MONITORING OF A VIBRIO-NATRIEGENS AND DESULFOVIBRIO-VULGARIS MARINE AEROBIC BIOFILM ON A STAINLESS-STEEL SURFACE IN A LABORATORY TUBULAR FLOW SYSTEM

In an aerobic bulk environment sulphate-reducing bacteria (SRB) can find suitable growth conditions on surfaces where other micro-organisms have developed an extensive biofilm. On metal surfaces they may induce or enhance corrosion. A laboratory tubular flow system was designed to study this phenomenon by creating a biofilm on stainless steel under dynamic conditions with Vibrio natriegens and Desulfovibrio vulgaris. The sulphate reducer colonized the surface, constituting approximately 5% of the total population. Its in situ growth rate, calculated by a simplified mathematical model, showed that the attached SRB multiplied at their settling locations. No significant difference with respect to corrosion enhancement was found in the electrochemical reactions of the metal between the control and the reactor, where D. vulgaris was present in the biofilm.