Bioprospecting for Thermozymes and Characterization of a Novel Lipolytic Thermozyme Belonging to the SGNH/GDSL Family of Hydrolases

Abstract

Functional screenings were conducted on two metagenomic libraries from hot springs in order to find novel thermozymes with potential biotechnological applications. These included enzymes acting on plant cell walls such as endoglucanases and exoglucanases, β-glucosidases, xylanases, and β-xylosidases, and broad application enzymes such as proteases and lipolytic hydrolases. Of all the enzymes found by this bioprospection, we selected a novel lipolytic enzyme for further characterization. The protein was found to belong to the SGNH/GDSL family of hydrolases. It was purified and its biochemical parameters determined. We found that the enzyme was most active at 60 °C and pH 9 using pNP-laurate as substrate and was highly thermostable. It also showed preference for short-chained substrates and activation with temperature and with certain detergents such as Tween 80. Proteins of this family of hydrolases are relevant for their broad substrate specificity, that coupled with this protein’s high temperature optima, broad pH range, and thermostability further highlights its biotechnological potential.

Characterization of a novel thermophilic metagenomic GH5 endoglucanase heterologously expressed in Escherichia coli and Saccharomyces cerevisiae

“…Metagenomic DNA was obtained from Muiño da Veiga hot spring, located in Galicia (northwest region of Spain), using the "Metagenomic DNA isolation kit for water" (Epicentre, USA) as described previously [51]. Up to 125L of hot spring water were processed for the extraction of high molecular weight DNA.…”