Expression, purification and use of the soluble domain of Lactobacillus paracasei beta-fructosidase to optimise production of bioethanol from grass fructans

Bioresour Technol. 2010 Jun;101(12):4395-402. doi: 10.1016/j.biortech.2010.01.084. Epub 2010 Feb 12.


Microbial inulinases find application in food, pharmaceutical and biofuel industries. Here, a novel Lactobacillus paracasei beta-fructosidase was overexpressed as truncated cytosolic protein ((t)fosEp) in Escherichia coli. Purified (t)fosEp was thermostable (10-50 degrees C) with a pH optimum of 5; it showed highest affinity for bacterial levan (beta[2-6] linked fructose) followed by nystose, chicory inulin, 1-kestose (beta[2-1] linkages) and sucrose (K(m) values of 0.5, 15, 15.6, 49 and 398 mM, respectively). Hydrolysis of polyfructose moieties in agriculturally-sourced grass juice (GJ) with (t)fosEp resulted in the release of >13 mg/ml more bioavailable fructose than was measured in untreated GJ. Bioethanol yields from fermentation experiments with Brewer's yeast and GJ+(t)fosEp were >25% higher than those achieved using untreated GJ feedstock (36.5[+/-4.3] and 28.2[+/-2.7]mg ethanol/ml, respectively). This constitutes the first specific study of the potential to ferment ethanol from grass juice and the utility of a novel core domain of beta-fructosidase from L. paracasei.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Biofuels*
  • Electrophoresis, Polyacrylamide Gel
  • Ethanol / metabolism*
  • Fermentation
  • Fructans / metabolism*
  • Hydrolysis
  • Lactobacillus / enzymology*
  • Models, Molecular
  • Molecular Sequence Data
  • Poaceae / metabolism*
  • Protein Structure, Tertiary
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / isolation & purification*
  • Recombinant Proteins / metabolism
  • Solubility
  • Substrate Specificity
  • Yeasts / growth & development
  • beta-Fructofuranosidase / chemistry*


  • Biofuels
  • Fructans
  • Recombinant Proteins
  • Ethanol
  • beta-Fructofuranosidase