Abstract:

Poultry litter (PL), which is usually used as organic fertilizer, is a source of nutrients, metals, veterinary pharmaceuticals and bacterial pathogens, which, through runoff, may end up in the nearest aquatic ecosystems. In this study, Leptodactylus chaquensis at different development stages (eggs, larval stages 28 and 31 here referred to as stages I, II and III respectively) were exposed to PL test sediments as follows: 6.25% (T1), 12.5% (T2); 25% (T3); 50% (T4); 75% (T5); 100% PL (T6) and to dechlorinated water as control. Larval survival, development endpoints (growth rate -GR-, development rate -DR-, abnormalities), antioxidant enzyme activities (Catalase -CAT- and Glutathione-S-Transferase -GST-), and genotoxic effect (DNA damage index by the Comet assay) were analyzed at different times. In stage I, no egg eclosion was observed in treatments T3-T6, and 50% of embryo mortality was recorded after 24 h of exposure to T2. In stages II and III, mortality in treatments T3-T6 reached 100% between 24 and 48 h. In the three development stages evaluated, the DR and GR were higher in controls than in PL treatments (T1, T2), except for those T1-treated larvae of stage II. Larvae of stage I showed five types of morphological abnormalities, being diamond body shape and lateral displacement of the intestine the most prevalent in T1, whereas larvae of stages II and III presented lower prevalence of abnormalities. In stage I, CAT activity was similar to that of control (p>0.05), whereas it was higher in T1- and T2- treated larvae of stages II and III than controls (p<0.05). In stages I and III, GST activity was similar to that of controls (p>0.05), whereas it was inhibited in T1-treated larvae of stage II (p<0.05). T1- and T2-treated larvae of stages II and III caused higher DNA damage respect to controls (p<0.05), varying from medium to severe damage (comet types II, III and IV). These results showed that PL treatments altered development and growth and induced oxidative stress and DNA damage, resulting ecotoxic for L. chaquensis larvae.

Author affiliation: Curi, Lucila Marilén. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Laboratorio de Saneamiento Ambiental. Cátedra de Ecotoxicología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Peltzer, Paola. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Laboratorio de Saneamiento Ambiental. Cátedra de Ecotoxicología; Argentina

Author affiliation: Martinuzzi, Candela Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Laboratorio de Saneamiento Ambiental. Cátedra de Ecotoxicología; Argentina

Author affiliation: Attademo, Andres Maximiliano. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Laboratorio de Saneamiento Ambiental. Cátedra de Ecotoxicología; Argentina

Author affiliation: Seib, S.. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Laboratorio de Saneamiento Ambiental. Cátedra de Ecotoxicología; Argentina

Author affiliation: Simoniello, Maria Fernanda. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Laboratorio de Saneamiento Ambiental. Cátedra de Ecotoxicología; Argentina

Author affiliation: Lajmanovich, Rafael Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Laboratorio de Saneamiento Ambiental. Cátedra de Ecotoxicología; Argentina

Abstract:

The present study examines the agrochemical application of macrospheres prepared with chitosan and chitosan-starch blends by an easy dripping technique, using a sodium tripolyphosphate aqueous solution as the crosslinking agent. These biopolymers form hydrogels that could be a viable alternative method to obtain controlled-release fertilizers (CRFs). Three different concentrations (ranging from 20 to 100 wt/wt% of chitosan) and two crosslinking times (2 or 4 h) were used. The resulting polymeric matrices were examined by scanning electron microscopy coupled with energy dispersive X-ray, X-ray diffraction, Fourier transform infrared spectroscopy, solid-state nuclear magnetic resonance, thermogravimetric analysis and differential scanning calorimetry. Ionotropic gelation and neutralization induced the formation of the macrospheres. The crosslinking time and the composition of the polymeric hydrogel controlled the crosslinking degree, the swelling behavior and the fertilizer loading capability. Potassium nitrate-loaded beads were shown to be useful as a controlled-release fertilizer. After 14 days of continuous release into distilled water, the cumulative concentration in the release medium reached between 70 and 93% of the initially loaded salt, depending on the matrix used. The prepared beads showed properties that make them suitable for use in the agrochemical industry as CRFs.

