title: Biocatalytic conversion of wheat bran hydrolysate using an immobilized GH43 beta-xylosidase.
abstract: To investigate the concept of a xylosidase-based process for the continuous production of xylose from arabinoxylan-containing feedstocks, a beta-xylosidase from Bacillus halodurans C-125 was immobilized and deployed in packed bed reactor (PBR). Among the several immobilization methods tested, glutaraldehyde-mediated immobilization on chitosan was the best both in terms of immobilization and activity yields (91% and 72.9%, respectively). In batch experiments the immobilized enzyme hydrolyzed wheat bran hydrolysates quite efficiently, consuming nearly all xylobiose and xylotriose after 6h. Its reusability showed only a 50% decrease of its activity after 92h. Using the chitosan-immobilized beta-xylosidase in a PBR, xylose productivity was 7.2g xylose l(-1)h(-1) and the conversion factor was 0.55 (derived from initial xylose in the substrate). The operational stability of the PBR was good, because only 25% of productivity was lost after the treatment of three batches of substrate over a 72-h period.
authors.affiliation: Fractionnement des Agroressources et Emballage, URCA, UMR INRA 614, Reims Cedex 2, France. Issam.Smaali@insat.rnu.tn
authors.forename: Issam
authors.initials: I
authors.lastname: Smaali
authors.forename: Caroline
authors.initials: C
authors.lastname: Rémond
authors.forename: Yousr
authors.initials: Y
authors.lastname: Skhiri
authors.forename: Michael J
authors.initials: MJ
authors.lastname: O'Donohue
mesh_terms: D001407:Bacillus / Q000201:enzymology*; D002384:Catalysis; D004043:Dietary Fiber; D004800:Enzymes, Immobilized / Q000737:chemistry; D010936:Plant Extracts / Q000737:chemistry*; D014908:Triticum / Q000737:chemistry*; D014990:Xylans / Q000737:chemistry*; D014994:Xylose / Q000138:chemical synthesis*; D014995:Xylosidases / Q000737:chemistry*
chemical_list: D004043:Dietary Fiber; D004800:Enzymes, Immobilized; D010936:Plant Extracts; D014990:Xylans; C085118:arabinoxylan; D014994:Xylose; D014995:Xylosidases; C026579:exo-1,4-beta-D-xylosidase