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Purification and some properties of a xylanase from Aspergillus sydowii MG49

M Ghosh1, G Nanda

  • 1Department of Microbiology, Bose Institute, Calcutta, India.

Insights

Aspergillus sydowii MG49 produces a xylobiohydrolase enzyme that breaks down xylan. Chemical analysis identified key amino acid groups within the enzyme's active site, crucial for its function.

Area of Science:

  • Biochemistry
  • Enzymology
  • Microbiology

Background:

  • Xylanases are crucial enzymes for biomass degradation.
  • Aspergillus sydowii is a fungal species known to produce various enzymes.

Purpose of the Study:

  • To characterize the 30-kDa exosplitting xylobiohydrolase produced by Aspergillus sydowii MG49.
  • To investigate the catalytic site and thermal stability of the purified xylanase.

Main Methods:

  • Enzyme purification from Aspergillus sydowii MG49.
  • Chemical modification of the purified xylanase.
  • Substrate protection analysis.
  • Thermal inactivation studies.

Main Results:

  • A 30-kDa xylobiohydrolase was produced by Aspergillus sydowii MG49 on xylan.
  • Chemical modification and substrate protection revealed tryptophan, carboxy, and amino groups at the enzyme's catalytic site.
  • The xylanase undergoes thermal inactivation via irreversible polymolecular aggregation.
  • Glycerol addition significantly slowed the rate of thermal inactivation.

Conclusions:

  • The catalytic site of the Aspergillus sydowii MG49 xylanase contains essential tryptophan and charged amino acid groups.
  • The enzyme's thermal stability is limited by aggregation, which can be mitigated by cryoprotectants like glycerol.

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