Question

Briefly describe how tests detecting amino acid catabolizing enzymes, and fermentation tests can be used to identify microorganisms in the laboratory.

Answer 1

The test which detect amino acid catalyzing enzymes helps in detection of the bacteria by identifying the color change. In this a tube with glucose is inoculated with a bacterium along with the specific amino acid and pH indicator. If the bacteria is an acid producing bacteria, pH indicator turns yellow in color as bacteria starts producing acid but when the bacteria is able to produce alkaline product it turns the tube into purple color. Hence this is how the enzymes helps in detection of which type of bacteria is present.

The fermentation test also helps in identifying and recognizing the bacteria and in this the test medium consists of protein, single carbohydrate along with a pH indicator. If the bacteria is able to catabolize the carbohydrate or protein, it tends to change the color which is shown by the pH indicator. If it is able to ferment and catabolize, it is able to produce gas. Some bacteria are able to produce bubbles and acid both due to catabolism of carbohydrate.