What is "mesophile"

n. An organism, especially a microorganism, that lives and thrives at moderate temperatures.

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 term is mainly applied to microorganisms. Organisms that prefer extreme environments are known as extremophiles.

The habitats of these organisms include especially cheese, yogurt, and mesophile organisms are often included in the process 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.

Organisms that prefer cold environments are termed psychrophilic, those preferring warmer temperatures are termed thermophilic or thermotrophs and those thriving in extremely hot environments are hyperthermophilic. Hyperthermophiles are a type of extremophile. All bacteria have their own optimum environmental surroundings and temperatures in which they thrive the most. A genome-wide computational approach has been designed by Zheng, et al. to classify bacteria into mesophilic and thermophilic.

Many factors are responsible for a given organism's optimal temperature range, but evidence suggests that the expression of particular genetic elements ( alleles) can alter the temperature-sensitive phenotype of the organism. A recently published study demonstrated that mesophilic bacteria could be genetically engineered to express certain alleles from psychrophilic bacteria, consequently shifting the restrictive temperature range of the mesophilic bacteria to closely match that of the psychrophilic bacteria.