The formation of biofilm by pathogenic microorganisms has become a problem in the livestock industry since it is considered a potential source of infection for farm animals while increasing microbial resistance to phy...The formation of biofilm by pathogenic microorganisms has become a problem in the livestock industry since it is considered a potential source of infection for farm animals while increasing microbial resistance to physical and chemical agents. Some plant extracts, such as soluble wheat extract, have been shown to be effective in inhibiting or destroying the biofilm of certain micro-organisms under specific conditions. The objective of this study is to evaluate the capacity of the pathogen to form biofilm on different surfaces used in livestock, as well as to evaluate the anti-biofilm capacity of the soluble wheat extract against <i>S. aureus</i> on these surfaces. The inhibition potential of inhibition or destruction of biofilm was tested in vitro. Wheat extract at a concentration of 0.29 mg/100mL showed anti-biofilm activity on <i>S. aureus</i>, inhibiting its formation, as well as destroying it greatly after a contact time of 24 hours, on those surfaces where the microorganism presents more adhesion capacity.展开更多
In this work, the impact of a wild-type nitrate-reducing Bacillus licheniformis strain on the corrosion behavior of X80 steel under anaerobic conditions was studied by electrochemical tests and biofilm characterizatio...In this work, the impact of a wild-type nitrate-reducing Bacillus licheniformis strain on the corrosion behavior of X80 steel under anaerobic conditions was studied by electrochemical tests and biofilm characterization. The bioelectrochemical, electrochemical, and chemical reactions between X80 steel and microorganisms were investigated comprehensively. The results show that B. licheniformis can accelerate the corrosion of X80 steel substrate in early immersing by two ways: biocatalytic cathodic nitrate reduction and acidification induced by bacterially-secreted acids. However, the corrosion rate of X80 steel decreased after immersing for ca. 1 week in B. licheniformis culture due to iron biomineralization. This work provides direct insights into the mechanism of microbiologically influenced corrosion of carbon steel by the nitrate-reducing bacterium.展开更多
The increasing utilization of titanium alloys in marine environments makes their microbiologically influenced corrosion study a timely matter.This work demonstrated that the corrosion ofTi-6 Al-4 V alloy was accelerat...The increasing utilization of titanium alloys in marine environments makes their microbiologically influenced corrosion study a timely matter.This work demonstrated that the corrosion ofTi-6 Al-4 V alloy was accelerated by a marine bacterium Shewanella algae in 2216 E medium with different Cl-level.Various electrochemical,pitting morphology and passive film analyses demonstrated that S.algae weakened the passive film,which made Cl-more aggressive.The synergy of those two factors caused considerable corrosion acceleration of the titanium alloy,leading to a maximum pit depth of 3.2μm and corrosion current density of 26.5 nA cm_(-2) in 2216 E medium with 3.50%(w/w)Cl^(-).展开更多
Tetrakis hydroxymethyl phosphonium sulfate(THPS) was enhanced by a 14-mer Peptide A, with its core12-mer sequence mimicking part of Equinatoxin II protein, in the mitigation of sulfate reducing Desulfovibrio ferrophil...Tetrakis hydroxymethyl phosphonium sulfate(THPS) was enhanced by a 14-mer Peptide A, with its core12-mer sequence mimicking part of Equinatoxin II protein, in the mitigation of sulfate reducing Desulfovibrio ferrophilus MIC(microbiologically influenced corrosion) of X80 carbon steel. Results proved that50 ppm(w/w) THPS was sufficient to mitigate the D. ferrophilus biofilm, and its very agressive MIC(19.7mg/cm^(2) in 7 days or 1.31 mm/a), but not 20 ppm THPS. To achieve effective mitigation at a low dosage of THPS, biofilm-dispersing Peptide A was added to 20 ppm THPS in the culture medium. Sessile cell counts were reduced by 2-log and 4-log after enhancement by 10 ppb and 100 ppb Peptide A, respectively. Enhancement efficiency(further reduction in corrosion rate) reached 69% for 10 ppb Peptide A and 83% for100 ppb Peptide A compared with 20 ppm THPS alone treatment, indicating that Peptide A was a good biocide enhancer for THPS.展开更多
In the presence of biofilms, stainless steels （SS） exhibits an increase in corrosion potential, called ennoblement. In the present study, the corrosion potential （Eco,） behavior of the duplex SS UNS S32760 was rec...In the presence of biofilms, stainless steels （SS） exhibits an increase in corrosion potential, called ennoblement. In the present study, the corrosion potential （Eco,） behavior of the duplex SS UNS S32760 was recorded simultaneously with the in situ marine biofilm formation in two areas at Arraial do Cabo, Southeastern Brazil. The biofilm at Forno Harbor （an anthropogenically disturbed area） was characterized by higher relative abundances of Bacteria at day 2, followed by diatoms （especially Navicula sp.） on day 10 and dinoflagellates on day 18, whereas no clear trend was recorded at Cabo Frio Island （an undisturbed area）. The ennoblement of Ecor values was site-dependent. In a complementary laboratory assay, biofilms were removed and the Eco values registered in sterile conditions for the subsequent 10 days and corroborated in situ results. Understanding biofilms and SS interactions has important implications for materials science and engineering decisions as well as helping to fill in imnortant gaps in this knowledge.展开更多
