Isolation and Screening of Polyhydroxybutyrate (PHB) Producing Bacteria from Soils

Polyhydroxybutyrates (PHBs) are macromolecules synthesized by bacteria. PHBs are the most promising type of bioplastic; they are nontoxic, biodegradable and biocompatible and have properties similar to those of conventional plastics. In the present study, an attempt was made to screen of different bacterial isolates accumulating PHB from soil samples collected from Istanbul, Turkey. A total of 86 different bacterial isolates were isolated from soil samples and a total of 32 isolates were suggested to be PHB producer when stained with Sudan Black B, a preliminary screening agent for lipophilic compounds. 13 bacterial isolates were selected as PHB producing isolates by using the Nile blue A dying technique. 16S rRNA gene sequences analysis showed that PHB producing 13 isolates belonged to Pseudomonas, Arthrobacter and Bacillus genera. The PHB from the isolates was extracted using the dispersion method of the hypochlorite and chloroform method. The highest PHB production and percentage productivity were obtained from Pseudomonas plecoglossicida M9 (0.94 PHB g/L; 78.8% PHB) and Pseudomonas baetica Y6 (0.81 PHB g/L; 74.3% PHB) respectively.