Isolation and characterization of bacteria and fungi with the ability to degrade petroleum hydrocarbons

Abstract

As the world’s population grows exponentially and the ceiling of needs continues to rise, attention to the impact of the exploitation of raw materials is necessary and to the problems that have arisen. Petroleum products released into the environment affect humans, animals and plants. The consequences of pollution depend on the organisms themselves and the chemical structure of the hydrocarbons but they have immediate and irreversible effects. This forces us to intervene urgently to think about serious solutions to slow down or reduce the pollution and its effects. This study aimed to isolate bacterial and fungal species from samples of petroleum products as well as a sample of soil contaminated with petroleum. Subsequently, a characterization of the isolates is carried out in order to select hydrocarbonoclastic microorganisms that have the ability to degrade these pollutants. Morphological features of the isolated microorganisms are identified by mean of macroscopic and microscopic observations. Moreover, their ability to degrade gasoline and diesel is assessed through the determination of their ability to grow on media containing these two hydrocarbons. As well, whether the isolate produce or not biosurfactants was assayed through the measure of the emulsifying index E24%, cell surface hydrophobicity (CSH) % and the qualitative drop collapse technique (DCT). Through this study we could isolate eight Gram positive and negative bacteria and one fungus belonging the genus Aspergillus. All the tested microbial isolates showed ability to grow on media containing gasoline and diesel in addition to their ability to produce biosurfactants with both hydrocarbons at different rates. Taking into consideration all the obtained results, the bacteria C26 showed the best potential for use as a bioremediation agent.