Fructooligosacharides production in aqueous medium with inulinase from Aspergillus niger and Kluyveromyces marxianus NRRL Y-7571 immobilized and treated in pressurized CO2

• Influence of pre-treatment using CO2 toward FOS production.
• Best results were found when enzymes were previously treated.
• An innovative and profitable alternative to the FOS industry.

This work investigated the influence of compressed CO2 treatment on the enzymatic activity of immobilized inulinases, and the production of fructooligosacharides in aqueous medium using these enzymes. The effects of system pressure, exposure time and depressurization rate on the enzymatic activity were evaluated through central composite designs (CCD) 23. Inulinase from Kluyveromyces marxianus NRRL Y-7571 presented an increase of 104% in the residual activity using CO2 at 275 bar submitted to 6 h treatment, at a depressurization rate of 10 kg m−3 min−1. For Aspergillus niger commercial inulinase, a decrease in enzyme activity was observed (residual activity of 39%) using CO2 treatment at 75 bar for 6 h exposure at the highest depressurization rate (200 kg m−3 min−1). Enzymatic activities changed significantly depending on the enzyme source and the experimental treatment conditions investigated. The values of FOS obtained using inulinases from A. niger were 30.64% of GF2; 13.90% of GF3 and 2.88% of GF4 in the medium containing inulin as substrate. Results demonstrate that the use of compressed CO2 might be of technological importance as a preceding, preparation step, to improve enzyme activity, hence helping the development of new biotransformation processes.