Producing Bio-surfactants Using Purified Microorganisms Isolated from Soils Contaminated with Diesel Fuel

Contamination of soil by diesel fuel can pose serious problems to ecosystems. For this reason some ways to remove diesel fuel from soil were developed by a number of researchers. The aim of this research is to extract bio-surfactant for treating soil contaminated with diesel fuel. In this study, 4 soil samples were taken from fields that had been exposed to diesel fuel over the years. The microorganisms that were able to produce bio-surfactant and remove diesel fuel were isolated from these samples. Ability of microorganisms to produce bio-surfactant was evaluated by emulsification test (E24). Finally solved bio-surfactant into nutrients culture was extracted and measured. Four strains of bacteria were isolated in this study. Results indicated that all bacteria were gram negative. The highest emulsification index was obtained from bacteria isolated from gas fuel station soil. In this study 1.1 gram of bio-surfactant was extracted per one liter of nutrients culture containing bacteria. The results showed that, some special bacteria are able to product enough bio-surfactant to treat soil contaminated diesel fuel.