What is Lipid and Lipase Test?

Lipid is the common term in biology which is used to denote the type of fats present in our body.

Generally, fats are formed by linking the ester bonds between three molecules of the fatty acids along with one molecule of glycerol.

Where simple fats are known as triglycerides or triacylglycerols, as they are composed of glycerol with three long fatty acids chain.

The enzyme which breaks simple fats into smaller components of the fatty acids is known as Lipase.

As in human, some microorganisms also contains lipase and they are classified depending on their ability to synthesize and secrete lipase.

Different types of simple fats are used for determining the type of microorganism to be tested.

Lipase is one of the enzymes presents in our pancreas, and it is synthesized in pancreases and released in to our digestive tract, only when we swallow food materials.

Lipase thus helps in breaking down the fats present in our food materials.

Specific levels are maintained in producing and utilizing the lipase such as maintaining the normal digestion and the cellular functions.

But abnormally levels of the enzyme present in the blood indicates some of the health issues.

However, Serum lipase test helps in measuring the amount of enzyme lipase present in our body.

Lipase test helps in detecting the health issues such as acute pancreatitis, chronic pancreatitis, celiac disease or pancreatic cancer.

Thus, increase level of lipase is noted in our body when we have any of these issues.

Lipase Test Objective

 The aim is to determine the ability of the micro-organism to produces the lipase.

 This test also helps to determine the bacteria on the basis of the activity of lipase.

 Here the variety of lipid substrates, including corn oil, olive oil and the soyabean oil are used commonly to identify the differential characteristics, between the members of the family Enterobacteriaceae, Neisseria, staphylococcus and Clostridium.

 Several varieties of fungal species can also be detected by lipolytic ability.

Lipase Test Principle

Generally, fats are formed by the linkage of esters between three molecules of fatty acids along with one molecule of glycerol. Simple fats are also known as triglycerides or triglycerols.

Lipases breaks the simple fats into its smaller components as fatty acids and glycerol.

Many types of bacteria are classified based on their ability to produce lipases.

For determining and identifying the type of organism and the variety of simple fats used and are being tested.

However, the smallest and simplest test components of triglycerides is tributyrin, which is considered as a common constituent in the lipase testing media.

But tributyrin is too large to enter the cell, so lipase is released to break it into smaller components, which becomes easy for the cells to uptake.

After hydrolysis, the glycerol is converted into dihydroxyacetone phosphate, an intermediate form of glycolysis.

The fatty acids are catabolized by the process β-oxidation; which converts it into a variety of end products which can be used by the cell for the producing energy.

Tributyrin oil is one of the types of lipid known as triglyceride. Other lipase tests are used as a various source of fat involving soybean oil, corn oil, olive oil, peanut oil, egg yolk.

Tributyrin agar is a differential medium, which tests the ability of an organism to produces an exo-enzyme, known as lipase, that hydrolyses tributyrin oil.

Tributyrin oil is prepared in the form of an emulsion, so that the agar appears opaque. When the plate is inoculated with a lipase-positive organism, clear zones will appear around the growth as the evidence of lipase activity. If no clear zones appear, the organisms are lipase negative.

Lipase Test Media

Tributyrin agar: Peptic digest of the animal tissue at 5.0 gram/litre, Yeast Extract of 3.0 gram/litre, Agar 15.0 gram/litre, pH is maintained at 7.5.

Lipase Test Procedure

 First the tributyrin agar medium is inoculated in a single line streaking of the organism.

 Inoculated medium is incubated in a gas-Pak jar immediately after streaking anaerobically at a temperature of 35 to 37ºC for about 24 to 48 hours.

 Then the clear zone can be observed around the area of bacterial growth.

Lipase Test Results

 In case of positive result, a clear zone is observed around the area of bacterial growth.

 If the test is negative, then there will be not be any clear zone around the area of bacterial growth.

Lipase Test Importance

 The lipase test, is generally used for detecting the enumerate lipolytic bacteria, specifically in diary products which contains high amount of fats.

 It also helps in detecting the variety of other lipid substrates such as olive oil, corn oil, and soya bean oil and also helps in selecting the characteristics of other members such as Enterobacteriaceae, clostridium, staphylo coccus and Neisseria.

 Clinically the blood test for lipase helps in detecting most of the acute pancreatic diseases and other characteristics symptoms related to pancreas.

 Lipase test is often performed either amylase test which helps in detecting the pancreatic diseases.