A novel layered cross-linked enzyme aggregates (CLEAs) of Candida sp. lipase was developed. In the preparation of the novel enzyme aggregates
nano-ZnO particles were modified and cross-linked
which were used as the core of the immobilized lipase
then enzyme molecules were cross-linked on the surface of the nanoparticles
which formed a layered structure. The obtained results showed the bovine serum albumin (BSA) was the suitable agent to modify nano-ZnO particles among the test agents. The other factors affecting the activity of nano layered CLEAs (BSA-N-LCLEAs)
such as ammonium sulfate saturation
concentration of glutaraldehyde
temperature and time for cross-linking reaction
were investigated. The optimum conditions were as follows:ammonium sulfate saturation 58%
glutaraldehyde concentration 3.5%
cross-linking temperature 0℃ and time 2 h. Compared with the traditional CLEAs
the recovered activity of BSA-N-LCLEAs increased about 196.5%. Scanning electron microscopy (SEM) characterization indicated that BSA-N-LCLEAs increased significantly compared to conventional CLEAs. Both pH stability and thermo stability of BSA-N-LCLEAs were improved. Furthermore
the layered CLEAs was used to synthesize astaxanthin succinate. The yields of astaxanthin were about 90%. The immobilized lipase could be reused for five batches
which indicated it had good operational stability.