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Although the use of agrochemicals allowed increasing the crops productivity, in many cases led to soil deterioration. In this study, eight composite samples from different soils of two locations (San Martín and Anta) in Salta, Argentina, were collected and analyzed. All the samples were from loamy Entisols (0–20 cm depth) under reduced tillage without and with direct spray application of glyphosate. Twenty six variables were determined (physical, chemical, and biological soil quality indicators). From them, those of higher specificity and sensitivity to changes following glyphosate application were identified by a stepwise reduction of variables aided by statistical analysis. Samples were grouped regarding location and application of glyphosate, to identify differential effects upon variables, and glyphosate sensitive variables were selected by discarding those influenced by other factors. Thence, they were used to compose a first approximation to a combined soil quality indicator (CSQI) to assess the effect of glyphosate use in agriculture upon the soil. Overall, the set of physical variables showed the same discriminating structure as the biological set. Finally, two biological, two chemical, and two physical indicators resulted as the most specific to quality variations by the application of the herbicide, being the most sensitive the microbial biomass carbon and the (Aminomethyl)phosphonic acid concentration in soil. When these two were considered into a CSQI, it was possible to discriminate samples with the application of glyphosate (lower quality) from those without application (higher quality). To the best of our knowledge, this is the first attempt to propose a CSQI that could play an important role to prevent degradation in soils subjected to glyphosate application, as it could aid in the early detection of soil quality loss. This would provide to land managers a decision tool to let the land rest from glyphosate application, to ensure sustainable practices in agriculture. Fil: Romano Armada, Neli. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; Argentina. Universidad Nacional de Salta. Facultad de Ingeniería; Argentina Fil: Amoroso, Maria Julia del R.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Rajal, Verónica Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; Argentina. Universidad Nacional de Salta. Facultad de Ingeniería; Argentina. Nanyang Technological University.; Singapur

Actinobacteria exhibit cosmopolitan distribution since their members are widely distributed in aquatic and terrestrial ecosystems. In the environment they play relevant ecological roles including recycling of substances, degradation of complex polymers, and production of bioactive molecules. Biotechnological potential of actinobacteria in the environment was demonstrated by their ability to remove organic and inorganic pollutants. This ability is the reason why actinobacteria have received special attention as candidates for bioremediation, which has gained importance because of the widespread release of contaminants into the environment. Among organic contaminants, pesticides are widely used for pest control, although the negative impact of these chemicals in the environmental balance is increasingly becoming apparent. Similarly, the extensive application of heavy metals in industrial processes lead to highly contaminated areas worldwide. Several studies focused in the use of actinobacteria for cleaning up the environment were performed in the last 15 years. Strategies such as bioaugmentation, biostimulation, cell immobilization, production of biosurfactants, design of defined mixed cultures and the use of plant-microbe systems were developed to enhance the capabilities of actinobacteria in bioremediation. In this review, we compiled and discussed works focused in the study of different bioremediation strategies using actinobacteria and how they contributed to the improvement of the already existing strategies. In addition, we discuss the importance of omic studies to elucidate mechanisms and regulations that bacteria use to cope with pollutant toxicity, since they are still little known in actinobacteria. A brief account of sources and harmful effects of pesticides and heavy metals is also given. 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: Sáez, Juliana María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Dávila Costa, José Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Colin, Veronica Leticia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Fuentes, María Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Cuozzo, Sergio Antonio. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Benimeli, Claudia Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Polti, Marta Alejandra. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Amoroso, Maria Julia del R.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina

Vinasse is a complex effluent created during production of ethyl alcohol, which can present serious pollution hazard in areas where it is discharged. A variety of technologies, many based upon recovery of the effluent via microbial pathways, are continually being evaluated in order to mitigate the pollution potential of vinasse. The present work reports on initial advances related to the effectiveness of the actinobacterium Streptomyces sp. MC1 for vinasse treatment. Alternative use of raw vinasse as a substrate for producing metabolites of biotechnological interest such as bioemulsifiers, was also evaluated. The strain was able to grow at very high vinasse concentrations (until 50% v/v) and remove over 50% of the biodegradable organic matter in a time period as short as 4 d. Potentially toxic metals such as Mn, Fe, Zn, As, and Pb were also effectively removed during bacterial growth. Decrease in the pollution potential of treated vinasse compared to raw effluent, was reflected in a significant increase in the vigour index of Lactuca sativa (letucce) used as bioremediation indicator. Finally, significant bioemulsifier productionwas detected when this strain was incubated in a vinasse-based culture medium. These results represent the first advances on the recovery and re-valuation of an actual effluent, by using an actinobacterium from our collection of cultures. Fil: Colin, Veronica Leticia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Planta Piloto de Procesos Industriales Microbiologicos; Argentina. Universidad San Pablo Tucumán; Argentina Fil: Juarez Cortes, Alvaro Agustin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Planta Piloto de Procesos Industriales Microbiologicos; Argentina Fil: Aparicio, Juan Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Planta Piloto de Procesos Industriales Microbiologicos; Argentina 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. Universidad del Norte Santo Tomás de Aquino; Argentina. Universidad Nacional de Tucumán; Argentina

Chlordane bioremediation using actinobacteria mixed culture is an attractive clean-up technique. Their ability to produce bioemulsifiers could increase the bioavailability of this pesticide. In order to select a defined actinobacteria mixed culture for chlordane remediation, compatibility assays were performed among six Streptomyces strains. The strains did not show growth inhibition, and they were assayed for chlordane removal, either as pure or as mixed cultures. In pure cultures, all of the strains showed specific dechlorination activity (1.42-24.20 EU mg(-1)) and chlordane removal abilities (91.3-95.5%). The specific dechlorination activity was mainly improved with cultures of three or four microorganisms. The mixed culture consisting of Streptomyces sp. A2-A5-A13 was selected. Their ability to produce bioemulsifiers in the presence of glucose or chlordane was tested, but no significant differences were observed (p > 0.05). However, the stability of the emulsions formed was linked to the carbon source used. Only in chlordane presence the emulsions retained 100% of their initial height. Finally, the selected consortium showed a high degree of sporulation in the pesticide presence. This is the first study on the effects that chlordane exerts on microbe morphology and emulsifier production for a defined mixed culture of Streptomyces with ability to remediate the pesticide.

