title: Characterization of sol-gel bioencapsulates for ester hydrolysis and synthesis.
abstract: Candida rugosa lipase was entrapped in silica sol-gel particles prepared by hydrolysis of methyltrimethoxysilane and assayed by p-nitrophenyl palmitate hydrolysis, as a function of pH and temperature, giving pH optima of 7.8 (free enzyme) and 5.0-8.0 (immobilized enzyme). The optimum temperature for the immobilized enzyme (50-55 degrees C) was 19 degrees C higher than for the free enzyme. Thermal, operational, and storage stability were determined with n-butanol and butyric acid, giving at 45 degrees C a half-life 2.7 times greater for the immobilized enzyme; storage time was 21 d at room temperature. For ester synthesis, the optimum temperature was 47 degrees C, and high esterification conversions were obtained under repeated batch cycles (half-life of 138 h).
authors.affiliation: Department of Chemical Engineering, State University of Maringa, Av. Colombo 5790, Bloco D-90, 87020-900, Maringa-PR, Brazil.
authors.forename: Cleide M F
authors.initials: CM
authors.lastname: Soares
authors.forename: Heizir F
authors.initials: HF
authors.lastname: de Castro
authors.forename: Juliana E
authors.initials: JE
authors.lastname: Itako
authors.forename: Flavio F
authors.initials: FF
authors.lastname: de Moraes
authors.forename: Gisella M
authors.initials: GM
authors.lastname: Zanin
mesh_terms: D020001:1-Butanol / Q000737:chemistry*; D020148:Butyric Acid / Q000737:chemistry*; D002175:Candida / Q000201:enzymology*; D020099:Coated Materials, Biocompatible / Q000737:chemistry; D004356:Drug Storage; D004789:Enzyme Activation; D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000737:chemistry; D004952:Esters; D005782:Gels / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D008049:Lipase / Q000737:chemistry*; D008422:Materials Testing; D044367:Phase Transition; D012821:Silanes / Q000737:chemistry*; D013696:Temperature
chemical_list: D020099:Coated Materials, Biocompatible; D004800:Enzymes, Immobilized; D004952:Esters; D005782:Gels; D012821:Silanes; C071718:methyltrimethoxysilane; D020148:Butyric Acid; D020001:1-Butanol; D008049:Lipase