What is Biochemical Characteristics?
In the last section we have learnt about the importance of biochemical tests. It must be clear now that biochemical tests are used to -
(1) identify the bacteria, and
(2) to provide insight into species's niche in the ecosystem.
Next, what are the biochemical characteristics specific to the microbial identification process? The characteristics considered for this purpose include:
1. Fermentation of Dextrose, sucrose, mannitol and lactose.
2. Gelatin liquefaction
3. Starch hydrolysis
4. Lipid hydrolysis
5. Casein hydrolysis
6. Litmus milk reaction
7. Nitrate reduction
8. Indol production
9. H2S Production
10. Methyl red test
11. Voges - Proskauer test
12. Citrate Utilization
13. Catalase activity
14. Urease activity
15. Oxidase activity, etc.
These biochemical tests can be used for differentiation among enteric bacteria and also bacteria other than enteric ones.
Many of these biochemical tests are discussed in the practical. The genus of bacteria can be identified by referring to the Table. It may be noted, however, that biochemical results may not be identical as given in table because the results may vary depending on the strains of each species used and the length of time the organism has been maintained in the stock culture. The following sub-section(s) discusses the various tests.