Post-harvest sugarcane residue (SCR), deposited on sugarcane fields after green harvesting, could serveas a substrate for fungal biomass and lignocellulolytic enzymes production. In the present study, themycelial growth of six strains (Trametes sp. YeH11, Bjerkandera sp. Y-HHM2, Phanerochaete sp. Y-RN1,Pleurotus sp. Y-RN3, Myrothecium sp. S-3.20 and Hypocrea nigricans SCT-4.4) was measured in-vitro byapplying a modified Gompertz equation. In-vitro assays showed shorter lag phases for fungi in modifiedCzapek, 0.3% and 1.0% molasses amended post-harvest SCR. Further increments in molasses concentrationsproduced a reduction on the specific growth rates for all tested fungi. Fungal degradation ofpost-harvest SCR and the concomitant enzyme production were tested under solid-state fermentation(SSF) of Czapek or molasses amended post-harvest SCR. Under SSF, Pleurotus sp. Y-RN3 produced thehighest laccase titers but no hydrolytic activity could be detected. Trametes sp. YeH11 and Myrotheciumsp. S-3.20 showed high endoglucanase activities. Endoxylanase production was detected exclusively inCzapek amended media. These findings have implications for the fungal treatment of post-harvest SCRand its potential impact on the use of these residues in the production of biofuels and ligninolyticenzymes. Fil: Maza, Marianela. Universidad Nacional de Tucuman. Facultad de Agronomia y Zootecnia. Sanidad Vegetal. Cátedra Fitopatologia; Argentina Fil: Pajot, Hipolito Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Planta Piloto de Procesos Industriales Microbiologicos; Argentina 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. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentina Fil: Yasem, Marta Graciela. Universidad Nacional de Tucuman. Facultad de Agronomia y Zootecnia. Sanidad Vegetal. Cátedra Fitopatologia; Argentina

The Northwest of Argentina has an important concentration of alcohol distilleries that generate large volumes of vinasse as final liquid residue of the process. Vinasse may have high concentrations of heavy metals and other toxins, which could enhance its toxicity if is not subjected to the conditioning treatments before their disposal into the environments. Many of the conventional methods for the removal of heavy metals from industrial wastes are not economic neither environmental friendly; thereby new alternatives based upon vinasse recovery by microbial action, are being evaluated. The actinobacterium Streptomyces sp. MC1 has been widely recognized for its ability to remove heavy metals from artificially contaminated systems. Their mycelia growth and ability to colonize substrates make it a suitable bioremediation agent. The current chapter reviewed the environmental impact of heavy metals from vinasse as well as the potential of this actinobacterium to remove them. First advances on the toxicity of the vinasse subjected to the strain action were also reviewed using Lactuca sativa seeds as bioremediation indicator. Fil: Colin, Veronica Leticia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Rulli, Macarena María. 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: del Gobbo, Luciana Melisa. 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: Amoroso, Maria Julia del R.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina

The replacement of synthetic surface-active compounds (SACs) by their microbial counterparts is carving out a niche for themselves in the field of bioremediation. However, the high cost of microbial products has limited their application at a realistic scale. In the current study, several hydrocarbon-degrading microorganisms were assayed as potential SAC producers in low-cost liquid media. Only the strain CC10, placed within the class Actinobacteria, was able to produce emulsifying molecules by using a combination of sugarcane vinasse or crude glycerol (as cheap carbon substrates) with urea or peptone (as nitrogen sources). The emulsifying activity of the supernatants and the stability of emulsions formed with motor oil depended on the carbon and nitrogen sources. However, the biodegradability of these metabolites was only associated with the carbon substrate, and it was always higher than the two tested synthetic surfactants, sodium dodecyl sulfate and Triton X-100. Also, a positive linear association between emulsifying and lipase activities of the CC10 supernatants was detected (r = 0.781; p = 0.219), with the maximum activities detected in the glycerol-peptone supernatant. Interestingly, this supernatant was able to emulsify different oily substrates, a property that could be used to increase the efficiency of the treatment of effluents with high fat content.

Agriculture is a primary source of income in several countries, including Argentina. Among the many agrochemicals used, glyphosate-based herbicides raised controversy, encouraging research to clarify if the benefits of their use outweigh their alleged harmfulness. In this spirit, this study assessed soil quality indicators on glyphosate-sprayed fields under natural (NC) and zero tillage conditions (ZT) in Northwest Argentina, to analyze the effect of the herbicide application on soil degradation. The ZT soils underwent five years of continuous spraying (2-4 times a year) after land clearing, while the NC soil, without any laboring practices, was subjected to two consecutive applications. Among the measured indicators (physical, chemical, and biological), water-stable aggregates (WSA), particulate organic matter (POM) and dehydrogenase activity (DHA) showed quality differences between ZT and NC samples. The highest values were found in NC (WSA 72%; POM 4.9%; DHA 1460 mg TPF/gsoil/d) and the lowest in ZT (WSA 13%; POM 1.69%; DHA 180 mg TPF/gsoil/d); showing a lower quality in ZT regarding structure stability, nutrient availability and microbial activity. A Discriminant Analysis revealed that as glyphosate application increased, the overall soil quality decreased within the NC samples, resembling that of ZT. Thus, soil health deterioration was attributed solely to glyphosate spraying in NC. Furthermore, multivariate analysis allowed identification of chemical indicators as of higher sensitivity to the short-term response after application, and biological indicators as more sensitive to long-term changes. The quality decline in time in the NC soil, caused by the use of glyphosate-based herbicides, could endanger the soils sustainability. Fil: Romano Armada, Neli. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; Argentina. Universidad Nacional de Salta. Facultad de Ingenieria; Argentina Fil: Amoroso, Maria Julia del R.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Rajal, Verónica Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; Argentina. Universidad Nacional de Salta. Facultad de Ingenieria; Argentina

Boron is widespread in the environment. Although contaminated soils are hard to recover different strategies have been investigated in the recent years. Bioremediation is one of the most studied because it is eco-friendly and less costly than other techniques. The aim of this research was to evaluate whether two Streptomyces strains isolated from boron contaminated soils in Salta, Argentina, may help remove boron from such soils. For this, they were grown in different liquid media with two boric acid concentrations and their specific growth rate and specific boric acid consumption rate were determined. Both strains showed great capacity to remove boron from the media. Increasing boric acid concentrations affected negatively the specific growth rate, however the specific boric acid consumption rate was superior. Boron bio-precipitates were observed when the strains grew in the presence of boric acid, probably due to an adaptive response developed by the cells to the exposure, for which many proteins were differentially synthetized. This strategy to tolerate high concentrations of boron by immobilizing it in bio-precipitates has not been previously described, to the best of our knowledge, and may have a great potential application in remediating soils contaminated with boron compounds. Fil: Moraga, Norma Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; Argentina Fil: Irazusta, Verónica Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; Argentina Fil: Amoroso, Maria Julia del R.. 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: Rajal, Verónica Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; Argentina. Nanyang Technological University; Singapur

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

Fil: Bourguignon, Natalia. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Tucuman. Planta Piloto de Procesos Industriales Microbiologicos (i); Argentina

