Growth temperature

Every microorganism has a minimum and maximum tolerable temperature. There are three critical temperatures for microorganisms that are generally determined by the temperature at which the microorganism’s enzyme function. Those three critical temperatures (also called cardinal temperature) are as follows:

  • Minimum growth temperature: the lowest temperature where cells can still divide
  • Maximum growth temperature: the highest temperature where cells can still divide
  • Optimum growth temperature: the temperature where cells divide most rapidly

The y axis of the graph presents the change of growth rate as the change of enzyme reaction rate. The x axis presents the temperature change. The reaction rate at the lowest temperature is equal to zero, and named “membrane gelling”. As the temperature increases, the reaction rate also increases, until it reaches the peak, called ”optimum”, where enzyme reaction reaches its maximum rate. After that point, the rate rapidly decreases until it reaches the maximum temperature, named “protein denaturation”.

Figure 1: Effect of temperature on microbial growth.

Temperature profoundly influences cell growth. Initially, rising temperature enhances growth until reaching the optimal level, beyond which growth declines significantly, ultimately reaching the maximum temperature. Temperature impacts enzyme activity and cell component rigidity. Higher temperatures accelerate enzymatic reactions, promoting faster growth. However, above the optimum, cell components suffer damage, leading to irreversible harm and cell death. Near the minimum temperature, growth slows, possibly due to the stiffening of the cytoplasmic membrane, hampering cell transportation functions. Industrial Yeast cells used in industrial applications are generally grown in the range of 20-40°C 20 to 40 degree Celsius.


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