Laboratoire Of Catalyse Et Environnement

Casablanca, Morocco

Laboratoire Of Catalyse Et Environnement

Casablanca, Morocco
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Arnold-Apostolides N.,Higher Institute for Agricultural Engineering for Mediterranean Countries | Cazier F.,Center Communications Of Mesures | Najm S.,Lebanese University | Labaki M.,Lebanese University | And 2 more authors.
Acta Horticulturae | Year: 2013

Satureja thymbra L. is a well known aromatic plant; endemic of the Mediterranean region and characterized by an oregano-like smell. It is frequently used as a spice and herbal tea in the Lebanese traditional medicine. Air dried aerial parts from S. thymbra were collected in Lebanon at random during April 2009. For 3 h the plant material was submitted to steam distillation using a clevenger-type apparatus to produce the essential oil with a yield of 0.84% (w/w). Oil was dried using anhydrous magnesium sulfate and stored at 4C. S. thymbra oil was analyzed by GC/MS. Nineteen compounds representing 98.8% of the oil sample were identified. The major components of Satureja thymbra L. oil were ?-terpinene (34.06%), carvacrol (23.07%) and thymol (18.82%). Also abundant were ?-cymene (7.58%), caryophyllene (3.96%), a-terpinene (3.53%) and myrcene (1.70%). The results of our study were compared to reports on the same or different species from other origins.


Elsellami L.,CNRS Research on Catalysis and Environment in Lyon | Elsellami L.,Laboratoire Of Catalyse Et Environnement | Vocanson F.,Jean Monnet University | Vocanson F.,CNRS Hubert Curien Laboratory | And 5 more authors.
Applied Catalysis A: General | Year: 2010

Phenylalanine (Phe) was chosen to study the TiO2 photocatalytic degradation of amino acids, which are at the origin of the formation of odorous compounds after chlorination. The photocatalytic degradation has been investigated in aqueous solutions containing TiO2 suspensions as photocatalyst, in order to assess the influence of various parameters, such as adsorption, initial concentration, pH and radiant flux on the photocatalytic process. Results showed no correlation between dark adsorption and photocatalytic degradation. A multilayer kinetic was observed in the dark with a monolayer corresponding to less that 1% of OH covered, whereas Langmuir-Hinshelwood model seems to modelize the photocatalytic disappearance of Phe. However, even if the form of the curve is similar to L-H model, the degradation of phenylalanine is not a kinetic of L-H as we could plan it by considering the adsorption of the phenylalanine in the dark. The study of the mineralization of carbon and nitrogen showed that nitrogen atoms were predominantly photoconverted into NH4 + and a total mineralization of nitrogen and carbon seems occur. The identification of the by-products by LC-MS reveal mono- and di-hydroxylation and nitrogen-carbon (N-C) cleavage. The effect of pH showed an increase of adsorption under acid pH but a decrease of disappearance rate. The more efficient degradation was found at basic pH. The evolution of hydroxylated compounds of phenylalanine as a function of conversion revealed the presence of more hydroxylated compounds at natural pH and at basic pH compared to acid pH suggesting a modification of mechanism with solution pH. The effect of the radiant flux evaluated under different initial concentration of phenylalanine allowed us to determine that Κ increases by increasing the radiant flux, whereas Κ decreases or remains constant from about a value of 3.5 mW/cm2. The disappearance rate as a function of radiant flux has been showed to reach a maximal value corresponding to a maximal quantum yield of 1.6%. © 2010 Elsevier B.V. All rights reserved.


Elsellami L.,CNRS Research on Catalysis and Environment in Lyon | Elsellami L.,Laboratoire Of Catalyse Et Environnement | Vocanson F.,Jean Monnet University | Vocanson F.,CNRS Hubert Curien Laboratory | And 6 more authors.
Applied Catalysis B: Environmental | Year: 2010

The adsorption equilibrium in the dark and under UV light, the kinetic of photocatalytic oxidation and the main initial pathways of tryptophan photocatalytic degradation has been investigated in aerated TiO2 Degussa P-25 aqueous suspensions illuminated at λ > 340 nm. Tryptophan has been chosen as a model of organic compounds of amino acids, elemental constituents of DNA, microorganisms, e.g. bacteria, fungi, virus among others to better understand their photocatalytic degradation. Langmuir and Langmuir-Hinshelwood models have been used to determine the adsorption, the rate constants and the surface coverage of TiO2. Despite a low coverage of the TiO2 surface in the dark a high photocatalytic degradability and initial mineralization occurred. However, the surface coverage of TiO2 was about doubled under UV light suggesting the formation of active sites under irradiation. LC-MS, LC-UV with or without derivatization analyses allowed us to identify, mono-, di- and tri-hydroxylated compounds, deamination of heterocycle, the formation of six organic acid, oxalic, oxamique, lactic, formic, acetic and propanoic acids and of three linear amino acids, serine, aspartic acid and glycine. A degradation mechanism is proposed to the formation of oxamic acid. The study of the mineralization of carbon and nitrogen showed the presence of trace of organic molecules mineralizable with difficulty. Nitrogen atoms were predominantly photoconverted into NH4 +. After more than 95% of carbon mineralization, NH4 +/NO3 - ratio was 4. The identification of the photocatalytic products, their evolution and the TOC evolution indicated three initial competitive pathways: about 50% of hydroxylation with 6-7% of the hydroxylation of carbon bearing NH2 and COO-, about 30% of decarboxylation and less than 20% of nitrogen-carbon (N-C) cleavage. © 2009 Elsevier B.V. All rights reserved.


