Organisms that can tolerate extreme conditions which can not be tolerated by other organisms belong to which kingdom of Whittaker's classification?

Arachaebacteria, a group of organisms of Monera, by virtue of having cell membrane having lipids with glycerol forming ether bonds with fatty acids, branched nature of fatty acids in the cell membrane and cell wall having pseudopeptidoglycan can withstand extreme conditions such as high acidity, temperature, alkaline and pressure conditions which can not be tolerated by other living organisms.