Fil: Briceno, Gabriela. Universidad de la Frontera. Nucleo Cientifico y Tecnologico en Recursos Naturales; Chile

tIn recent years, increasing interest has been shown in the use of bioemulsifiers as washing agents thatcan enhance desorption of soil-bound metals. However, high production costs derived from the useof expensive substrates for formulation of the fermentation media represent the main challenge forfull, large-scale implementation of bioemulsifiers. This work reports on a first study of bioemulsifierproduction by the actinobacterium Amycolatopsis tucumanensis DSM 45259 using different carbon andnitrogen sources. Preliminary results on the potential use of these compounds as washing agents for soilscontaminated with Cu(II) and Cr(VI) are also presented. The best specific production was detected usingglycerol and urea as carbon and nitrogen substrates, respectively. However, with all of the substratesused during the batch assay, the bioemulsifiers showed high levels of stability at extreme conditions ofpH, temperature, and salt concentration. Under the current assay conditions, the bioemulsifiers werenot effective in removing Cu(II) from soil. However, they were able to mediate Cr(VI) recovery, with theremoval percentage doubled compared to that seen when using deionized water. These findings appearpromising for the development of remediation technologies for hexavalent chromium compounds basedupon direct use of these microbial emulsifiers. Fil: Colin, Veronica Leticia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET- Tucumán. Planta Piloto de Procesos Industriales Microbiológicos (i); Argentina; Universidad San Pablo Tucumán; Argentina; Fil: Castro, María Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET- Tucumán. Planta Piloto de Procesos Industriales Microbiológicos (i); Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Química de San Luis; Argentina; Fil: Amoroso, Maria Julia del R.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET- Tucumán. Planta Piloto de Procesos Industriales Microbiológicos (i); Argentina; Universidad del Norte Santo Tomás de Aquino; Argentina; Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentina; Fil: Villegas, Liliana Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET- Tucumán. Planta Piloto de Procesos Industriales Microbiológicos (i); Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Química de San Luis; Argentina; Universidad del Norte Santo Tomás de Aquino; Argentina

The Salta Province – in the northwest of Argentina – is the main worldwide producer of hydroboracite and leads in exports of boron mineral and its derivatives in Latin America. In addition to the natural presence of boron compounds in the soils, there are others contaminated due to the boron mining industry. Although some bacteria are known to require boron for their growth or to be capable of storing boron, no studies have been published about Streptomyces or Lentzea genera's capacity to tolerate high boron concentrations, or about their metabolic capacities in boron contaminated environments. The results of this research show the isolation and molecular characterization of eight strains belonging to the actinobacteria phylum collected from different soils contaminated with high boron concentration in Salta state. The boron tolerance assays, which show that three of the strains were able to tolerate up 60–80 mM boron, demonstrate the potential capability of this group of bacteria to grow and maybe to remove boron from the environment. They appear to be promising, considering that these microorganisms are infrequent pathogens, are metabolically versatile and many Streptomyces can synthesize boron containing metabolites.

Pesticides are normally used to control specific pests and to increase the productivity in crops; as a result, soils are contaminated with mixtures of pesticides. In this work, the ability of Streptomyces strains (either as pure or mixed cultures) to remove pentachlorophenol and chlorpyrifos was studied. The antagonism among the strains and their tolerance to the toxic mixture was evaluated. Results revealed that the strains did not have any antagonistic effects and showed tolerance against the pesticides mixture. In fact, the growth of mixed cultures was significantly higher than in pure cultures. Moreover, a pure culture (Streptomyces sp. A5) and a quadruple culture had the highest pentachlorophenol removal percentages (10.6% and 10.1%, resp.),while Streptomyces sp.M7 presented the best chlorpyrifos removal (99.2%).Mixed culture of all Streptomyces spp. when assayed either as free or immobilized cells showed chlorpyrifos removal percentages of 40.17% and 71.05%, respectively, and for pentachlorophenol 5.24% and 14.72%, respectively, suggesting better removal of both pesticides by using immobilized cells. These results reveal that environments contaminated with mixtures of xenobiotics could be successfully cleaned up by using either free or immobilized cultures of Streptomyces, through in situ or ex situ remediation techniques. Fil: Fuentes, María Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos (i); Argentina; Fil: Briceño, Gabriela E.. Universidad de la Frontera; Chile; Fil: Sáez, Juliana María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos (i); Argentina; Fil: Benimeli, Claudia Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Tucumán. Unidad de Administración Territorial; Argentina; Universidad del Norte Santo Tomás de Aquino; Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos (i); Argentina; Fil: Diez, Maria Cecilia. Universidad de la Frontera; Chile; Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Tucumán. Unidad de Administración Territorial; Argentina; Fil: Amoroso, Maria Julia del R.. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos (i); Argentina; Universidad del Norte Santo Tomás de Aquino; Argentina

Surface-active compounds such as synthetic emulsifiers have been used for several decades, both for the degradation of hydrocarbons and increasing desorption of soil-bound metals. However, due to their high toxicity, low degradability, and production costs unaffordable for use in larger ecosystems, synthetic emulsifiers have been gradually replaced by those derived from natural sources such as plants or microbes. In previous studies, the bacterium Streptomyces sp. MC1 has shown the ability to reduce and/or accumulate Cr(VI), a highly promising advance in the development of methods for environmental clean-up of sites contaminated with chromium. Here, new studies on the production of emulsifier from this strain are presented. The cultivation factors that have a significant influence on emulsifier biosynthesis, as well as the interactions among them, were studied by factorial design. Based upon optimization studies, maximum bioemulsifier production was detected in the culture medium having an initial pH of 8 with phosphate 2.0 g L(-1) and Ca(+2) 1.0 g L(-1) added, with an emulsification index about 3.5 times greater compared to the basal value. Interestingly, in the presence of 5.0 g L(-1) Cr(VI), Streptomyces sp. MC1 retained about 65% of its emulsifier production ability. Partially purified emulsifier presented high thermo-stability and partial water solubility. These findings could have promising future prospects for the remediation of organic- and metal-contaminated sites.

Lindane is a cyclic, saturated and highly chlorinated pesticide with a broad spectrum, which has been used worldwide for many decades to control a variety of pests, and also in human health and veterinary. Afterward, it has been demonstrated that lindane and its isomers may cause serious damage to health in the short and long term. Besides, lindane is known to be persistent in the environment and tends to bioaccumulate along the food chain. Thus, lindane residues remain in the environment for a long time and have been recently found in water, soil, sediments, plants, and animals all over the world, and even in human fluids and tissues. In this context, nowadays, scientists, working all over the world, are involved in developing lindane remediation technologies including physical, chemical, and biological techniques. This article provides updated information on the biologic degradation of lindane using different microorganisms such as bacteria, fungi, and algae, under both aerobic and anaerobic conditions.

In the last few decades, highly toxic organic compounds like the organochlorine pesticide (OP) hexachlorocyclohexane (HCH) have been released into the environment. All HCH isomers are acutely toxic to mammals. Although nowadays its use is restricted or completely banned in most countries, it continues posing serious environmental and health concerns. Since HCH toxicity is well known, it is imperative to develop methods to remove it from the environment. Bioremediation technologies, which use microorganisms and/or plants to degrade toxic contaminants, have become the focus of interest. Microorganisms play a significant role in the transformation and degradation of xenobiotic compounds. Many Gram-negative bacteria have been reported to have metabolic abilities to attack HCH. For instance, several Sphingomonas strains have been reported to degrade the pesticide. On the other hand, among Gram-positive microorganisms, actinobacteria have a great potential for biodegradation of organic and inorganic toxic compounds. This review compiles and updates the information available on bacterial removal of HCH, particularly by Streptomyces strains, a prolific genus of actinobacteria. A brief account on the persistence and deleterious effects of these pollutant chemical is also given.

