Thermoacidophile

A thermoacidophile is an extremophilic microorganism that is both thermophilic and acidophilic; i.e., it can grow under conditions of high temperature and low pH.[1] The large majority of thermoacidophiles are archaea (particularly the crenarchaeota and euryarchaeota) or bacteria, though occasional eukaryotic examples have been reported.[2][3] Thermoacidophiles can be found in hot springs and solfataric environments, within deep sea vents, or in other environments of geothermal activity.[1]^:602 They also occur in polluted environments, such as in acid mine drainage.[4]

An apparent tradeoff has been described between adaptation to high temperature and low pH; relatively few examples are known that are tolerant of the extremes of both environments (pH < 2, growth temperature > 80°C).[1]^:602 Many thermoacidophilic archaea have aerobic or microaerophilic metabolism,[1]^:602 although obligately anaerobic examples (e.g. the Acidilobales) have also been identified.[5]

Sequencing the genome of a thermoacidophilic eukaryote, the red algae Galdieria sulphuraria, revealed that its environmental adaptations likely originated from horizontal gene transfer from thermoacidophilic archaea and bacteria.[2]