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The PU/Au-NPs conjugates based on poly(vinyl alcohol)-containing polyurethane microparticles coated with Au-NPs are prepared by a heat-treated method. The PU/Au-NPs conjugates are characterized by FT-IR , SEM, TEM analysis. The appearance of characteristic peaks in the FT-IR spectra at 1574 and 1624 cm − 1 , which are attributed to urethane groups, are presented for both PU and PU/Au-NPs conjugate. The absorption band at 1716-1718 cm − 1 , attributed to the hydrogen-bonded urethane carbonyl groups of PU/Au-NPs (13nm) -A is higher than that obtained for unmodifi ed PU. The Au-NPs (13nm) are found to be well dispersed in the PU. The Au-NPs (3.5nm) tend toward agglomeration when they are entrapped within PU. It is determined, that Au-NPs present in PU-Au conjugates quench the luminescence of PU.

β-galactosidase from Penicillium canescens was immobilized on chitosan, sepharose-4B, foamable polyurethane and some other carriers. The highest yield of immobilization (up to 98 %) was obtained by using chitosan as a carrier. The optimum pH and temperature were not significantly altered by immobilization. High stability of immobilized β-galactosidase during storage was demonstrated. Efficient lactose saccharification (over 90 %) in whey was achieved by using immobilized β-galactosidase.

A series of polyurethane (PU) microspheres, based on 4,4′‐diphenylmethane diisocyanate and 1,4‐butanediol or a mixture of 1,4‐butanediol and polyether glycol (M = 1400) were synthesized by a one‐step method. The obtained PU microspheres were characterized by infrared spectroscopy, polarizing optical microscopy and dynamic thermogravimetry. Morphology studies of PU microspheres revealed that the material consists of spherical particles with relatively narrow particle size distribution in the range 1–100 µm and preferably between 10 to 50 µm; the obtained polymers were thermally stable up to 533–573 K. Maltogenase from Bacillus stearothermophilus was immobilized onto PU microspheres, synthesized using different ratios of components. High yield (about 100%) and efficiency (over 100%) of immobilization were obtained. Copyright © 2006 John Wiley & Sons, Ltd.

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