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

In order to understand the mechanism involved in Rhodotorula mucilaginosa RCL-11 resistance to copper a proteomic study was conducted. Atomic absorption spectroscopy showed that the copper concentration in the medium decreased from 0.5 to 0.19 mM 48 h after inoculation of the yeast. Analysis of one-dimensional gel electrophoresis of crude cell extracts revealed expression of differential bands between cells with and without copper. In order to study this difference, two-dimensional electrophoresis of R. mucilaginosa RCL-11 exposed to Cu for 16, 24, and 48 h was carried out. Identification of differentially expressed proteins was performed by MALDI-TOF/TOF. Ten of the 16 spots identified belonged to heat shock proteins. Superoxide dismutase, methionine synthase and beta-glucosidase were also found over-expressed at high copper concentrations. The results obtained in the present work show that when R. mucilaginosa RCL-11 is exposed to 0.5 mM copper, differential proteins, involved in cell resistance mechanisms, are expressed. Fil: Irazusta, Verónica Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Planta Piloto de Procesos Industriales Microbiologicos; Argentina Fil: Estévez, Maria Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Planta Piloto de Procesos Industriales Microbiologicos; Argentina 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: Castellanos, Lucia Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Planta Piloto de Procesos Industriales Microbiologicos; Argentina

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

Four actinobacteria strains isolated from pesticide-contaminated soil were able to grow in the presence of 16.6 mg L−1 chlordane, an organochlorine pesticide. The strain that showed best growth after 96 h of incubation in synthetic medium with chlordane as the sole carbon source was identified as Streptomyces sp. A5. When Streptomyces sp. A5 was cultured in the presence of chlordane, the pesticide was degraded from the culture medium after 24 h of incubation. In soil assays, a reduction of 56% in γ-chlordane was observed after 28 days of incubation. This is the first report about chlordane degradation under aerobic conditions by a Streptomyces strain.

The aim of this work was to evaluate a strategy to reduce the bioavailable chromium fraction in soil, using a Cr(VI) resistant microorganism, Streptomyces sp. MC1, under non sterile conditions, with maize plants as bioindicator and/or bioremediator. Soil samples were contaminated with 100, 200 and 400 mg kg−1 of Cr(VI) or Cr(III). Bioavailable chromium (35%) was only detected in samples with Cr(VI). Soil samples with Cr(VI) 200 mg kg−1 were inoculated with Streptomyces sp. MC1, and bioavailable chromium decreased up to 73%. Zea mays seedlings were planted in soil samples contaminated with chromium. Plantlets accumulated chromium mainly as Cr(III), and biomass decreased up to 88%. Streptomyces sp. MC1 was inoculated in soil samples contaminated with 200 mg kg−1 of Cr(VI) and Z. mays seedlings were planted. Streptomyces sp. MC1 caused Z. mays biomass increase (57%), chromium accumulation and bioavailable chromium decreased up to 46% and 96%, respectively. This work constitutes the first contribution of cooperative action between actinobacteria and Z. mays in the bioremediation of Cr(VI) contaminated soil. The large removal capacity of bioavailable chromium by Streptomyces sp. MC1 and Z. mays infers that they could be successfully applied together in bioremediation of soils contaminated with Cr(VI).

The current study aimed to compare lindane degradation by pure and mixed cultures of Streptomyces sp. Cell-free extracts were assayed for potentiating dechlorinase activity and, based on these results, consortia of two to six microorganisms were assayed for their growth on and degradation of lindane. Furthermore, the role of bacterial consortia of lindane-degrading strains was examined in lindane decontamination soil assays. Four actinobacteria, previously isolated from a pesticide-contaminated area, were selected because of their tolerance to lindane and their ability to use the pesticide as sole carbon source. These strains as well as Streptomyces sp. M7 and Streptomyces coelicolor A3 were used to study specific dechlorinase activity (SDA) and lindane removal in mixed cultures. Pure cultures presented SDA in the presence of 1.66 mg L-1 lindane as carbon source. SDA was improved by certain mixed cultures until 12 times compared with pure cultures. Mixed cultures with two, three, and four strains showed maximum lindane removal of 46% to 68%, whereas combinations of five and six strains did not efficiently remove the pesticide from the culture medium. The Streptomyces sp. A2, A5, M7, and A11 consortium presented the lowest ratio between residual lindane concentration and SDA and could be a promising tool for lindane biodegradation.

Organochlorine pesticides are notorious, due to their high toxicity, persistence in the environment and their tendency to bioaccumulate. Their extensive use in the northwest of Argentina has left residues in the environment. Microbial degradation is an important process for pesticide bioremediation and actinomycetes have a great potential for that. The current study examined organochlorine pesticides in contaminated soil. Indigenous actinomycetes were isolated from contaminated samples to evaluate bacterial growth as well as pesticide removal and release of chloride ions as a result of degradation. Most of the isolated microorganisms belonged to the Streptomyces genus, except one, which belonged to Micromonospora. Bacterial growth depended on the microorganism and the pesticide present (chlordane, lindane or methoxychlor). Highest growth and pesticide removal were observed with chlordane. Twelve out of 18 studied strains released chloride into culture supernatants, and percentages were higher with chlordane as carbon source than with lindane or methoxychlor. These results are supported by principal component analysis. This is the first report about actinomycetes isolated from an illegal storage of organochlorine pesticide in Argentina with capacity to growth, remove and use different organochlorine pesticide.

A novel actinomycete strain, ABOT, isolated from copper-polluted sediments showed remarkable copper resistance as well as high bioaccumulation abilities. Classical taxonomic methods, including chemotaxonomy and molecular techniques, were used to characterize the isolate. Strain ABOT developed a honey-yellow substrate mycelium on all ISP media tested. Abundant, white, aerial mycelium was only formed on ISP 2, 5 and 7 and MM agar. Both types of hyphae fragmented into squarish rod-shaped elements. The aerial mycelium displayed spore-like structures with smooth surfaces in long, straight to flexuous chains. The organism has a type-IV cell wall lacking mycolic acids and type-A whole-cell sugar pattern (meso-diaminopimelic acid, arabinose and galactose) in addition to a phospholipid type-II profile. 16S rRNA gene sequence studies indicated that this organism is a member of the family Pseudonocardiaceae and that it forms a monophyletic clade with Amycolatopsis eurytherma NT202T. The DNA–DNA relatedness of strain ABOT to A. eurytherma DSM 44348T was 39.5 %. It is evident from these genotypic and phenotypic data that strain ABOT represents a novel species in the genus Amycolatopsis, for which the name proposed is Amycolatopsis tucumanensis sp. nov. The type strain is ABOT (=DSM 45259T =LMG 24814T).

