Softwood hemicellulose-degrading enzymes from Aspergillus niger: Purification and properties of a β-mannanase
Author
Summary, in English
The enzymes needed for galactomannan hydrolysis, i.e. β-mannanase, α-galactosidase and β-mannosidase, were produced by the filamentous fungus Aspergillus niger. The β-mannanase was purified to electrophoretic homogeneity in three steps using ammonium sulfate precipitation, anion-exchange chromatography and gel filtration. The purified enzyme had an isoelectric point of 3.7 and a molecular mass of 40 kDa. Ivory nut mannan was degraded mainly to mannobiose and mannotriose when incubated with the β-mannanase. Analysis by 1H NMR spectroscopy during hydrolysis of mannopentaose showed that the enzyme acts by the retaining mechanism. The N-terminus of the purified A. niger β-mannanase was sequenced by Edman degradation, and comparison with Aspergillus aculeatus β-mannanase indicated high identity. The enzyme most probably lacks a cellulose binding domain since it was unable to adsorb on cellulose.
Publishing year
1998
Language
English
Pages
199-210
Publication/Series
Journal of Biotechnology
Volume
63
Issue
3
Document type
Journal article
Publisher
Elsevier
Topic
- Biological Sciences
Keywords
- Hemicellulase
- α-Galactosidase
- Aspergillus niger
- β-Mannanase
Status
Published
ISBN/ISSN/Other
- ISSN: 1873-4863