Characterisation of Accurel MP1004 polypropylene powder and its use as a support for lipase immobilisation

Abstract

Accurel MP1004, a porous polypropylene powder, was characterised for lipase immobilisation. The particle size ranges between 40–80 mesh, corresponding to particle diameters of 177–420 μm. The pore distribution falls between macroporous and mesoporous domains. A crude lipase preparation from Mucor javanicus was immobilised on Accurel MP1004 by adsorption. During the adsorption process, by measuring the variation of pore volume and of pore size distribution of mesopores as a function of enzyme loading, a significant penetration of the enzyme molecules into the pores was found to occur. The various proteins in the crude lipase preparation are quickly adsorbed by the Accurel MP1004. However, they are progressively displaced by the lipase which shows a greater affinity for the support. A transesterification reaction, between glycerol tricaprylate and 1-butanol in solvent-free conditions, was catalysed by the lipase before and after the immobilisation process. The immobilisation on Accurel MP1004 improves the lipase performance both in terms of activity and of substrate conversion.