Question

What are four elemental macronutrients and two elemental micronutrients that are provided in a defined media broth for successful growth of microorganisms?  

Answer 1

Micro-organisms can be grown the laboratory in defined media which are designed to provide all the essential nutrients in solution for bacterial growth. There are two categories of essential nutrients: 1) Macro-nutrients (which are needed in large amounts) and 2) Micro-nutrients (which are needed in trace or small amounts).

Macro-nutrients usually help maintain the cell structure and metabolism. Micro-nutrients help enzyme function and maintain protein structure.

The four elemental macronutrients are :-

• Carbon - Basic structural component of compounds.
• Hydrogen - Constituent of organic compounds; electrons of hydrogen atoms are used in redox reactions..
• Oxygen - Component of many organic and inorganic compounds; O is the final electron acceptor in aerobic respiration.
• Nitrogen - It is a component of molecules of purines, pyrimidines, amino acids and cell wall peptidoglycan. Nitrogen source depends on the need of the microbe. It can be organic nitrogen only, ammonia, or nitrate, nitrite or nitrogen gas which are all converted to ammonia by the microbe as first step in its assimilation.

The two elemental micronutrients are :-

• Phosphorus - The cell takes up phosphate from the medium. Phosphate is a component of phosphoproteins, phospholipids, nucleic acids, and nucleotides.
• Sulphur - It is present and needed for amino acids methionine and cysteine and some coenzymes and vitamins. Sulphur for microbial use may be sulphate, thio-sulphate or sulphide, or it may be organic sulphur in amino acids or other organic sulphur containing molecules.