Electrochemical Bacterial Enrichment from Natural Seawater and Its Implications in Biocorrosion of Stainless-Steel Electrodes.

María José De La Fuente,Rodrigo De La Iglesia,Leslie K Daille,Magdalena Walczak,Francisco Armijo,Gonzalo E Pizarro,Ignacio T Vargas

doi:10.3390/ma13102327

María José De La Fuente, Rodrigo De La Iglesia + Show 5 more

Open Access

https://doi.org/10.3390/ma13102327

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Journal: Materials	Publication Date: May 19, 2020
Citations: 4	License type: CC BY 4.0

Affiliation: Pontificia Universidad Católica de Chile

Abstract

Microbial electrochemical technologies have revealed the opportunity of electrochemical enrichment for specific bacterial groups that are able to catalyze reactions of interest. However, there are unsolved challenges towards their application under aggressive environmental conditions, such as in the sea. This study demonstrates the impact of surface electrochemical potential on community composition and its corrosivity. Electrochemical bacterial enrichment was successfully carried out in natural seawater without nutrient amendments. Experiments were carried out for ten days of exposure in a closed-flow system over 316L stainless steel electrodes under three different poised potentials (−150 mV, +100 mV, and +310 mV vs. Ag/AgCl). Weight loss and atomic force microscopy showed a significant difference in corrosion when +310 mV (vs. Ag/AgCl) was applied in comparison to that produced under the other tested potentials (and an unpoised control). Bacterial community analysis conducted using 16S rRNA gene profiles showed that poised potentials are more positive as +310 mV (vs. Ag/AgCl) resulted in strong enrichment for Rhodobacteraceae and Sulfitobacter. Hence, even though significant enrichment of the known electrochemically active bacteria from the Rhodobacteraceae family was accomplished, the resultant bacterial community could accelerate pitting corrosion in 316 L stainless steel, thereby compromising the durability of the electrodes and the microbial electrochemical technologies.

Highlights

Microbial electrochemical technologies (METs) take advantage of microbial communities to catalyze redox reactions over electrodes [1,2,3,4]
We investigated whether the durability of Stainless Steel (SS) electrodes exposed to a marine environment changes according to the applied overpotential and the enrichment of specific bacteria, as well as the application of an overpotential as a microbial enrichment tool to improve the applicability and scalability of MET
The first experiment was carried out samples, and the second wasapplication conducted to the effects of both the applied potential to determine effect ofexperiment overpotential onisolate microbial enrichment from natural seawater microorganisms ontothe metal samples,and andthe the enriched second experiment was conducted isolate thecorrosion

Summary

Introduction

Microbial electrochemical technologies (METs) take advantage of microbial communities to catalyze redox reactions over electrodes [1,2,3,4]. The generation of METs were conceived to accomplish selective and energy-efficient treatment, remediation, and recovery of nutrients, metals, and by-products with industrial value [8]. Many of these novel and disruptive METs have only been tested at the laboratory scale and under controlled conditions. Some of the main ongoing challenges for METs are to overcome the practical limitations associated with (i) the performance requirements of cost-efficient materials used as electrodes, and (ii) the enrichment of specific microbial communities which can catalyze reactions of interest in a MET under natural, uncontrolled environmental conditions [9,10], which is related to the use of METs in the implementation of bioremediation strategies. In pilot systems, they exhibit limitations in terms of resistivity, mechanical strength, and cost [10,11,12]

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