Corrosion behaviour of AISI 304 stainless steel in presence of a biosurfactant produced by Pseudomonas fluorescens

Under certain conditions, some microorganisms are able to synthesize surface active compounds called biosurfactants (BS), which reduce the surface tension of water. BS characteristics depend on which microorganism produce them and therefore, on the microorganism culture conditions (temperature, pH, C, N-source,...). Numerous applications are known for these biomolecules, such as cleaning, bioremediation, and their use as a detergent, or in cosmetic formulations. Recently, a large amount of literature has been edited on the influence of BS on the interactions between pathogenic bacteria and inert surfaces. It has been shown that the modifications of surface properties by the adsorption of BS can reduce microbial adhesion. Some other studies on chemical surfactants have shown that the adsorption of surface-active compounds plays a major role in corrosion; they are indeed used as an interesting corrosion inhibition tool. Therefore, it seems very interesting to study the impact of BS as environment-friendly (since biological and biodegradable) corrosion inhibitors. In the present work, an attempt was made to study the corrosion behaviour of AISI 304 stainless steel in presence of BS produced by a Gram-negative bacteria, Pseudomonas fluorescens (Pf495). Corrosion tests were achieved on several surface oxidation states. The surface morphology of the corroded specimens was investigated using SEM. (c) 2006 Elsevier Ltd. All rights reserved.