Nutrient Requirement of Microorganisms
Microorganisms requires macronutrients, micronutrients and growth factors, for their growth. These nutrients help in constructing the cellular components like proteins, nucleic acids and lipids.
Elements that are required in large amounts are called macronutrients. Nitrogen (N), Carbon (C), Oxygen (O), Hydrogen (H), Sulphur (S) and Phosphorus (P), Potassium (K), Calcium (Ca), Magnesium (Mg) and Iron (Fe) are macro elements.
Nitrogen is needed for the synthesis of amino acids, nucleotides like purines and pyrimidines which are part of nucleic acids (DNA and RNA).
Phosphorus is a part of phospholipids, nucleotides like ATP and phosphodiester bonds of nucleic acids.
Carbon, Hydrogen and Oxygen are the backbone of all organic macromolecules like peptidoglycan, proteins and lipids and nucleic acids.
Sulphur is needed for the synthesis of thiamin, biotin, and aminoacids like cysteine and methionine.
Potassium, Calcium, Magnesium and Iron exist as cations in the cell. These element plays vital role in the metabolic activity of microorganisms. Potassium (K+) is needed for the activity of many enzymes Example: Pyruvate Kinase.
Calcium (Ca2+) is involved in the heat resistance of bacterial endospores.
Magnesium (Mg2+) binds with ATP and serves as a cofactor of enzymes like hexokinase.
Iron (Fe2+ or Fe3+) is present in cytochromes and act as cofactors for cytochrome oxidase, catalase and peroxidase.
Nutrients that are needed in trace quantities are called micronutrients. Example: Zinc (Zn), Molybdenum (Mo), Cobalt (Co), Manganese (Mn).
Besides macro and micronutrients, some microorganisms need growth factors like amino acids, purines and pyrimidines and vitamins. Example: Biotin is required by Leuconostoc sp and folic acid is required by Enterococcus faecalis.