Inhibition of manganese oxidising bacterial adhesion on pretreated stainless steel surfaces

Abstract

AISI type 304 stainless steel (SS) specimens in solution annealed and cleaned and passivated conditions were exposed to laboratory culture of Leptothrix sp. Epifluorescence studies and total viable count analysis of these specimens showed that bacterial density and biofilm coverage were the least on cleaned and passivated SS surfaces. To confirm whether MnS inclusions play a role in this, adhesion studies at applied potentials, surface characterisation studies using SEM and EDAX analysis and pitting studies with ferric chloride were carried out. These studies clearly revealed the removal of MnS inclusions. This removal leads to a significant reduction in the adhesion of Leptothrix sp. The significance of the present study is that pretreatment of SS by cleaning and passivation inhibited the adhesion of Leptothrix sp. This reduction in adhesion is responsible for the increased corrosion resistance of SS under biofilms in aqueous environments.