Process conditions optimization and study of pH and thermal stability of free and immobilized gutaminase-free recombinant L-asparaginase II of Pactobacterium carotovorum MTCC 1428 from Escherichia coli

Abstract

L-asparaginase (EC 3.5.1.1) is used for the treatment of acute lymphocytic leukemia and food processing of starch rich foods for reducing the acrylamide formation. In our current efforts, we have immobilized the purified glutaminase-free recombinant Lasparaginase II of Pectobacterium carotovorum MTCC 1428 from Escherichia coli BL21 (DE3) on glutaraldehyde activated chitosan beads. The purified recombinant L-asparaginase II has no partial glutaminase activity which is a pre-requisite to reduce the possibility of side effects during the course of anticancer therapy. In order to study the best conditions for the performance of free enzymes and immobilized enzymes, response surface methodology was used to optimize the pH and temperature of the process conditions. It was found that the most favorable pH and temperature for the free enzyme were pH 7.83 and 47.64°C while for the immobilized enzyme, the optimum pH and temperature levels were found to be 7.88 and 48.07 °C. Furthermore, the thermal and pH studies of free and immobilized enzymes were studied under various combinations of pH and temperature and finally the thermodynamic parameters of free and immobilized glutaminase-free recombinant asparaginase were evaluated.