Development of a liquid-liquid extraction method of resveratrol from cell culture media using solubility parameters

YesThe extraction of bioactive compounds, produced by plant cell cultures, directly from their culture medium, which contains other by-products, is a great challenge. Resveratrol extraction from its grapevine cell cultures is considered here as an example to improve the extraction processes from plant cell cultures using solubility parameters. Successive liquid-liquid extraction (LLE) processes were exploited to extract resveratrol from the culture medium with an extraction ratio approaching 100%, high selectivity and minimum amounts of solvents. The calculations of partition coefficients as a function of solubility parameters demonstrated that benzyl benzoate is the most suitable intermediate solvent to extract resveratrol from its aqueous medium. The calculations also illustrated the high ability of methanol and ethanol to extract resveratrol from benzyl benzoate. The physicochemical properties of benzyl benzoate and processing conditions were exploited to separate it from aqueous media and organic solvents. The agitation method, component ratios and extraction time were studied to maximize the extraction yield. Under the best studied conditions, the recovery of resveratrol from different culture media approached ∼100% with a selectivity of ∼92%. Ultimately, the improved extraction processes of resveratrol are markedly efficient, selective, rapid and economical.Mohammad Amin Mohammad gratefully acknowledges CARA (The Council for At-Risk Academics, Stephen Wordsworth and Ryan Mundy) for providing the financial support for an academic fellowship

Régulations hormonales non génomiques de la production du monoxide d'azote (no) dans les adipocytes de rat

PARIS7-Bibliothèque centrale (751132105) / SudocSudocFranceF

Centrifugal partition extraction of β-carotene from Dunaliella salina for efficient and biocompatible recovery of metabolites

International audienc

Production par Dunaliella salina et extraction en continu de b-carotène par couplage d'un photobioréacteur et d'une chromatographie de partage centrifuge

Les travaux présentés dans ce manuscrit traitent de la mise en place d un procédé permettant une production et une extraction en continu du b-carotène issu de microalgues. Ceci repose sur l association de deux systèmes, à savoir un photobioréacteur permettant la production en continu et sous conditions de stress de l algue Dunaliella salina enrichie en b-carotène, et une chromatographie de partage centrifuge (CPC) utilisée pour l extraction biocompatible de ce composé. La première partie de ce travail a donc consisté en la recherche de conditions particulières de culture permettant la production continue de Dunaliella salina enrichie en b-carotène, la synthèse de ce composé étant souvent au détriment de la croissance, empêchant alors ce mode de culture d être mis en place. L effet de l'ajout de fer à une source de carbone organique (acétate ou malonate) au milieu de culture a été étudié vis à vis de la croissance et de la biosynthèse du b-carotène. Les études préliminaires en mode discontinu ont montré que les ions Fe2+ stimulent la synthèse du b-carotène en induisant un stress oxydatif, mais avec toutefois une perte importante de biomasse en partie compensée par l ajout de la source organique. L ajustement des concentrations dans le milieu a permis de trouver le compromis nécessaire entre croissance et stress pour appliquer ce protocole à la culture continue en photobioréacteur, avec production de biomasse riche en b-carotène. La seconde partie de ce travail concerne la phase d'extraction. Un point critique a été lié au choix du solvant qui doit dans le cas présent permettre une extraction importante tout en restant biocompatible, et donc préserver les cellules vivantes lors de la phase d extraction. Ces deux effets étant contraires, une stratégie de sélection de solvants a été mise au point à partir des caractéristiques influençant chacun de ces deux aspects. L efficacité d extraction du mélange (décane-CH2Cl2) a ainsi été révélée. L utilisation de la CPC en tant qu extracteur a impliqué également une optimisation des conditions opératoires de ce procédé, permettant au final une extraction en continu tout en préservant la vitalité des microalgues, par percolation dans la CPC de la culture et du solvant de façon co-courante. Un essai de couplage entre le photobioréacteur de production et l extraction en CPC a finalement été réalisé, montrant la faisabilité et la pertinence du procédé par rapport aux techniques existantes.The works presented in this manuscript deal with the setting up of a process for continuous production and extraction of b-carotene from microalgae. This is based on the association of two systems, a photobioreactor allowing the continuous production of the algae Dunaliella salina enriched in b-carotene under stress conditions, and a centrifugal partition chromatography (CPC) used for the biocompatible extraction of this compound. The first part of this work was therefore the search of culture conditions allowing the continuous production of Dunaliella salina enriched in b-carotene, the synthesis of this compound being often at the expense of growth, previnting this culture mode to be established. The effect of adding iron to an organic carbon source (acetate or malonate) in the culture medium has been studied. The preliminary studies in batch showed that the ions Fe2+ stimulate the synthesis of b-carotene by inducing oxidative stress, but with a significant biomass loss partially offset by the organic source addition. The adjustment of the concentrations in medium has led to a compromise between growth and stress, and a protocol on continuous culture in photobioreactors, with production of biomass enriches in b-carotene, has been set up. The second part of this work was dedicated to the extraction phase. A critical point was the choice of a solvent which must allow a significant extraction while remaining biocompatible, thus preserving viable cells during the extraction phase. To solve this antagonism, a solvent selection has been developed from the characteristics affecting each of these two aspects. The extractive efficiency of the mixture (decane-CH2Cl2) has been highlighted. The use of CPC as an extractor needs the optimization of the operating conditions of this process, allowing a continuous extraction while maintaining the microalgal vitality, by percolation in CPC of the culture and the solvent in the co-current mode. A coupling between production in a photobioreactor and extraction in CPC has been finally achieved, showing the feasibility and the pertinence of the process compared to existing techniques.NANTES-BU Sciences (441092104) / SudocSudocFranceF

