PREPARATION OF COMBI-MAGNETIC CROSS-LINKED ENZYME AGGREGATES OF CELLULASE AND LIPASE

摘要

Combi-magnetic cross-linked enzyme aggregates (CLEAs) of cellulase and lipase were successfully prepared by co-precipitation of cellulase and lipase using 80% ammonium sulphate and later cross-linking the enzyme aggregates with 100 mM glutaraldehyde cross-linker on amino-functionalized magnetic nanoparticles in 6 h. The synthesized nanoparticles and immobilized enzymes were analyzed and confirmed through X-ray diffraction and Fourier transform infrared. Various parameters affecting the immobilization such as precipitating agent, precipitant concentration, amount of cross-linker, and time of cross-linking were studied. The combi-magnetic CLEAs showed better stability at higher temperature and pH as compared to free enzymes. After immobilization, the reusability retained more than 90% for the first three cycles, which further reduced due to leaching. V_(max) and K_m values show that the immobilized enzyme was more active compared to the free form, while affinity of the enzyme was reduced.