Microbial influenced corrosion by thermophilic bacteria

Central European Journal of Engineering, March 2012, Volume 2, Issue 1, pp 113-122
Microbial influenced corrosion by thermophilic bacteria
Suman Lata, Chhaya Sharma, Ajay K. Singh
1. Department of Paper Technology, IIT-Roorkee, Saharanpur Campus, Saharanpur, 247001, India
Abstract
Reports a study of microbial influenced corrosion (MIC) on stainless steels due to thermophilic bacteria Desulfotomaculum nigrificans. The purpose was to measure the extent of corrosion and correlate it with the growth of the biofilm by monitoring the composition of its extracellular polymeric substances (EPS).
Stainless steels 304L, 316L and 2205 were subjected to electrochemical polarization and immersion tests in the modified Baar’s media, control and inoculated, in anaerobic conditions at room temperature. Scanning electron microscopy (SEM)/energy dispersive spectroscopy (EDS) enabled identification of the chemicals present in/outside the pit. Results reveal maximum corrosive conditions when bacterial activity is highest.  This in turn minimizes the amount of carbohydrate and protein along with the increase in the fraction of uronic acid in carbohydrate in EPS of the biofilm. However, although bacterial activity and corrosion rate decreases, the amount of biofilm components continue to increase.
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