Biochemical Test

Biochemical tests are the tests that are performed on different bacteria for their identification on the basis of their biochemical activities towards different biochemical compounds.

  • Biochemical tests are one of the traditional methods for the identification of microorganisms, usually performed with phenotypic identification.
  • For many years these methods were employed extensively, and they continue to be used nowadays, especially in some laboratory routines where a particular type of microorganism has to be identified rapidly.
  • The ability of microorganisms to utilize certain biomolecules, resulting in useful organic compounds for themselves forms the basis of various biochemical tests.
  • Biochemical tests are of different types, where the identification or distinction between different microorganisms is made on various bases.
  • One of the traditional methods commonly used is a simple visual detection of the growth of the organism in the presence of essential nutrients by increased turbidity in the liquid medium.
  • In other tests, however, the results are based on the change in color of the medium as a result of the change in the pH of the medium.
  • Microorganisms can be classified into different groups on the basis of their reaction to such tests. Some tests even allow the distinction of microorganisms to the species level.
  • Biochemical tests are thus, essential as they are inexpensive and relatively simple to perform.
  • The physiology of bacteria and other microorganisms differs from one another, which allows for the differentiation of such microorganisms.
  • Biochemical tests, however, have some disadvantages. Despite being inexpensive and allowing both quantitative and qualitative information about the diversity of microorganisms present in a sample, these methods are laborious and time-consuming, and results are only observed after several days.
  • In some cases, false positives are obtained, especially when considering similar microbial species.

Biochemical Test ofย Citrobacter freundii

by
Biochemical test ofย Citrobacter freundii

Biochemical test of Citrobacter freundii ยญBasic Characteristics Properties (Citrobacter freundii) Capsule Negative (-ve) Catalase Positive (+ve) Citrate Positive (+ve) Flagella Positive (+ve) Gas from glucose Positive (+ve) Gelatin Hydrolysis Negative (-ve) … Read more

PYR Test: Principle, Media, Steps, Results, Uses

by
PYR Test

PYR test (L-Pyrrolidonyl-ฮฒ-naphthylamide test) is a biochemical test used to detect the ability of bacteria to produce pyrrolidonyl aminopeptidase enzyme using L-Pyrrolidonyl-ฮฒ-naphthylamide (PYR) as substrate. It was first reported in … Read more