Lipid Hydrolysis Test (Lipase Test)- Principle, Procedure, Results


Lipids are a diverse group of organic molecules that are insoluble in water but soluble in organic solvents. They include fats, oils, waxes, phospholipids, steroids, and other compounds. Lipids play important roles in energy storage, membrane structure, signaling, and hormone synthesis in living organisms.

Lipids are composed of smaller units called fatty acids and glycerol. Fatty acids are long chains of carbon and hydrogen atoms with a carboxyl group at one end. Glycerol is a three-carbon molecule with three hydroxyl groups. Fatty acids and glycerol can be joined together by an ester bond to form a triglyceride, which is the most common type of lipid in nature.

Lipase is an enzyme that catalyzes the hydrolysis of triglycerides into fatty acids and glycerol. Hydrolysis is the reaction of breaking down a molecule by adding water. Lipase is produced by many bacteria as an exoenzyme, which means it is secreted outside the cell to act on substrates in the environment.

Lipid hydrolysis test (lipase test) is a simple and rapid method to detect the ability of bacteria to produce lipase and hydrolyze lipid substrates. This test can be used for the identification and differentiation of various bacterial genera and species, especially those that are involved in food spoilage, dairy production, or pathogenesis.

The objective of lipid hydrolysis test is to determine whether a bacterial isolate can produce lipase and hydrolyze tributyrin, which is a simple triglyceride that serves as a substrate for lipase activity. The test is performed on a solid medium that contains tributyrin as the sole source of carbon and energy for bacterial growth. The presence or absence of a clear zone around the bacterial colonies indicates a positive or negative result for lipid hydrolysis, respectively.