title: Graphene oxide immobilized enzymes show high thermal and solvent stability.
abstract: The thermal and solvent tolerance of enzymes is highly important for their industrial use. We show here that the enzyme lipase from Rhizopus oryzae exhibits exceptionally high thermal stability and high solvent tolerance and even increased activity in acetone when immobilized onto a graphene oxide (GO) nanosupport prepared by Staudenmaier and Brodie methods. We studied various forms of immobilization of the enzyme: by physical adsorption, covalent attachment, and additional crosslinking. The activity recovery was shown to be dependent on the support type, enzyme loading and immobilization procedure. Covalently immobilized lipase showed significantly better resistance to heat inactivation (the activity recovery was 65% at 70 °C) in comparison with the soluble counterpart (the activity recovery was 65% at 40 °C). Physically adsorbed lipase achieved over 100% of the initial activity in a series of organic solvents. These findings, showing enhanced thermal stability and solvent tolerance of graphene oxide immobilized enzyme, will have a profound impact on practical industrial scale uses of enzymes for the conversion of lipids into fuels.
authors.affiliation: Department of Polymers, University of Chemistry and Technology Prague, Technická 5, 166 28 Prague 6, Czech Republic. sona.hermanova@vscht.cz.
authors.forename: Soňa
authors.initials: S
authors.lastname: Hermanová
authors.forename: Marie
authors.initials: M
authors.lastname: Zarevúcká
authors.forename: Daniel
authors.initials: D
authors.lastname: Bouša
authors.forename: Martin
authors.initials: M
authors.lastname: Pumera
authors.forename: Zdeněk
authors.initials: Z
authors.lastname: Sofer
mesh_terms: D000327:Adsorption; D004789:Enzyme Activation; D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000737:chemistry*; D006108:Graphite / Q000737:chemistry*; D008049:Lipase / Q000737:chemistry*; D008422:Materials Testing; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D010087:Oxides / Q000737:chemistry*; D011485:Protein Binding; D012997:Solvents / Q000737:chemistry*; D013696:Temperature
chemical_list: D004800:Enzymes, Immobilized; D010087:Oxides; D012997:Solvents; D006108:Graphite; D008049:Lipase