Microbial Nutrition and Growth

Key Concepts

• Microbial Nutrition: Essential for anabolism and growth.
  • Macronutrients: Required in large amounts.
    • Carbon: Vital for amino acids and sugars.
    • Nitrogen: Second most abundant; crucial for proteins, nucleic acids, and other cell constituents.
    • Phosphorus: Needed for nucleic acids and phospholipids.
    • Sulfur: Required for amino acids, some vitamins, and co-enzyme A.
  • Micronutrients (Trace Elements): Required in small amounts.
    • Iron: Significant in cellular respiration.

Sporulation

• Depletion of carbon and nitrogen can lead cells to sporulate, forming endospores.

Growth Process

• Binary Fission: Primary method of growth in microorganisms.
  • DNA Replication: DNA duplicates and remains attached to the cytoplasmic membrane during replication.
  • Cell Elongation: Cells grow to approximately twice their original size.
  • Septum Formation: Partition forms from inward growth of the cytoplasmic membrane, cell wall, and other structures.
    • Separation: Results in two cells, each with a DNA molecule.

Generation Time

• Definition: Time required for the formation of two cells from one.
  • Also known as doubling time.
  • Varies based on nutritional and genetic factors.
  • Example: E. coli replicates approximately every 20 minutes; other bacteria may vary in replication time.