In the present work, alpha- and beta-amylase enzymes from Zea mays malt were recovered by continuous extraction in a PEG/CaCl2 aqueous two-phase system (ATPS). The influences of the flux rate (R-Q), free area of vane (A(free)) and vane rotation (R-v) on enzyme recovery were studied by optimization using response surface methodology (RSM). The protein content and enzyme activity were measured from time to time in the extract and refined fluxes. RSM curves showed a squared dependence of recovery index with the R-Q, A(free) and R-v. The best system for recovering the maize malt enzymes was with low vane rotation and flux rate and high free area of vane. alpha- and beta-amylases were purified 130-fold in the salt-rich phase. (C) 2007 Elsevier B.V. All rights reserved.85841671227233