Preparation of nanoparticles which contains histidine for immobilization of Trametes versicolor laccase

Poly(hydroxyethyl methacrylate-N-methacryloly-(l)-histidinemethylester) [PHEMAH] nanospheres with an average size of 158.2 nm were prepared by surfactant free emulsion polymerization conducted in an aqueous dispersion medium. MAH was synthesized using methacryloyl chloride and l-histidine methyl ester. Then, Cu(II) ions were attached as a metal ligand because of its affinity towards proteins. Specific surface area of the PHEMAH nanospheres was calculated to be 1454 m²/g. The PHEMAH nanospheres were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Average particle size, size distribution, and surface charge measurements were also performed. Elemental analysis of MAH for nitrogen was estimated as 0.42 mmol/g nanosphere. Then, PHEMAH-Cu²⁺ nanospheres were used for laccase adsorption in a batch system. The maximum laccase adsorption was observed at pH 6.0. Laccase could be repeatedly adsorbed and desorbed with PHEMAH-Cu²⁺ nanospheres without noticeable loss in the adsorption capacity.