FIELD: biotechnology, microbiology. SUBSTANCE: invention relates to the novel improved method of isolation of clavulanic acid from an aqueous cultural broth of clavulanic acid producer. Mycelium, the main part of proteins and other suspended solid particles are removed by multistep continuous microfiltration at pH value between 5.8 and 6.2 and temperature from 20 to 40 C. Purified broth (an aqueous phase) can be purified additionally by ultrafiltration and final purified broth is concentrated by reverse osmosis. Then broth is extracted in countercurrent in centrifuge extractors with an organic solvent no mixing with water at pH value of medium 1 and 3. Water-soluble impurities are removed from the prepared organic phase by its washing out with water followed by drying under vacuum in fractionating column up to water content 0.1%, concentrating by evaporation and decolorizing with activated carbon. Then clavulanic acid in an organic phase is isolated and purified by reaction with N,N'-diisopropylethylenediamine to yield an intermediate N, N'-diisopropylethylene diammonium diclavulanate that is isolated and subjected for interaction with potassium 2-ethylhexanoate in isopropanol medium. EFFECT: improved method of isolation, enhanced purity of end product. 13 cl, 3 ex
