title: Molecular cloning and characterization of a GH11 endoxylanase from Chaetomium globosum, and its use in enzymatic pretreatment of biomass.
abstract: An endo-1,4-β-xylanase gene, xylcg, was cloned from Chaetomium globosum and successfully expressed in Escherichia coli. The complete gene of 675 bp was amplified, cloned into the pET 28(a) vector, and expressed. The optimal conditions for the highest activity of the purified recombinant XylCg were observed at a temperature of 40 °C and pH of 5.5. Using oat-spelt xylan, the determined K m, V max, and k cat/K m values were 0.243 mg ml⁻¹, 4,530 U mg⁻¹ protein, and 7,640 ml s⁻¹ mg⁻¹, respectively. A homology model and sequence analysis of XylCg, along with the biochemical properties, confirmed that XylCg belongs to the GH11 family. Rice straw pretreated with XylCg showed 30 % higher conversion yield than the rice straw pretreated with a commercial xylanase. Although xylanases have been characterized from fungal and bacterial sources, C. globosum XylCg is distinguished from other xylanases by its high catalytic efficiency and its effectiveness in the pretreatment of lignocellulosic biomass.
authors.affiliation: Department of Chemical Engineering, Konkuk University, 1 Hwayang-Dong, Gwangjin-Gu, Seoul 143-701, South Korea.
authors.forename: Raushan Kumar
authors.initials: RK
authors.lastname: Singh
authors.forename: Manish Kumar
authors.initials: MK
authors.lastname: Tiwari
authors.forename: Dongwook
authors.initials: D
authors.lastname: Kim
authors.forename: Yun Chan
authors.initials: YC
authors.lastname: Kang
authors.forename: Priyadharshini
authors.initials: P
authors.lastname: Ramachandran
authors.forename: Jung-Kul
authors.initials: JK
authors.lastname: Lee
mesh_terms: D018554:Avena / Q000737:chemistry; D018533:Biomass; D002597:Chaetomium / Q000201:enzymology* / Q000235:genetics; D003001:Cloning, Molecular; D043364:Endo-1,4-beta Xylanases / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D004795:Enzyme Stability; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008031:Lignin / Q000378:metabolism; D008958:Models, Molecular; D012275:Oryza / Q000737:chemistry; D018547:Plant Stems / Q000737:chemistry; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D013696:Temperature; D014990:Xylans / Q000378:metabolism
chemical_list: D011994:Recombinant Proteins; D014990:Xylans; C036909:lignocellulose; D008031:Lignin; D043364:Endo-1,4-beta Xylanases