The immobilization protocol greatly alters the effects of metal phosphate modification on the activity/stability of immobilized lipases

Abstract

Mineralization of immobilized enzymes has showed to couple the advantages of both processes. Here, the influence of the immobilization protocol on the effects of mineralization has been investigated. The lipases from Thermomyces lanuginosus and Candida rugosa were immobilized on octyl-, vinyl sulfone (VS) octyl (blocked with different nucleophiles) and glutaraldehyde- (at different pH values) agarose beads. The stability, activity and specificity of the biocatalysts were very different, both the differently blocked VS-biocatalysts and the glutaraldehyde biocatalysts prepared at different pH. All biocatalysts were submitted to mineralization using different metals. The activity, specificity and stability effects of the mineralization strongly depended on the enzyme and on the immobilization protocol. For the same enzyme, a mineralization protocol could be negative, positive or present no effect depending on the enzyme immobilization procedure and substrate. In the best cases, activity could be increased by a two-fold factor, while stability was significantly improved in many instances. These results highlight the great potential of mineralization of immobilized enzymes to improve their properties, as well as the great interactions that immobilization protocol and mineralization can exhibit. The combination of both methodologies greatly increases the possibilities to find a biocatalyst that can be suitable for a specific process.