Cloning and characterization of two functionally diverse lipases from soil metagenome

Abstract

IntroductionLipases are ubiquitous enzymes that catalyze the hydrolysis of fats and oils and form a large group of the enzymes. These enzymes also catalyze the hydrolysis of a wide range of carboxyl esters at the water lipid interface and reverse the reaction in the nonaqueous phase. During the last decade, lipases have gained importance, to a certain extent, over proteases and amylases, especially in food industry. Many lipases have been isolated from bacteria, fungi, plants, and animals, and have received much attention as biocatalysts. The enantioselective and regioselective nature of lipases has been used for the resolution of chiral drugs, fat modification, synthesis of cocoa butter substituent, biofuels, and flavor enhancers. Owing to their novel and multifunctional application, lipase-catalyzed processes have received great attention, mainly due to several advantages: (1) they are more environmentfriendly than bulk chemical syntheses, (2) they allow manufacture of higher quality products, (3) they are easy to recover and re-use and (4) they can be used in continuous operations.Although the microbial diversity in nature has been estimated by culture-independent methods, it is uncertain whether it would be possible to find a universal J. Gen. Appl. Microbiol., 59, 21 31 (2013) A soil metagenomic library was constructed and two functionally diverse lipase genes, SMlipB and SMlipD, were screened by a function-driven approach and characterized. The optimal temperature for enzyme activity of SMlipB and SMlipD was 50°C and 30°C, respectively, and optimal pH was determined to be 7.0 and 9.0, respectively. Both enzymes exhibited broad substrate specificity and showed enhanced activity in the presence of SDS and Tween 20. The SMlipB enzyme was highly resistant to many organic solvents, especially isopropanol, ethanediol, DMSO, methanol and xylene, whereas SMlipD activity was inhibited in all the solvents except xylene.

Identification and characterization of a novel salt‐tolerant esterase from a Tibetan glacier metagenomic library

“…Metagenomics is a new and rapidly developing field aimed at accessing novel genes and biocatalysts from environmental samples for biotechnological applications . Lipolytic enzymes have been identified from metagenomic DNA libraries prepared from environmental samples such as soils, activated sludge, marine sediments, marine sponges, pond water, lake water, and hot springs . Exploring extreme environments may be a promising strategy for the discovery of novel biocatalyst with unusual properties.…”