Fabrication of multi-enzyme@ZIF-8 for extraction of anthocyanins from black rice
The α-amylase&cellulase@ZIF-8(A&C@ZIF-8)nanoparticles with good catalytic activity and thermal stability are fabricated by in situ growth method in bulk solution to couple with solvent extraction process for effective extraction of anthocyanins from black rice.In these nanoparticles,the encapsulated α-amylase and cellulase allow dissociation of plant cell wall via hydrolysis of the α-1,4 glycosidic bond and β-1,4 glycosidic bond.Meanwhile,due to the spatial confinement of ZIF-8 matrix,both enzymes can exhibit good thermal stability and solvent tolerance.The A&C@ZIF-8 nanoparticles show polygonal-spherical shape with average sizes of 405nm,and loading content of 18%for both enzymes.The immobilized α-amylase and cellulase in the A&C@ZIF-8 nanoparticles show good tolerance in environment with temperature higher than 72℃,with their activities respectively 33.2%and 247.3%higher than that of their free enzyme counterparts.By coupling the A&C@ZIF-8 nanoparticles with ethanol-water system for co-extraction of anthocyanins from black rice,the extracted amount of anthocyanins can reach 200.39mg/100g,showing an 26.3%increase as compared to the extraction only with ethanol-water system.This work provides a new strategy for the innovative design and fabrication of enzyme-immobilized functional materials for extraction of actives in plant cells.