title: Hydrolysis of triacetin catalyzed by immobilized lipases: effect of the immobilization protocol and experimental conditions on diacetin yield.
abstract: The effect of the immobilization protocol and some experimental conditions (pH value and presence of acetonitrile) on the regioselective hydrolysis of triacetin to diacetin catalyzed by lipases has been studied. Lipase B from Candida antarctica (CALB) and lipase from Rhizomucor miehei (RML) were immobilized on Sepabeads (commercial available macroporous acrylic supports) activated with glutaraldehyde (covalent immobilization) or octadecyl groups (adsorption via interfacial activation). All the biocatalysts accumulated diacetin. Covalently immobilized RML was more active towards rac-methyl mandelate than the adsorbed RML. However, this covalent RML preparation presented the lowest activity towards triacetin. For this reason, this preparation was discarded as biocatalyst for this reaction. At pH 7, acyl migration occurred giving a mixture of 1,2 and 1,3 diacetin, but at pH 5.5, only 1,2 diacetin was produced. Yields were improved at acidic pH values and in the presence of 20% acetonitrile (to over 95%). RML immobilized on octadecyl Sepabeads was proposed as optimal preparation, mainly due to its higher specific activity. Each enzyme preparation presented very different properties. Moreover, changes in the reaction conditions affected the various immobilized enzymes in a different way.
authors: Departamento de Biocatalisis, Instituto de Catálisis-CSIC, Campus UAM-CSIC, Cantoblanco, 28049 Madrid, Spain.
authors: Karel
authors: K
authors: Hernandez
authors: Eduardo
authors: E
authors: Garcia-Verdugo
authors: Raul
authors: R
authors: Porcar
authors: Roberto
authors: R
authors: Fernandez-Lafuente
mesh_terms: D000097:Acetonitriles; D000180:Acrylic Resins / Q000737:chemistry*; D000327:Adsorption; D055162:Biocatalysis; D002175:Candida / Q000201:enzymology; D004075:Diglycerides / Q000378:metabolism*; D004789:Enzyme Activation; D004800:Enzymes, Immobilized / Q000378:metabolism*; D005656:Fungal Proteins / Q000378:metabolism*; D005976:Glutaral; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D057927:Hydrophobic and Hydrophilic Interactions; D008049:Lipase / Q000378:metabolism*; D008333:Mandelic Acids / Q000378:metabolism; D008863:Microspheres; D020103:Rhizomucor / Q000201:enzymology; D012997:Solvents; D013237:Stereoisomerism; D013696:Temperature; D014215:Triacetin / Q000378:metabolism*
chemical_list: D000097:Acetonitriles; D000180:Acrylic Resins; D004075:Diglycerides; D004800:Enzymes, Immobilized; D005656:Fungal Proteins; D008333:Mandelic Acids; D012997:Solvents; C414090:methyl mandelate; D008049:Lipase; C431349:lipase B, Candida antarctica; C037938:mandelic acid; D005976:Glutaral; D014215:Triacetin; C032159:acetonitrile