Immobilisation studies and catalytic properties of microbial lipase onto styrene-divinylbenzene copolymer

Microbial lipase from Candida rugosa was immobilised by physical adsorption onto styrene-divinylbenzene (STYDVB) copolymer. Two different coupling med ia were evaluated: aqueous solution (sodium phosphate buffer) and organic s olvent (heptane). The choice of the immobilisation medium had a large effec t on the hydrolytic and synthetic lipase activities. Better results were fo und when the coupling procedure was performed in the presence of heptane. T he effects of enzyme loading and support capacity regeneration were also st udied. Both, free and immobilised lipases were characterised by determining the activity profile as a function of pH, temperature and thermal stabilit y. For the immobilised lipase, operational and storage stabilities were als o determined. Operational stability tests indicated that a small enzyme dea ctivation occurs after 12 consecutive batches of 24 h each. Such results re vealed good potential for recycling under nonaqueous system. (C) 2000 Elsev ier Science S.A. All rights reserved.