In the present study, the growth and the Cu2+accumulation by roots, shoots and leaves of Zea mays were examined using copper sulphate in the range of 10−4 to 10−2 M. Plants of Z. mays did not show inhibition of growth in the presence of 10−4 to 10−2 M Cu2+; however, it was observed growth effects on root when different Cu2+ solution concentrations were used. Only the seedlings exposed to 10−2 M exhibited substantial root growth reduction, yielding only 56% of length with respect to the control. Seedlings exposed to 10−4 M Cu2+ exhibited 16% and 42% growth increase in shoots and leaves, respectively, when compared with the controls. The seedlings treated with 10−3 and 10−2 M Cu2+ were inhibited in shoot and leaf growth. The fresh weights in roots, shoots and leaves significantly decreased at 10−2 M Cu2+. The tolerance index, based on root length, was not significantly different for the three different treatments with copper. However, the total accumulation rate was very low at 10−4 and 10−3 M compared to 10−2 Cu treatments. The capacity of copper accumulation by roots, shoots and leaves of Z. mays plants increased concomitant to the copper concentration, arriving to 382 times more in roots, 157 in shoots and only 16 in leaves, all compared to the controls. Cu could be accumulated by roots, shoots and leaves when the initial concentrations were 10−3 and 10−4 M. However, when it was 10−2 M, the metal could not be accumulated by leaf and shoot levels; the roots could increase their copper accumulation capacity three times compared to the control. Z. mays has potential ability to accumulate Cu without being overly sensitive to Cu toxicity. Fil: Benimeli, Claudia Susana. 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 Fil: Medina, Analía. Universidad del Norte Santo Tomás de Aquino. Facultad de Ciencias de la Salud; Argentina Fil: Navarro, Carolina M.. Universidad del Norte Santo Tomás de Aquino. Facultad de Ciencias de la Salud; Argentina Fil: Medina, Roxana Beatriz. 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. Centro de Referencia para Lactobacilos; 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 Fil: Gómez, María I.. Universidad del Norte Santo Tomás de Aquino. Facultad de Ciencias de la Salud; Argentina

Synthesis of dechlorinase in Streptomyces sp. M7 was induced when the microorganism was grown in the presence of lindane (γ-hexachlorocyclohexane) as the only carbon source. Activity of cells grown with lindane was about four and half times higher compared to cells grown with glucose. Maximum dechlorinase activity was observed at 30°C in alkaline conditions pH (7.9) and the enzyme did not show cation dependency. Sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed one differential band with a molecular weight similar to serum albumin (M r 66,200), which corresponded to polynucleotide phosphorylase, an enzyme that plays an important role in the regulation system and could be involved in the regulation of the dechlorinase gene. Detected in cell-free extracts were γ-pentachlorocyclohexene and 1,3,4,6-tetrachloro-1,4-cyclohexadiene, both being products of the dechlorinase activity. This is the first time that the presence of an enzyme with dechlorinase activity has been demonstrated in an actinomycete strain isolated in Tucuman, Argentina. Characteristics of this enzyme revealed that Streptomyces sp. M7 could be useful in the future in bioremediation of soil or as a biosensor.

This work provides quantitative information on Cr(VI) reduction in soil samples by an indigenous actinomycete. Streptomyces sp. MC1, previously isolated from sugarcane, has shown ability to reduce Cr(VI) in liquid minimal medium. A reduction of 100 and 75% was obtained at initial Cr(VI) concentrations of 5 and 50 mg l(-1), respectively, after 48 h of incubation. Bioremediation ability of Streptomyces sp. MC1 was assayed in soil extracts and soil samples. Relative growth of Streptomyces sp. MC1 was 77 and 38% when grown in soil extract with 10 and 50 mg l(-1) of Cr(VI), respectively. MC1 was able to reduce 30% of Cr(VI) after 96 h of incubation with 10 mg l(-1) of Cr(VI), and reduction coincided with the exponential growth phase at pH 7 and 30 degrees C.In soil samples, Streptomyces sp. MC1 was able to reduce up to 94% of the Cr(VI) bioavailability (50 mg kg(-1)) after 7 d. These results were compared with non-inoculated soil samples with Cr(VI). Bioremediation activity of Streptomyces sp. MC1 was not inhibited by natural soil microbial flora. Besides, Streptomyces sp. MC1 growth was not inhibited by 50 mg kg(-1) of Cr(VI). In contrast to findings obtained by other authors, our results showed almost complete Cr(VI) removal from soil without any previous treatment, and without addition of any substrate and with a normal soil humidity level. These results confirm the Cr(VI)-contaminated soil bioremediation potential of Streptomyces sp. MC1.

Twenty-one yeast-like microorganisms were isolated from tannery effluents and from a nickel-copper mine in Argentina. They were tested for their Cu(II), Ni(II), Cd(II) and Cr(VI) tolerance in qualitative assays on solid medium. Three isolates were selected for their multiple tolerance to the different heavy metals and highest tolerance to Cr(VI). According to morphological and physiological analysis and 26S rDNA D1/D2 domain sequences the isolates were characterized as: Lecythophora sp. NGV-1, Candida sp. NGV-9 and Aureobasidium pullulans VR-8. Resistance of the three strains to high Cr(VI) concentrations and their ability to remove Cr(VI) were assessed using YNB-glucose medium supplemented with 0.5 and 1 mM Cr(VI). Chromate removal activity was estimated by measuring remaining Cr(VI) concentration in the supernatant using the colorimetric 1,5-diphenylcarbazide method and total chromium was determined by flame atomic absorption spectroscopy. The results indicate that the initial Cr(VI) concentration negatively influenced growth and the specific growth rate but stimulated the metabolic activity of the three strains; resistance to Cr(VI) by these strains was mainly due to reduction of Cr(VI) rather than chromium bioaccumulation. This study showed the potential ability of these strains as tools for bioremediation of Cr(VI) from contaminated sites.

The objective of the present study was to study the lindane bioremediation abilities of Streptomyces sp. M7 in soil samples and to know the pesticide effects on maize plants seeded in lindane-contaminated soil previously inoculated with Streptomyces sp. M7. When different initial pesticide concentrations (100, 150, 200, and 300 μg kg −1 ) were added to sterile soil, the microbial growth observed was similar to the control without lindane. A decrease of the residual lindane concentration was detected in soils samples in relation to the abiotic controls (29.1%, 78.03%, 38.81%, and 14.42%, respectively). The optimum Streptomyces sp M7 inoculum was selected in sterile soil spiked with lindane 100 μg kg −1 soil; it was 2 g kg −1 soil for obtaining the most efficient bioremediation process (56% removal). Lindane concentrations of 100, 200, and 400 μg kg −1 soil did not affect the germination and vigor index of maize plants seeded in contaminated soils without Streptomyces sp. M7. When this microorganism was inoculated at the same conditions a better vigor index was observed and 68% of lindane removal. These results confirm the lindane-contaminated soil bioremediation potential of Streptomyces sp. M7.

This work was conducted to study the removal of gamma-hexachlorocyclohexane (lindane) in a soil extract liquid medium (SE) by Streptomyces sp. M7 and to determine the influence of pH and temperature on bacterial growth and pesticide removal in this medium. When Streptomyces sp. M7 was cultured in SE supplemented with lindane 100 microg l(-1 )at different initial pH, the maximum growth was observed at pH 7 and the microorganism was not able to grow at pH 5 and 9; the highest pesticide removal (70.4%) by Streptomyces sp. M7 was noted at an initial pH of 7 at 4 weeks of incubation. The maximum removal (70% approximately) was observed when the microorganism was incubated in SE at 30 degrees C; although the optimal temperature for Streptomyces sp. M7 growth, with and without lindane, was 25 degrees C, and for the pesticide removal was 30 degrees C. The results of this study suggest that this actinomycete strain appears as an effective alternative in the remediation of lindane polluted sites.

