Characterization of beta-xylosidase enzyme from a Pichia stipitis mutant

Basaran P., Ozcan M.

BIORESOURCE TECHNOLOGY, vol.99, no.1, pp.38-43, 2008 (Journal Indexed in SCI) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 99 Issue: 1
  • Publication Date: 2008
  • Doi Number: 10.1016/j.biortech.2006.11.056
  • Title of Journal : BIORESOURCE TECHNOLOGY
  • Page Numbers: pp.38-43

Abstract

p-Xylosidase production was maximal for the mutant Pichia stipitis NP54376 grown on xylan as the sole carbon source. P-Xylosidase was purified from culture supernatant by (NH4)(2)SO4 precipitation and a hydrophobic interaction chromatography on phenyl sepharose. Optima of pH and temperature were 5.0 and 50 degrees C, respectively. The enzyme was inhibited by 2-mercaptoethanol (100%) and Fe3+ (80%), and moderately affected by Cu2+, Ag+, NH4+ 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 l(-1) glucose repressed P-xylosidase activity in the NP54376 strain. The K-m and V-max values on p-nitrophenyl-p-xylopyranoside were 1.6 mM and 186 mu mol p-nitrophenyl min(-1) mg(-1) protein, respectively. Analysis of the hydrolysis products by HPLC indicated that the major hydrolysis product is xylobiose in all the carbon sources tested. (C) 2006 Elsevier Ltd. All rights reserved.