Grupo UTN GISTAQ (Grupo de Investigación sobre temas Ambientales y Químicos)
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Item Isolation of microorganisms in effluents from a public health laboratory(Sociedad Argentina de Microbiología General, 2024-12-10) Fontana, Gimena Lilián; Hervot, Elsa Ivonne; Farías, Alejandro Rubén; Cuadra, Pablo Nicolás; Guidoli, Marcos GabrielThe waste from health facility laboratories consists largely of liquid effluents from automatic analyzers. In practice, these effluents are typically discharged into the sewer system without any prior treatment. Automatic analyzers use disinfectants, detergents, cleaning solutions, and other reagents that may eliminate pathogenic microorganisms. As a result, they generate effluents with a high load of chemical contaminants. If discharged directly into the sewage system without prior treatment, these contaminants can be considered a point source of various residual antimicrobial compounds and other pollutants that may promote the development of antimicrobial resistance. The objective of this study is to isolate environmental microorganisms capable of growing and degrading the chemical contaminants present in effluents generated by the analysis equipment and staining process of the Clinical Analysis Laboratory at Julio C. Perrando Hospital, located in Resistencia, Chaco Province.Item Analysis of herbicide biodegradation by native bacteria isolated from rice crop soils in Chaco, Argentina(Sociedad Argentina de Microbiología General, 2024-12-10) Cuadra, Pablo Nicolás; Farías, Alejandro Rubén; Jorge, Nelly Lidia; Vullo, Diana LiaIn Argentina, weed management in rice and other crops is often done with herbicides that persist in the soil for a long time. The incorrect and indiscriminate use of these agrochemicals has caused environmental problems, such as soil, groundwater and surface water contamination. Clomazone (CLM), an herbicide from the chemical group of oxazolidinones, is a selective pre- and post-emergence herbicide indicated for application in rice. Imazapyr and imazapic (IMR+IMC) are two herbicides that belong to the group of imidazolinones which interfere weed growth by inhibiting the action of the plant enzyme acetohydroxyacid synthase (AHAS). The objective of this work was to analyze the growth kinetics (GK) of bacterial strains isolated from rice crop soils with CLM and IMR+IMC as the only carbon source, and to analyze their biodegradation over time.Item Furfural removal from a polluted effluent by using a fluidized bed reactor(2023-10-02) Echeverría, Macarena Celeste; Cuadra, Pablo Nicolás; Sandoval, Evangelina; Benimeli, Claudia SusanaFurfural is a heterocyclic aromatic aldehyde and wastewaters derived from its production can contain around 800 mg l-1, which can cause toxic effects on living systems if released into the environment without proper treatment. In the present work, the furfural removal from a simulated effluent by a fluidized bed bioreactor filled with an actinobacteria biofilm on vegetable sponge (Luffa aegyptiaca) support was studied. For this, a suspension of a mixed culture of Nocardiopsis sp. L9, Streptomyces sp. A12 and M7, in TSB medium (D.O540nm=1) was prepared. The luffa support was cut in cubes of approximately 0.1 g, which were washed and sterilized. The bacterial biofilm production on luffa cubes was carried out in 250 ml Erlenmeyer flasks, which contained 0.5 g of the support and 60 ml of the bacterial suspension. After 96 h of incubation at 30 °C and 100 rpm, the colonized sponge cubes were introduced into the reactor for the bioremediation treatment. A laboratory-scale fluidized bed reactor was used, which had an inlet for the effluent to be treated in the lower side and an outlet for the treated effluent in the upper part. The furfural residual concentration in the treated effluent was evaluated by HPLC, every 24 h for 4 days. Ecotoxicity tests were carried out using Raphanus sativus seeds (radish, Punta Blanca variety). Bacterial colonization on vegetal sponge was also evaluated by scanning electron microscopy, before and after treatment. The analysis by HPLC showed a complete depletion of furfural in the effluent after 24 h of treatment. Microphotographs by scanning electron microscopy showed an increase in the presence of possible polymeric substances in luffa cubes at the end of treatment regarding to the initial time, as result of biofilm production by the actinobacterial consortium. The ecotoxicity tests with radish seeds