scholarly journals Inhibitive Properties of Benzyldimethyldodecylammonium Chloride on Microbial Corrosion of 304 Stainless Steel in a Desulfovibrio desulfuricans-Inoculated Medium

Materials ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 307 ◽  
Author(s):  
Chung-Wen Hsu ◽  
Tzu-En Chen ◽  
Kai-Yin Lo ◽  
Yueh-Lien Lee
Keyword(s):  
Stainless Steel ◽  
Laser Scanning ◽  
Steel Substrate ◽  
Desulfovibrio Desulfuricans ◽  
Corrosion Current ◽  
Laser Scanning Microscopy ◽  
304 Stainless Steel ◽  
Confocal Laser ◽  
Microbial Corrosion ◽  
Sulfate Reducing

Biocides are frequently used to control sulfate-reducing bacteria (SRB) in biofouling. The increasing restrictions of environmental regulations and growing safety concerns on the use of biocides result in efforts to minimize the amount of biocide use and develop environmentally friendly biocides. In this study, the antimicrobial activity and corrosion inhibition effect of a low-toxic alternative biocide, benzyldimethyldodecylammonium chloride (BDMDAC), on a 304 stainless steel substrate immersed in a Desulfovibrio desulfuricans (D. desulfuricans)-inoculated medium was examined. Potentiodynamic polarization curves were used to analyze corrosion behavior. Biofilm formation and corrosion products on the surfaces of 304 stainless steel coupons were examined using scanning electron microscopy (SEM), energy-dispersive X-ray spectrum, and confocal laser scanning microscopy (CLSM). Results demonstrated that this compound exhibited satisfactory results against microbial corrosion by D. desulfuricans. The corrosion current density and current densities in the anodic region were lower in the presence of BDMDAC in the D. desulfuricans-inoculated medium. SEM and CLSM analyses revealed that the presence of BDMDAC mitigated formation of biofilm by D. desulfuricans.

scholarly journals Antimicrobial and Anticorrosion Activity of a Novel Composite Biocide against Mixed Bacterial Strains in Taiwanese Marine Environments

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6156
Author(s):  
Soul-Yi Chang ◽  
Shih-Yen Huang ◽  
Yu-Ren Chu ◽  
Shun-Yi Jian ◽  
Kai-Yin Lo ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Laser Scanning ◽  
Electrochemical Impedance ◽  
Laser Scanning Microscopy ◽  
304 Stainless Steel ◽  
Single Type ◽  
Confocal Laser ◽  
Subtropical Climate ◽  
Marine Environments ◽  
Bacterial Strains

Taiwan is an island with a humid subtropical climate. The relatively warm seawater results in biofouling of the surfaces of marine facilities. Biocide application is a common practice for combating and eliminating adhesive fouling. However, a single type of biocide may have limited antimicrobial effects due to the relatively high microbial diversity in marine environments. Therefore, applying a mixture of various biocides may be necessary. In this study, the antimicrobial and anticorrosion properties of a newly designed composite biocide, namely a combination of thymol and benzyldimethyldodecylammonium chloride, were investigated by applying the biocide to 304 stainless steel substrates immersed in inocula containing bacterial strains from Tamsui and Zuoying harbors. The ability of 3TB and 5TB treatments to prevent sessile cells and biofilm formation on the 304 stainless steel coupon surface was determined through scanning electron microscopy investigation. In addition, confocal laser scanning microscopy indicated that the 5TB treatment achieved a greater bactericidal effect in both the Tamsui and Zuoying inocula. Moreover, electrochemical impedance spectroscopy revealed that the diameter of the Nyquist semicircle was almost completely unaffected by Tamsui or Zuoying under the 5TB treatment. Through these assessments of antimicrobial activity and corrosion resistance, 5TB treatment was demonstrated to have superior bactericidal activity against mixed strains in both southern and northern Taiwanese marine environments.

