Biodegradación de hidrocarburos de la comunidad bacteriana en condiciones de alta concentración en sales de sulfato

El Cordón Forestal es un suelo que pertenece a la formación Patagonia y que ha sufrido procesos de salinización, por la circulación de aguas subterráneas de elevada salinidad y en los últimos veinte años, por una deficiente planificación. El objetivo del trabajo es conocer las posibilidades de uan comunidad bacteriana adaptada a la alta salinidad del suelo del que proviene, de biodegradar hidrocarburos en condiciones salinas óptimas

Biodegradación de hidrocarburos de la comunidad bacteriana en condiciones de alta concentración en sales de sulfato

El Cordón Forestal es un suelo que pertenece a la formación Patagonia y que ha sufrido procesos de salinización, por la circulación de aguas subterráneas de elevada salinidad y en los últimos veinte años, por una deficiente planificación. El objetivo del trabajo es conocer las posibilidades de uan comunidad bacteriana adaptada a la alta salinidad del suelo del que proviene, de biodegradar hidrocarburos en condiciones salinas óptimas

[Influence of salinity and temperature on fatty acid composition of Pseudomonas fluorescens GNP-OHP-3 membrane]. / Influencia de la concentración salina y la temperatura en la composición de acidos grasos de membrana de Pseudomonas fluorescens GNP-OHP-3.

The bacteria respond to environmental changes modifying their composition. One of the most important modifications is the variation on fatty acid composition of cellular membranes to maintain the homeoviscosity. The action of temperature, hydrostatic pressure and solvents on Pseudomonas putida has been thoroughly studied. In this paper, the combined action of the temperature and salinity on fatty acid composition of cellular membranes of Pseudomonas fluorescens GNP-OHP-3, a bacterial strain isolated from a petroleum contaminated habitat, was studied. The modifications in the fatty acid composition of Pseudomonas fluorescens GNP-OHP-3 membrane were similar to those described for other members of Pseudomonas: an increase in saturated fatty acids and a decrease in unsaturated fatty acids were observed with the increase of the temperature. Variations of main fatty acids were in general erratic in the range of assayed saline concentrations. The variation of cyclopropane fatty acids could be expressed with mathematic equations that allowed to predict their percentage in relation to sodium chloride concentration.

Influencia de la concentración salina y la temperatura en la composición de ácidos grasos de membrana de Pseudomonas fluorescens GNP-OHP-3 / Influence of salinity and temperature on fatty acid composition of Pseudomonas fluorescens GNP-OHP-3 membrane

Las bacterias responden a los cambios ambientales modificando su composición, para evitar el daño que dichos cambios podrían ejercer. Una de las modificaciones más importantes es la variación de la composición de los ácidos grasos de las membranas celulares, que le permite mantener la homeoviscosidad ante situaciones de estrés. Trabajos previos han estudiado la acción de la temperatura, presión hidrostática y diferentes solventes sobre cepas de Pseudomonas putida. En este trabajo se estudió la acción conjunta de la temperatura y la salinidad sobre la composición de ácidos grasos de membranas celulares de Pseudomonas fluorescens GNP-OHP-3, una cepa bacteriana aislada de un hábitat contaminado con petróleo. Pseudomonas fluorescens GNP-OHP-3 respondió a las variaciones de temperatura modificando los ácidos grasos de sus membranas de manera similar a lo descripto en otros integrantes de su género: ante el aumento de temperatura se observó un incremento de ácidos grasos saturados y una disminución de los ácidos grasos insaturados. En el rango de concentraciones salinas ensayadas las variaciones de los ácidos grasos mayoritarios fueron en general erráticas. La respuesta de los ácidos grasos ciclo propano pudo expresarse con ecuaciones matemáticas que permitieron predecir el porcentaje de estos ácidos en relación a la concentración de cloruro de sodio.

