Biodegradation of Iprodione and Chlorpyrifos Using an Immobilized Bacterial Consortium in a Packed-Bed Bioreactor.

This work provides the basis for implementing a continuous treatment system using a bacterial consortium for wastewater containing a pesticide mixture of iprodione (IPR) and chlorpyrifos (CHL). Two bacterial strains (Achromobacter spanius C1 and Pseudomonas rhodesiae C4) isolated from the biomixture of a biopurification system were able to efficiently remove pesticides IPR and CHL at different concentrations (10 to 100 mg L-1) from the liquid medium as individual strains and free consortium. The half-life time (T1/2) for IPR and CHL was determined for individual strains and a free bacterial consortium. However, when the free bacterial consortium was used, a lower T1/2 was obtained, especially for CHL. Based on these results, an immobilized bacterial consortium was formulated with each bacterial strain encapsulated individually in alginate beads. Then, different inoculum concentrations (5, 10, and 15% w/v) of the immobilized consortium were evaluated in batch experiments for IPR and CHL removal. The inoculum concentration of 15% w/v demonstrated the highest pesticide removal. Using this inoculum concentration, the packed-bed bioreactor with an immobilized bacterial consortium was operated in continuous mode at different flow rates (30, 60, and 90 mL h-1) at a pesticide concentration of 50 mg L-1 each. The performance in the bioreactor demonstrated that it is possible to efficiently remove a pesticide mixture of IPR and CHL in a continuous system. The metabolites 3,5-dichloroaniline (3,5-DCA) and 3,5,6-trichloro-2-pyridinol (TCP) were produced, and a slight accumulation of TCP was observed. The bioreactor was influenced by TCP accumulation but was able to recover performance quickly. Finally, after 60 days of operation, the removal efficiency was 96% for IPR and 82% for CHL. The findings of this study demonstrate that it is possible to remove IPR and CHL from pesticide-containing wastewater in a continuous system.

Biosurfactant Production by Bacillus amyloliquefaciens C11 and Streptomyces lavendulae C27 Isolated from a Biopurification System for Environmental Applications.

Biosurfactant-producing bacteria can be found in contaminated environments such as biopurification systems (BPS) for pesticide treatments. A total of 18 isolates were screened to determine their ability to produce extracellular biosurfactants, using olive oil as the main carbon source. Out of the eighteen isolates, two strains (C11 and C27) were selected for biosurfactant production. The emulsification activities of the C11 and C27 strains using sunflower oil was 58.4 and 53.7%, respectively, and 46.6 and 48.0% using olive oil. Using molecular techniques and MALDI-TOF, the strains were identified as Bacillus amyloliquefaciens (C11) and Streptomyces lavendulae (C27). The submerged cultivation of the two selected strains was carried out in a 1 L stirred-tank bioreactor. The maximum biosurfactant production, indicated by the lowest surface tension measurement, was similar (46 and 45 mN/m) for both strains, independent of the fact that the biomass of the B. amyloliquefaciens C11 strain was 50% lower than the biomass of the S. lavendulae C27 strain. The partially purified biosurfactants produced by B. amyloliquefaciens C11 and S. lavendulae C27 were characterized as a lipopeptide and a glycolipid, respectively. These outcomes highlight the potential of the selected biosurfactant-producing microorganisms for improving pesticides' bioavailability and therefore the degradational efficacy of BPS.

Cadmium Removal from Giant Squid (Dosidicus gigas) Hydrolysate in Fixed-Bed Columns Packed with Iminodiacetic Resin: Tools for Scaling up the Process.

Giant squid hydrolysate (GSH) elaborated from different batches from a fishing company was evaluated for cadmium removal. Fixed-bed column packed with iminodiacetic resin as adsorbent was used. GSH solution at different cadmium concentrations were fed in the fixed-bed column and breakthrough curves were evaluated. A high degree of metal removal from the solution was achieved and the saturation point (Ce/C0 ≤ 0.8) was achieved more quickly at higher concentrations of cadmium. The maximum capacity of adsorption (q0) was obtained using the Thomas model, where 1137.4, 860.4, 557.4, and 203.1 mg g-1 were achieved using GSH with concentrations of 48.37, 20.97, 12.13, and 3.26 mg L-1, respectively. Five cycles of desorption of the resin with HCl (1 M) backflow and regeneration with NaOH (0.5 M) were also evaluated, where no significant differences (p-value > 0.05) were observed between each cycle, with an average of 935.9 mg g-1 of qmax. The in-series columns evaluated reached a total efficiency of 90% on average after the third column in GSH with a cadmium concentration of 20.97 mg L-1. This kind of configuration should be considered the best alternative for cadmium removal from GSH. Additionally, the chemical composition of GSH, which was considered a quality parameter, was not affected by cadmium adsorption.

