Biosurfactants Production During Diesel Biodegranation by Mixed Microbial Consortia Selected From Polluted Spolls

Abstract

<p>This work studies the biosurfactants production which enables the diesel biodegradation by<br />using mixed microbial consortia from polluted sites. It was carried out by culturing three microbial consortia<br />(named as XA, XB and XC) obtained from polluted soils, and enriched in diesel as sole carbon source.Batch<br />experiments were done to study the effects of three variables (temperature,hydrocarbon concentration and the<br />origin of the consortia) on the diesel biodegradation and the surface tension evolution. The three enriched<br />consortia contained similar bacterial genera and degraded diesel with similar efficiencies (approximately 90%).<br />Thermal inhibition was observed at 35 ºC. The evolution of surface tension was similar in all experiments: an<br />initial fast reduction followed by an increase once the diesel had been consumed. All three consortia were found<br />to be efficient biosurfactants producers. Consortia XB and XC had similar low biosurfactant yields (1.3 and<br />1.8 g g-1, respectively) and lower critical micelle concentration values (0.42 and 0.45 g L-1, respectively), while<br />XA generated a greater quantity of biosurfactants (6.9 gg-1). It was noted that the maximum diesel biodegradation<br />rate increased versus the biosurfactants yields. Despite some differences between the consortia due to their<br />different origins, especially concerning biosurfactants production, the diesel-enrichment process resulted in<br />adapted consortia with similar efficiencies for diesel biodegradation.</p>