A microbial fuel cell measuring system for corrosion assessment

Microbiologically Influenced Corrosion (MIC) is a huge problem for components put into service in unclean industrial systems and marine environment. For this reason, developing new and more effective testing methodologies for the study of this form of corrosion is surely an important need. An innovative approach consists in the use of Microbial Fuel Cells as environment in which to carry out tests to assess the resistance of a specific material to MIC. This new methodology will be described, presenting possible studies that can be performed and information that can be gained. Moreover, a new measuring setup has been developed, which enables researchers to get more specific information about the test, assessing all current flows inside the Fuel Cell. Two different materials (low carbon steel and stainless steel) have been used to carry out different experiments and validate the employed methodology. Results obtained with this measuring system have been then compared with those of a simpler setup, showing the effectiveness of this apparatus in studying MIC

Measurement techniques for microbial corrosion assessment

L'abstract è presente nell'allegato / the abstract is in the attachmen

Recent trends and advances in microbial electrochemical sensing technologies: An overview

Microbial electrochemical systems utilize the electrochemical interaction between microorganisms and electrode surfaces to convert chemical energy into electrical energy, offering a promise as technologies for wastewater treatment, bioremediation, and biofuel production. Recently, growing research attention has been devoted to the development of microbial electrochemical sensrs as biosensing platforms. Microbial electrochemical sensors are a type of microbial electrochemical technology (MET) capable of sensing through the anodic or the cathodic electroactive microorganisms and/or biofilms. Herein, we review and summarize the recent advances in the design of microbial electrochemical sensing approaches with a specific overview and discussion of anodic and cathodic microbial electrochemical sensor devices, highlighting both the advantages and disadvantages. Particular emphasis is given on the current trends and strategies in the design of low-cost, convenient, efficient, and high performing METs with different biosensing applications, including toxicity monitoring, pathogen detection, corrosion monitoring, as well as measurements of biological oxygen demand, chemical oxygen demand, and dissolved oxygen. The conclusion provides perspectives and an outlook to understand the shortcomings in the design, development status, and sensing applications of microbial electrochemical platforms. Namely, we discuss key challenges that limit the practical implementation of METs for sensing purposes and deliberate potential solutions, necessary developments, and improvements in the field

Benthic diatom monitoring and assessment of freshwater environments: standard methods and future challenges

Fil: Soizic, Morin. National Research Institute of Science and Technology for Environment and Agriculture; FranceFil: Gómez, Nora. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología Dr. Raúl A. Ringuelet; ArgentinaFil: Tornés, Elisabet. University of Girona. Institute of Aquatic Ecology; SpainFil: Licursi, Magdalena. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología Dr. Raúl A. Ringuelet; ArgentinaFil: Rosebery, Juliette. Aquatic Ecosystems and Global Changes Research Unit; Franc

Benthic diatom monitoring and assessment of freshwater environments: standard methods and future challenges

Fil: Soizic, Morin. National Research Institute of Science and Technology for Environment and Agriculture; FranceFil: Gómez, Nora. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología Dr. Raúl A. Ringuelet; ArgentinaFil: Tornés, Elisabet. University of Girona. Institute of Aquatic Ecology; SpainFil: Licursi, Magdalena. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología Dr. Raúl A. Ringuelet; ArgentinaFil: Rosebery, Juliette. Aquatic Ecosystems and Global Changes Research Unit; Franc

Auto-Accretion Powered by Microbial Fuel Cells in the Venetian Lagoon

Moto ondoso is the eroding of the Venetian canal walls from the impact forces of boat wake, which leads to expensive and time consuming canal wall maintenance. This project proposed the erection of a protective barrier in front of the canal walls to absorb the forces of moto ondoso. This barrier would be formed by auto-accretion, or the acceleration of naturally occurring accretion of seawater minerals on a submerged metallic surface from the power generated by a microbial fuel cell

Application of electro-active biofilms

The concept of an electro-active biofilm (EAB) has recently emerged from a few studies that discovered that certain bacteria which form biofilms on conductive materials can achieve a direct electrochemical connection with the electrode surface using it as electron exchanger, without the aid of mediators. This electro-catalytic property of biofilms has been clearly related to the presence of some specific strains that are able to exchange electrons with solid substrata (eg Geobacter sulfurreducens and Rhodoferax ferrireducens). EABs can be obtained principally from natural sites such as soils or seawater and freshwater sediments or from samples collected from a wide range of different microbially rich environments (sewage sludge, activated sludge, or industrial and domestic effluents). The capability of some microorganisms to connect their metabolisms directly in an external electrical power supply is very exciting and extensive research is in progress on exploring the possibilities of EABs applications. Indeed, the best known application is probably the microbial fuel cell technology that is capable of turning biomass into electrical energy. Nevertheless, EABs coated onto electrodes have recently become popular in other fields like bioremediation, biosynthesis processes, biosensor design, and biohydrogen production

MICROBIAL ABUNDANCE, DIVERSITY, AND POTENTIAL ACTIVITY IN BENTONITE CLAY

The Canadian deep geologic repository (DGR) concept for long-term safe storage and isolation of used nuclear fuel incorporates a multi-protective engineered barrier system. However, due to the inevitable presence of microorganisms and their metabolic products in a DGR, the integrity of the containers, and hence the repository, might be compromised. Therefore, the emphases of this thesis are to characterize and identify the microbial populations present in bulk and highly-compacted Wyoming MX-80 bentonite, to determine the conditions under which the survival and activity of microorganisms in highly-compacted bentonite clay (one of the engineered barriers) will be minimized or regulated, and to observe the microbial capacity to interact with bentonite particle under nutrient regime (clay-microbe aggregation study). To achieve these, culture-dependent and molecular biology methods (e.g., 16S rRNA sequencing), a range of analytical chemistry assays (e.g., sulfate turbidimetric method), pressure cell studies, microscopic technique (e.g., confocal laser microscopy (CLSM)), particle size analyses and laboratory-scale enrichment (or microcosm) assays were carried out. Culture-dependent techniques revealed the presence of spore-forming bacterial isolates belonging to phyla Actinobacteria and Firmicutes in bulk MX-80. Interestingly, when MX-80 bentonite was highly compacted, Gram-positive spore-formers were also identified after being exposed to the collective effect of > 2,000 kPa swelling pressure, 0.96 water activity, oxygen-free environment, and ≥ 1.6 g/cm3 dry density conditions for ~ 145 days and ~ 8 years. It was determined that microbial culturability was suppressed at or below background level (i.e., ≤ 2 x 102 Colony Forming Units per g) when the aforementioned parameters were applied and when 50 g/L NaCl solution infiltrated the highly-compacted bentonite (HCB). Sulfate reducing bacteria (SRB) in the HCB, however, were speculated to remain as spores during the incubation period since their microbial counts were similar at different dry densities. The enrichment assays for SRB containing bentonite clay slurry amended with carbon, electron donors and acceptors revealed that lactate was the preferred substrate for sulfidogenesis and that high salinity could impede the same process. Finally, the clay-microbe aggregation study showed that extracellular polymeric substance (EPS) contribute to the clay-microbe aggregation and that nutrient concentration, carbon substrate type and bentonite concentration affect EPS production. Overall, these studies are relevant to DGR operations because the results obtained will assist in understanding the potential consequences of microbial interactions with clay minerals