Purification of trypsinogen from bovine pancreas by combining aqueous two-phase partitioning and precipitation with charged flexible chain polymers

Studies on the partition and purification of trypsinogen (TRPz) – a precursor of trypsin – from pancreatic homogenate were performed in aqueous two-phase systems (ATPSs) formed by polyethylene glycol of molecular weight 1450 (PEG1450) and sodium citrate pH 8.20. Several variables such as tie line length (TLL), biomass composition and concentration and phase-volume ratio (Vr) were analyzed. Besides, a precipitation step with polyethyleneimine (PEI) – a positively charged flexible chain polymer – was assayed in order to improve the purification process. Nucleic acids were removed without a significant loss of TRPz content by applying a precipitation step on the homogenate with PEI 0.25% (w/w). ATPSs at long TLL showed TRPz recoveries (RTRPz) and purification factors (PF) higher than those at a short TLL. An enhancement of both the TRPz recovery and PF was observed when the Vr was lowered to 0.5. The best selectivity conditions led to attain almost 5-fold purification and 84% yield.