Bacteria require nutrients like carbon, nitrogen, phosphorus, and trace elements for growth and reproduction. These nutrients are used to build carbohydrates, lipids, proteins, and nucleic acids. Bacteria need macronutrients like carbon, nitrogen, and phosphorus in large amounts, as well as micronutrients like iron and zinc in very small amounts. Environmental factors like temperature, pH, and oxygen levels also influence bacterial growth. Proper nutrition and growth conditions are necessary for bacteria to successfully multiply.

1. BACTERIAL NUTRITION

2. Bacterial Nutrition
• Bacterial cell has its principle constituent as
water(80%) of total weight.
• Rest is protein, polysaccharides, lipids, nucleic
acids, mucopeptides.
• Bacteria require adequate nutrition, optium pH,
temperature and oxygen, etc. for growth and
multiplication.
• Bacteria requires the nutrition in large quantities,
because they are used to construct carbohydrates,
lipids, proteins, and nucleic acids.
• Several other elements are needed in very small
amounts.

3. Microbial Growth Conditions
1. Macronutrients
2. Micronutrients
3. Growth factors: Vitamins.
4. Environmental factors:
temperature; pH; Oxygen,
carbon, etc.

4. Microbial Nutrition
Nutrients:
• Substances in the environment used by
organisms for catabolism and anabolism.
1. Macronutrients: required in large amounts, including: carbon,
oxygen, hydrogen, nitrogen, sulfur, phosphorus (Components
of carbonhydrates, lipids, proteins, and mucleic acids );
potassium, calcium, magnesium and iron (cations and part of
enzymes and cofactors).
2. Micronutrients: Microbes require very small amounts of other
mineral elements, such as iron, copper, molybdenum, and zinc;
these are referred to as trace elements. Most are essential for
activity of certain enzymes, usually as cofactors.
• Growth Factors:
(i)amino acids, (ii) purines and pyrimidines, (iii) vitamins

5. Amino acids are needed for protein
synthesis,
Purines and pyrimidines for nucleic
acid synthesis.
Vitamins are small organic molecules
that usually make up all or part
enzyme cofactors, and only very small
amounts are required for growth.

6. Nutritional classification- based on how microorganism
satisfy Carbon, Energy & Electron
SOURCE Obtaining from with examples
Energy Sources
Phototrophs
Chemotrophs
Sunlight: Rhodospirillum rubrum
Chemical reactions: Escherichia coli
Carbon source
Autotrophs
Heterotrophs
CO2 sole or principal biosynthetic
carbon source: Chromatium okenii
Reduced, preformed, organic
molecules from other organisms: E.coli
Electron Sources
Lithotrophs
Organotrophs
Reduced inorganic molecules: Pseudomonas
pseudoflava
Organic molecules: E.coli

7. • Photolithotrophs: utilised inorganic(H2S)
compounds: Chromatium okenii
• Photoorganotrophs: utilised organic
compounds(fatty acid and alchol):
Rhodospirillum rubrum.

8. Growth factors: Vitamins
• GROWTH FACTOR AREREQUIRED IN MINUTE QUANTIES.

9. Water
• It is the major essential nutrient as it account
for about 80-90% of the total weight of cell.
• Highly polar compount
• Contains micro-nutrients and trace elements
required for the growth of all bacteria.