Characterization of a recombinant thermostable xylanase from hot spring thermophilic Geobacillus sp. TC-W7.
A xylanase-producing thermophilic strain, Geobacillus sp. TC-W7, was isolated from a hot spring in Yongtai (Fuzhou, China). Subsequently, the xylanase gene that encoded 407 amino acids was cloned and expressed. The recombinant xylanase was purified by GST affinity chromatography and exhibited maximum activity at 75 degrees C and a pH of 8.2. The enzyme was active up to 95 degrees C and showed activity over a wide pH range of 5.2 to 10.2. Additionally, the recombinant xylanase showed high thermostability and pH stability. More than 85% of the enzyme's activity was retained after incubation at 70 degrees C for 90 min at a pH of 8.2. The activity of the recombinant xylanase was enhanced by treatment with 10 mM enzyme inhibitors (DDT, Tween-20, 2-Me, or TritonX-100) and was inhibited by EDTA or PMSF. Its functionality was stable in the presence of Li+, Na+, and K+, but inhibited by Hg2+, Ni2+, Co2+, Cu2+, Zn2+, Pb2+, Fe3+, and Al3+. The functionality of the crude xylanase had similar properties to the recombinant xylanase except for when it was treated with Al2+ or Fe2+. The enzyme might be a promising candidate for various industrial applications such as the biofuel, food, and paper and pulp industries.
National Engineering Research Center of Juncao, Fuzhou, Fujian 350002, China. liubin618@hotmail.com
Bin
B
Liu
Ningning
N
Zhang
Chao
C
Zhao
Baixue
B
Lin
Lianhui
L
Xie
Yifan
Y
Huang
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D002846:Chromatography, Affinity / Q000379:methods; D003001:Cloning, Molecular; D004492:Edetic Acid / Q000378:metabolism; D043364:Endo-1,4-beta Xylanases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D004789:Enzyme Activation; D057075:Enzyme Assays; D004791:Enzyme Inhibitors / Q000378:metabolism; D004795:Enzyme Stability; D005290:Ferric Compounds / Q000378:metabolism; D005798:Genes, Bacterial; D020459:Genes, rRNA; D056506:Geobacillus / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D045482:Hot Springs / Q000382:microbiology; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D008672:Metals, Alkali / Q000378:metabolism; D019216:Metals, Heavy / Q000378:metabolism; D008969:Molecular Sequence Data; D017830:Octoxynol / Q000378:metabolism; D012336:RNA, Ribosomal, 16S / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D014990:Xylans / Q000378:metabolism
D001426:Bacterial Proteins; D004791:Enzyme Inhibitors; D005290:Ferric Compounds; D008672:Metals, Alkali; D019216:Metals, Heavy; D012336:RNA, Ribosomal, 16S; D011994:Recombinant Proteins; D014990:Xylans; D017830:Octoxynol; D004492:Edetic Acid; D043364:Endo-1,4-beta Xylanases