Abstract: The applications of aqueous two-phase extraction in concentration and separation of various kinds of antibiotics are discussed,with good results for the separation and purification of erythromycin and penicillin G.The given technology not only can be used in the separation of biological macromolecules,but also can concentrate the broth containing small solutes of biomolecules.The progress in the thermodynamic models and study on mass transfer for aqueous two-phase systems are also presented.The integration of biochemistry, pharmaceutical chemistry, chemical technology and chemical engineering is required to increase the scientific content of traditional antibiotic production,and is also the important path for solving practical commercial problems.When the products are fully water-soluble, such as antibiotics, sugars, glycopeptides, etc, the synthesis has to be carried out in aqueous medium.In this case the use of aqueous two-phase systems could be a suitable option for continuous extraction of the products.A new approach, the combination of aqueous two-phase systems and enzymes that are covalently immobilized inside the porous structure of a support,is used in the kinetically controlled synthesis of cephalolexin.The characteristics of this new approach are explained in detail and the experimental method is also discussed.A comparison of results of the biphasic synthesis with monophasic synthesis is given.In the biphasic synthesis the degree of hydrolysis of cephalolexin decreases significantly, and its yield increases effectively.