Stability of lipases in organic solvents is a vital factor for many industrial applica­tions. This feature of lipase is beneficial in transforming substrates which are poorly soluble or unstable in water. Moreover, at low water activity, lipases favor esterifica­tion reaction rather than hydrolysis which can be an added advantage in its applica­tion. Stability of immobilized B. cepacia lipase were tested in different solvents like phosphate buffer of pH 7, ethanol, methanol, isopropanol, 1-butanol, and я-hexane. The immobilized beads were incubated in the above-selected solvents at 25°C for 1 h. Thereafter, the solvent was decanted, and the catalytic activities of immobilized lipase were done in accordance with Sect. 12.5.2. The activity of immobilized lipase in phosphate buffer pH 7 was taken as reference for calculating relative activities of other solvents.

The solvent stability of immobilized lipase in hybrid matrix of alginate/к — carrageenan after cross-linking with glutaraldehyde is shown in Table 12.6. No dis­integration of the matrix was observed in any of the solvents used. This study showed that immobilized B. cepacia lipase was more stable in alcohols like ethanol, metha­nol, and isopropanol but showed lesser stability in acetone and butanol.