Isolation and screening of native polyhydroxyalkanoate producing bacteria from oil contaminated soils of Abadan refinery

Environmental contaminations due to petrochemical plastic usage have forced researchers to search new biological methods for biodegradable polymer production. The aim of this study was to find native PHA producing bacteria from Abadan oil refinery in order to be used in biodegradable polymer production studies. For this purpose soil samples were harvested from oil sludge contaminated soil of Abadan refinery. After primary enrichment, screening of PHA producing bacteria was done by PHA- Detection agar and was confirmed by Sudan black and Nile Blue A staining methods. These isolates were identified based on phenotypic methods and sequencing of 16s rRNA. Polymer extraction was performed and optimized using different concentrations of HClO and SDS. As a result of this study 26 different bacterial isolates were obtained from which 17 isolates were PHA producer with different potentiality. Based on the polymer accumulation 4 isolates were selected for further studies. The efficiency of PHA production in these isolates was 75.53±5.08, 82±19.05, 81.06±6.92 and 79.86±11.84%. Based on sequence analysis in NCBI database, these isolates were identified as Bacillus cereus. Discussion and With respect to the results of this study it can be suggested that oil contaminated soils due to high C/N and C/P ratios and also different carbohydrate contents are suitable candidates for PHA producer bacteria isolation. So the native strains in such habitats with high carbon content can be optimized for industrial polymer production.