Partitioning of pectinolytic enzymes in polyethylene glycol/potassium phosphate aqueous two-phase systems

Four different pectinolytic enzymes have been partitioned in polyethylene glycol (PEG)-potassium phosphate aqueous two-phase systems (20–15%). The influence of PEG molecular weight and the addition of sodium chloride were investigated. The best results concerning to the partition coefficients (Kp and Ke) and the yield recovery (R) were: PEG-400/phosphate with NaCl for exo-polygalacturonase (Ke=5.35 and R=89.5%), PEG-600/phosphate for pectin lyase (PL) (Ke=43.18 and R=98.5%) and pectinesterase (PE) (Ke=1.51 and R=69.6%), and PEG-10,000/phosphate for endo-polygalacturonase (Ke=1.35 and R=53.5%). The best purification factors were observed in the upper phase for the systems containing high molecular weight PEG without NaCl: PEG-6000 for exo-polygalacturonase (5.49 fold) and PEG-10,000 for endo-polygalacturonase (16.28 fold), PE (16.64 fold) and PL (14.27 fold).