title: GH11 xylanase from Emericella nidulans with low sensitivity to inhibition by ethanol and lignocellulose-derived phenolic compounds.
abstract: An endo-β-1,4-xylanase (X22) was purified from crude extract of Emericella nidulans when cultivated on submerged fermentation using sugarcane bagasse as the carbon source. The purified protein was identified by mass spectrometry and was most active at pH and temperature intervals of 5.0-6.5 and 50-60°C, respectively. The enzyme showed half-lives of 40, 10 and 7 min at 28, 50 and 55°C, respectively, and pH 5.0. Apparent Km and Vmax values on soluble oat spelt xylan were 3.39 mg/mL and 230.8 IU/mg, respectively, while Kcat and Kcat/Km were 84.6 s(-1) and 25.0 s(-1) mg(-1) mL. Incubation with phenolic compounds showed that tannic acid and cinnamic acid had an inhibitory effect on X22 but no time-dependent deactivation. On the other hand, ferulic acid, 4-hydroxybenzoic acid, vanillin and p-coumaric acid did not show any inhibitory effect on X22 activity, although they changed X22 apparent kinetic parameters. Ethanol remarkably increased enzyme thermostability and apparent Vmax and Kcat values, even though the affinity and catalytic efficiency for xylan were lowered.
authors.affiliation: Laboratory of Enzymology, Department of Cellular Biology, University of Brasília, Brasília, DF, Zip Code 70910-900, Brazil caio.gorgulho@gmail.com.
authors.forename: Caio de Oliveira Gorgulho
authors.initials: Cde O
authors.lastname: Silva
authors.affiliation: Laboratory of Enzymology, Department of Cellular Biology, University of Brasília, Brasília, DF, Zip Code 70910-900, Brazil Laboratory of Biochemistry and Protein Chemistry, Department of Cellular Biology, University of Brasília, Brasília, DF, Zip Code 70910-900, Brazil.
authors.forename: Elaine Nascimento
authors.initials: EN
authors.lastname: Aquino
authors.affiliation: Laboratory of Biochemistry and Protein Chemistry, Department of Cellular Biology, University of Brasília, Brasília, DF, Zip Code 70910-900, Brazil.
authors.forename: Carlos André Ornelas
authors.initials: CA
authors.lastname: Ricart
authors.affiliation: Laboratory of Microbiology, Department of Cellular Biology, University of Brasília, Brasília, DF, Zip Code 70910-900, Brazil.
authors.forename: Gláucia Emy Okida
authors.initials: GE
authors.lastname: Midorikawa
authors.affiliation: Laboratory of Microbiology, Department of Cellular Biology, University of Brasília, Brasília, DF, Zip Code 70910-900, Brazil.
authors.forename: Robert Neil Gerard
authors.initials: RN
authors.lastname: Miller
authors.affiliation: Laboratory of Enzymology, Department of Cellular Biology, University of Brasília, Brasília, DF, Zip Code 70910-900, Brazil.
authors.forename: Edivaldo Ximenes Ferreira
authors.initials: EX
authors.lastname: Filho
mesh_terms: D001547:Benzaldehydes / Q000378:metabolism; D002482:Cellulose; D002934:Cinnamates / Q000494:pharmacology; D003373:Coumaric Acids / Q000378:metabolism; D032842:Emericella / Q000201:enzymology*; D043364:Endo-1,4-beta Xylanases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D004795:Enzyme Stability; D000431:Ethanol / Q000494:pharmacology*; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008031:Lignin / Q000037:antagonists & inhibitors*; D010226:Parabens / Q000378:metabolism; D011422:Propionates; D031786:Saccharum / Q000378:metabolism; D013379:Substrate Specificity; D013634:Tannins / Q000494:pharmacology
chemical_list: D001547:Benzaldehydes; D002934:Cinnamates; D003373:Coumaric Acids; D010226:Parabens; D011422:Propionates; D013634:Tannins; C036909:lignocellulose; C029010:cinnamic acid; D000431:Ethanol; D002482:Cellulose; D008031:Lignin; C027433:bagasse; C004999:ferulic acid; C100058:vanillin; D043364:Endo-1,4-beta Xylanases; C495469:p-coumaric acid; C038193:4-hydroxybenzoic acid
keywords: characterization; enzymatic inhibition; lignocellulosic biomass; pre-treatment-derived compounds; purification