Esterase

About: Esterase is a research topic. Over the lifetime, 7622 publications have been published within this topic receiving 168270 citations.

Hydrolysis of rosmarinic acid from rosemary extract with esterases and Lactobacillus johnsonii in vitro and in a gastrointestinal model.

Abstract: Rosmarinic acid (RA) was identified as one of the main components of rosemary extracts and has been ascribed to a number of health benefits. Several studies suggested that after ingestion, RA is metabolized by gut microflora into caffeic acid and derivatives. However, only limited information on the microorganisms and enzymes involved in this biotransformation is available. In this study, we investigated the hydrolysis of RA from rosemary extract with enzymes and a probiotic bacterium Lactobacillus johnsonii NCC 533. Chlorogenate esterase from Aspergillus japonicus (0.02 U/mg) hydrolyzed 90% of RA (5 mg/mL) after 2 h at pH 7.0 and 40 degrees C. Complete hydrolysis of RA (5 mg/mL) was achieved with a preparation of L. johnsonii (25 mg/mL, 3.3 E9 cfu/g) after 2 h of incubation at pH 7.0 and 37 degrees C. No hydrolysis of RA was observed after the passage of rosemary extract through the gastrointestinal tract model (GI model). Thus, RA is hydrolyzed neither chemically under the conditions of the GI model (temperature, pH, and bile salts) nor by secreted enzymatic activity (lipase and pancreatic enzymes). The addition of L. johnsonii cells to rosemary extract in the GI model resulted in substantial hydrolysis of RA (up to 99%).

Biomass-to-bio-products application of feruloyl esterase from Aspergillus clavatus

Abstract: The structural polysaccharides contained in plant cell walls have been pointed to as a promising renewable alternative to petroleum and natural gas. Ferulic acid is a ubiquitous component of plant polysaccharides, which is found in either monomeric or dimeric forms and is covalently linked to arabinosyl residues. Ferulic acid has several commercial applications in food and pharmaceutical industries. The study herein introduces a novel feruloyl esterase from Aspergillus clavatus (AcFAE). Along with a comprehensive functional and biophysical characterization, the low-resolution structure of this enzyme was also determined by small-angle X-ray scattering. In addition, we described the production of phenolic compounds with antioxidant capacity from wheat arabinoxylan and sugarcane bagasse using AcFAE. The ability to specifically cleave ester linkages in hemicellulose is useful in several biotechnological applications, including improved accessibility to lignocellulosic enzymes for biofuel production.

Purification and characterization of a novel extracellular esterase from pathogenic Streptomyces scabies that is inducible by zinc.

Abstract: Native polyacrylamide gels of extracellular proteins produced by several Streptomyces isolates grown with suberin were assayed in situ for esterase activity. Two pathogenic isolates of Streptomyces scabies from different geographical regions were found to produce a similar esterase activity that was not produced by nonpathogenic strains. After treatment with EDTA, suberin no longer induced esterase production. Expression was restored when EDTA-treated suberin was supplemented with zinc. The optimal concentration of zinc required for esterase production was 2 microM. This esterase was purified from one of the pathogenic isolates and characterized. The enzyme was 38,000 daltons when determined by gel filtration on Sephadex G-100 and 36,000 daltons when determined by denaturing polyacrylamide gel electrophoresis. The esterase showed maximal activity in sodium phosphate buffer above pH 8.0, was stable to temperatures of up to 60 degrees C, and had an apparent Km of 125 microM p-nitrophenyl butyrate. Images