Forty-one isolated actinomycetes were used to study qualitative and semi-quantitative screening of chromium(VI) resistance. Chromate-removing activity was estimated using the Cr(VI) specific colorimetric reagent 1,5-diphenylcarbazide. Twenty percent of the isolates from El Cadillal (EC) and 14% of isolates from a copper filter plant (CFP) were able to grow at 13 mM of Cr(VI). All isolates from sugar cane (SCP) could grow up to Cr(VI) concentration of 17 mM. EC, CFP and SCP strains were able to remove 24%, 30% and more than 40% of Cr(VI), respectively. The highest and lowest Cr(VI) specific removal values were 75.5 mg g(-1) cell by M3 (CFP), and 1.5 mg g(-1) cell by C35 (EC) strains. Eleven Cr(VI) resistant strains were characterized and identified as species of the genera Streptomyces (10) and Amycolatopsis (1). Differences on actinomycete community composition between contaminated and non-contaminated soil were found. This study showed the potential capacity of actinomycetes as tools for Cr(VI) bioremediation.

Lindane is an organochlorine pesticide widely used in agriculture, human health, and veterinary. It is a persistent organic pollutant, representing a serious risk since its residues are still in the environment. The aim of this work was to evaluate the influence of the acclimation of free and immobilized Streptomyces consortium on lindane degradation in liquid and slurry systems. The actinobacteria consortium demonstrated stability since the survival of all members was confirmed after the acclimation period. It reached higher biomass (0.56-0.65 g L-1) and lindane removal (40-97%) than the consortium without acclimation (0.37-0.44 g L-1; 33-87%) when it was cultured in liquid medium with 20 and 50 mg L-1 of lindane. In contrast, lindane removal achieved by acclimated and immobilized consortium in slurry system (50%) did not present significant difference respect to the consortium without acclimation. Moreover, lindane degradation was confirmed by identification of three metabolites in liquid medium, 1,2- and 1,4-dichlorobenzene, and γ-pentachlorocyclohexene; and by determination of chloride ions released in slurry system. Bioassays with Lactuca sativa demonstrated the effectiveness of the bioremediation by the acclimated consortium in both systems, since the seedlings showed an improvement in its biological parameters compared to abiotic controls, confirming a significant decrease in toxicity. Fil: Sáez, Juliana María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Aparicio, Juan Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Amoroso, Maria Julia del R.. 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. 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

Background and aims: Plants and contaminant-degrading microbes are a suitable combination for the remediation of pesticides. The aim of this study was to evaluate the effectiveness of Streptomyces strains cultured with maize plants in relation to lindane removal.Methods: Four Streptomyces strains were cultured and added as both single and mixed cultures, along with maize plants, to artificially polluted hydroponic systems and soils. The effectiveness of the resulting soil bioremediation was then evaluated through phytotoxicity testing using lettuce seedlings.Results: In the hydroponic and soil experiments, similar levels of lindane removal were recorded in the inoculated and non-inoculated systems where maize plants were introduced. However, the vigor index (VI) of the maize plants was highest when grown in inoculated and artificially polluted soil. In the phytotoxicity assay, the VI of the lettuce seedlings increased with increasing bioremediation time for the soils, thus indicating the effectiveness of the process.Conclusions: Similar levels of lindane removal were recorded in both inoculated and non-inoculated planted systems, indicating that pesticide removal was not significantly affected by the bacterial inoculant. However, inoculation an actinobacteria consortium led to an increase in the VI of the maize and protected the plants against the existing toxicity. Furthermore, maize plants may attenuate the transient toxic effects of microbial lindane degradation. Fil: Alvarez, Analia. 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 Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Sáez, Juliana María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Planta Piloto de Procesos Industriales Microbiológicos (i); Argentina Fil: Giuliano, Agostina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Planta Piloto de Procesos Industriales Microbiológicos (i); 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

The aim of this work was to study the impact of environmental factors on the bioremediation of Cr(VI) and lindane contaminated soil, by an actinobacterium, Streptomyces sp. M7, in order to optimize the process.Soil samples were contaminated with 25μgkg-1 of lindane and 50mgkg-1 of Cr(VI) and inoculated with Streptomyces sp. M7. The lowest inoculum concentration which simultaneously produced highest removal of Cr(VI) and lindane was 1gkg-1. The influence of physical and chemical parameters was assessed using a full factorial design. The factors and levels tested were: Temperature: 25, 30, 35°C; Humidity: 10%, 20%, 30%; Initial Cr(VI) concentration: 20, 50, 80mgkg-1; Initial lindane concentration: 10, 25, 40μgkg-1.Streptomyces sp. M7 exhibited strong versatility, showing the ability to bioremediate co-contaminated soil samples at several physicochemical conditions. Streptomyces sp. M7 inoculum size was optimized. Also, it was fitted a model to study this process, and it was possible to predict the system performance, knowing the initial conditions. Moreover, optimum temperature and humidity conditions for the bioremediation of soil with different concentrations of Cr(VI) and lindane were determined. Lettuce seedlings were a suitable biomarker to evaluate the contaminants mixture toxicity. Streptomyces sp. M7 carried out a successful bioremediation, which was demonstrated through ecotoxicity test with Lactuca sativa Fil: Aparicio, Juan Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Planta Piloto de Procesos Industriales Microbiológicos (i); Argentina. Universidad Nacional de Tucumán; Argentina Fil: Simón Solá, María Zoleica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Planta Piloto de Procesos Industriales Microbiológicos (i); Argentina. Universidad Nacional de Tucumán; Argentina Fil: Benimeli, Claudia Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Planta Piloto de Procesos Industriales Microbiológicos (i); 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; Argentina Fil: Polti, Marta Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Planta Piloto de Procesos Industriales Microbiológicos (i); Argentina

Gamma-hexachlorocyclohexane (γ-HCH or lindane), one of the most commonly used pesticides, has been mainly used in agriculture; this pesticide is known to be highly toxic and persistent, causing serious water and soil contamination. The objective of the present work is to study the effect of low glucose concentration and the addition of lindane at different growing time on the pesticide detoxification ability of Streptomyces M7. After 96 h of incubation in synthetic medium containing glucose 0.6 g l–1 with the addition of lindane 100 μg l–1 at 20 h of incubation, a typical diauxic curve was obtained: glucose was the preferred substrate until 24 h, at 48 h, when the carbohydrate was depleted, the microorganism consumed the pesticide like carbon source. On the other hand, lindane removal induction was observed, which was greater when the pesticide was added to the medium at 20 h than 6 h of incubation. Between 72 and 96 h, a maximum of ∼86% of the Cl– was released when lindane was added to the medium at 20 h, whereas ∼70% and 67% Cl– was released in the medium when the pesticide was added at 0 and 6 h of incubation respectively. This is the first report of chloride release from inoculated medium supplemented with lindane, suggesting that the pesticide was degraded by Streptomyces sp. under aerobic conditions. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Eleven yeasts were isolated from wastewater sediment samples collected from a copper filter mine plant, located in the province of Tucumán, Argentina, and tested for their heavy metal tolerance. Two isolates were selected based on their multiple tolerance to different heavy metals and their copper biosorption capacity was studied. Analysis of the 26S rDNA D1/D2 domain sequences indicates that isolate RCL‐3 showed similarity with Candida sp. and RCL‐11 with Rhodotorula mucilaginosa . Growth performance and copper toxicity of both yeasts were evaluated using YNB‐glucose medium supplemented with 0.1, 0.2, 0.5 and 1 mM of Cu2+ solutions. Candida sp. RCL‐3 was able to grow up to 7 mg ml–1 biomass in the presence of either 0.1 or 0.2 mM Cu2+, and at 0.5 mM Cu2+ growth reached 5.5 mg ml–1. R. mucilaginosa RCL‐11 reached 8 mg ml–1 in the presence of 0.1 mM Cu2+, and values of 6.5 and 5.5 mg ml–1 biomass were obtained at 0.2 and 0.5 mM Cu2+, respectively. Copper accumulation profiles were different: the metal was librated from the intact cells by Candida sp. whereas R. mucilaginosa did not show release from the cells indicating intracellular storage. Specific biosorption of copper by both isolated yeasts showed increase with the initial copper supplied with the medium (up to 11.5 and 8.0 mg Cu g–1 biomass for Candida sp. and R. mucilaginosa , respectively). However, specific biosorption decreased with time. Fil: Villegas, Liliana Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Amoroso, Maria Julia del R.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Castellanos, Lucia Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina

