Table-1.

Adaptation strategies of microorganisms in fluctuating environments [44].

Microorganisms	Microorganism in extreme environments	Mechanism of adaptation	References
Acidithiobacillus ferrooxidans, Halarchaeum acidiphilum, Metallosphaera sedula, Thiobacillus prosperous, Acetobacter aceti	Acidophile (pH 0.5 to 5)	Efficient efflux system, acid tolerant membrane, proton exclusion and secondary transporters driven by protons	[45, 46]
Halorhodospira halochloris, Thiohalospira alkaliphila, Bacillus firmus, Natronomonas pharaonis	Alcaliphile (pH 8.5 to 11)	Efficient proton uptake system mediated by antiporters of the membrane, OH- ion	[45]
Psychrobacter adeliensis, P. aestuarii, P. alimentarius, P aquimaris, P. luti, P glacincola	Psychrophile (–10°C–40°C)	Synthesis of unsaturated fatty acids to prevent the decrease of membrane fluidity reduces the size of the cell and elevates cellular water in an ordered fashion	[47-49]
Serratia ureilytica	Thermophile (20°C–54°C)	Modified vegetative cells into resistant structures	[50]