Author affiliation: Perez Bravo, Jonas Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnología en Polímeros y Nanotecnología. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnología en Polímeros y Nanotecnología; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Química. Grupo de Aplicaciones de Materiales Biocompatibles; Argentina

Author affiliation: Francois, Nora. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnología en Polímeros y Nanotecnología. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnología en Polímeros y Nanotecnología; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Química. Grupo de Aplicaciones de Materiales Biocompatibles; Argentina

Abstract:

Oleaginous microalgae have a great potential as a feedstock for biodiesel and other biofuels. However, the current cost of producing biofuels from microalgae biomass is still high to envision massive and profitable commercialization in the near future. One of the drawbacks of implementing large-scale cultivation of these organisms is the unsustainable requirement of N-fertilizers. It is presumed that co-production of higher value by-products in the frame of a biorefinery would increase the profitability of producing oil from microalgae. The aim of this work is to provide proof-of-concept for the complete substitution of chemical N-fertilization by on-site biological N2 fixation in a process of microalgal oil production. We show the efficient conversion of biomass of a N2-fixing cyanobacterium into oil-rich microalgae biomass when the eukaryotic alga is fed with a cyanobacterium extract as a sole source of nutrients. Oil production yields in environmental photobioreactor simulations were in the range of current yields obtained at the expense of synthetic N-fertilizer and up to 20-fold higher than those reported when using plant feedstocks.

Author affiliation: Do Nascimento, Mauro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones En Biodiversidad y Biotecnología; Argentina. Fundación para Investigaciones Biológicas Aplicadas; Argentina

Author affiliation: Sánchez Rizza, Lara. Fundación Para Investigaciones Biológicas Aplicadas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones en Biodiversidad y Biotecnología; Argentina

Author affiliation: Arruebarrena Di Palma, Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones En Biodiversidad y Biotecnología; Argentina. Fundación para Investigaciones Biológicas Aplicadas; Argentina

Author affiliation: Dublan, María de Los Ángeles. Fundación Para Investigaciones Biológicas Aplicadas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones en Biodiversidad y Biotecnología; Argentina. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Agronomia; Argentina

Author affiliation: Salerno, Graciela Lidia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones En Biodiversidad y Biotecnología; Argentina. Fundación para Investigaciones Biológicas Aplicadas; Argentina

Author affiliation: Rubio, Luis Manuel. Universidad Politecnica de Madrid; España

Author affiliation: Curatti, Leonardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones en Biodiversidad y Biotecnología; Argentina. Fundación para Investigaciones Biológicas Aplicadas; Argentina

Abstract:

Maize production is affected by water and nitrogen (N) deficit either separately or joined, but this fact is not completely defined. The aim was to evaluate the fate of N in maize fertilized and subjected to water stress in controlled conditions. A greenhouse experiment was carried out at the University of Buenos Aires campus. The design was a 2 × 2 factorial with four replications. The factors were N: 70 and 140 kg N ha-1 as labeled urea (15N), and water: 100% or 50% of the potential evapotranspiration. The harvest of aerial and root biomass was carried out at R1 stage. Nitrogen in plants, soils nitrate, ammonia volatilization, and 15N percentage were determined. Obtained results only partially agree with previous research. Water stress depressed aerial biomass production independently of N doses. When water was limiting, the uptake of N from fertilizer was independent of N. When water was not limiting, N uptake increased with the higher N doses. Volatilization losses were 3.7 to 7.8% of N applied as fertilizer. Plant N recovers was around 45% of the N applied, except in treatment water stressed with high N rate (19%). Nitrate-N from the fertilizer in the soil at harvest and accumulated N from the fertilizer in plant were lineally related (r2 = 0.54; p < 0.001). Important destinations of N were accumulation in plant, volatilization and incorporation into soil organic matter. However, residual nitrate was a main fate in heavily fertilized and water deficit treatment. This process could lead to the eventual nitrate leaching. Copyright © Taylor & Francis Group, LLC.

