Nakamura_2018_Int.J.Biol.Macromol_120_1893

Esterases are widely applied in industrial processes due to their versatility, regio- and enantioselectivity, lack of cofactors and stability in organic solvents. Bacillus licheniformis, a microorganism frequently used in industrial and biotechnological applications such as dairy, baking, beverage, pulp and paper, detergent and cosmetics production, organic synthesis and waste management, is a promising source of esterases. Here we describe the biochemical and biophysical characterization of B. licheniformis carboxylesterase BlEst1 and its SAXS-derived molecular envelope. BlEst1 has optimal hydrolytic activity against pnitrophenyl acetate at pH7.0 and 40 degrees C. Furthermore, BlEst1 is stable in different organic solvents such as methanol, isopropanol and butanol. The BlEst1 homology model reveals a typical alpha/beta hydrolase core with an adjacent auxiliary domain, snuggly fitting the experimental low-resolution SAXS molecular envelope. Moreover, BlEst1 maintained considerable part of its activity in the presence of up to 5M NaCl and its thermal stability was significantly enhanced by the presence of salt, revealing its halotolerant character. The ability to work under harsh conditions makes BlEst1 an interesting candidate for industrial applications.