The bacteria respond to environmental changes modifying their composition. One of the most important modifications is the variation on fatty acid composition of cellular membranes to maintain the homeoviscosity. The action of temperature, hydrostatic pressure and solvents on Pseudomonas putida has been thoroughly studied. In this paper, the combined action of the temperature and salinity on fatty acid composition of cellular membranes of Pseudomonas fluorescens GNP-OHP-3, a bacterial strain isolated from a petroleum contaminated habitat, was studied. The modifications in the fatty acid composition of Pseudomonas fluorescens GNP-OHP-3 membrane were similar to those described for other members of Pseudomonas: an increase in saturated fatty acids and a decrease in unsaturated fatty acids were observed with the increase of the temperature. Variations of main fatty acids were in general erratic in the range of assayed saline concentrations. The variation of cycle propane fatty acids could be expressed with mathematic equations that allowed to predict their percentage in relation to sodium chloride concentration.

Influencia de la concentración salina y la temperatura en la composición de acidos grasos de membrana de Pseudomonas fluorescens GNP-OHP-3. / [Influence of salinity and temperature on fatty acid composition of Pseudomonas fluorescens GNP-OHP-3 membrane]

The bacteria respond to environmental changes modifying their composition. One of the most important modifications is the variation on fatty acid composition of cellular membranes to maintain the homeoviscosity. The action of temperature, hydrostatic pressure and solvents on Pseudomonas putida has been thoroughly studied. In this paper, the combined action of the temperature and salinity on fatty acid composition of cellular membranes of Pseudomonas fluorescens GNP-OHP-3, a bacterial strain isolated from a petroleum contaminated habitat, was studied. The modifications in the fatty acid composition of Pseudomonas fluorescens GNP-OHP-3 membrane were similar to those described for other members of Pseudomonas: an increase in saturated fatty acids and a decrease in unsaturated fatty acids were observed with the increase of the temperature. Variations of main fatty acids were in general erratic in the range of assayed saline concentrations. The variation of cyclopropane fatty acids could be expressed with mathematic equations that allowed to predict their percentage in relation to sodium chloride concentration.

[Biodegradability of the components of natural hydrocarbon mixtures previously submitted to landfarming]. / Biodegradabilidad de componentes de mezclas naturales de hidrocarburos previamente sometidas a landfarming.

The complex composition of the crude oil and the hydrocarbons that integrate the waste of the different stages of the oil industry turn this product a mixture that presents different difficulties for its elimination by biological methods. The objective of this paper was to study the biodegradation potential of autochthonous bacterial communities on hydrocarbons obtained from four polluted places and subjected to landfarming biorremediation system during a decade. The results showed a marked difference in biodegradability of the three main fractions of crude oil, aliphatic, aromatic, and polar fractions, obtained by column chromatography. All fractions were used as carbon source and energy. There were variations in the production of biomass among the different fractions as well as in the kinetics of biodegradation, according to the composition of each fraction.

Biodegradabilidad de componentes de mezclas naturales de hidrocarburos previamente sometidas a landfarming / Components biodegradability of natural hydrocarbon mixtures previously subjected to landfarming

La compleja composición del petróleo crudo, derivados y deshechos de las diferentes etapas de la industria petrolera hacen de este producto una mezcla que presenta diferentes dificultades para su eliminación por métodos biológicos. El objetivo de este trabajo fue mostrar el potencial de biodegradación de comunidades bacterianas autóctonas frente a hidrocarburos obtenidos de cuatro sitios contaminados y sometidos a biorremediación, en un sistema de Landfarming por casi un década. Los resultados mostraron una marcada diferencia de biodegradabilidad de las tres principales fracciones alifáticas, aromáticas, y polares, obtenidas por cromatografía en columna. Si bien todas las fracciones fueron utilizadas como fuente de carbono y energía, existieron variaciones importantes en la producción de biomasa entre ellas, como asimismo en la cinética de biodegradación, según la composición de cada fracción.

