Continuous production of fructooligosaccharides and invert sugar by chitosan immobilized enzymes: Comparison between in fluidized and packed bed reactors

•β-Fructofuranosidase and β-fructosyltransferase were immobilized on chitosan spheres.•FOS and invert sugar were produced continuously on enzymatic reactors.•Packed bed reactors presented better yields than fluidized bed reactors.•Packed bed reactor produced FOS continuously for 40 days without loss of activity.•FOS composition can be modulated by the flow rate.

In this work, β-fructofuranosidase and β-fructosyltransferase were covalently immobilized on chitosan spheres, using glutaraldehyde as a coupling agent, in order to produce invert sugar and fructooligosaccharides (FOS). Maxinvert L was used to make β-fructofuranosidase biocatalyst yielding 7000 HU/g. A partial purified β-fructosyltransferase from Viscozyme L was used to prepare the other biocatalyst yielding 2100 TU/g. The production of invert sugar and FOS was evaluated using different continuous enzymatic reactors: two packed bed reactors (PBR) and two fluidized bed reactors (FBR). The invert sugar production achieved a yield of 98% (grams of product per grams of initial sucrose) in the PBR and 94% in the FBR, whereas FOS production achieved a yield of 59% in the PBR and 54% in the FBR. It was also observed in both cases that varying the flow rate it is possible to modulate the FOS composition in terms of nystose and kestose concentrations. The operational stability of FOS produced in the PBR was evaluated for 40 days showing no reductions in yields.

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