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Evaluation and characterization of polyhydroxybutyrate produced by Azotobacter chroococcum

Ahmed A.Haroun, Marwa S.Abdel-Hamid

Production and characterization of biodegradable plastic namely polyhydroxybutyrate (PHB) in Azotobacter chroococcumhave been carried out using different carbon sources such as: ethanol, sugar cane molasses in comparison with glucose leading to develop a low cost process of PHB production. The accumulation of PHB granule in cells of A. chroococcum was significantly dependent on the content of carbon sources in themedium culture. In the case of using ethanol, the PHB producedwas high significant percentage (42 w/w%) in comparison with molasses and glucose (31 and 16 w/w %, respectively). Light, transmission and scanning electron microscopes (TEM and SEM) images of the staining cysts illustrated that different morphologies were obtained relative to that in the case of the vegetative one.Moreover, the physicochemical properties of the produced PHB were studied and evaluated using different analytical tools such as: Fourier transforminfrared spectroscopy (FTIR), nuclearmagnetic resonance spectroscopy (1H-NMR),X-ray diffraction pattern (XRD), high performance liquid chromatography (HPLC) and differential scanning calorimetry (DSC).