Tyrosinase-catalyzed phenol-mediated immobilization of β-agarase on L-lysine-coated magnetic particles for the production of neoagarooligosaccharides from Gelidium amansii

Cross-linked enzyme aggregates of β-agarase (Aga2) were immobilized on L-Lysine-coated magnetic nanoparticles (Lys@Fe3O4) for the production of neoagarooligosaccharides (NAOS) from Gelidium amansii. The support Lys@Fe3O4 was prepared one-pot in aqueous medium whereas Aga2 was engineered to carry five Tyrosine residues at its N-terminus (Aga2Y5N). Cross-linked immobilization of Aga2Y5N on Lys@Fe3O4 was effectively catalyzed by Tyrosinase but its efficiency was further improved with phenol addition, affording the best biocatalyst Aga2Y5N-TP@Lys@Fe3O4. Although its kinetic properties were slightly reduced, overall results showed that Aga2Y5N-TP@Lys@Fe3O4 performed remarkably better than free Aga2Y5N as reflected by its excellent stability at wider pH and temperature ranges. Moreover, Aga2Y5N-TP@Lys@Fe3O4 can be effectively collected and recycled through magnetization, unlike the free Aga2Y5N which cannot be easily retrieved from the reaction mixture after use. Hydrolysis results demonstrate the capability of...