title: Characterization of a purified thermostable xylanase from Caldicoprobacter algeriensis sp. nov. strain TH7C1(T).
abstract: The present study investigates the purification and biochemical characterization of an extracellular thermostable xylanase (called XYN35) from Caldicoprobacter algeriensis sp. nov., strain TH7C1(T), a thermophilic, anaerobic strain isolated from the hydrothermal hot spring of Guelma (Algeria). The maximum xylanase activity recorded after 24 h of incubation at 70 °C and in an optimized medium containing 10 g/L mix birchwood- and oats spelt-xylan was 250 U/mL. The pure protein was obtained after heat treatment (1 h at 70 °C), followed by sequential column chromatographies on Sephacryl S-200 gel filtration and Mono-S Sepharose anion-exchange. Matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF/MS) analysis indicated that the purified enzyme is a monomer with a molecular mass of 35,075.10 Da. The results from amino-acid sequence analysis revealed high homology between the 21 NH2-terminal residues of XYN35 and those of bacterial xylanases. The enzyme showed optimum activity at pH 11 and 70 °C. While XYN35 was activated by Ca(2+), Mn(2+), and Mg(2+), it was completely inhibited by Hg(2+) and Cd(2+). The xylanase showed higher specific activity on soluble oat-spelt xylan, followed by beechwood xylan. This enzyme was also noted to obey the Michaelis-Menten kinetics, with Km and kcat values on oat-spelt xylan being 1.33 mg/mL and 400 min(-1), respectively. Thin-layer chromatography soluble oat-spelt xylan (TLC) analysis showed that the final hydrolyzed products of the enzyme from birchwood xylan were xylose, xylobiose, and xylotriose. Taken together, the results indicated that the XYN35 enzyme has a number of attractive biochemical properties that make it a potential promising candidate for future application in the pulp bleaching industry.
authors.affiliation: Laboratory of Cellular and Molecular Biology, Microbiology Team, Faculty of Biological Sciences, University of Sciences and Technology of Houari Boumediene (USTHB), PO Box 32, El Alia, Bab Ezzouar, 16111 Algiers, Algeria; Aix Marseille University-IRD-University of Toulon-CNRS-Mediterranean Institute of Oceanography (MIO), UM 110, 13288 Marseille, France. Electronic address: amelbouanane@gmail.com.
authors.forename: Bouanane-Darenfed
authors.initials: BD
authors.lastname: Amel
authors.affiliation: Laboratory of Applied Microbiology, Faculty of Nature Science and Life, University of Bejaia, Targa Ouzemmour, 06000 Bejaia, Algeria.
authors.forename: Boucherba
authors.initials: B
authors.lastname: Nawel
authors.affiliation: Laboratory of Cellular and Molecular Biology, Microbiology Team, Faculty of Biological Sciences, University of Sciences and Technology of Houari Boumediene (USTHB), PO Box 32, El Alia, Bab Ezzouar, 16111 Algiers, Algeria.
authors.forename: Bouacem
authors.initials: B
authors.lastname: Khelifa
authors.affiliation: Maquav Team, Bioqual Laboratory, INATAA, Frères Mentouri Constantine 1 University, Ain El-Bey Street, 25000 Constantine, Algeria.
authors.forename: Gagaoua
authors.initials: G
authors.lastname: Mohammed
authors.affiliation: Aix Marseille University-IRD-University of Toulon-CNRS-Mediterranean Institute of Oceanography (MIO), UM 110, 13288 Marseille, France.
authors.forename: Joseph
authors.initials: J
authors.lastname: Manon
authors.affiliation: Laboratory of Biological Resources Conservation and Valuation, Faculty of Sciences, M'Hamed Bougara-Boumerdes University, 06000 Boumerdes, Algeria.
authors.forename: Kebbouche-Gana
authors.initials: KG
authors.lastname: Salima
authors.affiliation: Laboratory of Cellular and Molecular Biology, Microbiology Team, Faculty of Biological Sciences, University of Sciences and Technology of Houari Boumediene (USTHB), PO Box 32, El Alia, Bab Ezzouar, 16111 Algiers, Algeria.
authors.forename: Nateche
authors.initials: N
authors.lastname: Farida
authors.affiliation: Laboratory of Cellular and Molecular Biology, Microbiology Team, Faculty of Biological Sciences, University of Sciences and Technology of Houari Boumediene (USTHB), PO Box 32, El Alia, Bab Ezzouar, 16111 Algiers, Algeria.
authors.forename: Hacene
authors.initials: H
authors.lastname: Hocine
authors.affiliation: Aix Marseille University-IRD-University of Toulon-CNRS-Mediterranean Institute of Oceanography (MIO), UM 110, 13288 Marseille, France.
authors.forename: Ollivier
authors.initials: O
authors.lastname: Bernard
authors.affiliation: Aix Marseille University-IRD-University of Toulon-CNRS-Mediterranean Institute of Oceanography (MIO), UM 110, 13288 Marseille, France.
authors.forename: Cayol
authors.initials: C
authors.lastname: Jean-Luc
authors.affiliation: Aix Marseille University-IRD-University of Toulon-CNRS-Mediterranean Institute of Oceanography (MIO), UM 110, 13288 Marseille, France.
authors.forename: Fardeau
authors.initials: F
authors.lastname: Marie-Laure
mesh_terms: D000595:Amino Acid Sequence; D029662:Betula / Q000737:chemistry; D000068016:Eubacteriales / Q000201:enzymology*; D043364:Endo-1,4-beta Xylanases / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D004795:Enzyme Stability; D005965:Glucuronates / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007700:Kinetics; D008670:Metals / Q000494:pharmacology; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000378:metabolism; D013379:Substrate Specificity; D013696:Temperature; D014990:Xylans / Q000378:metabolism
chemical_list: D005965:Glucuronates; D008670:Metals; D009844:Oligosaccharides; D014990:Xylans; C570991:xylooligosaccharide; D043364:Endo-1,4-beta Xylanases
keywords: Caldicoprobacter algeriensis; Hydrolytic pattern; Pulp bleaching industry; Purification; Xylanase