Lindane is a chlorinated insecticide which was used worldwide. Nowadays its persistence, bioaccumulation and toxicity are well known. One of the strategies for its elimination is bioremediation. For this purpose, the use of slurry reactors for contaminated soils is considered an efficient technology. Moreover, using immobilized cells in this process could provide protection for microorganisms against the contaminants and also allows reuse. The aim of this study was to assess lindane removal from soil slurry by a Streptomyces consortium immobilized in cloth sachets, at different inoculum, lindane and slurry concentrations. In concentrated slurry, the higher lindane removal (35.3 mg Kg-1) was obtained with the medium inoculum (107 CFU g-1) and the higher lindane concentration tested, at 7 days of incubation. Although, lindane removal was also detected in abiotic controls, probably due to a physical phenomenon of adsorption of the pesticide to soil particles. Thus, these parameters were selected for evaluating the pesticide removal in a more diluted slurry. After 14 days of incubation, 28.7 mg Kg-1 of lindane was removed. Besides, phytotoxicity assay demonstrated that seeds grown on diluted slurries bioremediated during 7 and 14 days showed an improvement in biological paramethers, respect to non-bioremediated slurry. Fil: Sáez, Juliana María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Planta Piloto de Procesos Industriales Microbiologicos; Argentina Fil: Alvarez, Analia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Planta Piloto de Procesos Industriales Microbiologicos; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; Argentina Fil: Benimeli, Claudia Susana. Universidad del Norte Santo Tomás de Aquino; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Planta Piloto de Procesos Industriales Microbiologicos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman; Argentina Fil: Amoroso, Maria Julia del R.. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Planta Piloto de Procesos Industriales Microbiologicos; Argentina. Universidad del Norte Santo Tomás de Aquino; Argentina

Strain desinganted R22 and R25, isolated from Sali River sediments, Argentina, were highly resistant to chromium. these strains were shown by 16S rRNA sequencing studies to be Streptomyces spp.; this affiliation was consistent with morphological and chemical characteristics. Growth of R22 and R25 in medium containing 100 mg/l chromate was reduced by only 23% and 34%, respectively, compared with growth in medium without added chromium. Streptomyces sp. strains R22 and R25 both accumulated chromium with yields of 10.0 and 5.6 mg Cr/g of dry weight, respectively, and chromate concentration of 50 mg/ml. Cell fractionation studies with strain R22 showed that the great majority of the chromium were associated with the cell wall fraction. Streptomyces R22 and R25 may have applications in bioremediation of chromium contamination. Fil: Amoroso, Maria Julia del R.. 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. Instituto de Microbiología; Argentina Fil: Castro, Guillermo Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Duran, A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Tecnología Agroindustrial del Noroeste Argentino. Provincia de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial ; Argentina Fil: Peraud, O.. University of Maryland; Estados Unidos Fil: Oliver, G.. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Microbiología; Argentina Fil: Hill, R. T.. University of Maryland; Estados Unidos

We have isolated 25 new strains of streptomycetes from soil samples of a polluted site at the former uranium mine, Wismut, in eastern Thuringia, Germany. The strains grew on medium containing 1 mM NiCl2 and thus were resistant to the heavy metal ion. Seven of the strains were further characterized. All of these strains were resistant to heavy metals in various degrees with up to 10 mM resistance against NiCl2 supplied with the liquid minimal growth medium. The high level of resistance prompted us to look for high affinity nickel transporter genes thought to provide a means to eliminate the excess nickel ions form the cells. Degenerate oligonucleotide primers derived from sequences of P-type ATPase transporter genes of Gram negative bacteria identified a fragment which shows deduced amino acid sequence similarities to known high affinity nickel transporters. Investigation of two genes obtained from the isolates Streptomyces spec. E8 and F4 showed high sequence divergence. This was unexpected since a transmissible plasmid had been thought to convey heavy metal resistance.

Fifty-three strains of actinomycetes resistant to heavy metals were isolated from the Salí River in northwest Argentina. Screening procedures that involve solid and liquid synthetic media containing Cd(2+), Cu(2+), or Hg(2+) allowed the selection of six strains. These strains showed a quantitative sorption of Cd(2+) and Cu(2+) by more than 98% of the initial metal concentrations (0.1, 0.5, and 1.0 mM) tested.

Several fungal species were isolated from different sources: post-harvest sugarcane residue, soil, decomposing forest litter and from mycelia obtained from the inner parts of fresh fungal fruiting bodies collected in Las Yungas region (Argentina). These isolates were first screened for their ability to produce carboxymethyl cellulose (CMC) degradation and guaiacol oxidation. After primary screening, seventeen isolates were further tested for their ligninolytic ability by assessing polyphenoloxidase, laccase, manganese peroxidase and endoxylanase activities. Based on their lignocellulolytic activities, five isolates (named Bjerkandera sp. Y-HHM2, Phanerochaete sp. Y-RN1, Pleurotus sp. Y-RN3, Hypocrea nigricans SCT-4.4 and Myrothecium sp. S-3.20) were selected for liquid and solid-state fermentation assays in culture media including sugarcane debris. Lignocellulolytic enzymes production, dry mass loss and phenol concentration in the water soluble fraction were then evaluated. Results suggest that native strains with lignocellulolytic activity are suitable to increase post-harvest sugarcane residue decomposition and support the use of these strains as an alternative to pre and post-harvest burning. Biological treatments using Phanerochaete sp. Y-RN1, Pleurotus sp. Y-RN3 and Myrothecium sp. S-3.20 could be used to degrade and increase the accessibility to lignocellulose components of sugarcane residue. Fil: Maza, Marianela. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina 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: Pajot, Hipolito Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Planta Piloto de Procesos Industriales Microbiologicos; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentina Fil: Yasem, Marta Graciela. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; Argentina

