Shahgaldian, Patrick

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Shahgaldian
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Patrick
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Shahgaldian, Patrick

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  • Publikation
    Production of superparamagnetic nanobiocatalysts for green chemistry applications
    (Springer, 23.04.2016) Gasser, Christoph; Ammann, Erik; Schäffer, Andreas; Shahgaldian, Patrick; Corvini, Philippe [in: Applied Microbiology and Biotechnology]
    Immobilization 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
  • Publikation
    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. [in: Chemical Communications]
    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 Zeitschrift