The production of surface active compounds by micro-organisms and its possible significance in oil recovery

Summary

In general agreement withZoBell's results it has been found that cultures ofDesulfovibrio desulfuricans are able to release both Trinidal and Schoonebeek crude oils from oil-sand mixtures at atmospheric pressure and 30°C. The amount of oil liberated after 3 weeks in stationary bottle cultures, in excess of the quantities released in control experiments, varied from 5–35% of the oil originally present in the oil-sand mixture.

Under identical conditions oil release was obtained with a sterile medium to which Tween 20 had been added.

In the synthetic medium used, growth of the bacteria resulted as well in a markedly lowered surface tension, as in a lowered interfacial tension towards kerosene.

Experiments on oil release from a glass bead column by a slow current of an aqueous phase have been carried out. On comparing:a. sterile mediumb. medium in which sulphate reducing bacteria had been grown,c. sterile medium to which Tween 20 had been added, it was found that, in agreement with the result of the bottle experiments, the two latter liquids showed distinctly superior oil releasing powers.