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The use of immobilized biomass for polycyclic aromatic hydrocarbon (PAH) removal from a liquid phase is a very promising technology. For this technology to be economically viable, the biomass production and immobilization should be as cost-effective as possible. The aim of this work was to produce a low-cost PAH removal system consisting of an immobilized biomass on different supports. A co-culture formed by two PAH-degrading bacteria (Pseudomonas monteilii P26 and Gordonia sp. H19, autochthonous Patagonian strains) was used. Industrial by-products such as sugar cane molasses, corn steep liquor, whey permeate and crude glycerol were used in combination to formulate different low-cost growth media. Naphthalene, phenanthrene and pyrene removal was evaluated using immobilized bacteria in polyurethane foam cubes, in sand and in calcium alginate beads. The growth of P. monteilii P26 and Gordonia sp. H19 was satisfactory in the different media assayed. The culture medium containing 1% corn steep liquor-2% molasses was selected for biomass production for subsequent immobilization. The removal of PAHs in different immobilization systems could be attributed to both the supports and the bacteria (up to 88.9% pyrene removal in 12 days); thus, immobilized cell systems for removing PAHs from an aqueous phase are proposed. Fil: Alessandrello, Mauricio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Planta Piloto de Procesos Industriales Microbiologicos; Argentina Fil: Juárez Tomás, María Silvina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Planta Piloto de Procesos Industriales Microbiologicos; Argentina Fil: Isaac, Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Planta Piloto de Procesos Industriales Microbiologicos; Argentina. Universidad Nacional de Tucumán; Argentina Fil: Vullo, Diana Lia. Universidad Nacional de General Sarmiento; Argentina Fil: Ferrero, Marcela Alejandra. Universidad Nacional de Tucumán; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Planta Piloto de Procesos Industriales Microbiologicos; Argentina

The ability of Trametes versicolor strain BAFC 2234 to degrade4-nitrophenol in vivo and in vitro was evaluated. T. versicolor grew inthe presence of 0.5 mM 4-nitrophenol and degraded 98.4% of this toxiccompound in less than 96 h. The strain secreted different ligninolyticoxidoreductases such as laccase, Mn-peroxidase and versatile peroxidase.Substantial conversion of nitrophenol, a typical high-redox potentialphenolic substrate, is reported for versatile peroxidase for the firsttime; 2,4-dinitrophenol and a dimer were identified as products. T.versicolor immobilized on natural sponge-like material from Luffaaegyptiaca removed 97% of 4-nitrophenol (1 mM) over a period of 72 h. 4-Nitrophenol phytotoxicity decreased noticeably after fungal treatment. Fil: Levin, Laura Noemi. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Micología y Botánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Micología y Botánica; Argentina Fil: Carabajal, Maira Lia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Micología y Botánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Micología y Botánica; Argentina Fil: Hofrichter, Martin. Technical University of Dresden; Alemania Fil: Ullrich, René. Technical University of Dresden; Alemania

Streptomyces strains isolated from pesticide-contaminated sediments of Santiago del Estero, Argentina were able to grow in the presence of 1.66 mg L−1 of methoxychlor (MTX). Streptomyces sp. A14 showed the best growth in the presence of MTX in culture medium at 30 °C and pH 7. When soil microcosms were contaminated with MTX and inoculated with Streptomyces sp. A14, a decrease in MTX was detected in both concentrations assayed (8.33and 16.60 mg kg−1). This actinobacterium was able to remove the pesticide, reaching its maximum removal percentages (40% and 76%) after 28 days of incubation. Methoxychlor was gradually converted into 1,1-dichloro-2,2-bis(4-methoxyphenyl)ethane, 1,1-dichloro-2,2-bis(4-methoxyphenyl)ethylene, 1-chloro-2,2-bis(4-methoxyphenyl)ethane, and 2,2-bis(4-hidroxyphenyl)acetonitrile, indicating that MTX is dominantly degraded by dechlorination, dehydrogenation and CN-replacement, resulting in the production of several major degradation products. This is an interesting proposal as an alternative method for soil cleanup. This is the first report of methoxychlor degradation using a native Streptomyces strain under aerobic conditions. Fil: Bourguignon, Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Planta Piloto de Procesos Industriales Microbiológicos (i); Argentina Fil: Fuentes, María Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Planta Piloto de Procesos Industriales Microbiológicos (i); Argentina Fil: Benimeli, Claudia Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán; Argentina. Universidad del Norte Santo Tomás de Aquino; Argentina Fil: Cuozzo, Sergio Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Planta Piloto de Procesos Industriales Microbiológicos (i); Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; Argentina Fil: Amoroso, Maria Julia del R.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Planta Piloto de Procesos Industriales Microbiológicos (i); Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentina. Universidad del Norte Santo Tomás de Aquino; Argentina

