Xylanases from thermophilic archaea: A hidden treasure

Archaea are a domain of prokaryotic organisms that often inhabit extremophilic environments. Their enzymes are therefore of enormous biotechnological interest, due to their stability and activity in harsh conditions. Although bioprospection by the metagenomics of extreme environments has yielded many novel xylanases (endo-xylanases and β-xylosidades), most show a highest sequence similarity to bacteria or unculturable microorganisms and not to archaea.