Mesophile

Mesophiles are microorganisms that grow best in moderate temperature ranges. The typical mesophilic range is approximately 20-45°C, with most organisms having their optimum growth around 25-37°C. These organisms include many bacteria, yeasts, and molds, and they are contrasted with psychrophiles, which prefer cold conditions, and thermophiles, which thrive at higher temperatures.

Obligate mesophiles require moderate temperatures for growth, whereas facultative mesophiles can grow across a broader spectrum and may tolerate lower or higher temperatures to some extent. Common examples of mesophiles include Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Lactobacillus species, and Saccharomyces cerevisiae.

Mesophiles occupy a wide range of habitats, including soil, freshwater and marine environments, food matrices, plants, and animal or human bodies. In medical and industrial contexts, mesophiles are significant because many human pathogens are mesophilic, and mesophilic bacteria are widely used in fermentation and biotechnology. Temperature control is a key method to manage their growth; refrigeration slows their metabolism, while cooking or pasteurization can kill many mesophiles.

In laboratory settings, mesophiles are typically cultured at about 30-37°C to reflect their natural conditions and to optimize growth for routine experiments. Biochemical adaptations that support mesophily include enzymes with optimal activity near moderate temperatures and membrane lipid compositions that maintain appropriate fluidity across the growth range.