showed significant increases (p<0.05) in the vegetable biomarkers of seedlings obtained in the treated effluent, indicating that the toxic effects caused by furfural were reversed, confirming the effectiveness of the bioremediation process.Item Ensayos de resistencia en medios de cultivo sólidos de colonias bacterianas autóctonas en presencia del herbicida Kifix®(2023-09-01) Viera, María Florencia; Delgado, Lautaro; Sánchez Irigoyen, María Florencia; Ayala Bengler, Paula; Cuadra, Pablo NicolásEl presente trabajo tiene como objeto evaluar la resistencia de un grupo de 30 bacterias al herbicida Kifix, aisladas previamente en trabajos anteriores a partir de diferentes muestras de suelo de un cultivo arrocero ubicado en la localidad de Las Palmas, Chaco, con la finalidad de identificar aquellas que presenten mayor potencial de biodegradación para ser utilizadas en posteriores ensayos. Para ello, se realizó la inoculación de estos microorganismos mediante la técnica de estriado en placa de Petri, utilizando medios de cultivo nutritivos y oligotróficos, dosificados con concentraciones crecientes del contaminante. La evaluación del crecimiento bacteriano se llevó a cabo mediante observaciones macroscópicas de las siembras realizadas durante periodos de tiempo específicos. Los resultados obtenidos demostraron que 15 cepas son capaces de desarrollarse en un medio nutritivo tradicional y 12 en medios oligotróficos con concentraciones considerables del plaguicida, por lo que se pretende continuar con los ensayos a concentraciones más elevadas del agroquímico.Item Growth kinetics of soil bacteria in presence of pesticides applied for rice crop production(2023-10-05) Cuadra, Pablo Nicolás; Farías, Alejandro Rubén; Utgés, Enid Marta; Jorge, Nelly Lidia; Vullo, Diana LiaThe expansion of agricultural activity promoted the use of agrochemicals, whose permanence in the soil can cause serious contamination problems. Its infiltration into groundwater or runoff into surface watercourses, as well as their deposition in trophic chains, imply a latent risk to the balance of ecosystems. The present work objective is to analyze the growth kinetics of bacteria isolated from soils destined for rice cultivation in Las Palmas, Chaco, Argentina, in the presence of glyphosate, imazapic-imazapyr and clomazone, pesticides of current application. Two of 24 isolated bacteria named H5 and I2 were specially selected for this study because of their resistant to high agrochemical concentrations. Growth kinetics tests were carried out applying two methods to monitor biomass increase. One of these methods was based on biomass determination by dry weight (BPS) and the other by colony forming units/ml (CFU/ml) count using the drop technique (RMG). Initial inoculums were prepared in minimal saline medium (M9) with glucose 0,5%p/V and incubated at 30°C at 200 or 300 rpm for 24 h. Then, 5 ml of each were transferred to 50 ml of M9 with 1% V/V of the mixture of agrochemicals as the only carbon source to evaluate growth kinetics under these restrictive conditions. The formation of bacterial aggregates at the lowest agitation level was observed, interfering with biomass determinations. For this reason, the subsequent tests were carried out at 300 rpm to prevent the floc formation. To apply the BPS method, 1 ml culture samples were centrifuged 30 minutes, and the pellet obtained was dried for 10 h at 60°C to be subsequently weighed. For the RMG method, culture samples were taken and 10 µl drops of serial dilutions in NaCl 150 mM, were seeded in triplicates in Plate Count Agar (PCA). The growth kinetics was also analyzed by RMG with glucose as sole carbon source. The emulsification of clomazone formulation derived in turbidity in culture medium, generating interferences in the biomass estimation by the BPS method. Therefore, the only way to evaluate kinetic parameters was by the CFU/ml counting method by RMG at 300 rpm. In this way, growth curves for the two tested bacteria revealed generation times (tg) of 1.48 h and 7.46 h with division rates () of 0.68 h-1 and 0.15 h-1 for I2 and H5 respectively. Results obtained with glucose showed higher division rates and shorter generation times (I2=1,4 h-1,H5= 0,48 h-1, tgI2=0,73 h, tgH5=2.34 h) demonstrating a slowdown in bacterial growth by pesticide formulation consume. Further studies will be focused on the identification of degradation products to proceed with the application of mixed cultures in rice crop soil bioremediation microcosms experiments.