Culture and Detection of Campylobacter jejuni within Mixed Microbial Populations of Biofilms on Stainless Steel

2007 ◽  
Vol 70 (6) ◽  
pp. 1379-1385 ◽  
Author(s):  
SHERIASE Q. SANDERS ◽  
DOROTHY H. BOOTHE ◽  
JOSEPH F. FRANK ◽  
JUDY W. ARNOLD
Keyword(s):  
Stainless Steel ◽  
Campylobacter Jejuni ◽  
Laser Scanning ◽  
The United States ◽  
Laser Scanning Microscopy ◽  
Epifluorescence Microscopy ◽  
Confocal Laser ◽  
Atmospheric Conditions ◽  
Culture Methods ◽  
Bacterial Populations

Campylobacter jejuni is the most frequently reported cause of foodborne illness in the United States, but its survival outside the host is poor. The objective of this research was to examine the formation and composition of biofilms by C. jejuni alone and within mixed bacterial populations from the poultry-processing environment. C. jejuni growth was assessed with four media, two temperatures, and two atmospheric conditions to develop culture methods for liquid media that would allow growth within the biofilms. Growth kinetics was followed at four cell densities to determine temporal compatibility within biofilm mixtures. Analysis of the biofilms by confocal laser scanning microscopy showed that C. jejuni formed a biofilm when incubated without other bacteria. The average surface area of stainless steel covered by C. jejuni increased by 50% from 24 to 48 h, remained level to 96 h, and then decreased by 88% by 168 h. C. jejuni and mixed bacterial populations formed biofilms during incubation periods of up to 7 days. The area of the mixture was significantly greater than for C. jejuni alone at 24 h, was approximately the same at 48 h, and was significantly less by 168 h. When incubated with either of two initial inoculum densities of other bacteria, the number of C. jejuni was enhanced after 24 h. The intensity of fluorescence and cell viability were monitored by epifluorescence microscopy. This study provides the basis for studying interactions of Campylobacter spp. with other bacteria in the environment, which will aid in the design of effective intervention strategies.

scholarly journals Enhanced Inactivation of Salmonella and Pseudomonas Biofilms on Stainless Steel by Use of T-128, a Fresh-Produce Washing Aid, in Chlorinated Wash Solutions

2012 ◽  
Vol 78 (19) ◽  
pp. 6789-6798 ◽  
Author(s):  
Cangliang Shen ◽  
Yaguang Luo ◽  
Xiangwu Nou ◽  
Gary Bauchan ◽  
Bin Zhou ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Organic Matter ◽  
Laser Scanning ◽  
Hypochlorous Acid ◽  
Free Chlorine ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Content Type ◽  
Cell Responses ◽  
Depletion Rate

ABSTRACTThe effect of the washing aid T-128 (generally recognized as safe [GRAS] formulation, composed mainly of phosphoric acid and propylene glycol) on inactivation ofSalmonellaandPseudomonaspopulations in biofilms on stainless steel was evaluated under conditions of increasing organic matter loads in chlorinated wash solutions dominated by hypochlorous acid. Biofilms were formed statically on stainless steel coupons suspended in 2% lettuce extract after inoculation withSalmonella entericaserovar Thompson or Newport or withPseudomonas fluorescens. Coupons with biofilms were washed in chlorine solutions (0, 0.5, 1, 2, 5, 10, or 20 mg/liter at pH 6.5, 5.0 and 2.9), with or without T-128, and with increasing loads of organic matter (0, 0.25, 0.5, 0.75, or 1.0% lettuce extract). Cell populations on coupons were dispersed using intermittent, pulsed ultrasonication and vortexing and enumerated by colony counts on XLT-4 orPseudomonasagars. Cell responses to fluorescent viability staining of biofilm treatment washing solutions were examined using confocal laser scanning microscopy. Results showed that 0.1% T-128 (without chlorine) reducedP. fluorescensbiofilm populations by 2.5 log10units but did not reduceSalmonellapopulations. For bothSalmonellaandPseudomonas, the sanitizing effect of free chlorine (1.0 to 5.0 mg/liter) was enhanced (P< 0.05) when it was combined with T-128. Application of T-128 decreased the free chlorine depletion rate caused by increasing organic matter in wash waters and significantly (P< 0.05) augmented inactivation of bacteria in biofilms compared to treatments without T-128. Image analysis of surfaces stained with SYTO and propidium iodide corroborate the cultural assay results showing that T-128 can aid in reducing pathogen viability in biofilms and thus can aid in sanitizing stainless steel contact surfaces during processing of fresh-cut produce.

