The present invention relates to a composition for treating oil or oily substances on a surface or an upper layer of a body of a water, characterized in that the composition comprises a microbial biosurfactant obtained from Bacillus salmalaya. The present invention also provides a method for producing the composition, characterized by the steps of inoculating Bacillus salmalaya into a first media culture to produce an inoculum; transferring the inoculum to a second media culture to produce a Bacillus salmalaya growth culture; incubating the Bacillus salmalaya growth culture to produce a bacterial seed; inoculating the bacterial seed into a third media culture to obtain a broth culture; incubating the broth culture for producing the composition.