In self-suction phase-dispersing equipment

the extraction of penicillin from the mixture of penicillin and protein aqueous solution was studied. It was found that: the extraction equilibrium was not changed with the existence of protein

but the transfer speed of penicillin was slowed down. At the beginning of the process

the oil phase became turbid

settlement could not make the emulsion clear. But the more penicillin was extracted into oil phase

the more clearer the oil phase became. It was showed by Raman spectroscopy that the interactions between proteins and penicillin were much weaker than butyl acetates bindings with penicillin. The result explained why existence of proteins could make extraction of penicillin slow down

and not change the final extraction equilibrium. Data of interfacial tension indicated that the interfacial tension decreased with penicillins transferring into oil phase

which was in faVor of replacing protein from oil-aqueous interface by penicillin.