EFFECTS OF BIOLOGICALLY PRODUCED SURFACTANTS ON THE MOBILITY AND BIODEGRADATION OF PETROLEUM-HYDROCARBONS

A laboratory investigation was conducted to determine the effects of biologically produced surfactants (biosurfactants) on the solubility and biodegradation of petroleum hydrocarbons. Biosurfactants have been found to be produced by microorganisms during growth on insoluble organic substrates for the purpose of increasing substrate solubility so as to promote biological degradation. In this study, biosurfactants were produced by microorganisms during growth on two substrate groups, gasoline and a mixture of glucose with vegetable oil. Solubilization and biodegradation of selected gasoline compounds in the presence of biosurfactants were measured in both static batch and flow through column systems. Biosurfactants produced and used in this study acted similarly to commercial surfactants by increasing the solubility of gasoline compounds. Biosurfactants produced from growth on glucose and vegetable oil were effective at increasing the solubility of gasoline compounds but they inhibited biological degradation of these same compounds. Biosurfactants produced by microorganisms from growth on gasoline were also effective at increasing solubility but did not inhibit biodegradation. Laboratory column studies indicated that the effectiveness of biosurfactants for soil or groundwater remediation could be limited by the adsorption of the biosurfactant to soil.