Drag-Out in Metal Finishing Industries

International audienceCurrently, environmental regulations induce industrialists to implement source reduction techniques in order to comply with the prevention principle toward sustainable development. The project PIPSI (PIlotage Propre des Systegravemes Industriels/industrial system clean piloting) financing by Rhone-Alps Region is carried out with the aim to contribute to this objective. The study presented in this article concerns the pollution transfer in a metal finishing treatment line in order to minimise the environmental impact obtained notably with the pollution balance. Drag-out and draining phenomena have been particularly studied. Results obtained showed that a 10 seconds of draining reduced drag-out from 65 to 85% in terms of pieces design. Moreover, during the experiments, 5 drag-out levels were identified by medium values from 26 to 1700 ml m-2. So that, either a piece can be associated to a level or knowing the piece drag-out level, it is possible to evaluate its medium drag-out value. Then the pollution balance will be obtained more easily

ATF and Jun transcription factors, acting through an Ets/CRE promoter module, mediate lipopolysaccharide inducibility of the chemokine RANTES in monocytic Mono Mac 6 cells.

The chemokine RANTES is produced by a variety of tissues, including cells of the monocyte/macrophage lineage. RANTES expression is rapidly and transiently up-regulated in primary monocytes and the monocytic cell line Mono Mac 6 in response to stimulation by the bacterial product lipopolysaccharide (LPS). Transient transfection of Mono Mac 6 cells with RANTES reporter-promoter deletion constructs, in conjunction with DNase I footprinting and heterologous reporter gene assays, allowed identification of an LPS-responsive region within the RANTES promoter. Electrophoretic mobility shift assays (EMSA), methylation interference and EMSA supershift experiments were used to characterize sequences and transcription factors responsible for this LPS inducibility. The region, termed RANTES site G [R(G)], contains consensus sites for Ets and CRE/AP-1-like elements. Site-directed mutagenesis of the Ets site resulted in a loss of only 15 % of promoter activity, while mutation of the CRE/AP-1 site led to a loss of 40 % of LPS-induced promoter activity. The Ets site constitutively binds the Ets family member PU.1. LPS stimulation leads to an induction of ATF-3 and JunD factor binding to the CRE/AP-1 site. Thus, LPS induction of RANTES transcription is mediated, in part, through the activation and selective binding of ATF and Jun nuclear factors to the R(G) promoter module

ATF and Jun transcription factors, acting through an Ets/CRE promoter module, mediate lipopolysaccharide inducibility of the chemokine RANTES in monocytic Mono Mac 6 cells.

The chemokine RANTES is produced by a variety of tissues, including cells of the monocyte/macrophage lineage. RANTES expression is rapidly and transiently up-regulated in primary monocytes and the monocytic cell line Mono Mac 6 in response to stimulation by the bacterial product lipopolysaccharide (LPS). Transient transfection of Mono Mac 6 cells with RANTES reporter-promoter deletion constructs, in conjunction with DNase I footprinting and heterologous reporter gene assays, allowed identification of an LPS-responsive region within the RANTES promoter. Electrophoretic mobility shift assays (EMSA), methylation interference and EMSA supershift experiments were used to characterize sequences and transcription factors responsible for this LPS inducibility. The region, termed RANTES site G [R(G)], contains consensus sites for Ets and CRE/AP-1-like elements. Site-directed mutagenesis of the Ets site resulted in a loss of only 15 % of promoter activity, while mutation of the CRE/AP-1 site led to a loss of 40 % of LPS-induced promoter activity. The Ets site constitutively binds the Ets family member PU.1. LPS stimulation leads to an induction of ATF-3 and JunD factor binding to the CRE/AP-1 site. Thus, LPS induction of RANTES transcription is mediated, in part, through the activation and selective binding of ATF and Jun nuclear factors to the R(G) promoter module