Consulta: creatorFacets:"Bougaran, Gael"
Registros recuperados: 38
Data/hora: 06/06/2024 05:26:14

Effects of blue light on the biochemical composition and photosynthetic activity of Isochrysis sp. (T-iso)
Provedor de dados: 5
Autores: Marchetti, Julie; Bougaran, Gael; Jauffrais, Thierry; Lefebvre, Sebastien; Rouxel, Catherine; Saint-jean, Bruno; Lukomska, Ewa; Robert, Rene; Cadoret, Jean-paul.
In aquaculture, particularly in bivalve hatcheries, the biochemical composition of algal diets has a strong influence on larval and post-larval development. Biochemical composition is known to be related to culture conditions, among which light represents a major source of variation. The effects of blue light on biochemical composition and photosynthetic rate of Isochrysis sp. (T-iso) CCAP 927/14 were assessed in chemostat at a single irradiance (300 μmol photons m−2 s−1) and compared with white light. Two different dilution (renewal) rates were also tested: 0.7 and 0.2 d−1. Relative carbohydrate content was lower under blue light than under white light at both dilution rates, whereas chlorophyll a and photosynthesis activity were higher. In contrast,...
Tipo: Text
Palavras-chave: Isochrysis; Blue light; Photosynthesis; Proximate composition; Chemostat.
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00085/19599/17237.pdf

Screening and selection of growth-promoting bacteria for Dunaliella cultures
Provedor de dados: 5
Autores: Le Chevanton, Myriam; Garnier, Matthieu; Bougaran, Gael; Schreiber, Nathalie; Lukomska, Ewa; Berard, Jean-baptiste; Fouilland, E.; Bernard, Olivier; Cadoret, Jean-paul.
Previous studies have demonstrated that bacteria influence microalgal metabolism, suggesting that the selection and characterization of growth-promoting bacteria should offer a new strategy for improving industrial algal cultivation. In the present study, 48 cultivable bacteria were isolated from marine microalgae species and identified using 16S rRNA phylogenetic analysis. The recovered bacteria were found to be members of the α- and γ-Proteobacteria, Cytophaga–Flavobacterium–Bacteroides (CFB) and gram-positive monophyletic clusters. To address the effect of these bacteria on the growth of Dunaliella sp. individually, an experimental high-throughput tool was developed to simultaneously compare replicated associations. A two-step approach was used to...
Tipo: Text
Palavras-chave: Microalgae; Dunaliella; Bacteria; Interaction; Bacterial diversity.
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00142/25334/24768.pdf

Use comparative proteomics on a selected microalgae provides candidates for biofuel production.
Provedor de dados: 5
Autores: Garnier, Matthieu; Carrier, Gregory; Rogniaux, Helene; Nicolau, Elodie; Bougaran, Gael; Saint-jean, Bruno; Cadoret, Jean-paul.
Microalgae are photosynthetic microorganisms that have an extraordinary diversity which biotechnological potential is just beginning to be explored. Microalgae in biotechnology are presently the focus of an unprecedented surge in interest and investment worldwide. Understanding microalgal lipid accumulation under nitrogen starvation is of major interest for feedstocks, food and biofuel production. Although studies have been performed in model species, to this day it is critical to understand through particular mechanisms of biotechnological species. Tisochrysis lutea is traditionally used for aquaculture feed and presents advantages for lipid production. The wild type strain and a lipid over-accumulating selected mutant were used to perform the first...
Tipo: Text
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00176/28735/27203.pdf

