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Ergebnisse nach Hochschule und Institut
Publikation Immobilisation and stabilisation of glycosylated enzymes on boronic acid-functionalised silica nanoparticles(Royal Society of Chemistry, 2021) Nazemi, Seyed; Olesinska, Magdalena; Pezzella, Cinzia; Varriale, Simona; Lin, Chia-Wei; Corvini, Philippe; Shahgaldian, PatrickWe report a method of glycosylated enzymes’ surface immobilisation and stabilisation. The enzyme is immobilised at the surface of silica nanoparticles through the reversible covalent binding of vicinal diols of the enzyme glycans with a surface-attached boronate derivative. A soft organosilica layer of controlled thickness is grown at the silica surface, entrapping the enzyme and thus avoiding enzyme leaching. We demonstrate that this approach results not only in high and durable activity retention but also enzyme stabilisation.01A - Beitrag in wissenschaftlicher ZeitschriftPublikation Immobilization of an artificial imine reductase within silica nanoparticles improves its performance(Royal Society of Chemistry, 2016) Hestericová, Martina; Correro, Maria Rita; Lenz, Markus; Corvini, Philippe; Shahgaldian, Patrick; Ward, Thomas R.Silica nanoparticles equipped with an artificial imine reductase (biotinylated iridium complex conjugated with streptavidin) display marked redn. activity toward cyclic imines and NAD. The method, based on immobilization and protection of streptavidin on silica nanoparticles, shields the biotinylated metal cofactor against deactivation yielding >46,000 turnovers in pure samples and 4000 turnovers in crude cellular exts.01A - Beitrag in wissenschaftlicher ZeitschriftPublikation Production of superparamagnetic nanobiocatalysts for green chemistry applications(Springer, 23.04.2016) Gasser, Christoph; Ammann, Erik; Schäffer, Andreas; Shahgaldian, Patrick; Corvini, PhilippeImmobilization of enzymes on solid supports is a convenient method for increasing enzymatic stability and enabling enzyme reuse. In the present work, a sorption-assisted surface conjugation method was developed and optimized to immobilize enzymes on the surface of superparamagnetic nanoparticles. An oxidative enzyme, i.e., laccase from Trametes versicolor was used as model enzyme. The immobilization method consists of the production of superparamagnetic nanoparticles by co-precipitation of FeCl2 and FeCl3. Subsequently, the particle surface is modified with an organosilane containing an amino group. Next, the enzymes are adsorbed on the particle surface before a cross-linking agent, i.e., glutaraldehyde is added which links the amino groups on the particle surface with the amino groups of the enzymes and leads to internal cross-linking of the enzymes as well. The method was optimized using response surface methodology regarding optimal enzyme and glutaraldehyde amounts, pH, and reaction times. Results allowed formulation of biocatalysts having high specific enzymatic activity and improved stability. The biocatalysts showed considerably higher stability compared with the dissolved enzymes over a pH range from 3 to 9 and in the presence of several chemical denaturants. To demonstrate the reusability of the immobilized enzymes, they were applied as catalysts for the production of a phenoxazinone dye. Virtually, 100 % of the precursor was transformed to the dye in each of the ten conducted reaction cycles while on average 84.5 % of the enzymatic activity present at the beginning of a reaction cycle was retained after each cycle highlighting the considerable potential of superparamagnetic biocatalysts for application in industrial processes.01A - Beitrag in wissenschaftlicher Zeitschrift