Purification and characterization of β-glucosidases and β-xylosidase of Aspergillus niger NCIM 1207

Background: The extracellular β-glucosidases (cellulose and xylan induced) and xylan-induced β-xylosidase from Aspergillus niger NCIM 1207 were purified to homogeneity. The protocols were based on fractional ethanol precipitation, pH and thermal stability, and separation of impurities by thermal den...

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Published in:Biofuels (London) 2013-03, Vol.4 (2), p.203-217
Main Authors: Khisti, Ujwala, Gokhale, Digambar
Format: Article
Language:English
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Summary:Background: The extracellular β-glucosidases (cellulose and xylan induced) and xylan-induced β-xylosidase from Aspergillus niger NCIM 1207 were purified to homogeneity. The protocols were based on fractional ethanol precipitation, pH and thermal stability, and separation of impurities by thermal denaturation. Results: The molecular weights of all the three enzymes were 122 and 336 kDa as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and gel perme\ation chromatography. Mass spectrometric analysis revealed that cellulose and xylan-induced β-glucosidases showed 24 and 12% sequence coverage, respectively, with β-glucosidase A of A. niger CBS 513.88/FGSC A1513. Xylan-induced β-xylosidase exhibited 35% homology with probable exo-1,4-β-xylosidase of A. niger CBS 513.88/FGSC A1513 and 11% homology with β-glucosidase A of A. niger CBS 513.88/FGSC A1513. Conclusion: The enzymes are high-molecular weight proteins and are trimeric in nature. This is the first report on high-molecular weight trimeric β-xylosidase from fungal species.
ISSN:1759-7269
1759-7277
DOI:10.4155/bfs.12.92