Effect of the immobilization method of lipase from Thermomyces lanuginosus on sucrose acylation

Lipase from Thermomyces lanuginosus (formerly Humicola lanuginosa) was immobilized using granulation by incubating low-particle-size silica with the lipase. Granules with a particle diameter in the range 0.3-1 mm were obtained. The immobilized lipase was tested in the acylation of sucrose with vinyl laurate in mixtures of tert-amyl alcohol: dimethyl sulfoxide. Results were compared with immobilization of enzyme by adsorption on polypropylene (Accurel EP100), deposition on Celite by precipitation, and covalent attachment to Eupergit C. Granulated lipase converted >95% of sucrose into 6-O-lauroylsucrose in 6 h. Accurel-lipase was also very active, converting 70% of sucrose into monoester in 2 h. The residual activity of granules after five reaction cycles under the best reaction conditions was 72%; this value was considerably higher than the one observed for the same lipase adsorbed on Accurel (15% residual activity after five cycles).