scholarly journals Effect of Quorum Sensing on the Ability of Desulfovibrio vulgaris To Form Biofilms and To Biocorrode Carbon Steel in Saline Conditions

2019 ◽  
Vol 86 (1) ◽  
Author(s):  
Giantommaso Scarascia ◽  
Robert Lehmann ◽  
Laura L. Machuca ◽  
Christina Morris ◽  
Ka Yu Cheng ◽  
...  

ABSTRACT Sulfate-reducing bacteria (SRB) are key contributors to microbe-induced corrosion (MIC), which can lead to serious economic and environmental impact. The presence of a biofilm significantly increases the MIC rate. Inhibition of the quorum-sensing (QS) system is a promising alternative approach to prevent biofilm formation in various industrial settings, especially considering the significant ecological impact of conventional chemical-based mitigation strategies. In this study, the effect of the QS stimulation and inhibition on Desulfovibrio vulgaris is described in terms of anaerobic respiration, cell activity, biofilm formation, and biocorrosion of carbon steel. All these traits were repressed when bacteria were in contact with QS inhibitors but enhanced upon exposure to QS signal molecules compared to the control. The difference in the treatments was confirmed by transcriptomic analysis performed at different time points after treatment application. Genes related to lactate and pyruvate metabolism, sulfate reduction, electron transfer, and biofilm formation were downregulated upon QS inhibition. In contrast, QS stimulation led to an upregulation of the above-mentioned genes compared to the control. In summary, these results reveal the impact of QS on the activity of D. vulgaris, paving the way toward the prevention of corrosive SRB biofilm formation via QS inhibition. IMPORTANCE Sulfate-reducing bacteria (SRB) are considered key contributors to biocorrosion, particularly in saline environments. Biocorrosion imposes tremendous economic costs, and common approaches to mitigate this problem involve the use of toxic and hazardous chemicals (e.g., chlorine), which raise health and environmental safety concerns. Quorum-sensing inhibitors (QSIs) can be used as an alternative approach to inhibit biofilm formation and biocorrosion. However, this approach would only be effective if SRB rely on QS for the pathways associated with biocorrosion. These pathways would include biofilm formation, electron transfer, and metabolism. This study demonstrates the role of QS in Desulfovibrio vulgaris on the above-mentioned pathways through both phenotypic measurements and transcriptomic approach. The results of this study suggest that QSIs can be used to mitigate SRB-induced corrosion problems in ecologically sensitive areas.

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Arman Abdullah ◽  
Nordin Yahaya ◽  
Norhazilan Md Noor ◽  
Rosilawati Mohd Rasol

Various cases of accidents involving microbiology influenced corrosion (MIC) were reported by the oil and gas industry. Sulfate reducing bacteria (SRB) have always been linked to MIC mechanisms as one of the major causes of localized corrosion problems. In this study, SRB colonies were isolated from the soil in suspected areas near the natural gas transmission pipeline in Malaysia. The effects of ATCC 7757 and consortium of isolated SRB upon corrosion on API 5L X-70 carbon steel coupon were investigated using a weight loss method, an open circuit potential method (OCP), and a potentiodynamic polarization curves method in anaerobic conditions. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) were then used to determine the corrosion morphology in verifying the SRB activity and corrosion products formation. Results from the study show that the corrosion rate (CR) of weight loss method for the isolated SRB is recorded as 0.2017 mm/yr compared to 0.2530 mm/yr for ATCC 7757. The Tafel plot recorded the corrosion rate of 0.3290 mm/yr for Sg. Ular SRB and 0.2500 mm/yr forDesulfovibrio vulgaris. The results showed that the consortia of isolated SRB were of comparable effects and features with the single ATCC 7757 strain.


mBio ◽  
2017 ◽  
Vol 8 (5) ◽  
Author(s):  
Kara B. De León ◽  
Grant M. Zane ◽  
Valentine V. Trotter ◽  
Gregory P. Krantz ◽  
Adam P. Arkin ◽  
...  

ABSTRACT Biofilms of sulfate-reducing bacteria (SRB) are of particular interest as members of this group are culprits in corrosion of industrial metal and concrete pipelines as well as being key players in subsurface metal cycling. Yet the mechanism of biofilm formation by these bacteria has not been determined. Here we show that two supposedly identical wild-type cultures of the SRB Desulfovibrio vulgaris Hildenborough maintained in different laboratories have diverged in biofilm formation. From genome resequencing and subsequent mutant analyses, we discovered that a single nucleotide change within DVU1017, the ABC transporter of a type I secretion system (T1SS), was sufficient to eliminate biofilm formation in D. vulgaris Hildenborough. Two T1SS cargo proteins were identified as likely biofilm structural proteins, and the presence of at least one (with either being sufficient) was shown to be required for biofilm formation. Antibodies specific to these biofilm structural proteins confirmed that DVU1017, and thus the T1SS, is essential for localization of these adhesion proteins on the cell surface. We propose that DVU1017 is a member of the lapB category of microbial surface proteins because of its phenotypic similarity to the adhesin export system described for biofilm formation in the environmental pseudomonads. These findings have led to the identification of two functions required for biofilm formation in D. vulgaris Hildenborough and focus attention on the importance of monitoring laboratory-driven evolution, as phenotypes as fundamental as biofilm formation can be altered. IMPORTANCE The growth of bacteria attached to a surface (i.e., biofilm), specifically biofilms of sulfate-reducing bacteria, has a profound impact on the economy of developed nations due to steel and concrete corrosion in industrial pipelines and processing facilities. Furthermore, the presence of sulfate-reducing bacteria in oil wells causes oil souring from sulfide production, resulting in product loss, a health hazard to workers, and ultimately abandonment of wells. Identification of the required genes is a critical step for determining the mechanism of biofilm formation by sulfate reducers. Here, the transporter by which putative biofilm structural proteins are exported from sulfate-reducing Desulfovibrio vulgaris Hildenborough cells was discovered, and a single nucleotide change within the gene coding for this transporter was found to be sufficient to completely stop formation of biofilm.


2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Ivanilda Ramos de Melo ◽  
Severino Leopoldino Urtiga Filho ◽  
Fernando Jorge Santos Oliveira ◽  
Francisca Pessoa de França

Environmental and economic concerns accelerated biofuels research and industrial production. Many countries have been using diesel and biodiesel blends as fuels justifying research on biofilms formation and metals corrosion. Cylinders made of AISI-1020 carbon steel with an exposed area of 1587 mm2, water, and water associated with B3 fuel (diesel/biodiesel blend at 97 : 3 v/v) were used.The formation of biofilms was detected, and biocorrosion was detected on AISI-1020. The results showed a variation in sessile microflora during the experiments. In the biofilms, a significant concentration of aerobic, anaerobic, IOB,Pseudomonas aeruginosa, and sulfate-reducing bacteria was observed. The corrosion rates varied between0.45±0.01and0.12±0.01 mm/year, depending on the experimental conditions. The main corrosion products identified were various forms of FeOOH, magnetite, and all forms of FexSy. In systems where there were high levels of sulfate reducing bacteria, corrosion pits were observed. In addition, the aliphatic hydrocarbons present in the fluid containing 10% B3 were totally degraded.


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