304 stainless steel(SS) used as orthodontic wire during orthodontics faces the risk of microbiologically influenced corrosion(MIC) due to diverse flora environment. Hereinto, Streptococcus mutans(S. mutans)is the most...304 stainless steel(SS) used as orthodontic wire during orthodontics faces the risk of microbiologically influenced corrosion(MIC) due to diverse flora environment. Hereinto, Streptococcus mutans(S. mutans)is the most important cariogenic bacteria. In this work, MIC behavior of a new 304-Cu SS in presence of S. mutans was studied by the observations using scanning electron microscopy(SEM) and confocal laser scanning microscopy(CLSM) including live/dead staining, extracellular polymeric substance(EPS)staining and pitting corrosion, electrochemical test, and X-ray photoelectron spectroscopy(XPS). Above results showed that 304-Cu SS possessed excellent biofilm inhibition ability and presented lower corrosion current density(icorr), larger polarization resistance(Rp) and charge transfer resistance(Rct) in the presence of S. mutans, indicating that 304-Cu SS had a better MIC resistance against S. mutans. It was further affirmed by XPS results that the presence of Cu-oxide in passive film of 304-Cu SS inhibited the formation of biofilm.展开更多
In the oil and gas industry,microbiologically influenced corrosion(MIC) is a major threat to hydrotest,a procedure which is required to certify whether a pipeline can be commissioned.Seawater is frequently used as a h...In the oil and gas industry,microbiologically influenced corrosion(MIC) is a major threat to hydrotest,a procedure which is required to certify whether a pipeline can be commissioned.Seawater is frequently used as a hydrotest fluid.In this bio film prevention lab study,an oilfield biofilm consortium was grown in an enriched artificial seawater anaerobically at 37℃ for 60 days.The combination of 100 ppm(w/w) 2,2-dibromo-3-nitrilopropionamide(DBNPA)+100 nM(180 ppb) Peptide A(a biofilm dispersal agent) led to extra SRB(sulfate reducing bacteria),APB(acid producing bacteria) and GHB(general heterotrophic bacteria) sessile cell count reductions of 0.9-log,0.8-log and 0.6-log,respectively,compared with the outcome obtained by using 100 ppm DBNPA only.The Peptide Aenhancement also led to extra reductions of 44 % in weight loss,43 % in maximum pit depth,and 54 % in corrosion current density.展开更多
文摘The formation of biofilm by pathogenic microorganisms has become a problem in the livestock industry since it is considered a potential source of infection for farm animals while increasing microbial resistance to physical and chemical agents. Some plant extracts, such as soluble wheat extract, have been shown to be effective in inhibiting or destroying the biofilm of certain micro-organisms under specific conditions. The objective of this study is to evaluate the capacity of the pathogen to form biofilm on different surfaces used in livestock, as well as to evaluate the anti-biofilm capacity of the soluble wheat extract against <i>S. aureus</i> on these surfaces. The inhibition potential of inhibition or destruction of biofilm was tested in vitro. Wheat extract at a concentration of 0.29 mg/100mL showed anti-biofilm activity on <i>S. aureus</i>, inhibiting its formation, as well as destroying it greatly after a contact time of 24 hours, on those surfaces where the microorganism presents more adhesion capacity.
基金financially supported by the National Natural Science Foundation of China (No. 51871026)the National Key R&D Program of China (No. 2017YFF0210404)。
文摘In this work, the impact of a wild-type nitrate-reducing Bacillus licheniformis strain on the corrosion behavior of X80 steel under anaerobic conditions was studied by electrochemical tests and biofilm characterization. The bioelectrochemical, electrochemical, and chemical reactions between X80 steel and microorganisms were investigated comprehensively. The results show that B. licheniformis can accelerate the corrosion of X80 steel substrate in early immersing by two ways: biocatalytic cathodic nitrate reduction and acidification induced by bacterially-secreted acids. However, the corrosion rate of X80 steel decreased after immersing for ca. 1 week in B. licheniformis culture due to iron biomineralization. This work provides direct insights into the mechanism of microbiologically influenced corrosion of carbon steel by the nitrate-reducing bacterium.
基金financially supported by the National Natural Science Foundation of China(Nos.51871050 and 51901039)the Fund of Fujian Province Key Laboratory of Ship and Ocean Engineering+2 种基金the Natural Science Foundation of Liaoning Province(No.20180510041)the Liaoning Revitalization Talents Program(No.XLYC1907158)the Fundamental Research Funds for the Central Universities of the Ministry of Education of China(Nos.N180205021,N180203019,and N2002019)。
文摘The increasing utilization of titanium alloys in marine environments makes their microbiologically influenced corrosion study a timely matter.This work demonstrated that the corrosion ofTi-6 Al-4 V alloy was accelerated by a marine bacterium Shewanella algae in 2216 E medium with different Cl-level.Various electrochemical,pitting morphology and passive film analyses demonstrated that S.algae weakened the passive film,which made Cl-more aggressive.The synergy of those two factors caused considerable corrosion acceleration of the titanium alloy,leading to a maximum pit depth of 3.2μm and corrosion current density of 26.5 nA cm_(-2) in 2216 E medium with 3.50%(w/w)Cl^(-).
