Investigation of Bio clean-up of Crude oil-contaminated Soil using Rhamnolipid Biosurfactant

Nowadays, biosurfactants are widely used in various industries due to their wide range of applications. In this paper, the production of rhamnolipid biosurfactant from Pseudomonas aeruginosa PTCC 1340 as one of the most important biosurfactants was investigated using a sunflower oil carbon source. For this purpose, soil samples were contaminated by crude oil with API 33 artificially. In this study, the production of biosurfactant in the removal of crude oil was investigated. Moreover, the results of this study showed that the maximum amount of rhamnolipid production was 4.3 g/L. Rhamnolipid structure was examined and verified by TLC and FTIR analyzes. The study of the properties of the produced rhamnolipid showed that these substances had a high potential in reduction of surface tension, as the produced rhamnolipid reduced the surface tension of water from 69 mN/m to 26.8 mN/m. It  also showed that a considerable stability in mixing with NaCl salt up to a concentration of 15%. Finally, the results showed that Rhamnolipid supernatant  eliminated 75.17% of the crude oil in the soil, while the highest removal efficiency of the crude oil from the soil was 76.92% by SDS surfactant. According to the successfull results, it can be suggested that the produced rhamnolipid biosurfactant can be used as an alternative to chemical surfactants in various industries.