Exploring of extremophilicArchaeaand their enzymes had great significance to biocatalysis. Enzymes produced by Archaea allow improvement in multiple sectors of industry. They can help reduce the quantity of waste energy and material consumption, thus making the technology more environmentallyfriendly. This study aimed to screen hydrolytic extremozymes in different Soda LakesofWadi Al-Natrun, Egypt, by enzymatic agar-plate assays and molecular-based methods. Five hundred and thirty-fivehaloalkaliphilicarchaeal strains isolated from different Soda Lakes were screened for production of protease, amylase, pectinase, chitinase, cellulase, lipase and esterase at pH 10 and 25% NaCl (w/v). Furthermore, metagenomic DNA was extracted from water sample of Ga'ar Lake and constructed library were sequenced to identify the genes encoding target enzymes by using illumina Hiseq2000 system. By enzymatic agar-plate assay, all tested strains showed potential production of extracellular enzymes, a total of 39.4% of screened strains produced protease, 27.1% showed amylase activity, 25.9 % for lipase and 7.4% displayed cellulase activity, but none of tested strains produced chitinase or pectinase. While, by shotgun metagenomic technique, all genes encoding metabolically active hydrolytic enzymes studied were detected in water sample of Ga'ar Soda Lake.Metagenome-derived DNA libraries have focused on many classes of enzymes, among these hydrolytic enzymes were prominent. The results of both methods indicated that these soda lakes are prosperous with commercially valuable enzymes.
Key words: Extremozymes, extracellular activity, Metagenome, Soda Lakes, Egypt.