Abstract:
Stability of lipases from Pseudomonas fluorescens (Amano AK), Burkholderia cepacia (Amano PS) and
Candida antarctica B (Cal B), immobilized by sol-gel entrapment and sol-gel entrapment combined with adsorption on
Celite 545, was investigated by long-term incubation in seven different solvents. The immobilization has been carried out
using a ternary silane precursors system consisted of phenyl-trimethoxysilane, vinyl-trimethoxysilane and
tetramethoxysilane, at 1.6/0.4/1 molar ratio. The immobilized biocatalysts were incubated in various organic solvents for 7
days, at 25°C. The activity and enantioselectivity were assayed in the acylation reaction of 2-hexanol with vinyl acetate.
The activity of the immobilized biocatalysts was not significantly altered by the tested organic solvents, while the
enantioselectivity values of all immobilized enzymes were higher compared to the native ones. In the case of Cal B lipases
the operational stability was excelent as well, the transesterification activity remaining unchanged during 14 reuse cycles.
Keywords:
lipase, sol-gel entrapment, stability, organic solvent, reuse
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