Concentration of ultrafiltered benzylpenicillin broths by reverse osmosis

Concentration of benzylpenicillin filtered broths purified by ultrafiltrati on and fermented broths clarified by ultrafiltration was carried out by rev erse osmosis. This study was done using a reverse osmosis laboratory/pilot installation from Paterson Candy International Ltd, whose module has a tubu lar configuration and a membrane with a molecular weight cut-off of 100 Dal ton (ZF99) made of a polyamide film with a rejection of 99% of NaCl. It was concluded that reverse osmosis is an adequate technique to concentra te benzylpenicillin ultrafiltered broths, leading to low losses of benzylpe nicillin in the permeate and high benzylpenicillin recovery for high volume tric concentration factors.