AN ELECTROCHEMICAL METHOD FOR ASSESSING BIODEPOSITION ON STAINLESS-STEEL

The interactions between stainless steel surfaces and some biological materials are investigated using electrochemical techniques. Two lactic bacteria were studied: Leuconostoc mesenteroides, which is encapsulated and biosurfactant (dextran) producing and Streptococcus thermophilus, which is not encapsulated. Adding bacteria (or simply dextran) in a NaCl-containing electrolyte in contact with stainless steel, provokes some significant variations in the electrode potential. Conversely, in potentiostatic conditions, some anodic current variations are recorded. This electrochemical response is very sensitive to the considered biological material, the bacterial concentration and the electrochemical parameters as well. A decrease in the electrode potential lowers both the values of current variations and the number of deposited bacteria. Due to the presence of the capsular biopolymer (dextran), the adhesion of Leuconostoc mesenteroides, is expected to be independent of the solid surface properties when no polarization is applied. The present results suggest that the surface polarization acts as an inhibitor of the dextran adsorption. Finally, electrochemical techniques appear to be a powerful tool for investigating the interaction between bacteria and metallic surfaces.