Purification and characterisation of a β-1,4-xylanase from Remersonia thermophila CBS 540.69 and its application in bread making

Appl Biochem Biotechnol. 2014 Feb;172(4):1747-62. doi: 10.1007/s12010-013-0640-1. Epub 2013 Nov 22.

Abstract

This work reports the first investigation of Remersonia thermophila hemicellulosic hydrolytic enzyme production, with subsequent purification of an extracellular endo-β-1,4-xylanase (RtXyl) and its application in bread making. The research describes RtXyl purification from sorghum-induced submerged liquid cultures of this moderately thermophilic, aerobic, ascomycete fungus. The purified enzyme is a single subunit protein with a molecular mass of 42 kDa and exhibits glycosyl hydrolase family-10-like activity over a broad pH and temperature range. Optimal activity was measured at pH 6.0 and 65 °C respectively, which is suitable for bread making applications. Substrate specificity studies revealed that RtXyl is purely xylanolytic with no side-activities against other plant polysaccharides. The RtXyl catalytic efficiency (K cat/K m) was highest with oats spelt xylan (810.90 mg mL(-1) s(-1)), wheat arabinoxylan (809.52 mg mL(-1) s(-1)) and beechwood xylan (417.40 mg mL(-1) s(-1)) with less efficiency towards insoluble oats spelt xylan (236.40 mg mL(-1) s(-1)). Hydrolysis products analysed by thin layer chromatography yielded a range of xylosaccharides, predominantly xylotriose and xylobiose. RtXyl application in a basic wheat bread recipe at low dosages (0.297 XU/g) showed its suitability to increase loaf volume by 8.0 % compared with the control bread. RtXyl increased loaf softness by 19.6 % while reducing bread staling by 20.4 % up to 4 days of storage.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Ascomycota / enzymology*
  • Bread*
  • Catalysis
  • Endo-1,4-beta Xylanases / isolation & purification*
  • Endo-1,4-beta Xylanases / metabolism*
  • Enzyme Stability
  • Hydrolysis
  • Polysaccharides / metabolism
  • Triticum / chemistry
  • Xylans / metabolism

Substances

  • Polysaccharides
  • Xylans
  • hemicellulose
  • arabinoxylan
  • Endo-1,4-beta Xylanases