The present study reports two bacteria, designated 87I and 112A, which were isolated from soil and activated sludge samples from Hyderabad, India, and that are capable of producing poly-3-hydroxybutyrate (PHB). Based on phenotypical features and genotypic investigations, these microorganisms were identified as Bacillus spp. Their optimal growth occurred between 28 degrees C and 30 degrees C and pH 7. Bacillus sp. 87I yielded a maximum of 70.04% dry cell weight (DCW) PHB in medium containing glucose as carbon source, followed by 55.5% DCW PHB in lactose-containing medium, whereas Bacillus sp. 112A produced a maximum of 67.73% PHB from glucose, 58.5% PHB from sucrose, followed by 50.5% PHB from starch as carbon substrates. The viscosity average molecular mass (M (v)) of the polymers from Bacillus sp. 87I was 513 kDa and from Bacillus sp. 112A was 521 kDa. All the properties of the biopolymers produced by the two strains 87I and 112A were characterized.

The objective of this paper was to report a bacterium designated as 88D, capable of producing poly (3-hydroxybutyrate-co-3-hydroxyvalerate) [P (3HB-co-3HV)] copolymer from a single carbon source, which was isolated from a municipal sewage treatment plant in Hyderabad, India. This microorganism, based on the phenotypical features and genotypic investigations, was identified as Bacillus sp. The optimal growth of Bacillus sp. 88D occurred between 28 and 30 degrees C and at pH 7. The strain yielded a maximum of 64.62% dry cell weight (DCW) polymer in the medium containing glucose as carbon source, which was followed by 60.46% DCW polymer in glycerol containing medium. Bacillus sp. 88D produced P (3HB-co-3HV) from glucose or glycerol, when they were used as a single carbon substrate. This bacterium produced polyhydrxybutyrate (PHB) when sodium acetate was used as sole carbon substrate. The viscosity average molecular mass (Mv) of the copolymers ranged from 523 to 627 kDa. The physical, chemical and mechanical properties of the biopolymers were characterized.

Bacillus megaterium strain OU303A isolated from municipal sewage sludge was selected for the study of biosynthesis of polyhydroxybutyrate (PHB) and polyhydroxybutyrate-co-hydroxyvalerate P (HB-co-HV) copolymer. The strain yielded a maximum of 62.43% DCW polymer in the medium containing glycerol as carbon source, which was followed by 58.63% DCW polymer in glucose containing medium. We found that this strain was capable of producing 2.5% hydroxyvalerate copolymer from a single carbon substrate, glucose. The strain showed an increase in the amount of HV monomer content, when the precursor for the copolymer was included in the fermentation medium. The characterization of the biopolymers was carried out using FTIR, GC-MS, H 1 NMR and DSC. This is the first report of B. megaterium strain producing HV copolymer, without the addition of any precursor in the fermentation medium.

Bacterial isolates from sludge samples collected at a local municipal sewage treatment plant were screened for bacteria producing polyhydroxyalkanoates (PHA). Initially Sudan black B staining was performed to detect lipid cellular inclusions. Lipid-positive isolates were then grown in a nitrogen limitation E2 medium containing 2% (w/v) glucose to promote accumulation of PHA before the subsequent staining with Nile blue A. The positive isolates were quantified initially with a u.v. spectrophotometer, for a very large number of isolates (105) and among them high PHA-producing isolates (15) were selected and were confirmed by gas chromatographic analysis. The GC analysis showed the polymers produced by 13 of the selected isolates to be polyhydroxybutyrate (PHB), and the remaining two isolates produced polyhydroxybutyrate-co-hydroxyvalerate (PHB-co-HV) copolymer. The proportion of the PHA-positive bacterial isolates showed variability in the number of PHA accumulators during various months. The correlation of PHB production with the cell dry weight (CDW) was found to be statistically significant. The metabolism of PHB in these selected 15 isolates was studied using the Nile blue A staining, which showed an initial increase in the fluorescence followed by a decline, on further incubation. All the selected 15 isolates were classified to genus level by studying their morphological and biochemical characteristics. There were

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°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.