Screening of PHA (poly hydroxyalkanoate) producing bacteria from diverse sources

Synthetic plastics are non-degradable and cause waste disposal problems leading to environmental pollution. Bioplastics (polyhydroxyalkanoates) are considered good substitutes for petroleum derived synthetic plastics because of their similar physical and chemical properties. Main advantage of bioplastics is that they are of biological origin and can get degraded completely to CO2 and water under natural environment by the enzymatic activities of microorganisms. Poly-β-hydroxyalkanoates (PHA) are polyesters of various hydroxyalkanoates, synthesized by numerous bacteria as an intracellular carbon and energy storage compound under limited nutrient conditions and with excess carbon. Poly- β- hydroxy butyrate (PHB) is the best known polyhydroxyalkanoate. Considering the industrial interest of PHA, this work has been undertaken for the screening of PHA producing bacteria from diverse sources. In the present study, an attempt was made to isolate efficient PHB producing bacteria from diverse environmental samples. Different industrial wastes and soil samples were screened for bacteria possessing the ability to accumulate poly hydroxyalkanoate (PHA) granules. About 23 bacterial isolates were found to be promising PHA accumulating bacteria. Screening for PHA producers was performed by using E 2 medium. Accumulation of PHB granules in the organisms was analyzed by Sudan black method.