Satisfacción de los estudiantes ante una sesión de exploración cardiológica impartida por compañeros entrenados / Student satisfaction in response to a scanning session in cardiology given to trained students

Objetivo: Conocer la valoración de los estudiantes respecto a la simulación como herramienta de formación y la opinión sobre la figura del alumno instructor. Sujetos y métodos: El taller se realizó en el Centro de Simulación y tuvo una duración aproximada de 90 minutos. En cada sesión estaba el alumno instructor con diez compañeros. Los alumnos instructores fueron formados previamente por un profesor de cardiología. Al finalizar la sesión, los estudiantes cumplimentaron un cuestionario de satisfacción anónimo que contenía preguntas relacionadas con el aprendizaje basado en la simulación y sobre la capacidad de sus compañeros para actuar como formadores. Resultados: Se obtuvieron encuestas de 291 estudiantes: 150 de quinto y 141 de sexto curso (82,4% y 71,2% de los matriculados, respectivamente). Los datos obtenidos del cuestionario de satisfacción respecto a la metodología de aprendizaje obtuvieron puntuaciones entre 3,64 y 4,75 sobre 5. Las preguntas que valoraban la opinión acerca de los alumnos formadores obtuvieron valores entre 4,88 y 4,93 sobre 5. Conclusiones: La simulación es una herramienta docente complementaria muy valiosa. La participación de alumnos instructores podría ser una ayuda adicional en los talleres de simulación de exploración cardiológica

Aim: To acknowledge the students evaluation on the simulation as a training tool and their opinion on the ability of students as trainers. Subjects and methods: The workshop was held at the Simulation Center and lasted approximately 90 minutes. The student in charge of training had 10 peers in each session. Previously, these students were taught to become trainers by a professor in Cardiology. After the session, students completed an anonymously satisfaction survey with questions related to the simulation-based learning and the ability of their peers to act as trainers. Results: We obtained surveys from 291 students, 150 from fifth year and 141 from sixth year students (82.4% and 71.2% respectively of those enrolled). The data that we obtained from the satisfaction survey with reference to the learning methodology had a score between 3.64 and 4.75 out of 5. The questions that assessed the students’ opinions on the ability of their peers to act as trainers obtained values between 4.88 and 4.93 out of 5. Conclusions: Simulation is a valuable complementary teaching tool. Therefore, the participation of students as trainers could provide an additional assistance in the cardiological examination simulation workshops

Influence of novel lignocellulosic residues in a biobed biopurification system on the degradation of pesticides applied in repeatedly high doses

Background: The biobed is a simple biopurification system used to prevent the point-source pesticide contamination that occurs at farm level. The typical composition of the biomixture used in this system is soil, peat and straw in volumetric proportions of 1:1:2. The principal component is straw due to its positive effects on biological activity and thus pesticide degradation. However, access to straw can be limited in some regions, so it must be replaced by other more readily available lignocellulosic residues. Results: Therefore, two alternate lignocellulosic materials (barley husks and pine sawdust) were evaluated as partial substitutes for straw. The degradation of a repeatedly applied mixture of six pesticides by these alternates was assessed. The microbial respiration and fluorescein diacetate (FDA) hydrolysis activity were also assessed. The results showed that the highest degradation efficiency was found in mixtures containing straw and barley husks. Each biomixtures tested achieved a high degradation (50 to 90%) of all the pesticides used except iprodione. Repeated applications of pesticides resulted in a slowing of the degradation rate of all pesticide types in all biomixtures. FDA activity and microbial respiration were higher in the biomixtures containing barley husks and straw compared to the mixture with pine sawdust, a result consistent with the pesticide degradations observed. Conclusions: This paper demonstrates that the straw in the traditional biomixture can be partially replaced by other lignocellulosic materials to efficiently degrade a mixture of pesticides, even when the pesticides are added in successive applications and high concentrations.

Selection of white-rot fungi to formulate complex and coated pellets for Reactive Orange 165 decolourization

Six strains of white-rot fungi isolated from southern Chile were evaluated for their ergosterol/biomass correlation and ligninolytic potential in solid medium to formulate pellets for Reactive Orange 165 (RO165) decolourization. The fungus Anthracophyllum discolor was selected to formulate complex pellets (fungal mycelium, sawdust, and activated carbon), coated pellets (complex pellet + alginate) and simple pellets (fungal mycelium). The activity of ligninolytic enzymes (laccase, manganese peroxidase, manganese-independent peroxidase, and lignin peroxidase) was evaluated in both the complex and coated pellets in modified Kirk medium, and the morphology of the pellets was studied using scanning electron microscopy (SEM). Complex pellets of A. discolor showed a higher enzymatic production mainly MnP (38 U L-1 at day 15) compared to coated and simple pellets. Examinations using SEM showed that both pellets produced a black core that was entrapped by a layer of fungal mycelium. Decolourization of RO165 was demonstrated with all the pellets formulated. However, the highest and fastest decolourization was obtained with complex pellets (100 percent at day 8). Therefore, complex pellets of A. discolor can be used for the biological treatment of wastewater contaminated with RO165.

