SELECTIVE PERMEATION OF PROTEIN SOLUTE FROM CULTURE BROTH BY ELECTRO-MICROFILTRATION

Electro-microfiltration of culture broth was studied to control the se lective permeation of protein solute. A flat microfiltration membrane was sandwiched between two platinum electrode plates, between which a direct current was applied. Both model suspensions, including bovine s erum albumin (BSA) in baker's yeast suspension and real culture broth producing lytic enzyme, were filtrated in cross-flow mode. The influen ces of the suspension pH and the intensity of the electric field on se lective permeation of protein solute were studied. When the electrode on the permeate side was used as a cathode, BSA was concentrated to th e permeate solution because the BSA molecules was charged positively a t pH 3.5. Meanwhile, the BSA was rejected at pH 7 because of the elect ric repulsion force between the molecule and the electrode of permeate s side. The effects of electric field on the BSA. permeability increas ed with the lower permeate flux, and the higher intensity of electric current. The electro-microfiltration of real culture broth also has si milar properties in the filtration of the model suspension. It was cle arly found that a selective permeation of protein solutes could be con trolled by changing suspension pH.