Isolation and characterization of potent poly-( 3-hydroxybutyrate)(phb) producing bacteria from various environmental samples collected from locality of Bangalore

Bacterial isolates from sludge samples collected at a local area of Bangalore were screened for bacteria producing Polyhydroxyalkanoates (PHA) specifically for Poly (3-hydroxy butyrate) (PHB) at one month interval between April 2012 to March 2013. Initially Sudan Black B staining was performed to detect lipid cellular inclusions. PHB-positive isolates were then grown in a modified mineral E2 medium containing 1 (v/v) molasses with nitrogen limitation to promote accumulation of PHA before the subsequent staining with Nile blue A. The positive isolates were quantified initially with a UV-VIS spectrophotometer, for a very large number of isolates (364) and among them high PHB-producing isolates (12) were selected. The proportion of the PHB-positive bacterial isolates showed variability in the number of PHB accumulators during various months. Among all the bacterial CDW 63.67 cell dry weight PHB, is the highest report of PHB -accumulating bacteria from Metal plate industrial effluent (MEJN01) and next in Garden soil isolate (GSJN04) of about 45.89, when grown on the E2 mineral media supplemented with 1 molasses. The correlation of PHB production with the cell dry weight (CDW) was found to be statistically significant. The metabolism of PHB in the selected 12 isolates was studied using the Nile blue A staining, which showed an initial increase in the fluorescence followed by a decline after 72 hours, on further incubation. All the selected 12 isolates were classified to genus level by studying their morphological and biochemical characteristics. There were eight Bacillus species, one Escherichia species, one Azotobacter. species, and two Staphylococcus species.