Biofilm formation and corrosion behaviour of 1010 carbon steel in SRB cultures by microscopic techniques and electrochemical impedance spectroscopy

Biofilms cause various problems such as medical infections, fouling of water cooling system, product contamination, and microbiologically influenced corrosion (MIC)[1]. MIC accounts for as much as 20% of all forms of corrosion, amounting to billions of dollars in losses each year[2]. Among aerobic and anaerobic bacteria related to MIC, sulfate reducing bacteria (SRB) are most often blamed [3]. The ubiquity of these bacteria leads to a variety of impressive industrial, economic and ecological effects because of their proneness to generate large quantities of H2S. SRB are the main reason to cause the MIC by accelerating corrosion rate, inducing stress corrosion and pitting corrosion [4-6]. The aim of this study was to evaluate the corrosion associated with the formation of SRB biofilms on carbon steel surfaces. The bacterial strain used in the experiments was Desulfovibrio vulgaris cultured in Postgate´C. Carbon steel coupons of SAE 1010 were placed in the cultures for biofilm development during 1 and 7 days. Then, the coupons were extracted and bacterial adherence and biofilm formation were measured by viable bacteria counts, epifluorescence microscopy and by the crystal violet assay. Surface attack of carbon steel and biofilm morphology were analyzed by scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). Studies carried out allowed correlating the biofilm formation (Figure 1) with the different degree of attack suffered by the SAE 1010 carbon steel coupons. The impedance spectra (Figure 2) show that the charge transfer resistance increases with the time.Fil: Viera, Marisa Rosana. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Tecnología de Pinturas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones en Tecnología de Pinturas; Argentina17° Congreso Internacional de Metalurgia y MaterialesCopiapóChileSociedad Chilena de Metalurgia y MaterialesAsociación Argentina de Materiale

Dynamic Cr(III) uptake by Macrocystis pyrifera and Undaria pinnatifida biomasses

The increased industrial activity has resulted in the discharge of large amount of pollutants including non-degradable metals into the environment. Chromium is produced in several industrial processes and it can be found in the environment in two stable oxidation states, Cr(VI) and Cr(III). Cr(VI) is more hazardous due to its carcinogenic and mutagenic effects on living organisms. Although much less toxic, Cr(III) can also exert genotoxic effects under prolonged or severe exposure. It can be separated from the solution by precipitation but biosorption using brown algae seems to be an effective and sustainable treatment technique owing to its cost-effectiveness and environmental friendly characteristics. Macrocystis pyrifera and Undaria pinnatifida are two marine brown macroalgae with high capability of removing heavy metals including Cr(III) in batch mode of operation. In this work packed bed biosorption of Cr(III) by M. pyrifera and U. pinnatifida biomasses was evaluated.Fil: Plaza Cazón, Josefina del Carmen. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Centro de Investigación en Fermentaciones Industriales (i); Argentina;Fil: Viera, Marisa Rosana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Centro de Investigación y Desarrollo en Tecnología de Pinturas (i); Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Centro de Investigación en Fermentaciones Industriales (i); Argentina;Fil: Donati, Edgardo Ruben. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Centro de Investigación en Fermentaciones Industriales (i); Argentina

Natural compounds as additives in paints for controlling algal growth

Algae are a diverse group of photosynthetic organisms, ranging from microscopic single-cell micro-organisms to very large organisms, such as seaweed. Microalgae belonging to Chlorophyta (green algae) and Cyanophyta (blue-green algae) commonly occur in biofilms. In actual fact, these phototrophic biofilms are complex microbial communities formed by cyanobacteria, microalgae and heterotrophs all embedded in a mucilaginous matrix of exopolymeric substances (EPS), mainly composed of polysaccharides ranging between 50–90%.Fil: Gómez de Saravia, Sandra Gabriela. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Tecnología de Pinturas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones en Tecnología de Pinturas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; ArgentinaFil: Rastelli, Silvia Elena. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Tecnología de Pinturas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones en Tecnología de Pinturas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; ArgentinaFil: Viera, Marisa Rosana. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Tecnología de Pinturas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones en Tecnología de Pinturas; Argentina. Universidad Nacional de La Plata. Facultad de Ingeniería; Argentin

