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Biofilm formation by the manganese-oxidizing bacterium Leptothrix discophora strain SS-1 and corrosion of stainless steel
Nowadays it is generally accepted that microorganisms play a pivotal role in corrosion, by influencing and/or accelerating the electrochemical corrosion processes. Microbiologically influenced corrosion (MIC) is associated with biofilm formation leading to (in)direct changes of the materials surface characteristics. The biofilm is consisting of a heterogeneous matrix of extracellular polymeric substances (EPS), which is comprised mainly (in addition to water) of polysaccharides, proteins, lipids, and nucleic acids. The metabolic activity of biofilm cells and the EPS itself strongly influence the interfacial processes associated with the electrochemical processes. In this study the importance of biofilm formation and manganese oxidation for the corrosion of stainless steel was elucidate by using Leptothrix discophora SS-1 as model organism. The growth of L. discophora SS-1 cells was tested with two different growth media with and without addition of manganese ions. It was shown that the addition of manganese ions resulted in an increased lag phase as well as an increase in generation time (from approximately 2 h to 3 h). Concomitant with the oxidation of manganese(II) ions to manganese(IV) oxides the total ATP and protein content of stationary cultures decreased up to 40 % and 55 %, respectively. This indicates a negative effect of manganese ions on the physiology of L. discophora SS-1. The analysis of the (EPS) under four different growth conditions showed that L. discophora SS-1 adapts its EPS to the environmental conditions and that the EPS possess all features to facilitate biofilm formation on SS. The amount of uronic acids was increased in EPS extracted from cells grown in the presence of manganese ions. This indicates that the carboxyl groups of uronic acids might be involved in retaining manganese ions in the EPS for subsequent oxidation. Analysis of (un)saturated fatty acids identified C18:1 as a unique unsaturated fatty acid only present in EPS of cells grown in the presence of manganese ions. ...
Biofilm formation by the manganese-oxidizing bacterium Leptothrix discophora strain SS-1 and corrosion of stainless steel
Nowadays it is generally accepted that microorganisms play a pivotal role in corrosion, by influencing and/or accelerating the electrochemical corrosion processes. Microbiologically influenced corrosion (MIC) is associated with biofilm formation leading to (in)direct changes of the materials surface characteristics. The biofilm is consisting of a heterogeneous matrix of extracellular polymeric substances (EPS), which is comprised mainly (in addition to water) of polysaccharides, proteins, lipids, and nucleic acids. The metabolic activity of biofilm cells and the EPS itself strongly influence the interfacial processes associated with the electrochemical processes. In this study the importance of biofilm formation and manganese oxidation for the corrosion of stainless steel was elucidate by using Leptothrix discophora SS-1 as model organism. The growth of L. discophora SS-1 cells was tested with two different growth media with and without addition of manganese ions. It was shown that the addition of manganese ions resulted in an increased lag phase as well as an increase in generation time (from approximately 2 h to 3 h). Concomitant with the oxidation of manganese(II) ions to manganese(IV) oxides the total ATP and protein content of stationary cultures decreased up to 40 % and 55 %, respectively. This indicates a negative effect of manganese ions on the physiology of L. discophora SS-1. The analysis of the (EPS) under four different growth conditions showed that L. discophora SS-1 adapts its EPS to the environmental conditions and that the EPS possess all features to facilitate biofilm formation on SS. The amount of uronic acids was increased in EPS extracted from cells grown in the presence of manganese ions. This indicates that the carboxyl groups of uronic acids might be involved in retaining manganese ions in the EPS for subsequent oxidation. Analysis of (un)saturated fatty acids identified C18:1 as a unique unsaturated fatty acid only present in EPS of cells grown in the presence of manganese ions. ...
Biofilm formation by the manganese-oxidizing bacterium Leptothrix discophora strain SS-1 and corrosion of stainless steel
Thyssen, Christian (author) / Sand, Wolfgang
2018-08-07
Theses
Electronic Resource
English
ddc:572 , ddc:570 , Fakultät für Chemie , ddc:540 , Biofilm , MIC , Corrosion , Manganese oxidation
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