Biochemical tests are laboratory procedures that use specific chemical reactions to identify and characterize microorganisms, such as bacteria. These tests are often used to identify the presence of specific enzymes or metabolic pathways in a microorganism, which can help to distinguish it from other microorganisms.
Some common biochemical tests used in bacteriology include:
Oxidase test: This test is used to detect the presence of the enzyme cytochrome oxidase, which is involved in the metabolism of oxygen.
Catalase test: This test is used to detect the presence of the enzyme catalase, which helps to break down hydrogen peroxide.
Indole test: This test is used to detect the presence of the enzyme tryptophanase, which breaks down the amino acid tryptophan.
Nitrate reduction test: This test is used to detect the ability of a microorganism to reduce nitrate to nitrite.
Gelatinase test: This test is used to detect the ability of a microorganism to produce the enzyme gelatinase, which breaks down gelatin.
These are just a few examples of the many different biochemical tests that are used in bacteriology. Biochemical tests can be useful for identifying and classifying bacteria, and for understanding their metabolism and ecological role.
10 min read 
What is Nitrate Reduction Test? Purpose of Nitrate Reduction Test Principle of Nitrate Reduction Test Reactions of Nitrate Reduction Test Use of Zinc powder Use of A Durham tube Requirements Composition of Nitrate broth (medium) Ingredients Gms / Litre Peptic digest of animal tissue 5.000 Meat extract 3.000 Potassium nitrate 1.000 Sodium chloride 30.000 Final … Read more
15 min read 
What is Hydrogen Sulfide (H2S) Test? Hydrogen sulfide (H S)-producing bacteria Principle of Hydrogen Sulfide (H2S) Test Objective of Hydrogen Sulfide (H2S) Test Media for the detection of Hydrogen Sulfide (H₂S) Commonly used media for detecting hydrogen sulphide generation, sulphur sources, and sulphide indicators include the following: Media Sulfur source H₂S indicator Bismuth sulfite Peptones … Read more
25 min read 
What is Triple Sugar Iron Test (TSIA Test)? Purpose of Triple Sugar Iron Agar test (TSIA Test) The Triple Sugar Iron (TSI) Agar test, meticulously designed as a differential medium in tubed format, plays an instrumental role in microbiological diagnostics. Its primary objectives are multifaceted, as delineated below: Principle of TSIA Test The Triple Sugar … Read more
8 min read 
Purpose of Kligler’s Iron Agar Test Principle of Kligler’s Iron Agar Test Composition of Kligler Iron Agar Ingredients Gram/Liter Beef extract 3 gm Yeast extract 3 gm Peptone 15 gm Proteose peptone 5 gm Lactose 10 gm Glucose 1 gm Ferrous sulfate 0.2 gm Sodium chloride 5 gm Sodium thiosulfate 0.3 gm Agar 12 gm … Read more
24 min read 
What is the ornithine decarboxylase test? Objectives of Decarboxylase Test Principle of Ornithine decarboxylase test/Principle of Decarboxylase Test Requirement The combination of these specific media, reagents, and supplies facilitates the accurate execution of the Decarboxylase Test. Each component plays a distinct role, from providing essential nutrients and pH indicators in the medium to ensuring the … Read more
7 min read 
Test Name Acetate Utilization Test Detection Differentiate species based on ability to utilise acetate as the sole source of carbon. Typically used to distinguish Shigella spp. from Escherichia coli. Test organism It is best to use an acetate utilisation test to tell Shigella spp. from Escherichia coli. Test isolates are Gram-negative rods that don’t ferment … Read more
20 min read 
What is Methyl Red (MR) Test? Objectives of Methyl Red (MR) Test The objectives of the Methyl Red (MR) Test can be outlined as follows: Principle of Methyl Red test The principle of the Methyl Red (MR) test is based on assessing the ability of an organism to produce and maintain stable acid end products through … Read more
7 min read 
What is Nylander’s Test? Nylander’s Test, a renowned chemical assay, is primarily employed to ascertain the presence of reducing sugars within a given sample. Reducing sugars, as the name suggests, possess the inherent ability to act as reducing agents. Therefore, when these sugars, such as fructose and glucose, are subjected to alkaline conditions, they can … Read more
17 min read 
What is Ames Test? Definition of Ames Test The Ames test is a biological assay developed by Bruce Ames, used to assess the mutagenic potential of chemical compounds by observing their ability to induce mutations in specific strains of bacteria, primarily Salmonella typhimurium. A positive result indicates that the chemical may be mutagenic and potentially … Read more
18 min read 
Benedict’s test is a chemical test that is used to test for the presence of reduced sugars within an analytical test. Thus, simple carbohydrates that contain an aldehyde or free ketone functional group are detected using this test. The test is basing itself upon Benedict’s Reagent (also called Benedict’s solution) which is a complex mix of sodium carbonate, sodium citrate, and the pentahydrate of copper(II) Sulfate.