title: Characterization of a bacterial tannase from Streptococcus gallolyticus UCN34 suitable for tannin biodegradation.
abstract: The gene in the locus GALLO_1609 from Streptococcus gallolyticus UCN34 was cloned and expressed as an active protein in Escherichia coli BL21 (DE3). The protein was named TanSg1 since it shows similarity to bacterial tannases previously described. The recombinant strain produced His-tagged TanSg1 which was purified by affinity chromatography. Purified TanSg1 protein showed tannase activity, having a specific activity of 577 U/mg which is 41 % higher than the activity of Lactobacillus plantarum tannase. Remarkably, TanSg1 displayed optimum catalytic activity at pH 6-8 and 50-70 °C and showed high stability over a broad range of temperatures. It retained 25 % of its relative activity after prolonged incubation at 45 °C. The specific activity of TanSg1 is enhanced by the divalent cation Ca(2+) and is dramatically reduced by Zn(2+) and Hg(2+). The enzyme was highly specific for gallate and protocatechuate esters and showed no catalytic activity against other phenolic esters. The protein TanSg1 hydrolyzes efficiently tannic acid, a complex and polymeric gallotanin, allowing its complete conversion to gallic acid, a potent antioxidant. From its biochemical properties, TanSg1 is a tannase with potential industrial interest regarding the biodegradation of tannin waste or its bioconversion into biologically active products.
authors.affiliation: Laboratorio de Biotecnología Bacteriana, Instituto de Ciencia y Tecnología de Alimentos y Nutrición, ICTAN-CSIC, Juan de la Cierva 3, 28006, Madrid, Spain.
authors.forename: Natalia
authors.initials: N
authors.lastname: Jiménez
authors.forename: José María
authors.initials: JM
authors.lastname: Barcenilla
authors.forename: Félix López
authors.initials: FL
authors.lastname: de Felipe
authors.forename: Blanca
authors.initials: B
authors.lastname: de Las Rivas
authors.forename: Rosario
authors.initials: R
authors.lastname: Muñoz
mesh_terms: D001711:Biotransformation; D002265:Carboxylic Ester Hydrolases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002413:Cations, Divalent / Q000378:metabolism; D002846:Chromatography, Affinity; D003001:Cloning, Molecular; D020536:Enzyme Activators / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000378:metabolism; D004795:Enzyme Stability; D004926:Escherichia coli / Q000235:genetics; D006863:Hydrogen-Ion Concentration; D008670:Metals / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D013291:Streptococcus / Q000201:enzymology* / Q000235:genetics; D013379:Substrate Specificity; D013634:Tannins / Q000378:metabolism*; D013696:Temperature
chemical_list: D002413:Cations, Divalent; D020536:Enzyme Activators; D004791:Enzyme Inhibitors; D008670:Metals; D011994:Recombinant Proteins; D013634:Tannins; D002265:Carboxylic Ester Hydrolases; C022711:tannase