Question

Microbes can be classified according to the range of temperature in which they can grow.

Describe the different categories of microbes with temperature requirements for growth.

Give examples of microorganisms in each category of temperature tolerance

Answer 1

1) Microbes can be roughly classified according to the range of temperature at which they can grow. The growth rates are the highest at the optimum growth temperature for the organism. The lowest temperature at which the organism can survive and replicate is its minimum growth temperature. The highest temperature at which growth can occur is its maximum growth temperature. The different ranges of tolerant growth temperatures can vary according to other ecological factors.

Organisms categorized as mesophiles, which are adapted to moderate temperatures, with optimal growth temperatures ranging from room temperature to about 45 °C. Such as E. coli, Salmonella spp, and Lactobacillus spp. etc.

Organisms called psychrotrophs, which prefer cooler environments from a high temperature of 25 °C to refrigeration temperature about 4 °C. They are found in natural surroundings in temperate climates. They are also responsible for the spoilage of refrigerated food.

Organisms grow at optimum temperatures of 50 °C to a maximum of 80 °C are known as thermophiles. They are heat loving. They do not increase and grow at room temperature. They are distributed in hot springs, geothermal soils and manmade environments. Examples of thermophiles include Thermus aquaticus and Geobacillus spp.

Higher up on the extreme temperature scale are known as hyperthermophiles. They are distinguished by growth ranges from 80°C to a maximum of 110 °C, with some extreme examples that survive temperatures above 121 °C, the average temperature of an autoclave. The hydrothermal escapes at the bottom of the ocean are example of extreme surroundings, with temperatures reach an estimated 340 °C.