Immobilization of IMP-1 metallo-beta-lactamase: the promising approach for the removal of beta-lactam antibiotics

Metallo-beta-lactamase enzymes are produced by some bacteria which can hydrolyze beta-lactam antibiotics such as penicillins, cephalosporins, cephamycins, and carbapenems.As a result, these enzymes cause bacteria resistance to these antibiotics.In this study, for the first time, IMP-1 metallo-beta-lactamases enzyme was immobilized on CNBr-activated sepharose through covalent bonding.The optimum temperatures of enzyme activity for free and immobilized enzymes were 70°C and 60°C.The optimum pH of IMP-1 activity was 7.5 that after immobilization, changed to 6.5.Due to enzyme immobilization, K m and V max values were decreased from 727.9 to 230.5 µmol and from 71.47 to 10.76 µmol/min for penicillin G as substrate.After 20 reaction cycles, 75% of the enzyme activity was retained, according to a reusability analysis of the immobilized enzyme.Furthermore, as compared to free enzyme, the thermal and storage stability of immobilized enzyme was reduced.Consequently, immobilization of IMP-1 by covalent binding on carriers suitable as a novel biocatalyst can be applied as a promising approach with high efficiency and inexpensive for the removal of antibiotics in hospital and pharmaceutical wastewater.