Process for isolating thienamycin

Claim 1

A process for recovering the antibiotic thienamycin from fermentation broths or solutions containing said antibiotic which comprises (a) contacting said broths or solution, acidified to a pH of 2.4-4.5, with a water insoluble liquid ion exchanger which is dinonyl naphthalene sulfonic acid, or didodecylnaphthalene sulfonic acid, the exchanger being dissolved (2-15% by volume) in an organic solvent which is an alcohol of 4-10 carbon atoms, a ketone of 4-8 carbon atoms, or an ester of 4-10 carbon atoms, to extract the thienamycin; followed by (b) contacting the liquid ion exchanger system containing the thienamycin with an aqueous sodium bicarbonate, ammonium hydroxide sodium phosphate, potassium phosphate, or pyridine buffer solution to extract the thienamycin; followed by (c) contacting the aqueous extractant from the previous step, made alkaline to a pH of about 11, with a water insoluble liquid ion exchanger which is tricaprylyl methyl ammonium acetate, tricaprylyl methyl ammonium acetate, tricaprylyl methyl ammonium phosphate, tricaprylyl methyl ammonium propionate, or tricaprylyl methyl ammonium sulfate, in 5-30% by volume solution with said organic solvent of step (a); thereafter, (d) extracting this liquid ion exchanger system with an aqueous sodium acetate, potassium acetate, potassium chloride, hydrogen chloride, or sodium citrate buffer such as; and recovering the thienamycin.