Acs. Rizzatti et al., Purification and properties of a thermostable extracellular beta-D-xylosidase produced by a thermotolerant Aspergillus phoenicis, J IND MIC B, 26(3), 2001, pp. 156-160
Citations number
26
Categorie Soggetti
Biotecnology & Applied Microbiology",Microbiology
Journal title
JOURNAL OF INDUSTRIAL MICROBIOLOGY & BIOTECHNOLOGY
A beta -D-xylosidase was purified from cultures of a thermotolerant strain
of Aspergillus phoenicis grown on xylan at 45 degreesC. The enzyme was puri
fied to homogeneity by chromatography on DEAE-cellulose and Sephadex G-100.
The purified enzyme was a monomer of molecular mass 132 kDa by gel filtrat
ion and SDS-PAGE. Treatment with endoglycosidase H resulted in a protein wi
th a molecular mass of 104 kDa, The enzyme was a glycoprotein with 43.5% ca
rbohydrate content and exhibited a pi of 3.7. Optima of temperature and pH
were 75 degreesC and 4.0-4.5, respectively. The activity was stable at 60 d
egreesC and had a K-m of 2.36 mM for p-nitrophenyl-beta -D-xylopiranoside.
The enzyme did not exhibit xylanase, cellulase, galactosidase or arabinosid
ase activities. The purified enzyme was active against natural substrates,
such as xylobiose and xylotriose.