title: Laccase-modified silica nanoparticles efficiently catalyze the transformation of phenolic compounds.
abstract: A new system based on laccase-modified silica nanoparticles has been developed and tested for its ability to degrade a major endocrine disrupting chemical, 4,4'-isopropylidenediphenol (bisphenol A). The nanoparticles have been produced using the Stöber method and characterized using scanning electron microscopy, dynamic light scattering and zeta-potential measurements. The introduction of primary amino groups at the surface of these particles has been achieved using an organo-silane (amino-propyl-triethoxy-silane). The use of glutaraldehyde as bi-functional coupling agent allowed the efficient conjugation of a laccase from Coriolopsis polyzona at the surface of the nanoparticles, as monitored by measuring the amount of proteins coupled and the zeta-potential of the produced nanoparticles. The oxidative activity of the so-produced bio-conjugate was tested using radioactive-((14)C) labeled bisphenol A. Analytical methods based on high performance liquid chromatography coupled to mass spectrometry and gas chromatography allowing a convenient and reliable study of the enzymatic activity of the produced bio-conjugates have been developed. It is demonstrated that even if a decrease of the specific catalytic activity of the immobilized enzyme is measured, the activity of the bio-conjugate remains compatible with the application of these systems to the transformation of phenolic pollutants. Additionally, the developed analytical methods allowed the identification of the transformation products formed during the enzymatic reaction.
authors.affiliation: Institute for Ecopreneurship and, School of Life Sciences, University of Applied Sciences Northwestern Switzerland, Gründenstrasse 40, Muttenz CH-4132, Switzerland.
authors.forename: Patrick
authors.initials: P
authors.lastname: Galliker
authors.forename: Gregor
authors.initials: G
authors.lastname: Hommes
authors.forename: Dietmar
authors.initials: D
authors.lastname: Schlosser
authors.forename: Philippe F-X
authors.initials: PF
authors.lastname: Corvini
authors.forename: Patrick
authors.initials: P
authors.lastname: Shahgaldian
mesh_terms: D001559:Benzhydryl Compounds; D002384:Catalysis; D052244:Endocrine Disruptors / Q000378:metabolism*; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism; D005656:Fungal Proteins / Q000737:chemistry / Q000378:metabolism*; D042845:Laccase / Q000737:chemistry / Q000378:metabolism*; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D010636:Phenols / Q000378:metabolism*; D012822:Silicon Dioxide / Q000737:chemistry*; D000098826:Bisphenol A Compounds
chemical_list: D001559:Benzhydryl Compounds; D052244:Endocrine Disruptors; D004800:Enzymes, Immobilized; D005656:Fungal Proteins; D042845:Laccase; D010636:Phenols; D012822:Silicon Dioxide; C006780:bisphenol A; D000098826:Bisphenol A Compounds