8 research outputs found
LIGNIN VALORIZATION: FROM MOLECULES TO MATERIALS
No full textLIGNIN VALORIZATION: FROM MOLECULES TO MATERIALS
Chiara Allegretti1*, Gianmarco Griffini1, Arno Cordes2, Simon Fontanay3, Alberto Strini4, Julien Troquet3, Stefano Turri1, Paola D’Arrigo1,5
1Department of Chemistry, Materials and Chemical Engineering “Giulio Natta”, Politecnico of Milano,
p.zza L. da Vinci 32, Milano, Italy
2ASA Spezialenzyme GmbH Am Exer 19 C, Wolfenbüttel, Germany
3Biobasic Environnement, Biopôle Clermont Limagne, Saint-Beauzire, France
4Construction Technologies Institute - National Research Council of Italy (ITC-CNR), San Giuliano Mil., Italy
5The Protein Factory Research Center, via Mancinelli 7, Milano, Italy
*Corresponding author: [email protected]
Lignin is a highly complex phenolic matrix that acts as a binder in plants conferring them structural integrity and strength, and is one of the three major subcomponents of lignocellulosic biomass. Although burning lignin is still considered a valuable contribution in saving fossil sources, the exploitation of this extremely abundant natural polymer in terms of higher value-added applications is very appealing as it represents the only viable source to produce aromatic compounds as fossil fuels alternative. Due to the very broad composition in terms of molecular weight of the raw material, a pretreatment strategy becomes necessary for an efficient lignin valorization as macromolecular building block for polymeric materials or as precursor for aromatic small molecules.
To this end, a physical fractionation has been performed in this work, where Lignin (ProtobindTM1000) in a water/ethanol solution is subjected at first to microfiltration under vacuum in order to eliminate the insoluble residues. The permeate then undergoes a cross-flow filtration process using two subsequent membranes with cut-off of 3 kDa and 1 kDa. All the retentates and permeates have been fully characterized by GPC, GC-MS, ESI-MS, DSC, TGA and FT-IR.
This procedure is an essential tool for a thorough exploitation of the main three different fractions recovered, namely a high, an intermediate and a low molecular weight fraction. The first one is characterized by the presence of high molecular weight polymers and is used without further chemical modification for developing bio-based polymeric materials;[1] the last one can be separated by chromatography into small aromatic molecules for preparative organic chemistry; whereas the middle fraction, characterized by an intermediate molecular weight, is the ideal starting material for oxidative depolymerization assays.[2,3] On this fraction, a new cascade process has been investigated involving at first a chemical/photochemical step aiming at a partial conversion of macromolecules to low molecular weight intermediates followed by a biocatalytic step performed by different classes of O2-dependent laccases (EC 1.10.3.2) in the presence of TEMPO as a mediator. Promising results have been obtained and extensive research is now in progress.
Acknoledgements:
COST Action CM1303 Systems Biocatalysis
ValorPlus Project (grant agreement no FP7-KBBE-2013-7-613802
Two-step fractionation of a model technical lignin by combined organic solvent extraction and membrane ultrafiltration
No full textA fractionation method for technical lignin was developed, combining organic solvent extraction and membrane ultrafiltration of the solvent soluble component. This method was validated on a commercial wheat straw/Sarkanda grass lignin (Protobind 1000) using 2-butanone (MEK) as the solvent for both the extraction and the ultrafiltration operations. The parent lignin and the different obtained fractions were fully characterized in terms of chemical composition and physicochemical properties by gel permeation chromatography, gas chromatography/mass spectrometry (GC/MS), pyrolysis-GC/MS, total phenol contents, 31 P nuclear magnetic resonance ( 31 P NMR), thermogravimetric analysis, differential scanning calorimetry analysis, and Fourier-transform infrared spectroscopy. The results show that the proposed process allows a straightforward recovery of the different lignin fractions as well as a selective control over their molecular mass distribution and related dependent properties. Moreover, the operating flexibility of the Soxhlet/ultrafiltration process allows the treatment of lignins from different feedstocks using the same installation just by modulating the choice of the solvent and the membrane porosity with the best characteristics. This is one of the most important features of the proposed strategy, which represents a new fractionation approach with the potential to improve lignin valorization for materials science and preparative organic chemistry applications
Fractionation of Soda Pulp Lignin in Aqueous Solvent through Membrane-Assisted Ultrafiltration
No full textAn
industrial wheat straw lignin was fractionated by a multistep
process involving microfiltration followed by two membrane-assisted
ultrafiltration steps starting from an aqueous solvent solution. The
parent lignin and the different fractions were fully characterized
in terms of chemical composition and physicochemical properties by
gel permeation chromatography, gas chromatography–mass spectrometry,
high-performance liquid chromatography, thermogravimetric analysis,
differential scanning calorimetry analysis, and Fourier transform
infrared spectroscopy. The results show that the proposed process
allows us to selectively control the molar mass distribution of the
fractions and the related dependent properties. This strategy offers
a better understanding of the structural complexity of soda pulp raw
lignin and emerges as an essential tool for lignin valorization in
the context of material science and preparative organic chemistry
The Shoah, the Sacrifice, and the Animal in Elisabeth de Fontenay’s Thought
No full textThe Shoah, the Sacrifice, and the Animal in Elisabeth de Fontenay’s ThoughtThe article aims at presenting the views of a French philosopher Elisabeth de Fontanay on the issue of proximity between the Shoah and the inhuman, industrial treatment of animals.The author not only explains the history of such a contextualisation of the problem, but also tackles the question of the meaning of a sacrifice, which is a term often used to define both the extermination of the Jews and the mass animal slaughter.
