title: Lipase immobilization on differently functionalized vinyl-based amphiphilic polymers: influence of phase segregation on the enzyme hydrolytic activity.
abstract: Microbial lipase from  Candida rugosa  was immobilized by physical adsorption onto an ethylene-vinyl alcohol polymer (EVAL) functionalized with acyl chlorides. To evaluate the influence of the reagent chain-length on the amount and activity of immobilized lipase, three differently long aliphatic fatty acids were employed (C8, C12, C18), obtaining EVAL functionalization degrees ranging from 5% to 65%. The enzyme-polymer affinity increased with both the length of the alkyl chain and the matrix hydrophobicity. In particular, the esterified polymers showed a tendency to give segregated hydrophilic and hydrophobic domains. It was observed the formation of an enzyme multilayer at both low and high protein concentrations. Desorption experiments showed that  Candida rugosa  lipase may be adsorbed in a closed form on the polymer hydrophilic domains and in an open, active structure on the hydrophobic ones.  The best results were found for the EVAL-C18 13% matrix that showed hyperactivation with both the soluble and unsoluble substrate after enzyme desorption. In addition, this supported biocatalyst retained its activity for repetitive cycles.
authors.affiliation: Department of Chemistry and Material Technology, ENEA CR Casaccia , Via Anguillarese 301, 00123, Rome, Italy.
authors.forename: Mariangela
authors.initials: M
authors.lastname: Bellusci
authors.forename: Iolanda
authors.initials: I
authors.lastname: Francolini
authors.forename: Andrea
authors.initials: A
authors.lastname: Martinelli
authors.forename: Lucio
authors.initials: L
authors.lastname: D'Ilario
authors.forename: Antonella
authors.initials: A
authors.lastname: Piozzi
mesh_terms: D002175:Candida / Q000201:enzymology*; D004800:Enzymes, Immobilized / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D057927:Hydrophobic and Hydrophilic Interactions; D007700:Kinetics; D008049:Lipase / Q000737:chemistry* / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D011108:Polymers / Q000737:chemistry* / Q000378:metabolism*; D013696:Temperature; D014753:Vinyl Compounds / Q000737:chemistry*
chemical_list: D004800:Enzymes, Immobilized; D011108:Polymers; D014753:Vinyl Compounds; D008049:Lipase