1. Production of partially phosphorylated myo-inositol phosphates using phytases immobilised on magnetic nanoparticles
- Author
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U. Konietzny, Daniel Menezes Blackburn, Ralf Greiner, and Milko A. Jorquera
- Subjects
Environmental Engineering ,Inositol Phosphates ,Phosphatase ,Bioengineering ,Substrate Specificity ,Magnetics ,chemistry.chemical_compound ,Organic chemistry ,Phosphorylation ,Waste Management and Disposal ,chemistry.chemical_classification ,6-Phytase ,biology ,Renewable Energy, Sustainability and the Environment ,Hydrolysis ,Aspergillus niger ,Temperature ,Substrate (chemistry) ,General Medicine ,Hydrogen-Ion Concentration ,Enzymes, Immobilized ,biology.organism_classification ,Phosphate ,Enzyme assay ,Turnover number ,Kinetics ,Enzyme ,chemistry ,biology.protein ,Nanoparticles ,Phytase ,Nuclear chemistry - 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.
- Published
- 2013