title: Immobilization of lipase on chitin and its use in nonconventional biocatalysis.
abstract: Chitin was functionalized with hexamethylenediamine followed by glutaraldehyde activation, and its capacity to bind Candida rugosa lipase was investigated. The loading of 250 units g(-1) support showed to be effective, resulting in a uniform enzyme fixation with high catalytic activity. Both free and immobilized lipases were characterized by determining the activity profile as a function of pH, temperature, and thermal stability. For the immobilized lipase, the influence of the reaction temperature and substrate polarity in nonconventional biocatalysis was also analyzed. Production of butyl esters was found to be dependent on the substrate partition coefficient, which accounts the greatest value for the system butanol and butyric acid. The highest enzyme activity was found for the system butanol and caprylic acid at a reaction temperature of 40 degrees C. Under such conditions, the operational stability tests indicated that a small enzyme deactivation occurs after 12 batches, revealing a biocatalyst half-life of 426.7 h.
authors.affiliation: Biocatalysis Laboratory, Department of Chemical Engineering, Faculdade de Engenharia Química de Lorena, 12606-970 Lorena, SP, Brazil.
authors.forename: Fabrício M
authors.initials: FM
authors.lastname: Gomes
authors.forename: Ernandes B
authors.initials: EB
authors.lastname: Pereira
authors.forename: Heizir F
authors.initials: HF
authors.lastname: de Castro
mesh_terms: D000440:Butanols / Q000378:metabolism; D020148:Butyric Acid / Q000378:metabolism; D002175:Candida / Q000201:enzymology; D002384:Catalysis; D002686:Chitin / Q000737:chemistry*; D003432:Cross-Linking Reagents; D004800:Enzymes, Immobilized / Q000737:chemistry*; D007700:Kinetics; D008049:Lipase / Q000737:chemistry*; D013379:Substrate Specificity
chemical_list: D000440:Butanols; D003432:Cross-Linking Reagents; D004800:Enzymes, Immobilized; D020148:Butyric Acid; D002686:Chitin; D008049:Lipase