Abstract: It is found that a number of microorganisms in activated sludge in the process of waste water treatment can produce a variety of nomo-and co-poly-3-hydroxyalkanoates with a wide range of properties, which would be one of the methods to low the cost of PHA. In this paper, the biosynthesis of polyhydroxyalkanoates(PHA) by mixed bacterium growth on waste water was studied. The chemical structure of PHA, isolated from activated sludge in waste water treatment process using sodium acetate as attachment carbon source, was analyzed by ¹H NMRspectroscopy and gas chromatography mass spectrometry. The PHAproduced from activated sludge is a copolymer composed of 9 different monomer units, 3-hydroxybutyrate, 4-hydroxypentanoate, 3-hydroxydodecanoate, 3-hydroxy-tetradecanoate, 3-hydroxy-9-hexadecenoate, 3-hydroxyhexadecanoate, 3-hydroxy-11-octadecenoate, 3-hydroxy-9-octade-cenoate, 3-hydroxyoctadecanoate.

Key words: Polyhydroxyalkanoates, Bacterial synthesis, Structure characterization