Antagonistic Toxic Effects of Surfactants Mixtures to Bacteria Pseudomonas putida and Marine Microalgae Phaeodactylum tricornutum

Surfactants can be found in an ever-widening variety of products and applications, in which the combination of several types of surfactants is used to reinforce their properties, looking for synergistic effects between them. After use, they tend to be discarded into wastewater, ending up in aquatic bodies with concerning harmful and toxic effects. The aim of this study is the toxicological assessment of three anionic surfactants (ether carboxylic derivative, EC) and three amphoteric surfactants (amine-oxide-based, AO), individually and in binary mixtures of them (1:1 w/w), to bacteria Pseudomonas putida and marine microalgae Phaeodactylum tricornutum. Critical Micelle Concentration (CMC) was determined to demonstrate the capacity to reduce surface tension and the toxicity of the surfactants and mixtures. Zeta potential (ζ-potential) and micelle diameter (MD) were also determined to confirm the formation of mixed surfactant micelles. The Model of Toxic Units (MTUs) was used to quantify the interactions of surfactants in binary mixtures and to predict if the concentration addition or response addition principle can be assumed for each mixture. The results showed a higher sensitivity of microalgae P. tricornutum to the surfactants tested and their mixtures than bacteria P. putida. Antagonism toxic effects have been detected in the mixture of EC + AO and in one binary mixture of different AOs; this is to say, the mixtures showed lower toxicity than expected.Ministry of Universities of the Spanish Government within the predoctoral grant FPU (Ayudas para la Formacion de Profesorado Universitario) FPU17/0335

Influence of ozonation processes on the microbial degradation of surfactants

The influence of ozonation of aqueous solutions of non-ionic surfactants was investigated in this study. The research was conducted using solutions of amine oxide based surfactants. These surfactants constitute a particular class of non-ionic surfactants that exhibit cationic behaviour in acid solution, they show good foaming properties and are skin compatible. The ozonation process was carried out at 25ºC in a stirred tank reactor for 30 min, where gaseous ozone was bubbled. The degree of mineralization achieved after the ozonation process was evaluated by measuring the total organic carbon before and after ozonation. The influence of ozonation on biodegradability of the solutions was studied using the biodegradation test by Pseudomonas putida. Biodegradation efficiency of the ozonated amine oxides based surfactants was also evaluated. It was found that the effectiveness of ozonation depended on the chemical structure of surfactant molecule. Ozonation only slightly improved biodegradation of these surfactants

Silica micro-and nanoparticles reduce the toxicity of surfactant solutions

In this work, the toxicity of hydrophilic fumed silica microand nanoparticles of various sizes (7 nm, 12 nm, and 50 μm) was evaluated using the luminescent bacteria Vibrio fischeri. In addition, the toxicity of an anionic surfactant solution (ether carboxylic acid), a nonionic surfactant solution (alkyl polyglucoside), and a binary (1:1) mixture of these solutions all containing these silica particles was evaluated. Furthermore, this work discusses the adsorption of surfactants onto particle surfaces and evaluates the effects of silica particles on the surface tension and critical micellar concentration (CMC) of these anionic and nonionic surfactants. It was determined that silica particles can be considered as non-toxic and that silica particles reduce the toxicity of surfactant solutions. Nevertheless, the toxicity reduction depends on the ionic character of the surfactants. Differences can be explained by the different adsorption behavior of surfactants onto the particle surface, which is weaker for nonionic surfactants than for anionic surfactants. Regarding the effects on surface tension, it was found that silica particles increased the surface activity of anionic surfactants and considerably reduced their CMC, whereas in the case of nonionic surfactants, the effects were reversed

Insights into the optimisation of the Clean-In-Place technique: Cleaning, disinfection, and reduced environmental impact using ozone-based formulations

Chemical and food industries are focusing on reducing the economic and environmental impact of cleaning operations. This study aims to analyse the use of alkaline ozonated formulations to remove starch adhering to stainless steel surfaces, improving disinfection of mature biofilms with Listeria and Pseudomonas, and reducing the environmental impact of wastewater. Three key cleaning parameters have been analysed in a lab-simulated Clean-In-Place system (CIP): temperature (20−60 °C), time (20−120 min), and cleaning formulations containing ozone and surfactant (linear alkylbenzene sulfonate, alkylpolyglucoside, fatty ethoxylated alcohol, lauramine oxide) were assayed. Higher temperature, time, and ozone concentration improved starch removal and disinfection of the stainless-steel surfaces, as well as the environmental impact of cleaning wastewater. Therefore, ozone-based CIP protocols could provide new opportunities to achieve cleaner, greener, and safer industries by intensifying cleaning, disinfection, and wastewater treatment in one step, saving operational costs compared to conventional CIP techniques.Grupos de Investigación RNM332 y TEP21

