title: A thermostable GH26 endo-β-mannanase from Myceliophthora thermophila capable of enhancing lignocellulose degradation.
abstract: The endomannanase gene em26a from the thermophilic fungus Myceliophthora thermophila, belonging to the glycoside hydrolase family 26, was functionally expressed in the methylotrophic yeast Pichia pastoris. The putative endomannanase, dubbed MtMan26A, was purified to homogeneity (60 kDa) and subsequently characterized. The optimum pH and temperature for the enzymatic activity of MtMan26A were 6.0 and 60 °C, respectively. MtMan26A showed high specific activity against konjac glucomannan and carob galactomannan, while it also exhibited high thermal stability with a half-life of 14.4 h at 60 °C. Thermostability is of great importance, especially in industrial processes where harsh conditions are employed. With the aim of better understanding its structure-function relationships, a homology model of MtMan26A was constructed, based on the crystallographic structure of a close homologue. Finally, the addition of MtMan26A as a supplement to the commercial enzyme mixture Celluclast® 1.5 L and Novozyme® 188 resulted in enhanced enzymatic hydrolysis of pretreated beechwood sawdust, improving the release of total reducing sugars and glucose by 13 and 12 %, respectively.
authors.affiliation: Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, 9 Iroon Polytechniou Str., Zografou Campus, Athens, 15780, Greece.
authors.forename: Constantinos
authors.initials: C
authors.lastname: Katsimpouras
authors.affiliation: Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, 9 Iroon Polytechniou Str., Zografou Campus, Athens, 15780, Greece.
authors.forename: Maria
authors.initials: M
authors.lastname: Dimarogona
authors.affiliation: Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, 9 Iroon Polytechniou Str., Zografou Campus, Athens, 15780, Greece.
authors.forename: Pericles
authors.initials: P
authors.lastname: Petropoulos
authors.affiliation: Biochemical and Chemical Process Engineering, Division of Sustainable Process Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, SE-97187, Luleå, Sweden.
authors.forename: Paul
authors.initials: P
authors.lastname: Christakopoulos
authors.affiliation: Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, 9 Iroon Polytechniou Str., Zografou Campus, Athens, 15780, Greece. vtopakas@central.ntua.gr.
authors.forename: Evangelos
authors.initials: E
authors.lastname: Topakas
mesh_terms: D001711:Biotransformation; D003001:Cloning, Molecular; D004795:Enzyme Stability; D015870:Gene Expression; D006863:Hydrogen-Ion Concentration; D008031:Lignin / Q000378:metabolism*; D008958:Models, Molecular; D008970:Molecular Weight; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D020037:Sordariales / Q000201:enzymology*; D013379:Substrate Specificity; D013696:Temperature; D044902:beta-Mannosidase / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D011994:Recombinant Proteins; C036909:lignocellulose; D008031:Lignin; D044902:beta-Mannosidase
keywords: Characterization; Myceliophthora thermophila; Pichia pastoris; Synergism; Thermotolerant; β-Mannanase