Kerosene biodegradation ability and characterization of bacteria isolated from oil-polluted soil and water

With increasing production and consumption of oil, the inevitable spillage of oil presents a significant challenge to protecting the environment and human health. Bioremediation is an effective approach to address this challenge. In this research, three soil and two wastewater samples contaminated by petroleum and a sample of crude oil were collected from Bandar Abbas Refinery, Iran. These samples were used for isolation and identification of bacteria, which can be used for cleaning polluted lands. Twelve strains were isolated and cultured at 28 °C standard succinate medium from which carbon or sulfur resources were eliminated and kerosene was added. Three isolates were selected for identification because of their high growth rate in kerosene tests. The biodegradation activity of these bacteria was analyzed by gas chromatography. Using biochemical tests, 16S rDNA sequence, and API 20 E kit, it was revealed that these bacteria belong to Enterobacter cloacae, Enterobacter hormaechei, and Pseudomonas stutzeri. They were able to degrade 67.43%, 48.48%, and 65.48% of 5% kerosene as carbon source in seven days, respectively. Pseudomonas stutzeri and Enterobacter hormaechei could respectively degrade 54.14% and 12.98% of 10% kerosene as sulfur source in seven days. Hence, these bacteria can be considered as excellent candidates for petroleum biodegradation.