Purification and properties of thermostable xylanase and beta-xylosidase produced by a newly isolated Bacillus stearothermophilus strain.
We isolated a thermophilic bacterium that produces both xylanase and beta-xylosidase. Based on taxonomical research, this bacterium was identified as Bacillus stearothermophilus. Each extracellular enzyme was separated by hydrophobic chromatography by using a Toyopearl HW-65 column, followed by gel filtration with a Sephacryl S-200 column. Each enzyme in the culture was further purified to homogeneity (62-fold for xylanase and 72-fold for beta-xylosidase) by using a fast protein liquid chromatography system with a Mono Q HR 5/5 column. The optimum temperatures were 60 degrees C for xylanase and 70 degrees C for beta-xylosidase. The isoelectric points and molecular masses were 5.1 and 39.5 kDa for xylanase and 4.2 and 150 kDa for beta-xylosidase, respectively. Heat treatment at 60 degrees C for 1 h did not cause inhibition of the activities of these enzymes. The action of the two enzymes on xylan gave only xylose.
Nanmori
T
T
Department of Agricultural Chemistry, Faculty of Agriculture, Kobe University, Japan.
Watanabe
T
T
Shinke
R
R
Kohno
A
A
Kawamura
Y
Y
D001411:Geobacillus stearothermophilus / Q000201:enzymology* / Q000378:metabolism; D006026:Glycoside Hydrolases / Q000737:chemistry / Q000302:isolation & purification*; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D007526:Isoelectric Point; D008970:Molecular Weight; D043325:Xylan Endo-1,3-beta-Xylosidase; D014990:Xylans / Q000378:metabolism; D014995:Xylosidases / Q000737:chemistry / Q000302:isolation & purification*
D014990:Xylans; D006026:Glycoside Hydrolases; D014995:Xylosidases; D043325:Xylan Endo-1,3-beta-Xylosidase; C026579:exo-1,4-beta-D-xylosidase