Bacillus megaterium-induced biocorrosion on mild steel and the effect of Artemisia pallens methanolic extract as a natural corrosion inhibitor

Corrosion Behavior on 20# Pipeline Steel by Sulfate-Reducing Bacteria in Simulated NaCl Alkali/Surfactant/Polymer Produced Solution

The corrosion behavior of sulfate-reducing bacteria (SRB) on 20# carbon steel in the NaCl alkali-surfactant-polymer (ASP) flooding system was studied by scanning electron microscopy, electrochemical measurement, X-ray photoelectron spectroscopy, and laser confocal microscopy. The results showed that the presence of SRB results in a large viscosity loss of the system. SRB can use hydrolyzed polyacrylamide (HPAM) as a nutrient to grow, and the number of SRB remained at a high level after 15 days. Weight loss and electrochemical tests indicated that SRB promoted corrosion of pipeline steel. The corrosion of carbon steel in the early stage of immersion was inhibited by the biofilm formed on the surface, and the thick biofilm in the later stage of immersion caused serious pitting corrosion. The localized corrosion caused by SRB was not inhibited by HPAM and sodium petroleum sulfonate (surfactant) adsorbed on the surface.

Sporulation, Structure Assembly, and Germination in the Soil Bacterium Bacillus thuringiensis: Survival and Success in the Environment and the Insect Host

Bacillus thuringiensis (Bt) is a rod-shaped, Gram-positive soil bacterium that belongs to the phylum Firmicutes and the genus Bacillus. It is a spore-forming bacterium. During sporulation, it produces a wide range of crystalline proteins that are toxic to different orders of insects. Sporulation, structure assembly, and germination are essential stages in the cell cycle of B. thuringiensis. The majority of studies on these issues have focused on the model organism Bacillus subtilis, followed by Bacillus cereus and Bacillus anthracis. The machinery for sporulation and germination extrapolated to B. thuringiensis. However, in the light of recent findings concerning the role of the sporulation proteins (SPoVS), the germination receptors (Gr), and the cortical enzymes in Bt, the theory strengthened that conservation in sporulation, structure assembly, and germination programs drive the survival and success of B. thuringiensis in the environment and the insect host. In the present minireview, the latter pinpointed and reviewed.

Biofilm formation on copper and its control by inhibitor/biocide in cooling water environment

The present study has successfully identified the nitrate reducing bacteria present in the cooling water system and also investigated the performance of industrially applied biocide and inhibitor on the bacterial inhibition. In order to carry out the objective of this study, facilities and methods such as 16S rRNA gene sequencing, Lowry assay, SEM, EIS, ICP-MS and weight loss analysis were being utilized. In this study, two out of the five morphologically dis- similar colonies identified through 16S rRNA gene sequencing, namely the Massilia timonae and the Pseudomonas, were being utilized in the biocorrosion study on copper metal. From the surface analysis using SEM demonstrated the phenomenon of biofilm formation on the copper surface. 2-methylbenzimidazole has the addition of methyl group in the diazole ring position of benzimidazole it has create basicity environment and inhibit the metal deterioration. Meanwhile, it is also deducible from the EIS and protein analysis that com- bination of biocide with either of the inhibitors gives rise to better biocorrosion suppression (0.00178 mpy and 0.00171mpy) as compared to the sole effect of either biocide or inhibitor (0.00219 mpy, 0.00162 and 0.00143). Biocorrosion system biocide with MBM was found to exhibit 65% corrosion inhibition efficiency. Moreover, adoption of 2-Methylbenzimidazole seems to display better performance as compared to Multionic 8151, which is adopted in cooling water system.