Pseudomonas putida A (ATCC 12633) capable of degrading trimethylamine (TMA) was immobilized in calcium alginate. The TMA-degrading capacity of immobilized cells was compared to free cells in batch culture by changing temperature, pH, nutrient supplementation, and initial TMA concentration. Although immobilized cells showed good removal efficiencies in wider ranges of temperature (15 °C–35 °C) and pH (6.5–8.5) than free cells, the optimal conditions for TMA removal for both free and immobilized cells were 30 °C, in buffered medium (pH 7.5) without addition of nutrients. Immobilized cells degraded up 885 mg l−1 of TMA completely whereas the free cells degraded only 295 mg l−1. For all the TMA concentrations evaluated with immobilized cells (295–885 mg l−1), after 24 h, the degradation rate started to decline. This effect was attributed to the accumulation of intracellular TMA into the cells (8.3–15.3 mg l−1) which is sufficient to inhibit the first enzyme of the aerobic degradation of TMA by P. putida, the TMA dehydrogenase. The fact that the immobilized cells showed a high stability as regards their viability and degradability of high TMA concentrations revealed a good potential of this system for treating of TMA-contaminated site. Fil: Liffourrena, Andres Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Biología Molecular; Argentina Fil: Lucchesi, Gloria Ines. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Biología Molecular; Argentina

A bacterial strain resistant to phenol and Cr (VI) was isolated from an industrial polluted soil of Córdoba province (Argentina), which was identified as Pantoea sp. FC 1. This microorganism was able to use phenol as sole carbon source. In addition it was capable of reducing Cr (VI) to Cr (III) in mineral and nutrient media. The isolated strain exhibited some properties as plant-growth promoting bacterium (PGPB), such as production of Indole Acetic Acid (IAA) and synthesis of siderophores, as well as being capable of solubilizing inorganic phosphates. A rhizoremediation system using the association Pantoea sp. FC 1-Brassica napus hairy roots (HRs) was tested for phenol and Cr (VI) removal in a hydroponic system. Microbial inoculation improved both phenol removal and chromium accumulation efficiency by HRs, showing a significant increase in Cr (III) accumulation compared to non-inoculated HRs, exceeding 1000 mg kg−1. Cr (III) was detected in HR biomass and supernatants, suggesting a possible Cr (VI) reducing activity of B. napus HRs. Basic studies in plant model systems, such as HRs, provide additional useful information that could facilitate the transition of this technology into plants suitable for practical rhizoremediation applications. Fil: Ontañon, Ornella Mailén. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Biología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina Fil: González, Paola Solange. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Biología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina Fil: Ambrosio, Laura Fernanda. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Biología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina Fil: Paisio, Cintia Elizabeth. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Biología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina Fil: Agostini, Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Biología Molecular; Argentina

Biostimulation and bioaugmentation have been proposed as sustainable alternatives to physicochemical treatments for the environmental decontamination of polycyclic aromatic hydrocarbons (PAH). PAH-removing Pseudomonas monteilii P26 and Gordonia sp. H19, alone or combined with organic and inorganic biostimulants, were previously proposed as candidates to be included in biotechnological products to be used in eco-friendly decontamination processes. This work aims to study the effect of biostimulants on the growth, cell hydrophobicity and emulsifying activity of P. monteilii P26 and Gordonia sp. H19, and to evaluate the influence of selected biostimulants and bacterial inoculation procedure on PAH bioremoval. A complete factorial experimental design was applied to determine the effect of KNO3, K2HPO4, corn steep liquor (CSL) and a PAH mixture on the growth, cell hydrophobicity and bioemulsifying activity of bacterial cultures. The kinetics of PAH bioremoval was evaluated in simultaneous and sequential cultures of P. monteilii P26 and Gordonia sp. H19 in the presence of selected biostimulants. CSL was the only nutrient that exerted positive effects on all responses evaluated, although these effects were not significant in all cases. In mixed cultures, maximum bioremoval of phenanthrene and pyrene was evidenced when the bacterial strains were simultaneously inoculated, independently of the presence or absence of CSL. These results support the biotechnological characterization of two PAH-removing autochthonous Patagonian strains. Fil: Juárez Tomás, María Silvina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Carrasco, Marina Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina. Universidad Nacional de Tucumán; Argentina Fil: Lobo, Constanza Belén. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Alessandrello, Mauricio Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Sanchez, Leandro Arturo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Ferrero, Marcela Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina. Universidad Nacional de Tucumán; Argentina