Miri L.,Institute Pasteur du Maroc | Miri L.,CNRS Biomolecular Engineering Laboratory | Bouvier G.,French National Center for Scientific Research | Kettani A.,CNRS Biomolecular Engineering Laboratory | And 4 more authors.
Proteins: Structure, Function and Bioinformatics | Year: 2014

The HIV-1 integrase is an attractive target for the therapeutics development against AIDS, as no host homologue of this protein has been identified. The integrase strand transfer inhibitors (INSTIs), including raltegravir, specifically target the second catalytic step of the integration process by binding to the DDE motif of the catalytic site and coordinating Mg2+ ions. Recent X-ray crystallographic structures of the integrase/DNA complex from prototype foamy virus allowed to investigate the role of the different partners (integrase, DNA, Mg2+ ions, raltegravir) in the complex stability using molecular dynamics (MD) simulations. The presence of Mg2+ ions is found to be essential for the stability, whereas the simultaneous presence of raltegravir and Mg2+ ions has a destabilizing influence. A homology model of HIV-1 integrase was built on the basis of the X-ray crystallographic information, and protein marker residues for the ligand binding were detected by clustering the docking poses of known HIV-1 integrase inhibitors on the model. Interestingly, we had already identified some of these residues to be involved in HIV-1 resistance mutations and in the stabilization of the catalytic site during the MD simulations. Classification of protein conformations along MD simulations, as well as of ligand docking poses, was performed by using an original learning method, based on self-organizing maps. This allows us to perform a more in-depth investigation of the free-energy basins populated by the complex in MD simulations on the one hand, and a straightforward classification of ligands according to their binding residues on the other hand. Proteins 2014; 82:466-478. © 2013 Wiley Periodicals, Inc.


Elsellami L.,CNRS Research on Catalysis and Environment in Lyon | Elsellami L.,Laboratoire Of Catalyse Et Environnement | Elsellami L.,CNRS Hubert Curien Laboratory | Pigeot-Remy S.,CNRS Research on Catalysis and Environment in Lyon | And 4 more authors.
Environmental Technology | Year: 2010

Amino acids are at the origin of the formation of odourous compounds after chlorination treatment. Our objectives were to test the efficiency of a photocatalytic process to remove these types of compounds. Five amino acids (AA) - phenylalanine, tyrosine, tryptophan, glycine and alanine - have been chosen as model molecules. The photocatalytic degradation has been investigated in aqueous solutions containing TiO2 suspensions as photocatalysts, in order to assess the adsorption, the disappearance rate and the mechanism of degradation. Results showed that only a small amount of amino acid is adsorbed corresponding to less than 1% of OH covered for aromatic amino acids and about 10% for linear amino acids. A comparison of disappearance rate, total organic carbon (TOC) removal and intermediate for these five amino acids are presented and discussed, taking into account their nature. © 2010 Taylor & Francis.


Apostolides N.A.,British Petroleum | El Beyrouthy M.,British Petroleum | Dhifi W.,Manouba University | Najm S.,Lebanese University | And 4 more authors.
Journal of Essential Oil-Bearing Plants | Year: 2013

Essential oil (EO) from fresh aerial parts of Rosmarinus officinalis L. growing wild in Lebanon, was analyzed by GC-MS. Altogether, twenty-seven compounds, accounting for 93.83 % of the whole oil, were identified. 1,8-cineole (32.83 %), β-caryophyllene (12.94 %), borneol (11.65 %), camphor (10.33 %), bornyl acetate (4.19 %), α-pinene (4.10 %), and α-terpineol (3.87 %) were the main components of the oil. © 2013 Copyright Har Krishan Bhalla & Sons.


