Abstract

Polyhydroxybutyrate (PHB), produced by many microorganisms during stress condition, is an eco-friendly biodegradable polymer which can completely replace the petroleum-based commercial plastics. The study was aimed to screen a potent PHB-producing bacterium from municipal dumpsite areas and to analyze the effects of nutritional and environmental factors to enhance production of PHB. Acinetobacter sp. K3 was a potent PHB-producing soil bacterium identified by morphological, biochemical, and molecular techniques. The 16S rDNA nucleotide sequence of the bacterium was assigned the accession number: KT907046 in NCBI database. Effects of different carbon, nitrogen, pH, and temperatures on PHB production were analyzed to enhance its product yield. It grows at the rate of 0.105 g/h/L and PHB production achieved up to 4.8 g/L from 6.04 g/L dry cell weight (DCW) and PHB contents amount to 79.4 % w/w of total DCW. The above accumulated PHB was obtained at pH 8, temperature 40°C, mannitol, and urea used as carbon and nitrogen sources, respectively. Further, phbA, phbB, and phbC genes responsible for PHB production were amplified which confirms the presence of PHB using the gene-specific primers by polymerase chain reaction technique. This new strain could be used for further industrial production of biopolymer.

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