Purification and characterization of a GH11 xylanase from biobutanol-producing Clostridium beijerinckii G117

Appl Biochem Biotechnol. 2015 Mar;175(6):2832-44. doi: 10.1007/s12010-014-1470-5. Epub 2015 Jan 7.

Abstract

Most biobutanol-producing Clostridium strains are unable to ferment polysaccharides such as cellulose and xylan due to the lack of hydrolyzing enzymes. In this study, we show that Clostridium beijerinckii G117, a newly isolated biobutanol-producing strain, expresses xylanase enzyme in the presence of 1% beechwood xylan. The xylanase activity in the medium containing actively growing culture and 1% of beechwood xylan can reach up to 2.66 U/ml after 14 h of fermentation. Using salting-out and size-exclusion chromatography, we purify the crude xylanase by 8.7-fold from the supernatant with a yield of 32.2%. This purified xylanase has a molecular weight of 22.6 kDa, making it one of the smallest reported clostridial xylanases. Conserved domain analysis reveals that the xylanase belongs to glycoside hydrolase family 11 (GH11) but lacks a carbohydrate binding domain. When beechwood xylan is used as substrate for the xylanase, majority of the products are xylo-oligosaccharide (~98%), suggesting that this is an endo-1,4-β-xylanase.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Butanols / metabolism*
  • Clostridium beijerinckii / chemistry
  • Clostridium beijerinckii / enzymology*
  • Clostridium beijerinckii / genetics
  • Clostridium beijerinckii / metabolism
  • Endo-1,4-beta Xylanases / chemistry*
  • Endo-1,4-beta Xylanases / genetics
  • Endo-1,4-beta Xylanases / isolation & purification*
  • Endo-1,4-beta Xylanases / metabolism
  • Molecular Weight
  • Protein Structure, Tertiary
  • Xylans / metabolism

Substances

  • Butanols
  • Xylans
  • Endo-1,4-beta Xylanases