Chemical dispersants is one of the globally accepted remediation technique used for marine oil spill. However, the toxicity related with these dispersants confined its application in marine environment. Therefore, to overcome this problem, the employment of environmentally benign dispersants is one of the effective conceivable approach. In this study, the formulation comprised of choline based ionic liquid, choline laurate (ChoLau) and a biosurfactant, lactonic sophorolipids (LS) were used as a crude oil emulsifier. The toxicity of the newly developed formulation was evaluated to confirm their safe employment in sea water. The developed formulation worked effectively as a crude oil emulsifier and formed a stable crude oil emulsion. The toxicity study against Gram-positive and -negative bacteria depicts the �practically harmless� nature of the developed formulation. Thus, the results presented in this study showed that the new formulation can potentially replace the conventional dispersant used for marine oil spill remediation. © The Authors, published by EDP Sciences. This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0 (http://creativecommons.org/licenses/by/4.0/)