Purification de l'eau | EPFL Graph Search

vignette|Usine de traitement de l'eau à Fontburn, dans le nord de l'Angleterre. La purification de l'eau regroupe l'ensemble des techniques et méthodes permettant d'obtenir de l'« eau de procédé » à partir d'eau potable. Beaucoup d'industries utilisent de l'eau douce pour leurs procédés de production. L'eau de procédé peut avoir différents noms – et différentes caractéristiques – selon l'industrie et l'application, par exemple : « eau purifiée » et « eau pour préparation injectable » (eau PPI) dans l'industrie pharmaceutique ; « eau ultrapure » ou « eau » en microélectronique. La production de cette eau requiert l'utilisation de chaînes de traitement qui peuvent être plus ou moins complexes. Exemples de procédés industriels utilisant de l'eau purifiée Traitement de surface et galvanoplastie Traitement de surface Industrie pharmaceutique Eau purifiée L'eau purifiée est une eau destinée à la préparation de médicaments autres que ceux qui doi

Nature-inspired Circular-economy Recycling (NaCRe) for Proteins

Simone Giaveri

Since a few decades our planet has been loaded with billion tons of synthetic polymer-based materials, commonly named plastics. The large scale of plastic production, associated with its limited recyclability, are the driving force for the accumulation of such materials into the environment. Garbage patches, i.e. islands of plastics in the ocean, are striking evidences of this issue. A sustainable handling, that is production and disposal, of synthetic polymer-based materials is one of the greatest challenges that humanity has to face.Proteins and nucleic acids are natural polymers. Arguably, Nature produces an amount of such polymers that is higher with respect to man-made polymers. However, these materials do not accumulate into the environment, that is the approach used by Nature to handle these polymers is sustainable. The secret for its sustainaibility lies on the circularity in the materialsâ use. Indeed, proteins and nucleic acids are sequence-defined polymers that undergo depolymerization to monomers, and recycling into new materials by reassembling the so obtained monomers into arbitrarily different sequences. Organisms digest proteins into amino acids. These monomers are in turn polymerized to produce the protein of need, at the time of the protein synthesis.In this thesis we show that this process is achievable outside living organisms. Indeed, we depolymerized structurally different short peptides, and peptides mixtures into their constitutive amino acids, and recycled such monomers into biotechnologically relevant proteins (green, and red fluorescent proteins), by using an amino acid-free cell-free transcription-translation system. We further applied our methodology to recycle proteins with high relevance in materials engineering such as Î²-lactoglobulin films, used for water filtration, or silk fibroin solutions into green fluorescent protein. We were also successful in recycling mixtures composed of short peptides, and technologically relevant proteins into fluorescent proteins, as well as into bioactive enzymes (catechol 2,3-dioxygenase). Finally, we achieved multiple cycles of recycling (two cycles), and we demonstrated that the strategy can be expanded beyond the set of the twenty proteinogenic amino acids.Presented herein is a nature-inspired approach to recycling of soft materials, where unknown mixtures of polymers are recycled into the polymer of need, by the local community, at the time of recycling. The materials are costantly transformed into different ones, without any external feed, and there is no way to distinguish a new polymer from a recycled one. The strength of this method lies in its compatibility with the principles of circular economy.

EPFL2021

Solar disinfection of viruses (SODIS): inactivation of coliphages MS2 and phiX174, human adenovirus and echovirus in water from Switzerland and India

