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Poly (glycidyl methacrylate) - polystyrene diblocks copolymer grafted nanocomposite microspheres from surface - initiated atom transfer radical polymerization for lipase immobilization / Bunyamin Karagoz in Industrial & engineering chemistry research, Vol. 49 N° 20 (Octobre 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9655–9665 Titre : Poly (glycidyl methacrylate) - polystyrene diblocks copolymer grafted nanocomposite microspheres from surface - initiated atom transfer radical polymerization for lipase immobilization : Application in flavor ester synthesis Type de document : texte imprimé Auteurs : Bunyamin Karagoz, Auteur ; Gulay Bayramoglu, Auteur ; Begum Altintas, Auteur Année de publication : 2011 Article en page(s) : pp. 9655–9665 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Copolymer  Nanocomposite  Microspheres Résumé : 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-ATRP). Two different approaches for the covalent immobilization of lipase onto microspheres were studied for the first time: (1) 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. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101351u [article] Poly (glycidyl methacrylate) - polystyrene diblocks copolymer grafted nanocomposite microspheres from surface - initiated atom transfer radical polymerization for lipase immobilization : Application in flavor ester synthesis [texte imprimé] / Bunyamin Karagoz, Auteur ; Gulay Bayramoglu, Auteur ; Begum Altintas, Auteur . - 2011 . - pp. 9655–9665. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9655–9665 Mots-clés : Copolymer  Nanocomposite  Microspheres Résumé : 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-ATRP). Two different approaches for the covalent immobilization of lipase onto microspheres were studied for the first time: (1) 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. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101351u

Preparation of comb - type magnetic beads by surface - initiated ATRP / Gulay Bayramoglu in Industrial & engineering chemistry research, Vol. 51 N° 32 (Août 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 32 (Août 2012) . - pp. 10629-10640 Titre : Preparation of comb - type magnetic beads by surface - initiated ATRP : Modification with nitrilotriacetate groups for removal of basic dyes Type de document : texte imprimé Auteurs : Gulay Bayramoglu, Auteur ; M. Yakup Arica, Auteur Année de publication : 2012 Article en page(s) : pp. 10629-10640 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Basic  dye  Preparation Résumé : Magnetic poly(hydroxyethyl methacrylate-co-ethylene glycol dimethacrylate) (p(HEMA-EGDMA)) beads were synthesized via suspension polymerization. To prepare a novel core―shell type resin, the magnetic beads were grafted with poly(glycidyl methacrylate) (p(GMA)) via the surface-initiated atom transfer radical polymerization (SI-ATRP) method. The grafted p(GMA) fibrous chains on the magnetic beads were modified with nitrilotriacetate (NTA). The magnetic beads were characterized by FTIR, SEM, and VSM. The carboxyl group content of the p(HEMA-EGDMA-g-GMA)-NTA resin was found to be 9.63 mmol g―1 of beads by the potentiometric titration method. The adsorption of Crystal Violet (CV) and Methylene Blue (MB) as basic dyes by the NTA-modified magnetic beads was investigated. The influence of different experimental parameters such as pH, contact time, and temperature on the removal process was evaluated. The maximum adsorption capacity was found to be 230.1 and 197.5 mg/g for CV and MB, respectively. The adsorption process was described by the Langmuir model more correctly. Adsorption studies of CV and MB onto NTA-modified magnetic beads were also carried out in a magnetically fluidized reactor with different flow rates and initial dye concentrations. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26259767 [article] Preparation of comb - type magnetic beads by surface - initiated ATRP : Modification with nitrilotriacetate groups for removal of basic dyes [texte imprimé] / Gulay Bayramoglu, Auteur ; M. Yakup Arica, Auteur . - 2012 . - pp. 10629-10640. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 32 (Août 2012) . - pp. 10629-10640 Mots-clés : Basic  dye  Preparation Résumé : Magnetic poly(hydroxyethyl methacrylate-co-ethylene glycol dimethacrylate) (p(HEMA-EGDMA)) beads were synthesized via suspension polymerization. To prepare a novel core―shell type resin, the magnetic beads were grafted with poly(glycidyl methacrylate) (p(GMA)) via the surface-initiated atom transfer radical polymerization (SI-ATRP) method. The grafted p(GMA) fibrous chains on the magnetic beads were modified with nitrilotriacetate (NTA). The magnetic beads were characterized by FTIR, SEM, and VSM. The carboxyl group content of the p(HEMA-EGDMA-g-GMA)-NTA resin was found to be 9.63 mmol g―1 of beads by the potentiometric titration method. The adsorption of Crystal Violet (CV) and Methylene Blue (MB) as basic dyes by the NTA-modified magnetic beads was investigated. The influence of different experimental parameters such as pH, contact time, and temperature on the removal process was evaluated. The maximum adsorption capacity was found to be 230.1 and 197.5 mg/g for CV and MB, respectively. The adsorption process was described by the Langmuir model more correctly. Adsorption studies of CV and MB onto NTA-modified magnetic beads were also carried out in a magnetically fluidized reactor with different flow rates and initial dye concentrations. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26259767