Combined effects of temperature, irradiance and pH on   Teleaulax amphioxeia   (Cryptophyceae) physiology and feeding ratio for its predator   Mesodinium rubrum   (Ciliophora)
Provedor de dados: 5
Autores: Gaillard, Sylvain; Charrier, Aurelie; Malo, Florent; Carpentier, Liliane; Bougaran, Gael; Hégaret, Helene; Réveillon, Damien; Hess, Philipp; Séchet, Veronique.
The cryptophyte Teleaulax amphioxeia is a source of plastids for the ciliate Mesodinium rubrum and both organisms are members of the trophic chain of several species of Dinophysis. It is important to better understand the ecology of organisms at the first trophic levels before assessing the impact of principal factors of global change on Dinophysis spp. Therefore, combined effects of temperature, irradiance and pH on growth rate, photosynthetic activity and pigment content of a temperate strain of T. amphioxeia were studied using a full factorial design (central composite design 23*) in 17 individually controlled bioreactors. The derived model predicted an optimal growth rate of T. amphioxeia at a light intensity of 400 µmol photons · m‐2 · s‐1, more...
Tipo: Text
Palavras-chave: Dinophysis; Ecophysiology; Full factorial design; Global change; Mesodinium rubrum; Teleaulax amphioxeia.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00609/72155/70910.pdf

Effects of light and nitrogen availability on photosynthetic efficiency and fatty acid content of three original benthic diatom strains
Provedor de dados: 5
Autores: Cointet, Eva; Wielgosz-collin, Gaëtane; Bougaran, Gael; Rabesaotra, Vony; Gonçalves, Olivier; Méléder, Vona.
Microalgal biotechnology has gained considerable importance in recent decades. Applications range from simple biomass production for food and animal feed to valuable products for fuel, pharmaceuticals, health, biomolecules and materials relevant to nanotechnology. There are few reports of the exploration of wider microalgae biodiversity in the literature on high value microalgal compounds, however, because it is believed that there is little to be gained in terms of biomass productivity by examining new strains. Still, without diversity, innovation in biotechnology applications is currently limited. Using microalgal diversity is a very promising way to match species and processes for a specific biotechnological application. In this context, three benthic...
Tipo: Text
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00591/70269/68328.pdf

Effects of nitrogen limitation on Dunaliella sp.–Alteromonas sp. interactions: from mutualistic to competitive relationships.
Provedor de dados: 5
Autores: Le Chevanton, Myriam; Garnier, Matthieu; Lukomska, Ewa; Schreiber, Nathalie; Cadoret, Jean-paul; Saint-jean, Bruno; Bougaran, Gael.
Interactions between photosynthetic and non-photosynthetic microorganisms play an essential role in natural aquatic environments and the contribution of bacteria and microalgae to the nitrogen cycle can lead to both competitive and mutualistic relationships. Nitrogen is considered to be, with phosphorus and iron, one of the main limiting nutrients for primary production in the oceans and its availability experiences large temporal and geographical variations. For these reasons, it is important to understand how competitive and mutualistic interactions between photosynthetic and heterotrophic microorganisms are impacted by nitrogen limitation. In a previous study performed in batch cultures, the addition of a selected bacterial strain of Alteromonas sp....
Tipo: Text
Palavras-chave: Interactions; Nitrogen limitation; Microalgae; Bacteria; Chemostat; Dissolved organic matter (DOM); Dunaliella.
Ano: 2016
URL: https://archimer.ifremer.fr/doc/00344/45529/45087.pdf

La co-limitation par l'azote et le phosphore : étude des mécanismes chez la microalgue Tisochrysis lutea
Provedor de dados: 5
Autores: Bougaran, Gael.
Interactions between nitrogen (N) and phosphorus (P) on the growth of phytoplankton are not fully elucidated. Here, we propose the hypothesis that, since phosphorus plays a central role in energy, it can control the active transport of NO3. Our model for N-P co-limitation provides an asymmetric structure which reflects the respective roles of both nutrients and the differences in the control of absorption. The model succeeds in describing the different trends observed for N and P cell content in data sets taken from the literature. We further conducted experiments in batch and chemostat under different N: P ratios. Our results highlighted that P-limited cells were characterized by a low content of ATP and a low net absorption of NO3. When PO4 was...
Tipo: Text
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00293/40397/38912.pdf

