Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7082402 | Bioresource Technology | 2013 | 9 Pages |
Abstract
Phytases of different origin were covalently bound onto Fe3O4 magnetic nanoparticles (12 nm). Binding efficiencies of all three phytases were well above 70% relative to the number of aldehyde groups available on the surface of the magnetic nanoparticles. Temperature stability for all three phytases was enhanced as a consequence of immobilisation, whereas pH dependence of enzyme activity was not affected. Maximum catalytic activity of the immobilised phytases was found at 60 °C (rye), 65 °C (Aspergillus niger) and 70 °C (Escherichia albertii). The immobilised enzymes exhibited the same excellent substrate specificities and unique myo-inositol phosphate phosphatase activities as their soluble counterparts. However, the catalytic turnover number dropped drastically for the immobilised phytases. The amount of the desired partially phosphorylated myo-inositol phosphate isomer could be easily controlled by the contact time of substrate solution and immobilised enzymes. The immobilised phytases showed a high operational stability by retaining almost full activity even after fifty uses.
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Physical Sciences and Engineering
Chemical Engineering
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Authors
Ralf Greiner, Ursula Konietzny, Daniel Menezes Blackburn, Milko A. Jorquera,