α-l-Rhamnosidase (E.C. 3.2.1.40) from Brevundimonas sp. Ci19 was immobilized as a cross-linked enzyme aggregate (CLEA) via precipitation with acetone followed by glutaraldehyde cross-linking. The effects of precipitation and cross-linking on CLEA activity were investigated and characterized. Sixty percent acetone solution and 2.0 % glutaraldehyde were used at pH 7.0 for 1-h cross-linking reaction. The yield of rhamnosidase-CLEA was approximately 80 % starting from crude extracts or pure enzyme suggesting non-purification steps are required for extended use. No significant differences in optimum pH and temperature values of the enzyme were recorded after immobilization. The rham-CLEA recycled 4 times showed about 80 % rhamnosidase activity; meanwhile, in the fifth and six recycled time, the enzyme activity was reduced to about 40 and 20 %, respectively., Centro de Investigación y Desarrollo en Fermentaciones Industriales

The growth population and anthropogenic activity are constantly threatening the environment caused by the accumulation of different kinds of pollutants in the biosphere, especially in soils and sediments. Co-contaminated of environment with toxic organic and inorganic substance is often actually. For the remediation of soils contaminated with mainly petroleum, pesticide and heavy metals, several physical or chemical techniques have been developed inadequately. Inside the technologies “eco-friendly remediation,” the bioremediation have emerged as an option using natural biological activity. Bioremediation are methods where microorganisms degrade one or various pollutants to nontoxic compounds, so working individually or coordinately inside a microbial consortium. A microbial consortium is the natural association of two or more microbial populations of different species, which act together in a complex system. The success of a bioremediation process with pure cultures is very low and restricted. Therefore, use of a microbial consortium appears to be more feasible and reliable.

The class Actinobacteria represents an important component of the microbial population in soils. Their metabolic diversity and specific growth characteristics make them well suited as agents for bioremediation. Actinobacteria have an active role in the removal of xenobiotic heavy metals. Their ability has been demonstrated in culture media and in soil samples, either using pure cultures or consortia of Actinobacteria. They have a great adaptability that can be used to benefit the environment. Both whole cells and their products have potential applications in bioremediation processes.

More than one-third of contaminated areas are found to have more than one type of pollutant. Co-contaminated environments with metals and organic compounds are difficult to remediate because of the mixed nature of the pollulants. Actinobacteria is an important group of microorganisms found in soils, with high metabolic versatility and abilities to bioremediation. Actinobacteria are currently studied for bioremediation of soils contaminated by pesticides and heavy metals. In this chapter we review the potential of actinobacteria isolated from contaminated environments for simultaneous soil bioremediation of Cr(VI) and the organochlorine pesticide lindane. Four actinobacteria, tolerant to Cr(VI) and lindane mixture were used: Streptomyces spp. A5, M7, MC1 and Amycolatopsis tucumanensis DSM 45259. Sterilized soil samples were inoculated with actinobacteria strains, either individually or as a consortium (formed by all selected actinobacteria) then contaminated with Cr(VI) and lindane, and incubated at 30 °C for 14 days. All actinobacteria were able to grow and remove both contaminants, the consortium formed by Streptomyces spp. A5, M7, MC1 and A. tucumanensis showed the highest Cr(VI) removal, while Streptomyces sp. M7 produced the maximum lindane removal. In non-sterile soil samples, Streptomyces sp. M7 and the consortium removed more than 40 % of the lindane, while Streptomyces sp. M7 demonstrated the greatest Cr(VI) removal. According to these results, it could be concluded that the use of Streptomyces sp. M7 is the strategy more appropriate for the bioremediation of soils contaminated with Cr(VI) and lindane.

Environments co-contaminated with metals and organic compounds are difficult to remediate. Actinobacteria is an important group of microorganisms found in soils, with high metabolic versatility and potential for bioremediation. In this paper, actinobacteria were used to remediate soil co-contaminated with Cr(VI) and lindane. Five actinobacteria, tolerant to Cr(VI) and lindane mixture were selected: Streptomyces spp. A5, A11, M7, and MC1 and Amycolatopsis tucumanensis DSM 45259. Sterilized soil samples were inoculated with actinobacteria strains, either individually or as a consortium and contaminated with Cr(VI) and lindane, either immediately or after 7 days of growth, and incubated at 30 ºC during 14 days. All actinobacteria were able to grow and remove both contaminants, the consortium formed by Streptomyces spp. A5, M7, MC1 and A. tucumanensis showed the highest Cr(VI) removal, while Streptomyces sp. M7 produced the maximum lindane removal. In non-sterile soil samples, Streptomyces sp. M7 and the consortium removed more than 40% of the lindane, while Streptomyces sp. M7 demonstrated the greatest Cr(VI) removal. The most appropriate strategy for bioremediation of Cr(VI) and lindane co-contaminated soils would be the inoculation with Streptomyces sp. M7. These results represent the first report on successful bioremediation of soils contaminated simultaneously with Cr(VI) and lindane. Fil: Polti, Marta Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Planta Piloto de Procesos Industriales Microbiologicos; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; Argentina Fil: Aparicio, Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Planta Piloto de Procesos Industriales Microbiologicos; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentina Fil: Benimeli, Claudia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Planta Piloto de Procesos Industriales Microbiologicos; Argentina. Universidad del Norte Santo Tomás de Aquino; Argentina 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. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentina. Universidad del Norte Santo Tomás de Aquino; Argentina

Methoxychlor is an organochlorine pesticide used worldwide against several insect pests, resulting in human exposure. This pesticide mimics endocrine hormone functions, interfering with normal endocrine activity in humans and wildlife. For this reason, it is imperative to develop methods to remove this pesticide from the environment, and though, bioremediation using microorganisms results as an excellent strategy. Five Streptomyces spp. strains previously isolated from organochlorine-polluted sites and capable to grow and remove methoxychlor were combined as different mixed cultures to increase methoxychlor removal. From the 39 consortia tested, one consortium (Streptomyces spp. A6, A12, A14, M7) was selected because of its high pesticide removal and specific dechlorinase activity to be assayed on slurry and soil systems. This consortium showed higher biomass values (8.3 9 106 ± 5.7 9 105 CFU mL-1) and methoxychlor removal (56.2 ± 2.3 %) on enriched slurry than in nonenriched slurry (7.3 9 105 ± 1.2 9 105 CFU mL-1 and 45.6 ± 7.4 % of pesticide removal). In soil systems, Streptomyces consortium showed higher growth (1.0 9 1011 ± 5.0 9 1010 CFU g-1) than in enriched slurry, although differences in methoxychlor removal between both culture conditions were not statistically significant. Therefore, the selected Streptomyces consortium may be suitable for the development of in situ (soil) and ex situ (slurry bioreactor) bioremediation methods because of their potential to remove methoxychlor from different systems. Fil: Fuentes, María Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos (i); Argentina; Fil: Alvarez, Analia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos (i); Argentina; Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; Argentina; Fil: Sáez, Juliana María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos (i); Argentina; Fil: Benimeli, Claudia Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Tucumán. Unidad de Administración Territorial; Argentina; Universidad del Norte Santo Tomás de Aquino; Argentina; Fil: Amoroso, Maria Julia del R.. Universidad del Norte Santo Tomás de Aquino; Argentina; Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos (i); Argentina