Enzymes nonaqueous modification

The use of enzymes in esterification reactions to produce industrially important products, such as emulsifiers, surfactants, wax esters, chiral molecules, biopolymers, modified fats and oils, structured lipids, and flavor esters, is well documented. The use of lipases in aqueous and nonaqueous media has found applications in organic synthesis, chiral synthesis or resolution, modification of fats and oils, and in many other fields. Moreover, lipases are highly stable even under adverse conditions such as organic solvents and high temperatures (Gandhi et al., 2000 Hari Krishna Karanth, 2002). 

The chemical modification of enzymes to solubilize them in completely nonaqueous, nonpolar media has been attempted with some success. All methods of chemical modification of enzymes share the same principle the attachment of amphipatic reagents to the polar groups on the exterior of the native protein to stabilize the enzyme against denaturation by hydrophobic organic solvents. Depending on the nature of the interaction between the enzyme and the solubilizing agent, chemical modifications of enzymes can be classified into covalent and noncovalent ones. Various methods of enzyme modification adopted are summarized in Table 4.4. 

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