The effect of pH on bromelain partition from Ananas comosus by PEG4000/phosphate ATPS

in this work, the thermodynamic equilibrium and applying of peg4000/phosphate atps on the purification of bromelain extracted from pineapple was studied. a rigorous study of the equilibrium curves and tie-line length from peg4000/phosphate atps were done for the ph 6-11 at 25oc. results showed that there was augment in the peg and salt contents with the high ph value from peg4000/phosphate atps and two-phase formation needed only increasing the peg content. two tie-line length at ph 11 from peg4000/phosphate atps were optimal condition for bromelain purification, one on composition of 14% peg and 13% salt and other at 12.6% peg and 12.2% salt, while a 25-62 folds of enzyme was found. sds-page electrophoreses had one band only, which showed that bromelain was purified. optimum conditions of bromelain use were found at ph 7 and between 30-40oc.