Fluorene Removal by Biosurfactants Producing Bacillus megaterium

This paper describes the study of a surfactant-producing bacterial strain of Bacillus megaterium. The study determined the conditions that favor the production of surfactant and how this bacterial strain functions in the biodegradation of fluorene. Crude biosurfactant was produced from B. megaterium on mineral salt media (MSM) supplemented with either acetate ammonium (MSM-AA) or crude oil (MSM-CO) as sole carbon source. The B. megaterium showed the highest crude biosurfactant yield (2.99 ± 0.11 g L−1) when grown on MSM-AA, while a yield of 2.63 ± 0.04 g L−1 was found on MSM-CO. Biosurfactant activities were observed in both media with a 35.68 ± 1.05 and 28.48 ± 0.39 mN/m reduction in surface tension when using acetate ammonium and crude oil, respectively. FTIR spectroscopy showed that carbon substrates induce the same glycolipid classes for both MSM-AA and MSM-CO. The results clearly demonstrated that carbon substrates affect biosurfactant production in terms of yield, and that the increase of fluorene removal by approximately 1.5 and 2 compared to the control was due to the presence of the amended crude biosurfactant from MSM-AA and MSM-CO, respectively, after 28 days.