title: Thiol-functionalization of acrylic ester monomers catalyzed by immobilized Humicola insolens cutinase.
abstract: Immobilized cutinase HiC from the ascomycete Humicola insolens was applied as a novel biocatalyst for the synthesis of functionalized acryclic esters by transesterification. As a model reaction, transesterification of methyl acrylate with 6-mercapto-1-hexanol at a high molar ratio in a solvent free system was chosen. Besides two minor Michael-addition by-products, 6-mercaptohexyl acrylic ester was identified as the main product with the thiol as the functional end group. Reaction conditions were optimized regarding the influence of water (0-1.72 M), temperature (22-50 °C), product inhibition and addition of the radical inhibitor butylated hydroxytoluol (BHT; 0.14-0.71 M) on conversion and by-product formation. Highest conversion of 6-mercapto-1-hexanol to 6-mercaptohexyl acrylic ester (95.4 ± 0.3%) was achieved after 6h at 40 °C in the presence of 0.025% (w/w) water without formation of by-products in a solvent free system. Applying methyl methacrylate, transesterification with 6-mercapto-1-hexanol was significantly lower (43.6 ± 0.1%) compared to transesterification of methyl acrylate with 6-mercapto-1-hexanol.
authors.affiliation: Institute of Technical Biochemistry, Universitaet Stuttgart, Allmandring 31, 70569 Stuttgart, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Kazenwadel
authors.forename: Sabine
authors.initials: S
authors.lastname: Eiben
authors.forename: Steffen
authors.initials: S
authors.lastname: Maurer
authors.forename: Holger
authors.initials: H
authors.lastname: Beuttler
authors.forename: Dennis
authors.initials: D
authors.lastname: Wetzl
authors.forename: Bernhard
authors.initials: B
authors.lastname: Hauer
authors.forename: Katja
authors.initials: K
authors.lastname: Koschorreck
mesh_terms: D000179:Acrylates / Q000737:chemistry / Q000378:metabolism*; D000975:Antioxidants / Q000494:pharmacology; D001203:Ascomycota / Q000201:enzymology* / Q000235:genetics; D002084:Butylated Hydroxytoluene / Q000494:pharmacology; D002265:Carboxylic Ester Hydrolases / Q000235:genetics / Q000378:metabolism*; D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000235:genetics / Q000378:metabolism*; D004951:Esterification; D005800:Genes, Fungal; D000441:Hexanols / Q000378:metabolism; D008954:Models, Biological; D013438:Sulfhydryl Compounds / Q000378:metabolism
chemical_list: C503488:6-mercapto-1-hexanol; D000179:Acrylates; D000975:Antioxidants; D004800:Enzymes, Immobilized; D000441:Hexanols; D013438:Sulfhydryl Compounds; D002084:Butylated Hydroxytoluene; D002265:Carboxylic Ester Hydrolases; C019952:cutinase