Draft genomes and phenotypic characterization of Tisochrysis lutea strains. Toward the production of domesticated strains with high added value
Provedor de dados: 5
Autores: Carrier, Gregory; Baroukh, Caroline; Rouxel, Catherine; Duboscq-bidot, Laetitia; Schreiber, Nathalie; Bougaran, Gael.
Tisochrysis lutea is a microalga species currently used in aquaculture as a feed for shellfish, oysters and shrimps. It also has many other potential industrial applications, such as the production of neutral lipids for biofuels or the production of ω-3 fatty acids for nutraceuticals (human food complements). To efficiently exploit the potential of this microalga, however, higher lipid productivities are needed. To this end, improvement programs need to be developed and optimized. The diversity of strains available in microalgae has not yet been exploited in such improvement programs. In this study, the intra-strain diversity was observed and exploited to increase neutral lipid productivity. New clonal strains with higher neutral lipid productivity were...
Tipo: Text
Palavras-chave: Microalgae; Genome; Improvement program; Lipids; Tisochrysis lutea.
Ano: 2018
URL: http://archimer.ifremer.fr/doc/00411/52204/52927.pdf

Optimisation de l'enrichissement nutritif pour la culture d' Isochrysis galbana affinis Tahiti
Provedor de dados: 5
Autores: Bougaran, Gael; Le Dean, Loic; Loizel, Céline; Lukomska, Ewa; Picquet, Marie-lise; Kaas, Raymond; Muller-feuga, Arnaud.
La prymnésiophycée Isochrysis galbana affinis Tahiti (T -iso) est classiquement utilisée comme nourriture de larves de mollusques et de proies vivantes de poissons d'aquaculture dans la plupart des écloseries produisant des juvéniles de ces espèces. La solution d'enrichissement de Conway (SEC), élaborée en 1966 par Walne, est largement utilisée pour la production de T -iso en batch. Cependant, les apports nutritifs de cette solution d'enrichissement ne sont pas spécifiquement optimisés pour la culture de cette algue, participant à engendrer des coûts de production élevés (Valenzuala-Espinoza et al., 1999 ; Fabregas et al., 1986) et des effluents inépuisés. Dans les 15 dernières années, plusieurs auteurs sont parvenus à réduire le coût de solutions...
Tipo: Text
Ano: 2001
URL: http://archimer.ifremer.fr/doc/00304/41519/40727.pdf

Comparative proteomics reveals proteins impacted by nitrogen deprivation in wild-type and high lipid-accumulating mutant strains of Tisochrysis lutea
Provedor de dados: 5
Autores: Garnier, Matthieu; Carrier, Gregory; Rogniaux, Helene; Nicolau, Elodie; Bougaran, Gael; Saint-jean, Bruno; Cadoret, Jean-paul.
Understanding microalgal lipid accumulation under nitrogen starvation is of major interest for biomass feedstock, food and biofuel production. Using a domesticated oleaginous algae Tisochrysis lutea, we performed the first comparative proteomic analysis on the wild type strain and a selected lipid over-accumulating mutant. 2-DE analysis was made on these strains cultured in two metabolic conditions, with and without nitrogen deprivation, which revealed significant differences in proteomes according to both strain and nitrogen availability. Mass spectrometry allowed us to identify 37 proteins that were differentially expressed between the two strains, and 17 proteins regulated by nitrogen starvation concomitantly with lipid accumulation. The proteins...
Tipo: Text
Palavras-chave: Microalgae; Biotechnology; Lipid; Nitrogen; Proteomic; Selection.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00179/29012/27470.pdf

