Bacteria can adapt to various environmental factors such as temperature, pressure, ions, nutrients and toxic substances by modifying their membranes to maintain them in a fluid state. These modifications within the cytoplasmatic membrane particularly result from changes in the fatty acid composition and interaction between proteins and lipids. Fatty acids, mainly phospholipid fatty acids, play a role as a good biomarker of changes of physiological status of microorganisms caused by external factors. A greater understanding of the detailed physiological mechanisms of bacterial membrane lipid adaptation, especially to toxic substances and solvents, are important for researchers who use bacteria in bioremediation and biotransformation processes.