210 % in the residual activity using n-butane at 30 bar during 6 h exposure and with a depressurization rate of 20 bar/min. For commercial inulinase from Aspergillus niger, an increment of 142 % in the residual activity at 270 bar for 6 h treatment at the highest depressurization rate (100 bar/min) was observed. The use of compressed n-butane may be of technological relevance as a preceding, preparation step, towards improving enzyme activity, hence helping the development of new biotransformation processes.