“Immobilization” refers to localization or physical confinement of an enzyme (bio­catalyst) in a certain defined region of space on to a solid support or on a carrier matrix with retention of its catalytic activity. The main purpose of immobilizing an enzyme is for reuse so that the high cost of enzyme can be overcome to a certain extent. The term “immobilized enzyme” was recommended at the first Enzyme

Engineering Conference in 1971. Several factors determine the choice of a carrier material such as mechanical strength, microbial resistance, chemical durability, thermal stability, hydrophobic or hydrophilic character, loading capacity, ease of regeneration, and finally the cost (Karube et al. 1977). The main objective of enzyme immobilization is its economic application. Ease of control and uniformity of con­versions can also be derived by immobilizing the enzymes.

Lipases (triacylglycerol hydrolase, EC 3.1.1.3) are enzymes that can catalyze the hydrolysis of carboxylic ester link in the triacylglycerol moiety to form free fatty acids, di-monoglycerides, and glycerol. In addition to the main function which is hydrolysis of ester bonds, lipases can also catalyze the esterification, the creation of this link between alcohol hydroxyl groups and carboxyl groups of carboxylic acids. Lipases have a wide spectrum of biotechnological applications since they can cata­lyze esterification, hydrolysis, transesterification, alcoholysis, acidolysis, and ami — nolysis. In short, lipases are serine hydrolases which are of considerable physiological significance and industrial potential that can catalyze a number of reactions (Pandey et al. 1999; Jaeger and Eggert 2002; Vulfson 1994).