Author affiliation: Rimski Korsakov, Helena. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Ingeniería Agrícola y Uso de la Tierra. Cátedra de Fertilidad y Fertilizantes; Argentina

Author affiliation: Rubio, Gerardo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Ingeniería Agrícola y Uso de la Tierra. Cátedra de Fertilidad y Fertilizantes; Argentina

Author affiliation: Lavado, Raul Silvio. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Ingeniería Agrícola y Uso de la Tierra. Cátedra de Fertilidad y Fertilizantes; Argentina

Abstract:

Aims: Our objective was to evaluate if the relationship between quick indices of mineralizable N and soil N mineralization potential (No) is affected by long-term fertilization with inorganic fertilizers (IF) and/or poultry litter (PL). Methods: Samples from four long-term research sites that were fertilized with IF, IF+PL, or PL (>10 years) were aerobically incubated for 24 weeks to determine No. Soil No was then related to the results from the Illinois soil test analysis (ISNT), extractions with hot KCl, NaOH, or phosphate-borate (PB), and an anaerobic incubation (Nan). Results: All evaluated chemical methods were correlated with No (R2 > 0.59). However, the models to describe the association between the chemical methods and No differed depending on the fertilizer treatment, due to the inability of chemical indices to estimate the No increase observed in some PL-amended soils. In contrast, the relationship between Nan and No was not affected by fertilization strategy. Conclusions: Chemical indices can lead to the underestimation of soil N mineralization potential in PL-treated soils when the indices are calibrated in IF-amended soils, whereas the biological method Nan predicted No independently from the field’s fertilization history.

Author affiliation: Wyngaard, Nicolás. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Cabrera, Miguel L.. University of Georgia; Estados Unidos

Author affiliation: Shober, Amy. University of Delaware. Plant and Soil Sciences Department; Estados Unidos

Author affiliation: Kanwar, R.. Iowa State University. Department of Agricultural and Bio-systems Engineering; Estados Unidos

Abstract:

Several studies have shown that biostimulation can promote hydrocarbon bioremediation processes in Antarctic soils. However, the effect of the different nutrient sources on hydrocarbon removal heavily depends on the nutrients used and the soil characteristics. In this work, using a sample of chronically contaminated Antarctic soil that was exposed to a fresh hydrocarbon contamination, we analyzed how a complex organic nutrient source such as fish meal (FM) and a commercial fertilizer (OSEII) can affect hydrocarbon biodegradation and bacterial community composition. Both amended and unamended (control) biopiles were constructed and controlled at Carlini Station and sampled at days 0, 5, 16, 30 and 50 for microbiological, chemical and molecular analyses. FM caused a fast increase in both total heterotrophic and hydrocarbon degrading bacterial counts. These high values were maintained until the end of the assay, when statistically significant total hydrocarbon removal (71 %) was detected when compared with a control system. The FM biopile evidenced the dominance of members of the phylum Proteobacteria and a clear shift in bacterial structure at the final stage of the assay, when an increase of Actinobacteria was observed. The biopile containing the commercial fertilizer evidenced a hydrocarbon removal activity that was not statistically significant when compared with the untreated system and exhibited a bacterial community that differed from those observed in the unamended and FM-amended biopiles. In summary, biostimulation using FM in biopiles significantly enhanced the natural hydrocarbon-degradation activity of the Carlini station soils in biopile systems and caused significant changes in the bacterial community structure. The results will be considered for the future design of soil bioremediation protocols for Carlini Station and could also be taken into account to deal with diesel-contaminated soils from other cold-climate areas.

Author affiliation: Dias, Romina Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Fermentaciones Industriales. Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Fermentaciones Industriales; Argentina

Author affiliation: Ruberto, Lucas Adolfo Mauro. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Microbiología, Inmunología y Biotecnología. Cátedra de Virología; Argentina. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina

Author affiliation: Calabró López, Roberto Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Microbiología, Inmunología y Biotecnología. Cátedra de Virología; Argentina

Author affiliation: Lo Balbo, Alfredo. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina

Author affiliation: del Panno, Maria Teresa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Fermentaciones Industriales. Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Fermentaciones Industriales; Argentina

Author affiliation: Mac Cormack, Walter Patricio. Universidad de Buenos Aires; Argentina. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina

Abstract:

Leaching of fertilizers is one of the main reasons of nitrate concentration increases in underground waters. We studied the effect of fertilizers and biosolids on nitrate accumulation in soil depth. We determined nitrates at different depths of a beheaded Vertic Argiudoll, near La Plata city. The application of biosolids in high doses (equivalent to 200 Mg ha-1(wet weight basis) for one year, showed significant nitrate accumulation at soil depth in relation to the check. The application of mineral fertilizers and biosolids in doses equivalent to 25 Mg ha-1 (wet weight basis) for three successive years showed lower risk of nitrate leaching. A plot fertirrigated (soluble fertilizers) showed high nitrate accumulation in soil depth and then high contamination risk. The clayey soil texture did not limit the risk of nitrate leaching.

