Marine biosurfactants, III. Toxicity testing with marine microorganisms and comparison with synthetic surfactants

Eight synthetic and nine biogenetic surfactants were tested on their toxicity. Because of their possible application as oil dispersants against oil slicks on sea, the test organisms used were marine microorganisms (mixed and pure cultures of bacteria, microalgae, and protozoa). Bacterial growth was hardly effected or stimulated, whilst that of algae and flagellates was reduced. All substances tested were biodegraded in sea water. The bioluminescence of Photobacter phosphoreum (Microtox test) was the most sensitive test system used. A ranking shows that most biogenetic surfactants were less toxic than synthetic surfactants. No toxicity could be detected with the glucose-lipid GL, produced by the marine bacterium Alcaligenes sp. MM1.