Aprendizaje de la historia clínica con pacientes simulados en el grado de Medicina / Learning to take medical histories through patients simulation in undergraduate Medical School students

Objetivos. La utilización de la simulación es habitual en medicina para mejorar el conocimiento y habilidades de competencias. Se pueden utilizar pacientes virtuales, simuladores y pacientes simulados. Nosotros planteamos que alumnos de quinto y sexto curso actúen como pacientes simulados para que sus compañeros de primero aprendan la anamnesis de la historia clínica. Sujetos y métodos. Un total de 207 alumnos de primer curso de grado aprendieron a realizar la historia clínica en una sala de urgencias del centro de simulación entrevistando a pacientes simulados, que eran sus compañeros de quinto y sexto curso. Se evaluaron las historias clínicas realizadas, y para conocer el grado de satisfacción de los estudiantes se pidió que cumplimentasen un cuestionario anónimo tanto a los alumnos de primer curso como a los de cursos superiores. Resultados. La valoración de la calidad de las historias clínicas fue de 8,2 sobre 10. Esta metodología ha sido muy bien valorada. A la pregunta ‘¿el entrenamiento con pacientes simulados ayuda al aprendizaje para la realización de la historia clínica?’, los alumnos de primero puntuaron 9, y los de quinto y sexto, 9,2. Al ítem ‘¿trabajar con pacientes simulados mejora sus habilidades de comunicación?’, ambos grupos puntuaron 8,6. Y para ‘¿es adecuado el aprendizaje de la historia clínica mediante pacientes simulados previo a su aprendizaje con pacientes reales?’, ambos grupos puntuaron 9,3. La valoración de la experiencia como paciente simulado fue de 9,3. Conclusión. El aprendizaje de la historia clínica en primer curso del grado de Medicina mediante pacientes simulados resulta beneficioso para los alumnos. Un contacto temprano con la clínica a partir del aprendizaje basado en la simulación podría mejorar la formación de los estudiantes (AU)

Aims. Simulation techniques are commonly used in medical education to improve the acquisition of knowledge, abilities and competencies. Several methods have been proposed: virtual patients, high fidelity devices and standard patients. We propose the use of 5th-6th year Medical School students acting as patients when teaching history taking to their 1st year colleagues. Subjects and methods. A total of 207 students from 1st year Medical School underwent training in history taking at the Simulation Center, with senior students acting as actors. The quality of the written medical records was evaluated by two medical doctors. The satisfaction of all students involved in the course was evaluated through an anonymous voluntary questionnaire. Results. The average score of the written medical histories was 8.2/10, more than satisfactory for our goals. Students’ satisfaction rate was high. Mean score on questions inquiring the usefulness of patient simulation in learning how to perform a clinical history was 9/10 and 9.2/10 for first and fifth-sixth year students respectively. Questions on improvement of communication skills scored 8.6/10 and 8.6/10 respectively. The fruitfulness of training with simulated patients before practicing with real patients was 9.3/10 and 9.3/10 respectively. Finally, the assessment of the whole course with simulated patients was of 9.3/10. Conclusion. Learning history taking in first year Medical School with simulated patients acted by senior students was beneficial and user-friendly for both students and actors. An early contact with the clinical practice through simulated patients could improve performance and safety (AU)

Improving the adsorption capacity and solid structure of natural volcanic soil using a foaming-sintering process based on recycled polyethylene terephthalate (PET).

The volcanic soils of southern Chile have demonstrated a high capacity to adsorb environmental pollutants, but for an industrial application, a stable solid material is necessary. The objective of this work was to produce a stable ceramic material through a process involving volcanic soil-polyurethane foam produced with recycled polyethylene terephthalate (PET)-polyols, and further thermal treatment. The selected foam formulation with 35.4% volcanic soil (< 63 microm) seems to be the most suitable for thermal treatment, with temperature steps at 700, 850, 1000 and 1200 degrees C. The porous ceramic material obtained has a stable solid form and an improved chlorophenols adsorption capacity (comparable to natural zeolites) that makes it suitable for advanced wastewater treatment and landfill leachate depuration.

Evaluation of sequential aerated treatment of wastewater from hardboard mill

Wastewater from a hardboard mill characterized by a high organic content (15-30 g/L COD) was studied in a bench scale sequential aerated system in order to define a start up strategy. Inlet COD concentration varied from 0.5 to 25 g/L and the hydraulic retention time was maintained at 5 days. The sequential system proposed could reduce BOD, COD, TSS and phenol over 90 percent except when the inlet COD concentration was lower than 25 g/L.

Água residual proveniente de uma indústria de tabuleiro de fibra dura caracterizada por ter um elevado conteúdo orgânico (15-30 g/L DQO) foi estudada utilizando um sistema arejado seqüêncial de forma a definir uma estratégia de start up. A concentração de DQO na entrada do sistema variou na faixa de 0,5-25 g/L e o tempo de residência hidráulico foi mantido em 5 dias. O sistema seqüêncial proposto reduziu DBO, DQO, SST e fenol sobre 90 por cento quando a concentração de DQO na entrada foi menor a 25 g/L.