Green immobilization of lipase based on a catechol-polyamine coating for efficient synthesis of octenyl succinic...

The chemical immobilization method typically employs glutaraldehyde to create covalent linkages between enzymes and supports. While this approach offers high stability and reusability, its lack of eco-friendliness and suboptimal biocompatibility often result in enzyme deactivation, ultimately compromising immobilization efficiency. To replace non-green linker like glutaraldehyde, we developed a novel strategy by coating magnetic polyacrylamide microspheres with a catechol-polyamine network. This biocompatible and environmentally friendly network coating not only provides a mild microenvironment for enzymes and abundant grafting sites, but also enables precise control over quinone group density by varying the polyamine species, thereby optimizing enzyme loading and catalytic performance. The immobilized lipase exhibited a high activity recovery of 86.2%, corresponding to 174% of the activity of previously reported glutaraldehyde-immobilized systems. The reusability retained 72.8% activity after 10 cycles-outperforming most reported systems (typically about 37% after 5 cycles). The immobilized lipase catalyzed the synthesis of octenyl succinic anhydride modified (OSA starch) with a substitution degree of 0.0265, markedly outperforming the free enzyme (0.0165) and underscoring its strong potential for industrial biocatalysis.