Nutritional Requirements of Bacteria

• Bacteria, like all living organisms, require a variety of nutrients to grow and reproduce.

• These Nutritional Requirements of Bacteria can be categorized into macronutrients and micronutrients.
  

Bacteria Nutritional Requirements

Macronutrients:

A. Carbon:

• Fundamental for cellular structure and energy. Sources include carbohydrates, lipids, proteins, and carbon dioxide.

B. Nitrogen:

• Essential for amino acids, nucleotides, and other cellular constituents. Sources include ammonia, nitrate, nitrogen gas (for nitrogen-fixing bacteria), and organic nitrogen compounds.

C. Phosphorus:

• Required for nucleic acids, phospholipids, ATP. Common source is phosphate.

D. Sulfur:

• Important for amino acids (cysteine and methionine) and coenzymes. Sources include sulfate and sulfur-containing amino acids.

E. Potassium, Magnesium, Calcium, and Iron:

• Serve various roles in enzyme activation, cellular structure, and electron transport.

Micronutrients

1. Potassium (K): Enzyme activation and cellular functions.

2. Magnesium (Mg): Stabilizes ribosomes, membranes, and nucleic acids; involved in enzyme reactions.

3. Calcium (Ca): Important for cell wall stability and spore formation.

4. Iron (Fe): Essential for electron transport proteins and enzymes.

Growth Factors

• Vitamins: Often function as coenzymes in metabolic pathways.

• Amino Acids: Required for protein synthesis.

• Purines and Pyrimidines: Needed for nucleic acid synthesis.

Classification of Bacteria by Energy Sources

Classification of Bacteria by Energy Sources

1. Phototrophs:

• Energy Source: Light

• Example: Cyanobacteria (photosynthetic bacteria that use light energy to produce organic compounds).

2. Chemotrophs:

• Energy Source: Chemical compounds

• Subtypes:

A. Chemoautotrophs (Lithotrophs):

• Energy Source: Inorganic chemicals (e.g., hydrogen sulfide, ammonia)

• Example: Nitrosomonas (oxidizes ammonia to nitrite)

B. Chemoheterotrophs (Organotrophs):

• Energy Source: Organic compounds

• Example: Escherichia coli (uses glucose and other organic molecules for energy).

3. Autotrophs:

• Carbon Source: Carbon dioxide

• Example: Nitrifying bacteria (convert ammonia into nitrates, using carbon dioxide for their carbon source).

4. Heterotrophs:

• Carbon Source: Organic compounds

• Example: Lactobacillus (uses organic molecules like lactose as both carbon and energy sources).