Efeito de surfactantes na estimativa da densidade bacteriana em amostras de petróleo

Abstract

The effect of the surfactants (Tween 60), polyoxyethylene monooleate (Tween 80), cetyl, trimethyl ammonium bromide (CTAB) and sodium dodecyl sulfate (SDS) on the estimation of bacterial density (sulfate reducing bacteria SRB and General Anaerobic Bacteria GanB) was examined in the petroleum samples. In order to carry out the experiments, we selected three different mixtures of oil and water to be representative of the real samples. The first one contains a high proportion of oil, the second contains a medium proportion and the last one contains a low proportion. The most probable number (MPN) was used to estimate the bacterial density. The concentrations of the surfactants used in this work were determined in a previous study. The results showed that the addition of surfactants did not improve the SRB quantification for the high or medium proportion of oil of the petroleum samples. On other hand, Tween 60 and Tween 80 showed a significantly increase on the GanB quantification when their concentrations were 0.01% and 0.03% m/v, respectively. CTAB increased the SRB and GanB estimation for the low proportion of oil of the petroleum sample when its concentration was 0.001% and 0.0001% m/v, respectively