beta -Xylosidase recovery by micelles using cetyl trimethyl ammonium bromide (CTAB) cationic surfactant was verified under different experimental conditions. A 2(5.1) fractional factorial design with center points was employed to verify the influence of the following factors on enzyme extraction: pH (x,), CTAB concentration (chi (2)), electrical conductivity (chi (3)), hexanol concentration (,v,), and butanol concentration (chi (5)). Statistical analysis of the results shows that of the five variables studied only hexanol and electrical conductivity did not have significant effects on the recovery of beta -xylosidase. The other factors had significant effects in increasing order: (chi (1)) > (chi (2)) > (chi (5)). The model predicts a recovery value of about 45%, which is similar to that obtained experimentally (43.5%).