Biofilm formation by sulfate reducing bacteria and biocorrosion of metals in seawater

Abstract

Titanium biocorrosion was investigated under the influence of axenic cultures of two sulfate reducing bacteria, Desulfovibrio singaporenus (EF178280) and Desulfovibrio desulfuricans (ATCC 27774) in semi-continuous and continuous systems imitating the real conditions of seawater. Electrochemical impedance spectroscopy (EIS), scanning electron microscoye (SEM) and atomic force microscopy (AFM) as well as Inductively coupled plasma mass spectroscopy (ICP-MS) was utilized for the qualitative and quantitative analyses of biofilm and corrosion pit formation on the metal surface. The role of SRB in biocorrosion is also discussed.A novel bacterium (named TA1L) was isolated from a biofilm on titanium substratum in Singapore local marine environment. Cell morphology and physiology showed that the bacterium shared common characteristics of SRB. 16S-rRNA gene sequence analysis demonstrated that the bacterium is a member of Desulfovibrio genus which is closely related to Desulfovibrio bizertensis and Desulfovibrio singaporenus. The role of TA1L in initiating and promoting biocorrosion of different metals is presented.