Alex Dionisio Calado

Access to safe drinking water remains a challenge in many regions of the world. New methods to treat drinking water are constantly developped and improved in both in industrialised countries and in developing countries. SODIS is an interesting household-level disinfection technique that simply consists of pouring water into a PET bottle and exposing it to sunlight for at least 6 hours. Bacteria are efficiently inactivated by sunlight during SODIS, but the efficiency of SODIS on virus removal is much less studied. In this work, the inactivation of bacteriophages MS2 and phiX174, and human echovirus and adenovirus was studied in three different waters, two from India and one from Switzerland. Good removal (4 logs in 6 hours at 22°C and a fluence rate of 600 1.34 kJ/cm2) of MS2 was achieved in Swiss tap water, while less efficient inactivation was achieved in both Indian waters for MS2 and echovirus (1 log in 6 hours at 22°C and a fluence rate of 1.34 kJ/cm2). Both phiX174 and adenovirus were much more resistant to SODIS disinfection and less than 1 log of inactivation was obtained in Swiss tap water for phiX174. However, inactivation was not significantly different from the dark control in Indian water and for all experiments with adenovirus. Echovirus was inactivated similarly than MS2 and adenovirus was equally slow as phiX174. An increased temperature during SODIS enhanced inactivation substantially; 6 logs in 6 hours could be expected at 45 °C and with a fluence rate of 1.34 kJ/cm2. Indirect-solar inactivation was responsible for the MS2 removal, while direct inactivation via sunlight absorption of genome was not occurring during SODIS. We argue that iron could be responsible for the formation of reactive oxygen species which react with the viruses and yield their inactivation. The slower inactivation in Indian waters was probably due to the quenching effect of the higher concentration of organic matter. Removal of echoviruses during SODIS could be sufficient (4 logs in 6 hours) particularly at higher temperatures and for water with a low organic matter content. In contrast, SODIS may not be effective to remove Adenoviruses.

2013

Characterization of the 5HT3 receptor in live cells and in vitro

Veronica Ponce de Leon

The serotonin type 3 receptor (5HT3R) is a homopentameric, cation selective channel that mediates fast excitatory transmission in the nervous system. It is a member of the Cys-loop family of receptors that include the nicotinic acetylcholine receptor (nAChR), the γ-amino butyric acid (GABA) type A and C and glycine receptors. The 5HT3 receptor is involved in behavioral and digestive disorders and it is therefore an important therapeutic target. The 5-HT3 receptor was expressed in mammalian HEK cells (chapter 2) stably and transiently, and its expression was optimized to obtain 1.6 x 106 receptors per cell for its solubilisation (chapter 3) and purification (chapter 4). Solubilisation of the receptor was evaluated under different conditions such as using CHAPS and C12E9 detergents and homogenization procedures such as vortexing and thurraxing the membranes. Radioligand binding assays indicated that the amount of solubilised receptor was similar in both cases. The stability of the receptor at different temperatures was evaluated. The receptor was more stable when kept at -20 °C compared to 4 or 37 °C. Purification of the 5-HT3 receptor from HEK cells was performed by tandem IMAC (Immobilized Metal ion Affinity chromatography)/IMAC purification and IMAC/streptactin flow column chromatography. The 5-HT3R was obtained 50% pure and a yield of 10 pmoles of receptor binding sites per gram of starting material (dry cells) was obtained. Purified receptor preparations were homogenous. Finally, the receptor was concentrated 5.5 times, which allowed the incorporation of the receptor in lipid vesicles for further studies. Detergent solubilised 5-HT3R was incorporated in lipid vesicles and the functionality of the receptor was assessed by studying calcium ion permeability of the channel using calcium ion sensitive fluorophores (chapter 5). The effect of the cAMP dependent kinase (PKA), on the 5-HT3R was investigated by measuring the KD of the radioactive ligand [3H]GR65630 to the receptor in cells where PKA was activated or inhibited (chapter 6). Finally a dose-response curve of the binding activity of the 5-HT3R upon activation of the PKA was assayed in both HEK and CHO cells (chapter 6). Radioligand binding assays indicated that upon activation of the PKA, there was a decrease of the KD of 30% indicating an increase in the receptor binding affinity to 5-HT upon activation of the PKA (chapter 6). A kinase and cytoskeleton binding protein PDLI1 that was co-purified with the receptor was found phosphorylated upon PK activation (chapter 6). As PDLI1-like proteins are adaptor proteins between kinases, cytoskeleton proteins and sometimes receptors, the latter may be involved in the kinase activation of the receptor. These results contribute to the optimization of the receptor expression, solubilisation and purification in mammalian cells for its incorporation in lipid vesicles and for further structural studies. In addition, this work gave new insights to the mechanisms of channel regulation by PKA phosphorylation at the cell membrane and the intermediate proteins that are involved.

EPFL2009