Biodegradabilidad de componentes de mezclas naturales de hidrocarburos previamente sometidas a landfarming / Components biodegradability of natural hydrocarbon mixtures previously subjected to landfarming

La compleja composición del petróleo crudo, derivados y deshechos de las diferentes etapas de la industria petrolera hacen de este producto una mezcla que presenta diferentes dificultades para su eliminación por métodos biológicos. El objetivo de este trabajo fue mostrar el potencial de biodegradación de comunidades bacterianas autóctonas frente a hidrocarburos obtenidos de cuatro sitios contaminados y sometidos a biorremediación, en un sistema de Landfarming por casi un década. Los resultados mostraron una marcada diferencia de biodegradabilidad de las tres principales fracciones alifáticas, aromáticas, y polares, obtenidas por cromatografía en columna. Si bien todas las fracciones fueron utilizadas como fuente de carbono y energía, existieron variaciones importantes en la producción de biomasa entre ellas, como asimismo en la cinética de biodegradación, según la composición de cada fracción. (AU)

Biodegradabilidad de componentes de mezclas naturales de hidrocarburos previamente sometidas a landfarming. / [Biodegradability of the components of natural hydrocarbon mixtures previously submitted to landfarming]

The complex composition of the crude oil and the hydrocarbons that integrate the waste of the different stages of the oil industry turn this product a mixture that presents different difficulties for its elimination by biological methods. The objective of this paper was to study the biodegradation potential of autochthonous bacterial communities on hydrocarbons obtained from four polluted places and subjected to landfarming biorremediation system during a decade. The results showed a marked difference in biodegradability of the three main fractions of crude oil, aliphatic, aromatic, and polar fractions, obtained by column chromatography. All fractions were used as carbon source and energy. There were variations in the production of biomass among the different fractions as well as in the kinetics of biodegradation, according to the composition of each fraction.

[Analysis of aromatic hydrocarbon catabolic genes in strains isolated from soil in Patagonia]. / Análisis de genes catabólicos de hidrocarburos aromáticos en cepas aisladas de suelos de la Patagonia.

Seven strains belonging to genus Pseudomonas were isolated from an enrichment with hydrocarbon mixtures. Tests for enzyme activities showed that five strains used predominantly the catabolic meta-pathway for aromatic hydrocarbon degradation. Furthermore, the xylE gene which encodes a catechol 2,3-dioxygenase was amplified by PCR, and in two strains the nahAc gene, a key enzyme for naphthalene catabolism, was also found. The xylE gene might be a good marker to identify aromatic hydrocarbon degrading bacteria in soils from Patagonia.

Análisis de genes catabólicos de hidrocarburos aromáticos en cepas aisladas de suelos de la Patagonia / Analysis of aromatic hydrocarbon catabolic genes in strains isolated from soil in Patagonia

Seven strains belonging to genus Pseudomonas were isolated from an enrichment with hydrocarbon mixtures. Tests for enzyme activities showed that five strains used predominantly the catabolic meta-pathway for aromatic hydrocarbon degradation. Furthermore, the xylE gene which encodes a catechol 2,3-dioxygenase was amplified by PCR, and in two strains the nahAc gene, a key enzyme for naphthalene catabolism, was also found. The xylE gene might be a good marker to identify aromatic hydrocarbon degrading bacteria in soils from Patagonia.