Author affiliation: Rimski-korsakov, Helena. Universidad de Buenos Aires. Facultad de Agronomía; Argentina

Author affiliation: Alconada Magliano, Margarita María. Universidad Nacional de La Plata; Argentina

Author affiliation: Lavado, Raul Silvio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; Argentina

Abstract:

The biological nitrogen fixation carried out by some Bacteria and Archaea is one of the most attractive alternatives to synthetic nitrogen fertilizers. In this study we compared the effect of controlling the maximum activation state of the Azotobacter vinelandii glutamine synthase by a point mutation at the active site (D49S mutation) and impairing the ammonium-dependent homeostatic control of nitrogen- fixation genes expression by the ΔnifL mutation on ammonium release by the cells. Strains bearing the single D49S mutation were more efficient ammonium producers under carbon/energy limiting conditions and sustained microalgae growth at the expense of atmospheric N2 in synthetic microalgae– bacteria consortia. Ammonium delivery by the different strains had implications for the microalga's cell-size distribution. It was uncovered an extensive cross regulation between nitrogen fixation and assimilation that extends current knowledge on this key metabolic pathway and might represent valuable hints for further improvements of versatile N2-fixing microbial-cell factories.

Author affiliation: Ortiz Marquez, Juan César Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones En Biodiversidad y Biotecnología; Argentina. Fundación para Investigaciones Biológicas Aplicadas; Argentina

Author affiliation: Do Nascimento, Mauro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones En Biodiversidad y Biotecnología; Argentina. Fundación para Investigaciones Biológicas Aplicadas; Argentina

Author affiliation: Curatti, Leonardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones En Biodiversidad y Biotecnología; Argentina. Fundación para Investigaciones Biológicas Aplicadas; Argentina

Abstract:

Short-term response of microbial respiration after treatment with different doses of the herbicides mesulfuronmethyl (MET), 2,4-D, and glyphosate (GLY) was studied in microcosms of soils collected in three agricultural sites of the Southerns Pampas region, Buenos Aires Argentina. The influence of diammonium phosphate on carbon dioxide evolution when applied with the highest doses of the herbicides, was also investigated. MET had no effect on microbial respiration of an acidic soil of San Roman (pH 6.06), even at the highest rate. However, MET inhibited microbial respiration in soils of Bordenave (pH 7.4) at rate of 0.1 mg /Kg soil. Low applications rates of GLY and 2,4-D, produced only transitory effects on CO2 evolution whereas the addition of highest doses of these herbicides stimulated microbial activity. On the other hand, trhe addition of fertilizer to soil treated with a high dose of GLY temporarily inhibited CO2 release.

Author affiliation: Zabaloy, Maria Celina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Universidad Nacional del Sur. Departamento de Agronomia. Laboratorio de Biología del Suelo; Argentina

Author affiliation: Gomez, Marisa Anahi. Universidad Nacional del Sur. Departamento de Agronomia. Laboratorio de Biología del Suelo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Abstract:

The steady-state operation of a continuous industrial fluidized-bed granulator for urea production with multiple growth and cooling beds in series is modeled. The model is based on mass and energy balances, which account for the behavior of all the phases that coexist within the unit, as well as the bed hydrodynamics patterns. The granules growth that occurs through the deposition of droplets on urea seeds, followed by water evaporation and solidification of the urea present in the solution, is taken into account by considering the concentrated nature of the inlet urea solution. The proposed mathematical model successfully predicts industrial data for different plant capacities. The total urea dissolution heat is the most important thermal effect involved in the growth chambers. The granulator operation provides significant heat and mass transfer within the unit, with the water evaporation being almost complete and the outlet gas and particle temperatures being very similar.

Author affiliation: Bertin, Diego Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Química; Argentina

Author affiliation: Mazza, German Delfor. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina. Universidad Nacional del Comahue. Facultad de Ingeniería; Argentina

Author affiliation: Piña, Juliana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Química; Argentina

Author affiliation: Bucala, Veronica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Química; Argentina