Document Detail


Highly thermostable xylanase of the thermophilic fungus Talaromyces thermophilus: purification and characterization.
MedLine Citation:
PMID:  18668373     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
A thermostable xylanase from a newly isolated thermophilic fungus Talaromyces thermophilus was purified and characterized. The enzyme was purified to homogeneity by ammonium sulfate precipitation, diethylaminoethyl cellulose anion exchange chromatography, P-100 gel filtration, and Mono Q chromatography with a 23-fold increase in specific activity and 17.5% recovery. The molecular weight of the xylanase was estimated to be 25 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and gel filtration. The enzyme was highly active over a wide range of pH from 4.0 to 10.0. The relative activities at pH5.0, 9.0, and 10.0 were about 80%, 85.0%, and 60% of that at pH7.5, respectively. The optimum temperature of the purified enzyme was 75 degrees C. The enzyme showed high thermal stability at 50 degrees C (7 days) and the half-life of the xylanase at 100 degrees C was 60 min. The enzyme was free from cellulase activity. K (m) and V (max) values at 50 degrees C of the purified enzyme for birchwood xylan were 22.51 mg/ml and 1.235 micromol min(-1) mg(-1), respectively. The enzyme was activated by Ag(+), Co(2+), and Cu(2+); on the other hand, Hg(2+), Ba(2+), and Mn(2+) inhibited the enzyme. The present study is among the first works to examine and describe a secreted, cellulase-free, and highly thermostable xylanase from the T. thermophilus fungus whose application as a pre-bleaching aid is of apparent importance for pulp and paper industries.
Authors:
Ines Maalej; Ines Belhaj; Najla Fourati Masmoudi; Hafedh Belghith
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2008-07-31
Journal Detail:
Title:  Applied biochemistry and biotechnology     Volume:  158     ISSN:  1559-0291     ISO Abbreviation:  Appl. Biochem. Biotechnol.     Publication Date:  2009 Jul 
Date Detail:
Created Date:  2009-07-02     Completed Date:  2009-10-01     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8208561     Medline TA:  Appl Biochem Biotechnol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  200-12     Citation Subset:  IM    
Affiliation:
Laboratoire de Génétique Moléculaire des Eucaryotes, Centre de Biotechnologie de Sfax, Sfax, Tunisia.
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MeSH Terms
Descriptor/Qualifier:
Chromatography, Gel
Chromatography, Ion Exchange
DEAE-Cellulose
Endo-1,4-beta Xylanases / biosynthesis,  chemistry,  isolation & purification*,  metabolism*
Enzyme Stability
Hydrolysis
Kinetics
Resins, Synthetic
Talaromyces / enzymology*,  metabolism
Temperature
Xylans / metabolism
Chemical
Reg. No./Substance:
0/Resins, Synthetic; 0/Xylans; 83453-40-1/Mono Q; 9013-34-7/DEAE-Cellulose; EC 3.2.1.8/Endo-1,4-beta Xylanases

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