Microbial influenced corrosion by thermophilic bacteria

Abstract

The present study was undertaken to investigate microbial influenced corrosion (MIC) on stainless steels due to thermophilic bacteria Desulfotomaculum nigrificans. The objective of the study 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). The toxic effect of heavy metals on MIC was also observed. For this purpose, 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) were used to identify the chemicals present in/outside the pit. The results show maximum corrosive conditions when bacterial activity is highest, which 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. It is also observed that the toxicity of metals ions affect the bacterial activity and EPS production. It was observed that Desulfotomaculum sp. has the ability to biodegrade its own EPS.

The Role of Oral Cavity Biofilm on Metallic Biomaterial Surface Destruction–Corrosion and Friction Aspects

“…With increased study time (from 28 to 56 days) the number of biocorrosion initialization products increased [ 99 , 100 ]. Similar data are presented in other papers [ 103 , 104 ]. The results of these microscopic observations show that titanium alloy is more resistant to sulfate-reducing bacteria, as is the case with typical electrochemical corrosion tests [ 105 ].…”

“…Research presented in the paper of Lates et al [ 94 ] demonstrates that SRB are responsible for the potential difference between the surface corroded by microorganisms and the area free from bacterial activity. This leads to the formation of local pitting on the metal surface, in the form of pitting corrosion wear [ 103 , 104 ]. In addition, their metabolic activity in combination with organic compounds can lead to the formation of aggressive corrosion products, e.g., organic acids [ 108 ].…”

Heritability Estimates of Adult Body Weight and Egg Production Traits in Indigenous Uttara Chickens

“…The 32 weeks body weight was lower as observed in Kadaknath [8]. The 36 weeks body weight in females was comparable with White Leghorn [9]. The 40 weeks body weight in females was comparable with White…”

Effect of Saliva and Mucin-Based Saliva Substitutes on Fretting Processes of 316 Austenitic Stainless Steel

“…In addition, metal ions released during corrosion from metal dental constructions can enter the gastrointestinal tract and accumulate in the stomach, liver, kidneys, spleen, bones, lungs, brain, or mucosa. Numerous studies [4,48] indicate the importance of corrosion resistance of biomaterials in the oral environment. The results of such tests should be used in the development of chemical compositions of alloys for dentistry and saliva substitutes [49,50].…”