Key words: Elisabeth de Fontenay, Shoah, sacrifice, animals, mass slaughte
Zagłada, ofiara i zwierzęta w myśli Elisabeth de Fontenay
No full textThe Shoah, the Sacrifice, and the Animal in Elisabeth de Fontenay’s ThoughtThe article aims at presenting the views of a French philosopher Elisabeth de Fontanay on the issue of proximity between the Shoah and the inhuman, industrial treatment of animals.The author not only explains the history of such a contextualisation of the problem, but also tackles the question of the meaning of a sacrifice, which is a term often used to define both the extermination of the Jews and the mass animal slaughter.
Key words: Elisabeth de Fontenay, Shoah, sacrifice, animals, mass slaughte
Two-Step Fractionation of a Model Technical Lignin by Combined Organic Solvent Extraction and Membrane Ultrafiltration
No full textS.4615-4626A fractionation method for technical lignin wasdeveloped, combining organic solvent extraction and membraneultrafiltration of the solvent soluble component. Thismethod was validated on a commercial wheat straw/Sarkandagrass lignin (Protobind 1000) using 2-butanone (MEK) as thesolvent for both the extraction and the ultrafiltrationoperations. The parent lignin and the different obtainedfractions were fully characterized in terms of chemicalcomposition and physicochemical properties by gel permeationchromatography, gas chromatography/mass spectrometry (GC/MS), pyrolysis-GC/MS, total phenol contents, 31Pnuclear magnetic resonance (31P NMR), thermogravimetric analysis, differential scanning calorimetry analysis, and Fouriertransforminfrared spectroscopy. The results show that the proposed process allows a straightforward recovery of the differentlignin fractions as well as a selective control over their molecular mass distribution and related dependent properties. Moreover,the operating flexibility of the Soxhlet/ultrafiltration process allows the treatment of lignins from different feedstocks using thesame installation just by modulating the choice of the solvent and the membrane porosity with the best characteristics. This isone of the most important features of the proposed strategy, which represents a new fractionation approach with the potentialto improve lignin valorization for materials science and preparative organic chemistry applications.4Nr.
Concentration dependence of in vitro biotransformation rates of hydrophobic organic sunscreen agents in rainbow trout S9 fractions: Implications for bioaccumulation assessment
No full textPerfil de los factores de riesgo asociados a la aparición de la primera infección intrahospitalaria en pacientes con quemaduras de segundo y tercer grado atendidos en el pabellón de Quemados de la Unidad de Servicios de Salud U. S. S. Simón Bolívar desde 1 de Enero hasta 31 de Julio del año 2018
No full text102 páginasEn los pacientes con quemaduras existen diversos factores de riesgo, que favorecen la aparición de infecciones intrahospitalarias, una complicación frecuente debido a la condición fisiológica provocada por la lesión. Actualmente esto representa un serio problema de salud pública, el cual conlleva aumento significativo en la morbimortalidad y costos en salud. Se realiza un análisis descriptivo, retrospectivo y univariado que tiene como fin caracterizar los factores de riesgo asociados a la aparición de la primera de infección intrahospitalaria en pacientes con quemaduras de segundo y tercer grado en la Unidad de Servicios de Salud U.S.S. Simón Bolívar desde el 1 de enero hasta el 31 de julio del año 2018. En primer lugar, se seleccionó la población de estudio mediante criterios de inclusión y exclusión previamente establecidos, permitiendo así la caracterización de la población objeto. Posterior a esto se desarrolló un formulario para la recolección de información suministrada por las historias clínicas del pabellón de quemaduras en la U.S.S. Simón Bolívar, luego se procede analizar los datos encontrados, mediante frecuencias para variables cualitativas y prueba shapiro wilk para establecer la normalidad de las variables cuantitativas. Dentro de los factores de riesgo encontrados en el presente estudio asociados a la aparición de IAAS en los pacientes quemados son: ser remitido de otra institución, pertenecer al grupo de adultez, sufrir quemadura por llama o electricidad, presentar quemadura grado II superficial y profunda, demoras en el primer acto quirúrgico, modulación inadecuada de la respuesta inmune y fisiológica de los pacientes con quemaduras, presentar dos o mas segmentos comprometidos por la quemadura, y estancia hospitalaria prolongada.In patients with burns there are several risk factors that favor the appearance of nosocomial infections, a frequent complication due to the physiological condition caused by the injury. Currently, this represents a serious public health problem, which entails a significant increase in morbidity and mortality and health costs. A descriptive, retrospective and univariate analysis is carried out with the purpose of characterizing the risk factors associated with the appearance of the first intrahospital infection in patients with second and third degree burns in the U.S.S. Simón Bolívar from January 1 to July 31 of the year 2018. First, the study population was selected through previously established inclusion and exclusion criteria, thus allowing the characterization of the target population. Among the risk factors associated with IAAS were: Be remitted after 24 hours, time of the first surgical act, burned body segments, depth of burn, unmodulated inflammatory response, microbiology of the hospital and nutritional status of the patient.Incluye bibliografíaPregradoMédico(a) Cirujan
