Liquefied petroleum gas as solvent medium for the treatment of immobilized pectinases

•Pectinase immobilized in support hybrid alginate/gelatin/calcium oxalate (AGOCa).•Treatment with pressurized fluid had influence on enzyme activity and stability of the pectin lyase.•The biocatalyst activity was always higher than on the non-treated one.•The results obtained here might be useful as a basis for the selection of appropriate process conditions, so the catalyst can be applied in bio-transformation reactions.

This work is aimed at assessing the influence of pressurized fluids treatment on the enzymatic activity of pectin lyase (Pectinex® Ultra SP-L and Pectinex® Mash) immobilized in hybrid polymer-inorganic of alginate/gelatin/calcium oxalate (AGOCa). The effects of system pressure (30-190 bar), exposure time (1-6 h) and depressurization rate (20-100 bar/min), using liquefied petroleum gas (LPG) on the enzymatic activity of pectin lyase and pectin methyl esterase have been evaluated through Central Composite Rotational Design (CCRD) 23. The pectin lyase Pectinex® Ultra SP-L presented a 14% increase in residual activity using LPG at 30 bar during 1 h exposure with a 100 bar/min depressurization rate and the commercial Pectinex® Mash had a 38% increment observed at 190 bar for 1 h treatment at 20 bar/min depressurization rate. Enzyme extracts immobilized on alginate-gelatin remained at approximately 60% of pectin lyase (Pectinex® Mash) activity on the sixth recycle after treatment LPG. However, approximately 53% of the pectin lyase (Pectinex® Ultra SP-L) remained until the third recycle. The treatment with pressurized LPG increases the catalytic power of pectinases, hence constituting an interesting solvent to improve the enzyme activity before its use in the process or to carry out reactions using LPG as reaction medium in a enzymatic gas-solid system.

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