Continuous production of xylooligosaccharides in a packed bed reactor with immobilized–stabilized biocatalysts of xylanase from Aspergillus versicolor

•An endo-xylanase from Aspergillus versicolor was immobilized on different agarose supports.•The derivative xyl–glyoxyl–agarose was about 700 times more stable than the soluble enzyme.•Glyoxyl derivative produced mainly xylobiose and little amount of xylose was observed only at the end of the hydrolysis.•The catalytic activity was fully retained after 10 consecutive cycles of hydrolysis.•The highly stable derivative was employed in a packed bed reactor for continuous synthesis of xylooligosaccharides.

The production of xylooligosaccharides (XOS) using a packed-bed enzymatic reactor was studied at lab-scale. For this, a xylanase from Aspergillus versicolor was immobilized on different supports. The optimal derivative was xylanase immobilized on glyoxyl-agarose supports. This derivative preserved 85% of its catalytic activity; it was around 700-fold more stable than the soluble enzyme after incubation at 60 °C and was able to be reused for at least 10 1 h-cycles retaining full catalytic activity. About 18% of oligosaccharides with prebiotic interest (X2–X6) were produced by the glyoxyl derivative in batch hydrolysis. The production of xylobiose was 2.5-fold higher using the immobilized preparation than with soluble enzyme and small concentrations of xylose (<0.1%) were observed only at the end of the reaction. The derivative was employed on a packed bed reactor, and the continuous operation with no recirculation reached 56% and 70% of the end of reaction with flow rates of 60 mL/h and 12 mL/h, respectively. In continuous operation with recirculation at a flow rate of 60 mL/h, the reaction was completed after four hours.

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