Inulinase (EC 3.2.1.7) produced by Kluyveromyces marxianus NRRL Y-7571 by solid state fermentation of sugarcane bagasse was purified from culture broth by ethanol precipitation and ultrafiltration. The effects of the concentration of ethanol and the rate of addition of ethanol to the crude extract on the purification yield and purification factor were assessed using the experimental design technique. Precipitation caused an activation of enzyme and allowed purification factor up to 2-fold. After precipitation with ethanol 55% (v/v) and a flow rate of 10 mL/min, followed by ultrafiltration with a 100 kDa membrane, the inulinase could be purified by a factor of 5.5-fold with 86.1% yield. (C) 2011 Elsevier B.V. All rights reserved.