The polysaccharide arabinogalactan (AG) can provide a low cost alternative to the fractionated dextrans for use with polyethylene glycol (PEG) in aqueous two-phase, two-polymer systems. The narrow molecular weight range and low viscosity at high concentration of AG provide for predictable and reproducible separations under a variety of conditions. The partition behavior of bovine serum albumin (BSA) was studied under varying conditions of pH, AG:PEG concentration ratios, and PEG molecular weights. Batch extractive bioconversions of corn starch to cyclodextrin and glucose were demonstrated using AG-PEG systems.