Isolation and Characterization of Two PHA Producing Strains Isolated from Soil Sample of Nalgonda District

Two whitish-colored gram positive strains producing Polyhydroxyalkanoates (PHAs) were isolated from a soil sample from Nalgonda district in the Telangana state of India. With the help of Sudan black B staining, ten isolates with lipids, which showed bluish black color were selected from twenty six bacterial strains which were selected randomly and purified from the serial diluted plate. Among ten isolates, 3D1 and 3D10 isolates were confirmed with Nile blue A and Nile Red staining for their PHA granules producing capacity. These two isolates grew optimally at a temperature of 37 degrees C and a pH of 9. Furthermore, these strains were able to resist NaCl up to 10%, whereas, optimum NaCl required for the growth of 3D1 was 2%, but optimum NaCl required for the growth of 3D10 was shown to be 4%. PHAs produced by the two strains, 3D1 and 3D10, were extracted and quantified, which produced 68% PHA with a polymer concentration of 4.902 g/L and 61% PHA with a polymer concentration of 4.023 g/L, respectively. Biochemical, Morphological and Molecular characterization were performed on these two isolates. These two strains, 3D1 and 3D10, were closely related to Bacillus sonorensis with similarity of 99.51% and Bacillus safensis subsp. safensis with similarity of 99.66%, respectively. The 16S rDNA gene sequences of these two isolates were submitted to the NCBI Gene bank and the accession numbers were also sought.