thoroughly mixed with the alcohol filtered and the filtrate collected and concentrated in an alternative method the whole broth can be extracted by the addition of one volume of alkanol preferably methanol and filtered to remove solid impurities the alkanol extract is then adsorbed on 34 diaion 34 hp 20 styrene divinylbenzene copolymer mitsubishi chemical industries ltd resin and eluted with 100 alkanol 34 diaion 34 sp 207 brominated or other commercially available styrene divinylbenzene copolymer also may be employed a second dilution hp 20 adsorption elution step is utilized to concentrate the sample in preparation for chromatographic separations sometimes a third dilution hp 20 adsorption elution step may be desirable for volume reduction the alcoholic solvent to be employed in the initial extraction of the active agent from the solid nutrient medium or from the mycelial pad may be any of the lower alcohols such as methanol ethanol isopropanol and the like methanol is preferred if the active agent is partitioned from the alkanol or methanol solution then suitable solvents are esters such as ethyl acetate isopropyl acetate butyl acetate or ketones such as methyl ethyl ketone the chromatographic separation may be carried out by employing conventional column chromatography with non ionic resin or by high performance liquid chromatography employing reverse phase resin the fractions containing the antibiotic compound i may be.