Biosurfactants are amphiphilic surface-active agents that mainly produced by various micro- organisms. In this study, the anti-biofilm and inhibition of bacterial adhesion activities of two bacterial biosurfactants were investigated.

After extraction and evaluation of Bacillus cereus and Serratia nematodiphila biosurfctants, inhi- bition of bacterial adhesion and anti-biofilm effects of them on Staphylococcus aureus and Pseudomonas aeruginosa were determined.

On average, the synergistic effect of two bacterial biosurfactants, caused about 60% decrease in adhesion and about 80% decrease in biofilm formation of S. aureus and P. aeruginosa.

The results of this study showed that combination of B. cereus and S. nematodiphila biosurfactants would in- crease the potential of attachment inhibition and biofilm eradication with very low toxicity.