scholarly journals On the Occurrence of Anoxic Microniches, Denitrification, and Sulfate Reduction in Aerated Activated Sludge

1999 ◽  
Vol 65 (9) ◽  
pp. 4189-4196 ◽  
Author(s):  
Andreas Schramm ◽  
Cecilia M. Santegoeds ◽  
Helle K. Nielsen ◽  
Helle Ploug ◽  
Michael Wagner ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Sulfate Reduction ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Sulfate Reducing ◽  
Dissimilatory Sulfite Reductase ◽  
Sulfate Reduction Rates ◽  
Anoxic Zones

ABSTRACT A combination of different methods was applied to investigate the occurrence of anaerobic processes in aerated activated sludge. Microsensor measurements (O2, NO2 −, NO3 −, and H2S) were performed on single sludge flocs to detect anoxic niches, nitrate reduction, or sulfate reduction on a microscale. Incubations of activated sludge with15NO3 − and35SO4 2− were used to determine denitrification and sulfate reduction rates on a batch scale. In four of six investigated sludges, no anoxic zones developed during aeration, and consequently denitrification rates were very low. However, in two sludges anoxia in flocs coincided with significant denitrification rates. Sulfate reduction could not be detected in any sludge in either the microsensor or the batch investigation, not even under short-term anoxic conditions. In contrast, the presence of sulfate-reducing bacteria was shown by fluorescence in situ hybridization with 16S rRNA-targeted oligonucleotide probes and by PCR-based detection of genes coding for the dissimilatory sulfite reductase. A possible explanation for the absence of anoxia even in most of the larger flocs might be that oxygen transport is not only diffusional but enhanced by advection, i.e., facilitated by flow through pores and channels. This possibility is suggested by the irregularity of some oxygen profiles and by confocal laser scanning microscopy of the three-dimensional floc structures, which showed that flocs from the two sludges in which anoxic zones were found were apparently denser than flocs from the other sludges.

scholarly journals Biofilm Degradation of Nontuberculous Mycobacteria Formed on Stainless Steel Following Treatment with Immortelle (Helichrysum italicum) and Common Juniper (Juniperus communis) Essential Oils

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 362
Author(s):  
Dolores Peruč ◽  
Dalibor Broznić ◽  
Željka Maglica ◽  
Zvonimir Marijanović ◽  
Ljerka Karleuša ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Essential Oils ◽  
Laser Scanning ◽  
Nontuberculous Mycobacteria ◽  
Bacterial Count ◽  
Water Disinfection ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Juniperus Communis ◽  
Common Juniper

Nontuberculous mycobacteria, like other opportunistic premise plumbing pathogens, produce resistant biofilms on various surfaces in the plumbing system including pipes, tanks, and fittings. Since standard methods of water disinfection are ineffective in eradicating biofilms, research into new agents is necessary. Essential oils (EOs) have great potential as anti-biofilm agents. Therefore, the purpose of this research was to investigate the potential anti-biofilm effect of common juniper (Juniperus communis) and immortelle (Helichrysum italicum) EOs. Minimum inhibitory concentrations (MIC), minimum bactericidal concentrations (MBC), and minimum effective concentrations of EOs on Mycobacterium avium, M. intracellulare, and M. gordonae were tested. Additionally, biofilms on the surface of a stainless steel disc were treated with single or mixed concentration of EOs, in order to investigate their degeneration via the bacterial count and confocal laser scanning microscopy (CLSM). H. italicum EO showed the strongest biofilm degradation ability against all Mycobacteria strains that were tested. The strongest effect in the biofilm degradation after the single or mixed applications of EOs was observed against M. gordonae, followed by M. avium. The most resistant was the M. intracellulare biofilm. Synergistic combinations of J. communis and H. italicum EOs therefore seem to be an effective substance in biofilm degradation for use in small water systems such as baths or hot tubs.