基金financial support from Saudi Aramcothe China Scholarship Council for studying in the USA+2 种基金supports by the National Key Research and Development Program of China (No. 2018YFF0215002)Key Laboratory of Materials Chemistry for Energy Conversion and Storage Ministry of Education (2018)The Foundation of Hubei Key Laboratory of Materials Chemistry and Service Failure (2017)。
文摘Tetrakis hydroxymethyl phosphonium sulfate(THPS) was enhanced by a 14-mer Peptide A, with its core12-mer sequence mimicking part of Equinatoxin II protein, in the mitigation of sulfate reducing Desulfovibrio ferrophilus MIC(microbiologically influenced corrosion) of X80 carbon steel. Results proved that50 ppm(w/w) THPS was sufficient to mitigate the D. ferrophilus biofilm, and its very agressive MIC(19.7mg/cm^(2) in 7 days or 1.31 mm/a), but not 20 ppm THPS. To achieve effective mitigation at a low dosage of THPS, biofilm-dispersing Peptide A was added to 20 ppm THPS in the culture medium. Sessile cell counts were reduced by 2-log and 4-log after enhancement by 10 ppb and 100 ppb Peptide A, respectively. Enhancement efficiency(further reduction in corrosion rate) reached 69% for 10 ppb Peptide A and 83% for100 ppb Peptide A compared with 20 ppm THPS alone treatment, indicating that Peptide A was a good biocide enhancer for THPS.
文摘In the presence of biofilms, stainless steels （SS） exhibits an increase in corrosion potential, called ennoblement. In the present study, the corrosion potential （Eco,） behavior of the duplex SS UNS S32760 was recorded simultaneously with the in situ marine biofilm formation in two areas at Arraial do Cabo, Southeastern Brazil. The biofilm at Forno Harbor （an anthropogenically disturbed area） was characterized by higher relative abundances of Bacteria at day 2, followed by diatoms （especially Navicula sp.） on day 10 and dinoflagellates on day 18, whereas no clear trend was recorded at Cabo Frio Island （an undisturbed area）. The ennoblement of Ecor values was site-dependent. In a complementary laboratory assay, biofilms were removed and the Eco values registered in sterile conditions for the subsequent 10 days and corroborated in situ results. Understanding biofilms and SS interactions has important implications for materials science and engineering decisions as well as helping to fill in imnortant gaps in this knowledge.
基金supported financially by the National Natural Science Foundation of China (Nos. 51501199, 51631009 and U1906226)the National Key Research and Development Program of China (No. 2016YFB0300205)。
文摘304 stainless steel(SS) used as orthodontic wire during orthodontics faces the risk of microbiologically influenced corrosion(MIC) due to diverse flora environment. Hereinto, Streptococcus mutans(S. mutans)is the most important cariogenic bacteria. In this work, MIC behavior of a new 304-Cu SS in presence of S. mutans was studied by the observations using scanning electron microscopy(SEM) and confocal laser scanning microscopy(CLSM) including live/dead staining, extracellular polymeric substance(EPS)staining and pitting corrosion, electrochemical test, and X-ray photoelectron spectroscopy(XPS). Above results showed that 304-Cu SS possessed excellent biofilm inhibition ability and presented lower corrosion current density(icorr), larger polarization resistance(Rp) and charge transfer resistance(Rct) in the presence of S. mutans, indicating that 304-Cu SS had a better MIC resistance against S. mutans. It was further affirmed by XPS results that the presence of Cu-oxide in passive film of 304-Cu SS inhibited the formation of biofilm.
基金financially supported by PTT Exploration and Production, ThailandChinese Society for Corrosion and Protection。
文摘In the oil and gas industry,microbiologically influenced corrosion(MIC) is a major threat to hydrotest,a procedure which is required to certify whether a pipeline can be commissioned.Seawater is frequently used as a hydrotest fluid.In this bio film prevention lab study,an oilfield biofilm consortium was grown in an enriched artificial seawater anaerobically at 37℃ for 60 days.The combination of 100 ppm(w/w) 2,2-dibromo-3-nitrilopropionamide(DBNPA)+100 nM(180 ppb) Peptide A(a biofilm dispersal agent) led to extra SRB(sulfate reducing bacteria),APB(acid producing bacteria) and GHB(general heterotrophic bacteria) sessile cell count reductions of 0.9-log,0.8-log and 0.6-log,respectively,compared with the outcome obtained by using 100 ppm DBNPA only.The Peptide Aenhancement also led to extra reductions of 44 % in weight loss,43 % in maximum pit depth,and 54 % in corrosion current density.