Hafi M.A.,Holy Spirit University of Kaslik | Cazier F.,Center Communications Of Mesures | Aboukais A.,Laboratoire Of Catalyse Et Environnement | Jocelyne B.,Holy Spirit University of Kaslik | Beyrouthy M.E.,Holy Spirit University of Kaslik
Journal of Essential Oil-Bearing Plants | Year: 2015

The chemical composition of the water-distilled and free solvent (milestone) oils from several samples of cones (berries), leaves and twigs of Lebanese Juniperus excelsa M. Bieb. collected during two consecutive years were analyzed by GC and GC-MS. Thirty constituents were identified and accounted for 89.4-99.5 % of the total oil. The main component in the leaves, cones and twigs of the oil was α-pinene which accounted for 6.9 to 68.9; 78.3 to 89.8 and 75 to 95.2 % respectively in leaves, twigs and berries; we note here that big differences in α-pinene content in leaves were observed according to the year and distillation method: 6.9-27.7 (Leaves Milestone 2010), 30.6-49.5 (Leaves Clevenger 2010) and 52.8-68.8 (Leaves Clevenger 2011). The major component was followed by δ-3-carene whose respective amounts were of 3.3 to 22.1 in the leaves; 1.1 to 2.6 in the twigs and 0.9 to 2.4 in the berries and α-cedrol (8.7 to 57.0 in the leaves; 1.2 to 8.1 in the twigs and traces to 4.8 in the berries). The highest amounts of α-pinene were in the cones (95.3 %) whereas those of δ-3-carene and α-cedrol were in leaves (respectively 22.2 and 57 %). Their amounts in the different plant organs varied significantly. This study has demonstrated that the essential oils of Juniperus excelsa MB. leaves, cones and twigs exhibit changes in yields and compositions more likely due to the growth or ripening and climatic factors. © 2015 Har Krishan Bhalla & Sons.


El Beyrouthy M.,Holy Spirit University of Kaslik | Cazier F.,Center Communications Of Mesures | Arnold N.A.,Holy Spirit University of Kaslik | Aboukais A.,Laboratoire Of Catalyse Et Environnement
Journal of Essential Oil-Bearing Plants | Year: 2015

Abstract: Seasonal variation in chemical composition of essential oils obtained from fresh aerial parts of S. cuneifolia was determined by GC and GC-MS. The fresh plant materials were collected before and after flowering, and during beginning and maturation fruit stage from two different locations. Thirty five components were identified; carvacrol (20.4-52.1 %), p-cymene (9.1-30.2 %) and γ-terpinene (5.9-23.9 %) were the main components. In general, the qualitative composition of the components appeared to be relatively stable but carvacrol, p-Cymene and γ-terpinene showed variability. We also note that phenolics and monoterpene hydrocarbons were the major components. All the essential oils were found to be rich in carvacrol reaching the highest rate (52.1 %) during full blooming stage, while the highest percentage of thymol ranging (18.7 %) was reached only in the sample of essential oil from S. cuneifolia collected in the region of Ehden. © 2015 Har Krishan Bhalla & Sons.


Lachheb H.,CNRS Research on Catalysis and Environment in Lyon | Lachheb H.,Laboratoire Of Catalyse Et Environnement | Dappozze F.,CNRS Research on Catalysis and Environment in Lyon | Houas A.,Laboratoire Of Catalyse Et Environnement | Guillard C.,CNRS Research on Catalysis and Environment in Lyon
Journal of Photochemistry and Photobiology A: Chemistry | Year: 2012

Amino-acids are elemental constituents of microorganisms, e.g. bacteria, fungi, virus, mold, among others and are at the origin of the formation of odorous compounds after chlorination treatment due to the filtration of these microorganisms. Our study aims at studying the photocatalytic degradation of cysteine chosen as model of amino acid for understanding better the photocatalytic chemical pathway of microorganisms. The kinetics of adsorption in the dark and under UV light, the kinetics of photocatalytic oxidation, the effect of pH and the main initial pathways of cysteine degradation have been investigated in aerated TiO 2 Degussa P-25 aqueous suspensions illuminated at λ > 340 nm. Langmuir and Langmuir-Hinshelwood kinetics were observed respectively in the dark and under UV light. The coverage of TiO 2 surface under UV revealed a coverage of TiO 2 equivalent to that in the dark, indicating no modification of adsorption sites under irradiation. This behaviour is in agreement with a geometrical adsorption of cysteine as proved by using the molecular surface of cysteine and by taking into account the accessibility of water molecules. The effect of pH on adsorption and photocatalytic degradation showed a good correlation between dark adsorption and photocatalytic degradation. The mineralisation of organic carbon and nitrogen shows the presence of traces of organics hardly mineralisable but also the formation of similar amount of NH 4 + and NO 3 - ions from the beginning of the reaction contrarily to what was observed for other amino-acids. This behaviour is explained by the different ionisation states of cysteine. Taking into account the evolution of Total Organic Carbon, sulphate, nitrate and ammonium, an initial reaction pathway has been proposed. © 2012 Elsevier B.V.

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