scholarly journals Inactivation Efficacy of 405 nm LED Against Cronobacter sakazakii Biofilm

2020 ◽  
Vol 11 ◽  
Author(s):  
Yixiao Huang ◽  
Quanwei Pei ◽  
Ruisha Deng ◽  
Xiaoying Zheng ◽  
Jialu Guo ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Laser Scanning ◽  
Light Emitting Diode ◽  
Treated Group ◽  
Attenuated Total Reflection ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Pcr Analysis ◽  
Cronobacter Sakazakii ◽  
Sensitivity Change

The objectives of this study were to evaluate the inactivation efficacy of a 405-nm light-emitting diode (LED) against Cronobacter sakazakii biofilm formed on stainless steel and to determine the sensitivity change of illuminated biofilm to food industrial disinfectants. The results showed that LED illumination significantly reduced the population of viable biofilm cells, showing reduction of 2.0 log (25°C), 2.5 log (10°C), and 2.0 log (4°C) between the non-illuminated and LED-illuminated groups at 4 h. Images of confocal laser scanning microscopy and scanning electron microscopy revealed the architectural damage to the biofilm caused by LED illumination, which involved destruction of the stereoscopic conformation of the biofilm. Moreover, the loss of biofilm components (mainly polysaccharide and protein) was revealed by attenuated total reflection Fourier-transformed infrared spectroscopy, and the downregulation of genes involved in C. sakazakii biofilm formation was confirmed by real time quantitative PCR analysis, with greatest difference observed in fliD. In addition, the sensitivity of illuminated-biofilm cells to disinfectant treatment was found to significantly increased, showing the greatest sensitivity change with 1.5 log reduction between non-LED and LED treatment biofilms in the CHX-treated group. These results indicated that 405 nm LED illumination was effective at inactivating C. sakazakii biofilm adhering to stainless steel. Therefore, the present study suggests the potential of 405 nm LED technology in controlling C. sakazakii biofilms in food processing and storage, minimizing the risk of contamination.

Biofilm Formation and Stainless Steel Corrosion Analysis of Leptothrix discophora

2015 ◽  
Vol 1130 ◽  
pp. 79-82 ◽  
Author(s):  
Christian Thyssen ◽  
David Holuscha ◽  
Jens Kuhn ◽  
Friederike Walter ◽  
Wolfram Fürbeth ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Biofilm Formation ◽  
Manganese Oxides ◽  
Laser Scanning ◽  
Steel Corrosion ◽  
Open Circuit ◽  
Laser Scanning Microscopy ◽  
Microbiologically Influenced Corrosion ◽  
Confocal Laser ◽  
Pitting Potential

Bioleaching and biocorrosion are based on similar biochemical processes. Microbe-surface interaction, biofilm formation and concomitant extracellular polymeric substance (EPS) production gained increasing interest in the past decades. Nowadays it is generally accepted that biofilm formation and an accompanying formation of manganese oxides by manganese oxidizing bacteria such as Leptothrix spp. account for one type of pitting corrosion of stainless steel (SS). However, little is known about biofilm formation, EPS composition of manganese oxidizing microorganisms and their influence on microbiologically influenced corrosion. Consequently, we studied biofilm formation of Leptothrixdiscophora, the biooxidation of manganese in biofilms on floating filters as well as biofilm formation on stainless steel and the involved corrosion processes. Cells were visualized by epifluorescence (EFM) or confocal laser scanning –microscopy (CLSM). Additionally, the influence of biofilm formation and biooxidation of manganese by L. discophora on the open circuit potential (OCP) and pitting potential (Epit) of stainless steel was measured using a 3 electrode setup. L. discophora grew well in biofilms on floating filters and on SS coupons and incorporated in both conditions Mn2+ in the form of MnO2 from the bulk phase into the biofilm. OCP measurements of actively manganese-oxidizing biofilms on stainless steel showed a significant ennoblement of ≥200 mV.

scholarly journals Development of a methodology for measuring the evolution of duplex stainless-steel low-temperature plasma nitrided phases expansion using confocal laser scanning microscopy