Análisis de genes catabólicos de hidrocarburos aromáticos en cepas aisladas de suelos de la Patagonia / Analysis of aromatic hydrocarbon catabolic genes in strains isolated from soil in Patagonia

Seven strains belonging to genus Pseudomonas were isolated from an enrichment with hydrocarbon mixtures. Tests for enzyme activities showed that five strains used predominantly the catabolic meta-pathway for aromatic hydrocarbon degradation. Furthermore, the xylE gene which encodes a catechol 2,3-dioxygenase was amplified by PCR, and in two strains the nahAc gene, a key enzyme for naphthalene catabolism, was also found. The xylE gene might be a good marker to identify aromatic hydrocarbon degrading bacteria in soils from Patagonia.(AU)

Análisis de genes catabólicos de hidrocarburos aromáticos en cepas aisladas de suelos de la Patagonia. / [Analysis of aromatic hydrocarbon catabolic genes in strains isolated from soil in Patagonia]

Seven strains belonging to genus Pseudomonas were isolated from an enrichment with hydrocarbon mixtures. Tests for enzyme activities showed that five strains used predominantly the catabolic meta-pathway for aromatic hydrocarbon degradation. Furthermore, the xylE gene which encodes a catechol 2,3-dioxygenase was amplified by PCR, and in two strains the nahAc gene, a key enzyme for naphthalene catabolism, was also found. The xylE gene might be a good marker to identify aromatic hydrocarbon degrading bacteria in soils from Patagonia.

Biosynthesis of fatty acids and triacylglycerols by 2,6,10,14-tetramethyl pentadecane-grown cells of Nocardia globerula 432.

Nocardia globerula strain 432 was able to synthesize triacylglycerols (TAG) during cultivation on 2,6,10,14-tetramethyl pentadecane (pristane) under nitrogen-limiting conditions. Within these cells, 4,8,12-trimethyl tridecanoic acid was the major fatty acid detected. Fatty acids with an odd number of carbon atoms and minor amounts of even-numbered fatty acids were also observed. Experiments carried out with acrylic acid, an inhibitor of beta-oxidation, suggested that odd-numbered fatty acids such as C15:0, C17:0 and 10-methyl C17:0 were synthesized de novo using propionyl-CoA, the beta-oxidation product, as precursor. Although N. globerula 432 incorporated mainly straight chain fatty acids into TAG, the branched fatty acid 4,8,12-trimethyl tridecanoic acid also appeared, to some extent, in the acylglycerols. The importance of TAG biosynthesis by pristane-grown cells of N. globerula strain 432 is discussed.

[Microbiological controls and control points in a hake fillets manufacturing process for exportation]. / Controles microbiológicos y puntos de control en una planta elaboradora de filet de merluza para exportación.

Indicator and foodborne pathogen microorganisms in the "for export" hake fillets manufacturing were investigated in this study. Critical control points were identified and prevention activities and control were proposed during seafood elaboration process. 45 samples of hake from sequential processing operation stages, 15 ice samples and 12 water samples from utensil washing, were collected. The samples were analyzed for their content of aerobic mesophilic bacteria, psychrotrophic bacteria, enterobacteria, total and fecal coliform bacteria, Staphylococcus aureus and the presence of Escherichia coli, Salmonella and Shigella. The analysis of the samples collected from the factory revealed that the amounts of aerobic mesophile bacteria increased during manual filleting and packaging, in comparison with raw material. Psychrotrophic bacteria were the predominant microorganisms, specially in hake samples. In addition, high levels of enterobacteria, which do not occur normally in fish, were detected in raw hake samples. Staphylococcus aureus, Escherichia coli, Salmonella and Shigella, were not isolated from any samples in this study. The goal of this work is to establish microbiological risks in the hake fillets manufacturing process and, therefore to make possible corrective and control actions to assure the quality and safety of seafood.

[Contents of various nutrients, minerals and seasonal fluctuations in Porphyra columbina, an edible marine algae from the Argentine Patagonian++ coast]. / Contenido de algunos nutrientes, minerales y variaciones estacionales en Porphyra columbina, alga comestible de la Costa Patagónica argentina.

