Nowadays petroleum-based plastics have become a consequential part of our human lives. The non-degradable nature of petroleum-based polymers causes serious risks to the environment. Polyhydroxybutyrate (PHB), a storage granule of energy and carbon reserve in many bacteria attracts significant attention in recent years due to its biodegradable nature. Many bacterial strains (Ralstonia eutropha, Alcaligenes latus, Pseudomonas putida and Aeromonas hydrophila) are known for the natural synthesis of PHB under nutrient limited conditions. This study aims at identifying a novel microorganism that produces PHB naturally and to characterize the strains and synthesized polymer. Among 74 distinct isolates from various sources,5 strains (NAA1, NAA2, NAA3, NAA4 and NAA5) showed the presence of PHB in preliminary screening using Sudan Black B stain, Nile red, and Nile blue A staining methods. The microscopic examination of these strains using Sudan Black B stain and Safranin (counter stain) further confirmed the presence of PHB granules. The cell growth, pH change and PHB production of these 5 strains were evaluated under shake flask conditions. Among them, NAA2 and NAA4 produced 87.5% and 74% of PHB respectively from its total cell dry weight. The obtained polymers were extracted through sodium hypochlorite-chloroform extraction method and employed for the 1H NMR and FTIR analysis. The16S rRNA sequencing revealed that the isolated strains were Bacillus pacificus and Klebsiella quasipneumoniae and the phylogenetic tree exhibiting their evolutionary relationship was constructed.