2019 CSCE Annual Conference - Laval (Greater Montreal) Conference
Mr. Mohammad Rahimi (Presenter)
Dr. Catherine Mulligan, Concordia University
Contamination of water and soil with crude oil and petroleum compounds frequently occurs. Removal of oil contamination is often not economically feasible by traditional remediation techniques. Therefore, the development of effective, fast, and bio-based remediation methods that can lessen the damaging effects of oil contamination and lower treatment costs are of great importance. Numerous oil-degrading bacteria with biosurfactant production ability have been isolated from oil-related environments. However, less attention has been given to the application of these compounds in the oil-related activities. For this purpose, in this study, new oil-degrading bacteria with the biosurfactant (BS) production ability were discovered with excellent properties for oil bioremediation application. Several oil-degrading bacteria with biosurfactant production ability were discovered from samples including oily tailings pond waste, petroleum-contaminated soil, and light and heavy crude oils by using the enrichment culture technique with Bushnell-Hass media. The biodegradation tests were conducted in flasks containing mineral salt medium (350 ml, pH, 7; salinity of 30 ppt) and crude oil as the only carbon source (2 mL) to determine the contribution of oil-degrading bacteria in the crude oil biodegradation. Flasks were incubated on an orbital shaker (Thermolyne AROS) at 120 rpm and temperature (26 ± 1°C) for five weeks. Moreover, the produced biosurfactants physicochemical properties, quality, and quantity were determined using surface tension (ST) and oil-displacement methods. The level of oil degradation at different periods of biodegradation was monitored weekly by analysis of the remaining of total petroleum hydrocarbons using a gas chromatograph (GC-FID). A total of five oil-degrading bacteria were discovered from oily tailings ponds waste (1 species), petroleum-contaminated soil (two species), light crude oil (one species) and heavy crude oil (one species). All species showed biosurfactant production ability. The lowest surface tensions of supernatants were between 55 mN/m to 40 mN/m. The minimum ST belonged to the BS produced by species discovered from oily tailings pond waste (40 mN/m). Moreover, an average crude oil biodegradation of 70% was obtained with all the isolated bacteria from samples during the five weeks of biodegradation period. This study confirmed the fast and effective biodegradation of crude oil by the isolated bacteria with the biosurfactant production as the main mechanism of oil uptake.