Dynamic Cr(III) uptake by Macrocystis pyrifera and Undaria pinnatifida biomasses

Background: The increased industrial activity has resulted in the discharge of large amount of pollutants including non-degradable metals into the environment. Chromium is produced in several industrial processes and it can be found in the environment in two stable oxidation states, Cr(VI) and Cr(III). Cr(VI) is more hazardous due to its carcinogenic and mutagenic effects on living organisms. Although much less toxic, Cr(III) can also exert genotoxic effects under prolonged or severe exposure. It can be separated from the solution by precipitation but biosorption using brown algae seems to be an effective and sustainable treatment technique owing to its cost-effectiveness and environmental friendly characteristics. Macrocystis pyrifera and Undaria pinnatifida are two marine brown macroalgae with high capability of removing heavy metals including Cr(III) in batch mode of operation. In this work packed bed biosorption of Cr(III) by M. pyrifera and U. pinnatifida biomasses was evaluated. Results: The shapes of the breakthrough curves were rather different for each biomaterial. Parameters like the breakthrough time (tb) andzone mass transfer (MTZ) showed that U. pinnatifida has greater affinity for Cr(III). The maximum adsorption capacity at the exhaustion operating time (te) demonstrated that M. pyrifera has higher retention capacity of Cr(III). The experimental data were fitted to Thomas, Yoon-Nelson and Dose-Response models. The best correlation coefficient (0.94 or 0.96) was obtained with Dose-Response that accurately describes the uptake behaviour of Cr(III) on the seaweed biomasses under different experimental conditions. The FT-IR spectra evidenced that Cr(III) adsorption occurred mainly by interaction between metal and carboxylate groups present on both the seaweed surfaces. Conclusions: M. pyrifera and U. pinnatifida biomasses are efficient biosorbents for Cr(III) adsorption under a continuous mode of operation although differences between uptake capacities suggest different mechanisms involved in the biosorption.Facultad de Ciencias ExactasCentro de Investigación y Desarrollo en Fermentaciones Industriale

Hygienic coatings with nano-functionalized diatomaceous earth by Equisetum giganteum – Mediated green synthesis

Background: Microbiological growth on indoor surfaces has a negative impact on human health. Antimicrobial materials are intensely studied to prevent biodeterioration in an indoor environment. The present work seeks the green synthesis of an eco-friendly and cheap antimicrobial nano-functionalized filler from diatomaceous earth to be applied to the formulation of paints. Methods: Adsorption of silver ions and a green synthesis with Equisetum giganteum L. aqueous extract of nano functionalized diatomaceous earth was carried out. The nano-functionalized fillers were characterized by four ier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), transmission electron micro scopy (TEM) and energy dispersive spectrometry (EDS). The antimicrobial activity was also assessed. Waterborne paints were formulated and prepared, then bioassays were performed to assess their antimicrobial efficiency. Significant findings: For the first time E. giganteum aqueous extract has been employed for the nano functionalization of diatomaceous earth (DE). Functionalized DE has the potential to prevent biodeterioration with 25 mg of silver per 100 g of paint, which has resulted in an eco-friendly alternative for hygienic coatings.Centro de Investigación y Desarrollo en Tecnología de Pintura

Formulation and evaluation of paint films added with nanofunctionalized diatomaceous earth by green synthesis

Las nanopartículas de plata muestran actividad frente a un amplio espectro de hongos, virus y bacterias resistentes a los productos más tradicionales. No obstante, las nanopartículas libres en solución son proclives a la agregación, la oxidación y por consiguiente a la pérdida de propiedades potenciadas por su exposición a determinadas condiciones ambientales por lo que su asociación con otros compuestos constituye una alternativa para su uso. En el área de Recubrimientos Antimicrobianos del CIDEPINT se desarrolló un trabajo donde se empleó con éxito tierra de diatomeas (TD), un conocido pigmento carga, como soporte para la síntesis de un compuesto híbrido bioactivo basado en amonio cuaternario. Argentina es uno de los 10 países con mayores reservas naturales de TD y el cuarto exportador a Estados Unidos que es el mayor productor y consumidor a nivel mundial. En tal sentido, resulta interesante, además de mitigar el biodeterioro, asignar valor agregado a este recurso natural abundante en el país. El presente trabajo tiene como objetivo el estudio de películas de pinturas aditivadas con TD nanofuncionalizadas (TDNF) durante el tiempo de servicio, para profundizar en la eficiencia del material sometido al envejecimiento natural.Facultad de Ciencias Agrarias y Forestale

Fungal deterioration of a phosphate conversion coating

El acero al carbono es un material ampliamente empleado en múltiples aplicaciones, como por ejemplo construcción, energía, electrodomésticos, transporte, entre otras. Sin embargo, su escasa resistencia a la corrosión restringe su uso en muchas otras aplicaciones. La formación de una película de conversión de fosfato sobre la superficie de acero es una técnica muy empleada para aumentar la resistencia a la corrosión del acero al carbono, especialmente durante el transporte y almacenaje del material. En estos casos, el acero podría estar expuesto a ambientes húmedos, favorables para el desarrollo de microorganismos. Muchos microorganismos son capaces de solubilizar fosfatos insolubles y los hongos son particularmente importantes en este sentido. En este trabajo se analizó, empleando medidas electroquímicas (curvas de polarización potenciodinámicas) y observación mediante lupa estereoscópica y microscopía electrónica de barrido (MEB), como se afecta la protección otorgada por dos tipos de películas de conversión de fosfato al acero al carbono, al ser expuestas al crecimiento de Aspergillus niger MN371276.Facultad de Ciencias Agrarias y Forestale

Evaluation of biocides in oilfield environments using fluorescent <i>in-situ</i> hybridization