Chlorpyrifos (CP) is a widely used agricultural insecticide that is hazardous to both the environment and human health. Therefore, it is an essential to develop approaches to remove this compound from contaminated soils, water and sediments. In this study, actinobacteria were isolated from an agricultural soil that had received continuous applications of CP. Four strains were selected as a result of their tolerance to 50 mg L -1 of CP in agar plate and they were identified as Streptomyces sp. based on 16S rDNA. According to relationship of CP degradation and microbial growth studies, two isolates were selected and were named Streptomyces sp. strain AC5 and Streptomyces sp. strain AC7. The strains were cultivated in liquid medium with CP at concentrations of 25 mg L -1 and 50 mg L -1 for 72 h. The results indicated that both strains were able to rapidly degrade CP with about 90% degradation after 24 h of incubation. A different pattern of CP degradation was observed when its main metabolite, 3,5,6-trichloro-2-pyridinol (TCP) was monitored. A maximum concentration of 0.46 mg L -1 of TCP was produced by Streptomyces sp. strain AC5 and its concentration decreased as a function of time. In contrast, TCP production by Streptomyces sp. AC7 increased over time from 1.31 mg L -1 to 4.32 mg L -1. CP degradation was associated to microbial growth of the strains, pH modification, glucose consumption and organic acids excretion in the liquid medium. This work constitutes one of the few reports of Streptomyces as CP-degraders. Given the high CP degradation observed here, the Streptomycetes strains show a good potential as CP-degrading actinobacteria. Fil: Briceño, G.. Universidad de la Frontera; Chile Fil: Fuentes, María Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Planta Piloto de Procesos Industriales Microbiologicos; Argentina Fil: Palma, G.. Universidad de la Frontera; Chile Fil: Jorquera, M. A.. Universidad de la Frontera; Chile Fil: Amoroso, Maria Julia del R.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Planta Piloto de Procesos Industriales Microbiologicos; Argentina Fil: Diez, M. C.. Universidad de la Frontera; Chile

The organochlorine pesticide (OP) lindane was removed from minimal medium (MM) by two Streptomyces native strains, while growing on maize root exudates (REs) as a primary carbon and energy source. REs supported 55 and 35% of lindane removal by Streptomyces sp. strains A5 and M7, respectively, corroborating the hypothesis that co-metabolism may be a plant/microbe interaction important to bioremediation. In addition, residual lindane concentration was more than half of the amount in MM supplemented with glucose compared to MM supplemented with REs, suggesting that exudates could be more appropriate carbon source to support aerobic dehalogenation of the pesticide. Lindane-degrading activity was detected in REs, which could explain 42% of lindane removal in REs-lindane assay, without microorganisms. Because Streptomyces sp. A5 showed maximum biomass and the highest pesticide removal in REs-lindane assay, it was found to be the most promising strain regarding their future application. These results showed that phytostimulation of OP-degrading actinobacteria by maize REs are therefore likely to be a successful strategy for the remediation of lindane-contaminated environments. Fil: Alvarez, Analia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; Argentina Fil: Yañez, M. L.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentina Fil: Benimeli, Claudia Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina. Universidad del Norte Santo Tomás de Aquino; Argentina Fil: Amoroso, Maria Julia del R.. Universidad del Norte Santo Tomás de Aquino. Facultad de Ciencias de la Salud; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentina

The dynamics of the microbial community structure of a full-scale upflow anaerobic sludge blanket reactor has been analyzed using culture-independent 16S rRNA-based methods. During the start-up of the process, denaturing gradient gel electrophoresis of bacterial rDNA showed significant changes in the structure of the bacterial community, but only a slight increase in the bacterial diversity. Associated with the shifts in bacterial populations, significant changes in the relative abundance of different methanogenic species are revealed by taxon-specific dot-blot experiments. The ratio of archaeal 16S rRNA to bacterial 16S rRNA, but none of the individual microbial taxons, correlated with the maximum allowable daily organic loading rate. The results argue against the notion that many anaerobic wastewater treatment systems fail due to the lack of adequate inoculum. Fil: Casserly, Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina Fil: Erijman, Leonardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina