title: A novel alkaliphilic xylanase from the newly isolated mesophilic Bacillus sp. MX47: production, purification, and characterization.
abstract: A newly isolated bacterial strain, Bacillus sp. MX47, was actively producing extracellular xylanase only in xylan-containing medium. The xylanase was purified from the culture broth by two chromatographic steps. The xylanase had an apparent molecular weight of 26.4 kDa with an NH(2)-terminal sequence (Gln-Gly-Gly-Asn-Phe) distinct from that of reported proteins, implying it is a novel enzyme. The optimum pH and temperature for xylanase activity were 8.0 and 40 °C, respectively. The enzyme activity was severely inhibited by many divalent metal ions and EDTA at 5 mM. The xylanase was highly specific to beechwood and oat spelt xylan, however, not active on carboxymethyl cellulose (CMC), avicel, pectin, and starch. Analysis of the xylan hydrolysis products by Bacillus sp. MX47 xylanase indicated that it is an endo-β-1,4-xylanase. It hydrolyzed xylan to xylobiose as the end product. The K(m) and V(max) values toward beechwood xylan were 3.24 mg ml(-1) and 58.21 μmol min(-1) mg(-1) protein, respectively.
authors.affiliation: Department of Biological Science, Myongji University, Yongin, Gyeonggido 449-728, South Korea.
authors.forename: Won-Jae
authors.initials: WJ
authors.lastname: Chi
authors.forename: Da Yeon
authors.initials: DY
authors.lastname: Park
authors.forename: Yong-Keun
authors.initials: YK
authors.lastname: Chang
authors.forename: Soon-Kwang
authors.initials: SK
authors.lastname: Hong
mesh_terms: D001407:Bacillus / Q000145:classification / Q000166:cytology / Q000302:isolation & purification* / Q000378:metabolism*; D049109:Cell Proliferation; D043364:Endo-1,4-beta Xylanases / Q000096:biosynthesis* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D010802:Phylogeny; D014990:Xylans / Q000378:metabolism
chemical_list: D014990:Xylans; D043364:Endo-1,4-beta Xylanases