carrier can be used successfully in tyrosine purification.