Liquid-liquid extraction, combined with chemical reaction, can improve overall Yields of product. Reactive extraction is an alternative for separations in bioprocessing, for example, for the production of carboxylic acids such as lactic or citric acid, alcohols such as ethanol, or antibiotics such as penicillin, cephalosporin or streptomycin. A method for the design of reactive extraction cascades was used for the recovery of Penicillin G and for lactic acid from aqueous mixtures using mixtures Of organic solvents with reactive amines as extractants. Effects of such variables as residence time, flow rates, pH, number of stages and amine concentration arc quantified. Designs capable of essentially complete recovery are reported.