The influence of the marine Bacillus cereus over carbon steel, stainless corrosion, and copper coupons

The present study evaluated the influence of the marine bacteria Bacillus cereus Mc-1 on the corrosion of 1020 carbon steel, 316L stainless steel, and copper alloy. The Mc-1 strain was grown in a modified ammoniacal citrate culture medium (CFA.ico-), CFA.ico- with sodium nitrate supplementation (NO_3-), and CFA.ico- with sodium chloride supplementation (NaCl). The mass loss and corrosion rate were evaluated after the periods of 7, 15, and 30 days. The results showed that in CFA.ico- and CFA.ico- medium added NO_3- the corrosion rates of carbon steel and copper alloy were high when compared to the control. Whereas the medium was supplemented with NaCl, despite the rates being above the averages of the control system, they were considerably below the previous results. In general, the corrosion rates induced by Mc-1 on 316L coupons were below the results compared to carbon steel and copper alloy. When analyzing the corrosion rate measurements, regardless of the culture medium, the corrosion levels decreased consistently after 15 days, being below the levels evaluated after 7 days of the experiment. Our analyses suggest that B. cereus Mc-1 has different influences on corrosion in different metals and environmental conditions, such as the presence of NO_3- and NaCl. These results can help to better understand the influence of this bacteria genus on the corrosion of metals in marine environments.

Biodegradation and Characterization of Streptomyces sp. (JMCACA3) from Acid Corroded Iron Plate

From acid corroded iron plates five different types of actinobacteria were isolated. Among the five, JMCACA3 strain was selected for the present study. In ISP media, JMCACA3 strain showed well-developed aerial and substrate mycelia were observed. This strain showed good growth in 12 different carbon and 4 different nitrogen sources. The 16S rRNA sequence of phylogenetic analysis by neighbor-joining method identified the studied strain belongs to Streptomyces sp. The biodegradation activity of the strain analyzed by UV and FTIR analysis, which revealed that the various concentrations of Benzimidazole inhibitor with JMCACA3 culture showed slightly varied results. For weight loss method, mild steel coupons incubated with JMCACA3 culture, Benzimidazole inhibitor + JMCACA3 culture and mixed sample showed that JMCACA3 strain utilized the inhibitor as their energy source and the weight the coupons were slightly varied, evidenced by XRD spectra and showed Fe₂O₃ corrosion products. Our study concluded that the JMCACA3 strain, an iron-reducing actinobacteria which utilizes and converted the corrosion inhibitor Benzimidazole as their energy source. So, it is very urgent to develop more powerful corrosion inhibitor from green biocide or microbial-based biocide and their analog which incorporated into the pre-existing Benzimidazole to increase the corrosion inhibitor level against the biofilm of actinobacterial influenced corrosion.

Microbial influenced corrosion of processing industry by re-circulating waste water and its control measures - A review

In this review article, illustrating the impact and fundamental stuff of microbially influenced corrosion (MIC) along with mechanism, maintenance of materials, human life, wellbeing and inhibitors for cooling towers. Corrosion is a natural mechanism of oxidation and reduction of metal ions by chemical and electrochemical processes and microorganism accumulation. MIC occurs through the aggregation of microbes which can be secreting the extra polymeric substances (EPS) that oxidation of the metal surface. According to the reviews, in the cooling water system, the corrosion begins in the anode charge because its oxidation reaction quickly takes place on the metal surface than the cathode charge. Annihilate the corrosion process needs certain helper substances such as chemical or green compounds, called inhibitors. Corrosion inhibitors typically adopt the adsorption mechanism due to the presence of organic hetero atoms. Chemical and green inhibitors are used to prevent corrosion processes and since ancient times, vast quantities of chemical inhibitors have been used in industry due to their effectiveness and consistency. But still, the chemical inhibitors are more toxic to humans and the environment. Instead of chemical inhibitors, green inhibitors (natural products like plant leaves, flowers, stem, buds, roots and sea algae) are developed and used in industries. Generally, green inhibitors contain natural compounds, high inhibition efficiency, economic, eco- and human-friendly, and strong potential features against corrosion. Thus, a lot of research is ongoing to discover the green inhibitors in various parts of plants and seaweeds.