Effects of water activity on Vmax and KM of lipase catalyzed transesterification in organic media

• DOI: 10.1007/bf00131760
• Publication Date: 2004-11-02T23:36:51Z
• Authors: Roberto Bovara; Giacomo Carrea; Gianluca Ottolina; Sergio Riva
• Keywords: 0303 health sciences; 03 medical and health sciences

The Vmax and KM of various forms of lipase from Pseudomonas cepacia (powder, adsorbed onto Celite or covalently linked to polyethylene glycol) were determined in organic solvents preequilibrated to water activities (aw) from <0.1 to 0.84. The model reaction was the transesterification between n-octanol and vinyl butyrate. It was found that KM for the nucleophile increased with increasing aw for all three lipase forms. Vmax increased with increasing aw for polyethylene glycol-lipase, whereas there was an optimum at intermediate aw values (0.11 – 0.38) for lipase powder and Celite-immobilized lipase.