Simultaneous hydrocarbon biodegradation and biosurfactant production by oilfield-selected bacteria

Abstract

Aims: To study the bacterial diversity associated with hydrocarbon biodegradation potentiality and biosurfactant production of Tunisian oilfields bacteria.;Methods and Results: Eight Tunisian hydrocarbonoclastic oilfields bacteria have been isolated and selected for further characterization studies. Phylogenetic analysis revealed that three thermophilic strains belonged to the genera Geobacillus, Bacillus and Brevibacillus, and that five mesophilic strains belonged to the genera Pseudomonas, Lysinibacillus, Achromobacter and Halomonas. The bacterial strains were cultivated on crude oil as sole carbon and energy sources, in the presence of different NaCl concentrations (1, 5 and 10%, w/v), and at 37 or 55 degrees C. The hydrocarbon biodegradation potential of each strain was quantified by GC-MS. Strain C450R, phylogenetically related to the species Pseudomonas aeruginosa, showed the maximum crude oil degradation potentiality. During the growth of strain C450R on crude oil (2%, v/v), the emulsifying activity (E24) and glycoside content increased and reached values of 77 and 1.33 g l(-1), respectively. In addition, the surface tension (ST) decreased from 68 to 35.1 mN m(-1), suggesting the production of a rhamnolipid biosurfactant. Crude biosurfactant had been partially purified and characterized. It showed interest stability against temperature and salinity increasing and important emulsifying activity against oils and hydrocarbons.;Conclusions: The results of this study showed the presence of diverse aerobic bacteria in Tunisian oilfields including mesophilic, thermophilic and halotolerant strains with interesting aliphatic hydrocarbon degradation potentiality, mainly for the most biosurfactant produced strains.;Significance and Impact of the Study: It may be suggested that the bacterial isolates are suitable candidates for practical field application for effective in situ bioremediation of hydrocarbon-contaminated sites

Study Onmicrobial Diversity of Biosurfactant Producing Bacteria From Contaminated Enviromental Samples.

“…It enhances the bioavailability of the oil and thus increases the biodegradation rate (Bredholt et al, 1998;Minf et al, 2011;Hassanshahian et al, 2012). Very often the growth of microorganisms on hydrocarbons is accompanied by the emulsification of the hydrocarbon in the medium, and in most cases this has been attributed to the production of surface-active compounds (Desai and Banat,1997).…”

Characterization and Evaluation of Polycyclic Aromatic Hydrocarbon (PAH) Degrading Bacteria Isolated from Oil Contaminated Soil

“…The rate of petrol degradation was maximum (31.9%) at the end of 15 days interval period by Achromobacter. Recently, Achromobacter sp has been reported to utilize polycyclic aromatic hydrocarbons [46][47][48][49][50]. PAH degradation by Pseudomonas strains is well characterized [51].…”

Biodegradation of malodorous mercaptans by a novel Staphylococcus capitis strain isolated from gas-washing wastewaters of the Tunisian Chemical Group

“…The surface tension was measured by a Gibertini Tensiometer (TSD 132389, Milan, Italy) as previously described in the literature (Mnif et al 2011). The values given represent the mean of three replicates (±standard deviation, SD).…”