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• Factors that affect microbial growth

  • Availability of nutrients
  • Moisture
  • Temperature
• Availability of nutrients


  • All living organisms require nutrients
  • Appropriate nutrients must be available
  • e.g. Carbon, Oxygen, Hydrogen, Nitrogen, Phosphorus, and Sulfur as well as other elements
• Moisture

  All living organisms require water to carry out their normal metabolic processes and most will die in environments containing too little moisture
• Temperature

  • Every organism has an optimum growth temperature
  • Temperature at which the organism grow best
  • Every organism has also minimum growth temperature below which it ceases to grow

  
• Bacterial growth


  1. Increase in the number of organisms rather than an increase in their size

  2. When the bacterial cell reaches its optimum size, it divides by binary fission into two daughter cells

  3. On solid medium, binary fission continues through many generations until a colony is produced

  4. A bacterial colony is a mound or pile of bacteria containing millions of cells

  5. Binary fission continues for as long as the nutrient supply, water and space allow and ends when the nutrients are depleted or the concentration of cellular waste products reaches a toxic level
• Culturing bacteria in the laboratory


  • Typically, depending on the medium used, individual species of microorganisms form colonies of characteristics size and shape
  • Even when mixed population has been properly cultured, one distinguish one from the other based on overall appearance of the colonies

  
• Competitive analysis helps identify strengths, weaknesses, opportunities, and threats (SWOT) of both direct and indirect competitors.
• The third step is to analyze the information gathered and consider different options for addressing the problem.
• Optimum growth temperature


  The temperature at which an organism grows best
• Minimum growth temperature


  The temperature below which an organism will stop growing
• Thermophiles


  Organisms that can grow at high temperatures, above 100°C
• Temperature range


  The range of temperatures where an organism can grow and survive
• Mesophiles


  Organisms that grow best at moderate temperatures, typically between 20-45°C
• Psychrophiles


  Organisms that can grow at low temperatures, below 0°C