ABSTRACT
This chapter explores the archaea, i.e., thermophilic, and psychrophilic archaea that have caught the interest of researchers in the recent years, due to their cellular and molecular adaptations and prospective applications. Archaeol based lipids in some thermophilic archaea have further modifications, including condensation in a macrocyclic glycerol diether, aberrant isoprenoid chain length, or the presence of a tetritol diether. Therefore, the described archaeal lipids diversity can be considered as a unique taxonomic marker for our understanding of the phylogenetic relationships among archaeal organisms. Till the 19th century there were only two domain systems which included bacteria and eukarya. Later, due to the differences at the molecular level, a third domain was successfully proposed, called ‘archaea’. The cell membrane is a major barrier of the cell, which separates the vital cytoplasm from the surrounding environment. The major component of the cell membrane is phospholipids, which is involved in a wide variety of cellular processes.