Mitochondrial Na+ controls oxidative phosphorylation and hypoxic redox signalling

All metazoans depend on O2 delivery and consumption by the mitochondrial oxidative phosphorylation (OXPHOS) system to produce energy. A decrease in O2 availability (hypoxia) leads to profound metabolic rewiring. In addition, OXPHOS uses O2 to produce reactive oxygen species (ROS) that can drive cell adaptations through redox signalling, but also trigger cell damage1–4, and both phenomena occur in hypoxia4–8. However, the precise mechanism by which acute hypoxia triggers mitochondrial ROS production is still unknown. Ca2+ is one of the best known examples of an ion acting as a second messenger9, yet the role ascribed to Na+ is to serve as a mere mediator of membrane potential and collaborating in ion transport10. Here we show that Na+ acts as a second messenger regulating OXPHOS function and ROS production by modulating fluidity of the inner mitochondrial membrane (IMM). We found that a conformational shift in mitochondrial complex I during acute hypoxia11 drives the acidification of the matrix and solubilization of calcium phosphate precipitates. The concomitant increase in matrix free-Ca2+ activates the mitochondrial Na+/Ca2+ exchanger (NCLX), which imports Na+ into the matrix. Na+ interacts with phospholipids reducing IMM fluidity and mobility of free ubiquinone between complex II and complex III, but not inside supercomplexes. As a consequence, superoxide is produced at complex III, generating a redox signal. Inhibition of mitochondrial Na+ import through NCLX is sufficient to block this pathway, preventing adaptation to hypoxia. These results reveal that Na+ import into the mitochondrial matrix controls OXPHOS function and redox signalling through an unexpected interaction with phospholipids, with profound consequences in cellular metabolism

Applications and Advances in Electronic-Nose Technologies

Electronic-nose devices have received considerable attention in the field of sensor technology during the past twenty years, largely due to the discovery of numerous applications derived from research in diverse fields of applied sciences. Recent applications of electronic nose technologies have come through advances in sensor design, material improvements, software innovations and progress in microcircuitry design and systems integration. The invention of many new e-nose sensor types and arrays, based on different detection principles and mechanisms, is closely correlated with the expansion of new applications. Electronic noses have provided a plethora of benefits to a variety of commercial industries, including the agricultural, biomedical, cosmetics, environmental, food, manufacturing, military, pharmaceutical, regulatory, and various scientific research fields. Advances have improved product attributes, uniformity, and consistency as a result of increases in quality control capabilities afforded by electronic-nose monitoring of all phases of industrial manufacturing processes. This paper is a review of the major electronic-nose technologies, developed since this specialized field was born and became prominent in the mid 1980s, and a summarization of some of the more important and useful applications that have been of greatest benefit to man

Biodegradación y toxicidad de tensioactivos comerciales

Tesis Univ. Granada. Departamento de Ingeniería Química. Leída el 21 de octubre de 200

Experiencias del uso de plataformas de enseñanza virtual en las enseñanzas técnicas en el curso 2009/2010 en la Universidad de Granada

En el presente trabajo se plantea la experiencia de varios profesores en el uso de las plataformas de enseñanza virtual, concretamente Moodle, en asignaturas tanto de carácter presencial como de carácter semipresencial dentro de las ramas técnicas de la enseñanza universitaria. Se analizan las ventajas e inconvenientes planteados en su uso, desde el punto de vista de los profesores, durante el curso académico 2009-2010

Experiencias del uso de plataformas de enseñanza virtual en las enseñanzas técnicas en el curso 2009-2010 en la Universidad de Granada

Resumen tomado de la publicaciónSe plantea la experiencia de varios profesores en el uso de las plataformas de enseñanza virtual, concretamente Moodle, en asignaturas tanto de carácter presencial como de carácter semipresencial dentro de las ramas técnicas de la enseñanza universitaria. Se analizan las ventajas e inconvenientes planteados en su uso, desde el punto de vista de los profesores, durante el curso académico 2009-2010.NavarraUniversidad Pública de Navarra. Biblioteca Universitaria; Campus de Arrosadia; 31006 Pamplona; Tel. +34948169060; Fax +34948169069; [email protected]