Exploring ionic liquids based on pyrrolidinium and imidazolium cations with low toxicity towards Escherichia coli for designing sustainable bioprocesses.

Ionic liquids (ILs) are widely applied in many bioprocesses involving microorganisms due to their unique properties. In this work, the toxicity of imidazolium and pyrrolidinium ionic liquids towards E. coli., a bacterium for which there are limited toxicity data in the literature, was determined. For its simplicity, the nephelometry method was used to estimate ionic liquid toxicity values. The influence of the cation and the alkyl chain length of the cation and anion was analysed. Pyrrolidinium cations were seen to be less toxic than imidazolium cations, while an increase in the alkyl chain length of both pyrrolidinium and imidazolium cations increased the toxicity. Among the anions studied, dimethylphosphate ([Me2PO4]) was the less toxic, while the EC50 for the ionic liquid 1-butyl-3-methylpyrrolidinium dimethylphosphate ([C1C4Pyr][Me2PO4]) was close to 200 mM. Furthermore, a dicationic ionic liquid based on imidazolium and pyrrolidinium cations was synthetized and its toxicity toward E. coli was analysed, maintaining a growth rate of 100 % in the range 0-0.76 mM. The methodology used in this work allows to easily find the less toxic ionic liquids that are biocompatible with E. coli to be used in new bioprocesses.

Synthesis of low cost organometallic-type catalysts for their application in microbial fuel cell technology.

Microbial fuel cells (MFCs) are a promising technology that generates electricity from several biodegradable substrates and wastes. The main drawback of these devices is the need of using a catalyst for the oxygen reduction reaction at the cathode, which makes the process relatively expensive. In this work, two low cost materials are tested as catalysts in MFCs. A novel iron complex based on the ligand n-phenyledenparaethoxy aniline has been synthesized and its performance as catalyst in single chamber MFCs containing ionic liquids has been compared with a commercial inorganic material such as Raney nickel. The results show that both materials are suitable for bioenergy production and wastewater treatment in the systems. Raney nickel cathodes allow MFCs to reach a maximum power output of 160 mW.m-3 anode, while the iron complex offers lower values. Regarding the wastewater treatment capacity, MFCs working with Raney nickel-based cathodes reach higher values of chemical oxygen demand removal (76%) compared with the performance displayed by the cathodes based on Fe-complex (56%).

Ionic liquid technology to recover volatile organic compounds (VOCs).

Volatile organic compounds (VOCs) comprise a wide variety of carbon-based materials which are volatile at relatively low temperatures. Most of VOCs pose a hazard to both human health and the environment. For this reason, in the last years, big efforts have been made to develop efficient techniques for the recovery of VOCs produced from industry. The use of ionic liquids (ILs) is among the most promising separation technologies in this field. This article offers a critical overview on the use of ionic liquids for the separation of VOCs both in bulk and in immobilized form. It covers the most relevant works within this field and provides a global outlook on the limitations and future prospects of this technology. The extraction processes of VOCs by using different IL-based assemblies are described in detail and compared with conventional methods This review also underlines the advantages and limitations posed by ionic liquids according to the nature of the cation and the anions present in their structure and the stability of the membrane configurations in which ILs are used as liquid phase.

Microalgae as substrate in low cost terracotta-based microbial fuel cells: Novel application of the catholyte produced.

In this work, the by-product generated during the operation of cylindrical MFCs, made out of terracotta material, is investigated as a feasible means of degrading live microalgae for the first time. In addition to the low cost materials of this design, the reuse of the solution produced in the cathode renders the technology truly green and capable of generating bioenergy. In this study, the effect of a light/dark cycle or dark conditions only on the digestion of live microalgae with the catholyte is investigated. The results show that a combination of light/dark improves degradation and allows algae to be used as substrate in the anode. The addition of 12.5mL of a 1:1 mix of catholyte and microalgae (pre-digested over 5days under light/dark) to the anode, increases the power generation from 7µW to 44µW once all the organic matter in the anode had been depleted.

Process design and economic analysis of a hypothetical bioethanol production plant using carob pod as feedstock.

A process for the production of ethanol from carob (Ceratonia siliqua) pods was designed and an economic analysis was carried out for a hypothetical plant. The plant was assumed to perform an aqueous extraction of sugars from the pods followed by fermentation and distillation to produce ethanol. The total fixed capital investment for a base case process with a capacity to transform 68,000 t/year carob pod was calculated as 39.61 millon euros (€) with a minimum bioethanol production cost of 0.51 €/L and an internal rate of return of 7%. The plant was found to be profitable at carob pod prices lower than 0.188 €/kg. An increase in the transformation capacity of the plant from 33,880 to 135,450 t/year was calculated to result in an increase in the internal rate of return from 5.50% to 13.61%. The obtained results show that carob pod is a promising alternative source for bioethanol production.

Menopausia: actitudes y conocimientos en un grupo de medicos internos, de la facultad de medicina, de la Universidad de Antioquia / Menopause: attiude an knowledge in a group of final-year medical students of the school of medicine of the University of Antioquia

Se presentan los resultados de una encuesta realizada a los médicos de la Facultad de Medicina de la Universidad de Antioquia, en el segundo semestre de 1997. El proyecto se realizó con el doble propósito de construir conocimiento sobre el tema del climaterio femenino y, en segundo lugar, para aportar elementos pertinentes a la discusión de cambio curricular en que está empeñada la Facultad y la Universidad. Partimos de la hipótesis de que la historia personal del individuo limita las actitudes y condiciona el desarrollo de motivación y destrezas sobre un tema determinado. Se utilizó el censo y las técnicas de encuesta y escala Lickert para indagar sobre variables socioculturales, demográficas y de carácter científico/técnico. Se encontró que el nivel de conocimientos, medido por la nota, fue de 2.85 + 0.83; la actitud frente a la terapia fue baja en el 44 por ciento y alta en el 40 por ciento. Como se había previsto en la hipótesis, la relación entre actitudes y conocimientos fue directa, pero la asociación con variables sociodemográficas no pudo determinarse debido a la homogenidad de la población

Inhibition of renal, cardiac and corneal (Na(+)-K+)ATPase by 12(R)-hydroxyeicosatetraenoic acid.

12(R)-hydroxy-5,8,10,14-eicosatetraenoic acid [12(R)-HETE] is one of the major arachidonate metabolites of the corneal epithelial cytochrome P450 system. We studied its inhibitory effect on different preparations of (Na(+)-K+)ATPase. 12(R)-HETE had no effect on ATPase activity in the absence of Na+ and K+. However, it inhibited ouabain-sensitive (Na(+)-K+)ATPase obtained from bovine corneal epithelium, rat kidney and rat heart ventricle in a concentration-dependent manner with an IC50 of 10(-6) M. Its enantiomer, 12(S)-HETE, was inactive at 10(-7) M and 10(-6) M, but it inhibited (Na(+)-K+)ATPase at higher doses, an effect also seen with arachidonic acid. 12(R)-HETE as an endogenous metabolite of arachidonic acid may modulate physiological and pathophysiological processes by affecting (Na(+)-K+)ATPase activities in vivo.