[ExpertScie]

In various pharmaceutical manufacturing plants and in medical field, biochemical tests are performed to identify microorganisms.
Such biochemical test helps in differentiating bacteria and thus is a way to diagnose the cause of infections and other disease related to micro-organisms. This test indicates different characteristics of microorganism with respect to subjected bio-chemicals and thus helps in their identification up to species level.
Once this identification is done, specific recommendations/corrective actions are implemented for treatments and further resolution of microbial infection or contamination.
Bio-chemical test includes Catalase test, Carbohydrate oxidation fermentation tests, MR-VP test, Simmon’s citrate test, Nitrogen metabolism – urea Hydrolysis test etc.
These tests are done under aseptic conditions under totally controlled environments. This is to avoid un-wanted contamination and to keep the validity of test.
In catalase test, oxygen is used as final electron acceptor by many micro-organisms the breakdown of H2O2 into water and oxygen molecules is characterized by bubble formation and this indicates the result as Positive (+). Eg. Staphyloccocus aureus.
In Carbohydrate fermentation test, acid and gases production are detected. Acid production is indicated with color change and it shows that microorganism under test are capable of utilizing various carbohydrates.
MRVP test, which is abbreviation of Methyl Red Voges Proskauer is test to know if organic acid is produced, the positive result is just a no change in color of MR chemical indicator.
Simmon’s citrate test is to identify the ability of bacteria to ferment citrate. In this test when citric acid or sodium citrate is in solution, it loses sodium ion to form citrate ion. This Citrate is break down to pyruvate. When a bacterium uses Citrate, medium turns alkaline.
Another test which is employed in identification of microorganism is Urea test. In this test, Urease breaks down urea into ammonia and carbon dioxide.
Bio-chemical test is fundamental concept in microbiology which helps in identification of micro-organism of interest out of hundreds of samples.