Identification and characterization of polyhydroxyalkanoates producing Acinetobacter spp. isolated from contaminated soils, landfills, and waste dumping sites in the province of Baghdad, Iraq

Polyhydroxyalcanoates (PHAs) are well-known biodegradable polymers produced by bacteria under certain conditions. In this study, 100 different locally bacterial isolates after cultivating ecological models on Modified Solid Nutrient Medium from samples collected from hydrocarbon contaminated soil and landfills and waste dumping places in different sites of Baghdad, Iraq. By performing a microscopic examination after staining the bacterial isolates with Gram stain, it was found that sixty-seven isolates are gram-negative. All bacterial isolates were screened for PHA production by staining using Sudan black B. PHA production was detected in twenty-three bacterial isolates. Our findings indicate that five isolates accumulated a high PHA, ranging 25-56%, with an increase in the dry-weight of cells, ranging 1.20-3.53g\100ml (in a medium containing 10gm/l glucose, pH=7; incubated at 37°C after 48hrs) were Sphingomonass paucimobilis, Klebsiella pneumonia, Citrobacter braakii, C. sediakii, and Acinetobacter lowffii. Vitek test was done to support the characterization of A. lowffii as the most efficient isolate in PHA production. Extracted compound on FTIR-analysis gave characteristic C=O peak of PHA, thus, confirming the isolate to be PHA producer.