2021 ◽  
Vol 40 (1) ◽  
Author(s):  
Carlos Eduardo Alves Feitosa ◽  
Rodrigo Perito Cardoso ◽  
Silvio Francisco Brunatto
Keyword(s):  
Stainless Steel ◽  
Low Temperature ◽  
Duplex Stainless Steel ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Low Temperature Plasma ◽  
Temperature Plasma ◽  
Innovative Methodology ◽  
Different Response

Samples of duplex stainless steel SAF 2507 were low-temperature plasma nitrided to characterize separately, on the surface, the behavior of its ferrite and austenite phases in relation to two competing processes, that is, one caused by enrichment by nitrogen, resulting in possible expansion, and the other caused by the removal of superficial atoms via sputtering, which may lead to the retraction of the studied phases. Since these phases have different different compositions and crystalline structures, of which the diffusivity and solubility of nitrogen in them are dependent, a different response for each type of phase can be expected. In this article, an innovative methodology has been developed to quantify and clarify which effects are predominant in the course of nitriding for each of these phases. The results indicate that phase expansion prevails over sputtering.

scholarly journals Effect of Cast Defects on the Corrosion Behavior and Mechanism of UNS C95810 Alloy in Artificial Seawater

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1790 ◽  
Author(s):  
Xu Zhao ◽  
Yuhong Qi ◽  
Jintao Wang ◽  
Zhanping Zhang ◽  
Jing Zhu ◽  
...  
Keyword(s):  
Corrosion Behavior ◽  
Laser Scanning ◽  
Galvanic Corrosion ◽  
Corrosion Current ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electrochemical Testing ◽  
Alloy Microstructure

To study the effect of cast defects on the corrosion behavior and mechanism of the UNS C95810 alloy in seawater, an investigation was conducted by weight loss determination, scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), X-ray diffraction (XRD) and electrochemical testing of the specimen with and without cast defects on the surface. The results show that the corrosion rate of the alloy with cast defects is higher than that of the alloy without cast defects, but the defects do not change the composition of the resulting corrosion products. The defects increase the complexity of the alloy microstructure and the tendency toward galvanic corrosion, which reduce the corrosion potential from −3.83 to −86.31 mV and increase the corrosion current density from 0.228 to 0.23 μA⋅cm−2.

scholarly journals Experimental Study on Water-Jet Shock Microforming Process Using Different Incident Pressures

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
James Kwasi Quaisie ◽  
Wang Yun ◽  
Xu Zhenying ◽  
Yu Chao ◽  
Fuzhu Li ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Stainless Steel ◽  
High Speed ◽  
Laser Scanning ◽  
Thickness Distribution ◽  
Water Jet ◽  
304 Stainless Steel ◽  
Confocal Laser ◽  
Process Technology ◽  
The Cross

The purpose of this paper is to demonstrate a new process technology using the cavitation phenomenon, mainly a water-jet shock microforming, for the fabrication of a metallic foil. 304 stainless steel was exposed to a high-speed submerged water jet with different incident pressures and certain working conditions. In this experiment, a KEYENCE VHX-1000C digital microscope, confocal laser-scanning microscope (Axio CSM 700), and micro-Vickers hardness tester were utilized to observe the forming depth, surface quality, thickness distribution, and section hardness distributions under different incident pressures. The experimental results indicated that the surface morphology of the metal foils attained good geometrical features under this dynamic microforming method and there were no cracks or fracture. The forming depth and surface roughness increased with the incident pressure. In addition, the forming depth increased from 124.7 μm to 327.8 μm, while the surface roughness also increased from 0.685 μm to 1.159 μm at an incident pressure of 8 MPa to 20 MPa. Maximum thickness thinning of the formed foils occurred at the fillet region when the thickness thinning ratio was 21.27% under the incident pressure of 20 MPa, and there was no fracture at the bottom or the fillet region. The tested hardness indicated that during the cold-rolled state of the sample, the hardness sample increased slightly along the cross section of the formed region and the hardness of the annealed 304 stainless steel foils increased significantly along the cross-sectional region.

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