Porphyra columbina (Rodophyta Bangiales), one of the most important edible seaweeds, grows abundantly in the southern Argentine coast. Their mineral content and seasonal fluctuations were determined because there is no national data about their nutritional value. Samples were collected from April 1993 to February 1994 from Golfo San Jorge (30 Km South of Comodoro Rivadavia). Algae were washed with sea water and dried at room temperature (20-2 degrees C) for 24 hs, following the local processing procedure. Moisture and ashes were determined according to A.O.A.C. After mineralization with nitric acid sodium and potassium were determined by flame photometry; calcium, magnesium and iron by atomic absorption spectrophotometry (AAS); and phosphorus by Gomori's method. The results, expressed per 100 g dry algae showed the following values: moisture content: 7.03 to 11.00 g/100 g; ashes: 16.18 to 22.70 g/100 g; sodium: 3.18 to 6.41 g/100 g; potassium 1.24 to 1.96 g/100 g; magnesium: 600 to 836 mg/100 g; phosphorus: 78 to 276 mg/100 g; calcium: 63 to 108 mg/100 g and iron: 3.9 to 26.4 mg/100 g. The results of composition of algae as manufactured in the region showed important seasonal differences, with the highest values of ashes, sodium, potassium and magnesium in winter season (June and July).

[Taxonomic aspects of strains from Patagonia and type strains of Desulfovibrio]. / Aspectos taxonómicos de cepas patagónicas y cepas tipo del genero Desulfovibrio.

Fourteen type strains and 42 indigenous strains of Desulfovibrio were studied and taxonomic numeric methods were applied (Cluster Analysis, Principal Coordinates Analysis, Correspondence Analysis). The type strains as well as the indigenous ones share a low quantity of carbon and energy sources. Type strains have a taxonomic structure which shows net clusters; indigenous strains possess a grading (or "adjustment") in their positive reactions hence the taxonomic structure is not so clear. Both classifications are firm since they suffer minimal changes when they are joined.

Aspectos taxonómicos de cepas patagónicas y cepas tipo del genero Desulfovibrio / [Taxonomic aspects of strains from Patagonia and type strains of Desulfovibrio]

Fourteen type strains and 42 indigenous strains of Desulfovibrio were studied and taxonomic numeric methods were applied (Cluster Analysis, Principal Coordinates Analysis, Correspondence Analysis). The type strains as well as the indigenous ones share a low quantity of carbon and energy sources. Type strains have a taxonomic structure which shows net clusters; indigenous strains possess a grading (or [quot ]adjustment[quot ]) in their positive reactions hence the taxonomic structure is not so clear. Both classifications are firm since they suffer minimal changes when they are joined.

Aspectos taxonómicos de cepas patagónicas y cepas tipo del genero Desulfovibrio. / [Taxonomic aspects of strains from Patagonia and type strains of Desulfovibrio]

Fourteen type strains and 42 indigenous strains of Desulfovibrio were studied and taxonomic numeric methods were applied (Cluster Analysis, Principal Coordinates Analysis, Correspondence Analysis). The type strains as well as the indigenous ones share a low quantity of carbon and energy sources. Type strains have a taxonomic structure which shows net clusters; indigenous strains possess a grading (or [quot ]adjustment[quot ]) in their positive reactions hence the taxonomic structure is not so clear. Both classifications are firm since they suffer minimal changes when they are joined.

[Analysis of principal coordinates and factorial correspondence analysis applied to the taxonomy of type strains of Desulfovibrio]. / Análisis de coordenadas principales y análisis factorial de correspondencia aplicados a la taxonomía de cepas tipo del género Desulfovibrio.

Bacterial taxonomy using mathematical methods can be carried out with different techniques. Two techniques are used in this paper: analysis of principal coordinates and factor analysis of correspondences. The first one allows 2 and 3 dimension graphs of bacteria, thus showing their relationship considering proximity. The second one gives new data because it is an analysis which allows to connect bacteria to the reactions which identify them. In order to carry out these analyses 14 strains of the Desulfovibrio genus were studied, thus obtaining a classification consistent with other numeric method (group analysis with Simple Matching coefficient of average bond) to which it adds new information.