Low-temperature magnetic modification of sensitive biological materials

• Low-temperature magnetic modification of sensitive non-magnetic materials.
• Magnetically responsive immobilized enzymes prepared from non-magnetic precursors.
• Magnetized immobilized enzymes were stable during eight repeated reaction cycles.

Nano- and microparticles consisting of magnetic iron oxides were prepared by microwave-assisted synthesis from ferrous sulfate. They were applied to the direct magnetic modification of sensitive and labile non-magnetic biomaterials (such as plant and seagrass based materials and enzymes immobilized on non-magnetic carriers) at temperatures −20 and −80 °C. These conditions warrant stable magnetic modification of non-magnetic biomaterials, e.g. cellulose, lignocellulose, or starch based ones. We have also magnetically modified enzymes immobilized on non-magnetic carriers, for example lipase immobilized on cellulose powder and glucose isomerase immobilized on solid carrier granules. It was observed that a substantial fraction of the activity is maintained by this method and that all the magnetically modified enzymes were stable during eight repeated reaction cycles with only a negligible decrease in activity over time.