Physiology of cold-adapted microorganisms
Résumé
Microorganisms able to grow at low temperature, that is near 0°C, have been known for over 100 years in natural and manmade cold environments such as marine and continental waters, soils and foods. Until recently, the molecular basis of cold adaptation was poorly investigated. Most studies have been pragmatic, dealing with food microorganisms (mainly bacteria) with the aim of preventing their growth. During the late 1960s and 1970s, many papers were published on the ecology as well as the physiology of cold-adapted microorganisms. Most are now seldom referred to or even considered by those working in the field of cold adaptation. Except for lipid composition, more fundamental research was restricted by the lack of tools for such investigations. Moreover, most studies dealt with the heat sensitivity of cold-adapted microorganisms, which, although being of interest, is a consequence not the cause of cold adaptation. Others considered the effect of chilling on mesophiles such as Escherichia coli, which is mesophilic and cannot grow at 0°C, and cannot be considered as a universal model for organisms growing at low temperatures.