Magnetic Nanobiocatalysts Based on Immobilized Cellulase.

Biocatalysts based on magnetically responsive supports and the immobilized enzyme - cellulase- demonstrated the high activity in the carboxymethylcellulose (CMC) hydrolysis. Magnetic supports were obtained by two ways: (i) the synthesis of magnetite nanoparticles (NPs) followed by silica shell coating, (ii) the form magnetite NPs by crystallization ones in the pores of mesoporous silica. Physico-chemical methods (low-temperature nitrogen adsorption, scanning electron microscopy, electron-transparent specimens for transmission electron microscopy and magnetic measurements) were utilized for characterization of the structure and surface of the obtained magnetic support. The loading of the enzyme on magnetic supports of both types was approximately the same and amounted to 75-78 %. Cellulase immobilized on magnetic mesoporous silica (SiO₂@Fe₃O₄@CEL) showed 87 % activity of the free enzyme. The scientific novelty of this work is that the controlled pore size in the mesopore range allows bulky enzyme molecules to be immobilized. The large surface area improves catalytic efficiency by increasing enzyme loading and finely dispersing biocatalyst molecules. The limiting effect of mesopores can improve the stability of the enzyme and its resistance to extreme pH and temperature. However, the use of immobilized cellulase may be limited due to the efficiency of the regeneration process. As a solution to this problem, the use of magnetic nanoparticles incorporated into a mesoporous silica matrix is proposed. The magnetic nanobiocatalyst can be easily removed from the reaction mixture using an external magnet. [ABSTRACT FROM AUTHOR]