What is the optimal temperature range for psychrotolerant organisms?

Psychrotolerant organisms, also known as psychrotolerants, are capable of surviving and growing at low temperatures, typically exhibiting maximum growth rates in ranges that are higher than the strict psychrophiles. While psychrophiles thrive in extreme cold, typically below 15°C, psychrotolerant organisms can grow in temperatures that are just above freezing and can also tolerate conditions at ambient temperatures.

The primary characteristic of psychrotolerant organisms is their ability to function in a broader temperature range, usually from just below freezing to around room temperature. The optimal temperature range for these organisms is typically around 20°C to 40°C, allowing them to thrive in environments that fluctuate between colder conditions and more temperate settings. This adaptability enables them to inhabit environments like tundra soils, cold waters, or food products that might be stored under refrigeration while being capable of growth at more moderate temperatures as well.

Other temperature ranges mentioned do not accurately represent the optimal growing conditions for psychrotolerant organisms. For example, temperatures from 0°C to 4°C are too low for optimal growth and align more with the lower limits of their activity. Ranges below freezing or near freezing are also not optimal for growth but are tolerated during colder periods or environments