Nanosized tin dioxide — Unexplored carrier for lipase immobilization

A lipase from Rhizopus delemar (RhDL) was adsorbed on two tin dioxides with different textural characteristics (nanoSnO2-A-RhD and nanoSnO2-B-RhD). All biochemical characteristics obtained for them were compared with those for RhDL on silica. NanoSnO2-A exhibited the highest protein loading capacity (75%), however, the highest specific activity was measured for nanoSnO2-B-RhD (33.8 U/mg prot.). The immobilization enhanced thermal-, pH- and solvent stability of RhDL. For example, nanoSnO2-A-RhD is still fully active after one-hour heating at 60 °C and preserved 70% of its activity at pH 9. When applied in the isoamyl acetate synthesis, a complete conversion of substrates was obtained with nanoSnO2-A-RhD in hexane and SBA-15-RhD in hexadecane for 12 h. The performance of the three biocatalysts in several consecutive cycles was estimated as well.

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► Rhizopus delemar lipase was adsorbed on two SnO2 (pore sizes 3.0 and 7.0 nm).
► Thermal-, pH- and solvent stability of the lipase was enhanced upon immobilization.
► Novel biocatalysts have shown good synthetic activity in hydrophobic solvents.
► The novel preparations were applied in six consecutive synthetic cycles.