Microbiologically influenced corrosion and souring of oilfield reservoirs are process frequently provoked by the sulphate-reducing bacteria. The most common method applied in the industry for preventing or controlling the deleterious effect caused by the presence of microorganisms is the addition of chemical agents (biocides) aimed at killing the microorganisms or inhibiting the microbial growth. Traditionally, biocide selection and testing are based on NACE standard TM0194 which implies the use of culturing for enumerating the bacteria surviving the treatment. To overcome culturing limitations, we used Fluorescent in-situ Hybridization to assist in the evaluation of biocides applied in water production treatment plants. Biocides were based on THPS (40% (B1); 75% (B2)) and 40% of a mixture (1/1, v/v) of THPS and benzalkonium chloride (B3) applied at two concentrations: 50 and 400 mg/L. The relation between the number of cells visualized with the fluorescent probes Eub338 and SRB385 (for eubacteria and SRB populations respectively) and the DAPI-stained cells (PR%) was used as an indication of the biocide efficiency. B1 and B3 gave a high PR% indicating that the chemical induced the metabolic cell activity. Only the highest B2 concentration showed effectiveness on eubacteria and SRB populations. Thus, through the application of FISH we were able to distinguish concentration effects of the THPS, discriminating sublethal from net inhibitory effects. The possibility of including FISH into the protocols for the control of the biocides in water treatment plants could improve the biocide selection and the adjustment of their concentration in order to maintain the water system with a low density of metabolically active cells. This would avoid the misuse of chemicals with their consequent economic and ecological impacts.Centro de Investigación y Desarrollo en Fermentaciones IndustrialesCentro de Investigación y Desarrollo en Tecnología de Pintura

Evaluation of biocides in oilfield environments using fluorescent <i>in-situ</i> hybridization

Microbiologically influenced corrosion and souring of oilfield reservoirs are process frequently provoked by the sulphate-reducing bacteria. The most common method applied in the industry for preventing or controlling the deleterious effect caused by the presence of microorganisms is the addition of chemical agents (biocides) aimed at killing the microorganisms or inhibiting the microbial growth. Traditionally, biocide selection and testing are based on NACE standard TM0194 which implies the use of culturing for enumerating the bacteria surviving the treatment. To overcome culturing limitations, we used Fluorescent in-situ Hybridization to assist in the evaluation of biocides applied in water production treatment plants. Biocides were based on THPS (40% (B1); 75% (B2)) and 40% of a mixture (1/1, v/v) of THPS and benzalkonium chloride (B3) applied at two concentrations: 50 and 400 mg/L. The relation between the number of cells visualized with the fluorescent probes Eub338 and SRB385 (for eubacteria and SRB populations respectively) and the DAPI-stained cells (PR%) was used as an indication of the biocide efficiency. B1 and B3 gave a high PR% indicating that the chemical induced the metabolic cell activity. Only the highest B2 concentration showed effectiveness on eubacteria and SRB populations. Thus, through the application of FISH we were able to distinguish concentration effects of the THPS, discriminating sublethal from net inhibitory effects. The possibility of including FISH into the protocols for the control of the biocides in water treatment plants could improve the biocide selection and the adjustment of their concentration in order to maintain the water system with a low density of metabolically active cells. This would avoid the misuse of chemicals with their consequent economic and ecological impacts.Centro de Investigación y Desarrollo en Fermentaciones IndustrialesCentro de Investigación y Desarrollo en Tecnología de Pintura

Dynamic Cr(III) uptake by Macrocystis pyrifera and Undaria pinnatifida biomasses

Background: The increased industrial activity has resulted in the discharge of large amount of pollutants including non-degradable metals into the environment. Chromium is produced in several industrial processes and it can be found in the environment in two stable oxidation states, Cr(VI) and Cr(III). Cr(VI) is more hazardous due to its carcinogenic and mutagenic effects on living organisms. Although much less toxic, Cr(III) can also exert genotoxic effects under prolonged or severe exposure. It can be separated from the solution by precipitation but biosorption using brown algae seems to be an effective and sustainable treatment technique owing to its cost-effectiveness and environmental friendly characteristics. Macrocystis pyrifera and Undaria pinnatifida are two marine brown macroalgae with high capability of removing heavy metals including Cr(III) in batch mode of operation. In this work packed bed biosorption of Cr(III) by M. pyrifera and U. pinnatifida biomasses was evaluated. Results: The shapes of the breakthrough curves were rather different for each biomaterial. Parameters like the breakthrough time (tb) andzone mass transfer (MTZ) showed that U. pinnatifida has greater affinity for Cr(III). The maximum adsorption capacity at the exhaustion operating time (te) demonstrated that M. pyrifera has higher retention capacity of Cr(III). The experimental data were fitted to Thomas, Yoon-Nelson and Dose-Response models. The best correlation coefficient (0.94 or 0.96) was obtained with Dose-Response that accurately describes the uptake behaviour of Cr(III) on the seaweed biomasses under different experimental conditions. The FT-IR spectra evidenced that Cr(III) adsorption occurred mainly by interaction between metal and carboxylate groups present on both the seaweed surfaces. Conclusions: M. pyrifera and U. pinnatifida biomasses are efficient biosorbents for Cr(III) adsorption under a continuous mode of operation although differences between uptake capacities suggest different mechanisms involved in the biosorption.Facultad de Ciencias ExactasCentro de Investigación y Desarrollo en Fermentaciones Industriale