BACKGROUND: The main goal of this work is to assess the influence of pressurized liquefied petroleum gas (LPG) treatment on the enzymatic activity of immobilized inulinases. The effects of process variables were evaluated through 23 experimental design. RESULTS: Inulinase from Klyveromyces marxianus NRRL Y-7571 presented an increase of 163% in residual activity using LPG at 30 bar during 1 h exposure using a depressurization rate of 20 bar min-1. For Aspergillus niger commercial inulinase, an increment of 129% in residual activity was observed at 30 bar for 1 h treatment at the highest depressurization rate (20 bar min-1). Enzymatic activities changed significantly depending on the enzyme source and the experimental treatment conditions investigated, such as exposure time, depressurization rate and pressure. CONCLUSION: Hence, compressed LPG appears to be a promising technique with practical relevance as a preparation step to improve enzyme activity, thus helping the development of new biotransformation processes. (c) 2012 Society of Chemical Industry