Characterization of ß-xylosidase Enzyme from a Pichia Stipitis Mutant
b-Xylosidase production was maximal for the mutant Pichia stipitis NP54376 grown on xylan as the sole carbon source. b-Xylosidase
was purified from culture supernatant by (NH4)2SO4 precipitation and a hydrophobic interaction chromatography on phenyl sepharose.
Optima of pH and temperature were 5.0 and 50 C, respectively. The enzyme was inhibited by 2-mercaptoethanol (100%) and Fe3+
(80%), and moderately affected by Cu2+, Ag+, NHþ4
and Mg2+ and SDS. The purified xylosidase hydrolyzed xylobiose and xylo-oligosaccharides
and it did not exhibit activity against cellulose, starch, maltose and cellobiose. 2.5 g l1 glucose repressed b-xylosidase activity
in the NP54376 strain. The Km and Vmax values on p-nitrophenyl-b-xylopyranoside were 1.6 mM and 186 lmol p-nitrophenyl
min1 mg1 protein, respectively. Analysis of the hydrolysis products by HPLC indicated that the major hydrolysis product is xylobiose
in all the carbon sources tested.
BASARAN Pervin;
OZCAN Meltem;
2008-12-05
ELSEVIER SCI LTD
JRC35915
0960-8524,
http://www.sciencedirect.com,
https://publications.jrc.ec.europa.eu/repository/handle/JRC35915,
10.1016/j.biortech.2006.11.056,
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