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Vejar N, Gutiérrez S, Tareelap N, Alvarado C, Solís R, Guerra C, Pineda F, Sancy M, Páez M. Influence of Bacillus safensis and Bacillus pumilus on the electrochemical behavior of 2024-T3 aluminum alloy. Bioelectrochemistry 2022; 143:107950. [PMID: 34592630 DOI: 10.1016/j.bioelechem.2021.107950] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 08/18/2021] [Accepted: 09/15/2021] [Indexed: 11/20/2022]
Abstract
In this work, electrochemical techniques were employed to evaluate the contribution to the corrosion and corrosion inhibition of 2024-T3 aluminum alloy by two Gram-positive bacteria. In addition, polarized impedance was used to determine the microbial effect on the cathodic and anodic reactions. These microorganisms were collected from a tropical environment due to the favorable bacterial growth of this kind of climate. The alloy was exposed to the sterile medium and inoculated for up to 12 days evaluating the microbiological and electrochemical behavior. The results by linear scanning voltammetry showed that the B. safensis and B. pumilus caused a dual effect of increase and decrease currents, and through electrochemical impedance spectroscopy, showed in some cases, inductive loop, which could be associated with local corrosion and another case, an increasing impedance could be related to protection. In addition, a morphological characterization was performed by scanning electron microscopy before and after exposure, showing an increase in copper precipitation in the vicinity of the intermetallic phases by bacteria, attributed to local corrosion, but, in general, a significant effect of damages was not observed.
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Affiliation(s)
- Nelson Vejar
- Centro de Investigación y Desarrollo en Ciencias Aeroespaciales, Fuerza Aérea de Chile, Av. José Miguel Carrera 11087, Santiago, Chile.
| | - Sebastián Gutiérrez
- Centro de Investigación y Desarrollo en Ciencias Aeroespaciales, Fuerza Aérea de Chile, Av. José Miguel Carrera 11087, Santiago, Chile
| | - Napachat Tareelap
- School of Energy, Environment and Materials, King Mongkut's University of Technology Thonburi, 126 Pracha Uthit Road, Bangmod, Thungkru, Bangkok 10140, Thailand
| | - Claudia Alvarado
- Centro de Investigación y Desarrollo en Ciencias Aeroespaciales, Fuerza Aérea de Chile, Av. José Miguel Carrera 11087, Santiago, Chile
| | - Roberto Solís
- Centro de Investigación y Desarrollo en Ciencias Aeroespaciales, Fuerza Aérea de Chile, Av. José Miguel Carrera 11087, Santiago, Chile
| | - Carolina Guerra
- Escuela de Construcción Civil, Facultad de Ingeniería, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, Macul, Santiago, Chile
| | - Fabiola Pineda
- Centro de Nanotecnología Aplicada, Facultad de Ciencias, Universidad Mayor, Santiago, 8580745, Chile
| | - Mamié Sancy
- Escuela de Construcción Civil, Facultad de Ingeniería, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, Macul, Santiago, Chile
| | - Maritza Páez
- Universidad de Santiago de Chile, Av. Libertador Bernardo ÓHiggins 3363, Santiago, Chile
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Espinoza-Vergara J, Molina P, Walter M, Gulppi M, Vejar N, Melo F, Urzua M, Muñoz H, Zagal JH, Zhou X, Azocar MI, Paez MA. Effect of pH on the Electrochemical Behavior of Hydrogen Peroxide in the Presence of Pseudomonas aeruginosa. Front Bioeng Biotechnol 2021; 9:749057. [PMID: 34938720 PMCID: PMC8685425 DOI: 10.3389/fbioe.2021.749057] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 11/10/2021] [Indexed: 11/13/2022] Open
Abstract
The influence of pH on the electrochemical behavior of hydrogen peroxide in the presence of Pseudomonas aeruginosa was investigated using electrochemical techniques. Cyclic and square wave voltammetry were used to monitor the enzymatic activity. A modified cobalt phthalocyanine (CoPc) carbon electrode (OPG), a known catalyst for reducing O2 to H2O2, was used to detect species resulting from the enzyme activity. The electrolyte was a sterilized aqueous medium containing Mueller-Hinton (MH) broth. The open-circuit potential (OCP) of the Pseudomonas aeruginosa culture in MH decreased rapidly with time, reaching a stable state after 4 h. Peculiarities in the E / I response were observed in voltammograms conducted in less than 4 h of exposure to the culture medium. Such particular E/I responses are due to the catalase's enzymatic action related to the conversion of hydrogen peroxide to oxygen, confirming the authors' previous findings related to the behavior of other catalase-positive microorganisms. The enzymatic activity exhibits maximum activity at pH 7.5, assessed by the potential at which oxygen is reduced to hydrogen peroxide. At higher or lower pHs, the oxygen reduction reaction (ORR) occurs at higher overpotentials, i.e., at more negative potentials. In addition, and to assess the influence of bacterial adhesion on the electrochemical behavior, measurements of the bacterial-substrate metal interaction were performed at different pH using atomic force microscopy.
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Affiliation(s)
- Javier Espinoza-Vergara
- Departamento de Química de Los Materiales, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile.,Corrosion and Protection Center, Department of Materials, University of Manchester, Manchester, England, United Kingdom
| | - Paulo Molina
- Departamento de Química de Los Materiales, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile
| | - Mariana Walter
- Departamento de Química de Los Materiales, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile
| | - Miguel Gulppi
- Departamento de Química de Los Materiales, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile
| | - Nelson Vejar
- Chilean Air Force, Aerospace Sciences Research and Development Centre (CIDCA), San Bernardo, Santiago, Chile
| | - Francisco Melo
- Departamento de Física, Facultad de Ciencias, Universidad de Santiago de Santiago de Chile, Avenida Ecuador, Santiago, Chile
| | - Marcela Urzua
- Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Hugo Muñoz
- Departamento de Química de Los Materiales, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile
| | - José H Zagal
- Departamento de Química de Los Materiales, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile
| | - Xiaorong Zhou
- Corrosion and Protection Center, Department of Materials, University of Manchester, Manchester, England, United Kingdom
| | - Manuel I Azocar
- Departamento de Química de Los Materiales, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile
| | - Maritza A Paez
- Departamento de Química de Los Materiales, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile
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