Poly(glycidyl methacrylate)-Polystyrene Diblocks Copolymer Grafted Nanocomposite Microspheres from Surface-Initiated Atom Transfer Radical Polymerization for Lipase Immobilization: Application in Flavor Ester Synthesis

Karagöz B., Bayramoglu G., Altintas B., BICAK N., Arica M. Y.

INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH, vol.49, no.20, pp.9655-9665, 2010 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 49 Issue: 20
  • Publication Date: 2010
  • Doi Number: 10.1021/ie101351u
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.9655-9665
  • Istanbul Technical University Affiliated: Yes


Functional hairy poly(styrene-b-glycidylmethacrylate) (P(S-GMA)) brushes were generated by grafting from bromoacetylated poly(styrene-divinylbenzene) (P(S-DVB)) microspheres via surface-initiated atom transfer radical polymerization (SI-AIRP). Two different approaches for the covalent immobilization of lipase onto microspheres were studied for the first time: (I) direct immobilization of lipase to the polymer brushes via their epoxy groups, and (2) immobilization of lipase via glutaraldehyde coupling after attachment of a spacer arm (hexamethylendiamine (HMDA)) to the polymer brushes. The covalent immobilization of the lipase on microspheres after spacer-arm attachment and glutaraldeyhde coupling was found to be the more effective than the direct binding method. In this case, a maximum value of the immobilized enzyme activity 498.5 U g(-1) was found with an enzyme loading of 27.6 mg per gram of support. Thermal and storage stabilities increase upon immobilization on the P(S-DVB)-g-P(S-GMA)-HMDA-GA microspheres. Finally, esterification reactions have been performed to produce ethyl acetate and isoamyl acetate in a solvent-free system and in n-hexane using lipase-immobilized P(S-DVB)-g-P(S-GMA)-HMDA-GA microspheres. The immobilized lipase was effectively reused in successive batch runs in a solvent-free system for isoamyl acetate synthesis, and only 21% activity was lost after 10 cycles.