Mesophiles

A mesophile is an organism that grows best in moderate temperature, neither too hot nor too cold, typically between 20 and 45 °C (68 and 113 °F). The optimal temperature is 37 °C.The term is mainly applied to microorganisms. Organisms that prefer extreme environments are known as extremophiles. Mesophiles have diverse classifications, belonging to two domains: Bacteria, Archaea, and to kingdom Fungi of domain Eucarya. Mesophiles belonging to the domain Bacteria can either be gram-positive or gram-negative. Gram-positive bacteria have a cell layer made of peptidoglycan and stains purple. Gram-negative bacteria also contains peptidoglycan, yet the layer is extremely thin and stains red or pink. Oxygen requirements for mesophiles are not just confined to aerobic or anaerobic. There are three basic shapes of mesophiles: coccus, bacillus, and spiral.

The habitats of mesophiles can include cheese and yogurt. They are often included during fermentation of beer and wine making. Since normal human body temperature is 37 °C, the majority of human pathogens are mesophiles, as are most of the organisms comprising the human microbiome.

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