Microalgues: de petits végétaux aux grandes promesses !
Provedor de dados: 5
Autores: Bougaran, Gael; Saint-jean, Bruno.
Pour nos sociétés modernes, en quête de nouveaux procédés et de molécules actives innovantes, les microalgues représentent un formidable potentiel. Leurs nombreuses espèces et leur biodiversité constituent un réservoir de métabolites et de propriétés biochimiques quasi-inexploré, pour le développement de nouvelles applications biotechnologiques.
Tipo: Text
Ano: 2014
URL: https://archimer.ifremer.fr/doc/00252/36321/34885.pdf

Optimisation de la production en écloserie de mollusques : Mise au point d'un pilote industriel de production phytoplanctonique en continu et des techniques associées pour leur intégration en écloserie commerciale
Provedor de dados: 5
Autores: Angeri, S.; Bougaran, Gael; Connan, Jean-paul; Jouin, Jean-claude; Kaas, Raymond; Le Dean, Loic; Legrand, J.; Loubiere, K.; Lukomska, Ewa; Olivo, Erell; Picquet, Marie-lise; Pruvost, J.; Robert, Rene.
Les travaux présentés dans le cadre de ce rapport d'activité rendent compte des avancées réalisées sur le plan (1) biologique, avec d'une part une étude sur le comportement du genre Chaetoceros en culture continue et, d'autre part, les résultats d'expérimentations sur les performances d'élevages larvaires réalisés sur la base de cultures de microalgues en continu, et (2) technologique, avec la continuité des actions de développement du photobioréacteur destiné aux écloseries commerciales ainsi que des périphériques indispensables à son intégration dans le secteur aquacole.
Tipo: Text
Ano: 2007
URL: http://archimer.ifremer.fr/doc/00304/41518/40726.pdf

Comparative Transcriptome of Wild Type and Selected Strains of the Microalgae Tisochrysis lutea Provides Insights into the Genetic Basis, Lipid Metabolism and the Life Cycle
Provedor de dados: 5
Autores: Carrier, Gregory; Garnier, Matthieu; Le Cunff, Loic; Bougaran, Gael; Probert, Ian; De Vargas, Colomban; Corre, E; Cadoret, Jean-paul; Saint-jean, Bruno.
The applied exploitation of microalgae cultures has to date almost exclusively involved the use of wild type strains, deposited over decades in dedicated culture collections. Concomitantly, the concept of improving algae with selection programs for particular specific purposes is slowly emerging. Studying since a decade an economically and ecologically important haptophyte Tisochrysis lutea (Tiso), we took advantage of the availability of wild type (Tiso-Wt) and selected (Tiso-S2M2) strains to conduct a molecular variations study. This endeavour presented substantial challenges: the genome assembly was not yet available, the life cycle unknown and genetic diversity of Tiso-Wt poorly documented. This study brings the first molecular data in order to set up...
Tipo: Text
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00175/28662/27089.pdf

The Potential of Microalgae for the Production of Bioactive Molecules of Pharmaceutical Interest
Provedor de dados: 5
Autores: Mimouni, Virginie; Ulmann, Lionel; Pasquet, Virginie; Mathieu, Marie; Picot, Laurent; Bougaran, Gael; Cadoret, Jean-paul; Morant-manceau, Annick; Schoefs, Benoit.
Through the photosynthetic activity, microalgae process more than 25% of annual inorganic carbon dissolved in oceans into carbohydrates that ultimately, serve to feed the other levels of the trophic networks. Besides, microalgae synthesize bioactive molecules such as pigments and lipids that exhibit health properties. In addition, abiotic stresses, such as high irradiance, nutrient starvation, UV irradiation, trigger metabolic reorientations ending with the production of other bioactive compounds such as omega-3 fatty acids or carotenoids. Traditionally, these compounds are acquired through the dietary alimentation. The increasing, and often unsatisfied, demand for compounds from natural sources, combined with the decrease of the halieutic resources,...
Tipo: Text
Palavras-chave: Bioactive compound; Alga; Pigment; Lipid; Health benefit; Abiotic stress; Metabolic reorientation; Diatom.
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00118/22894/20847.pdf

Modeling continuous cultures of microalgae colimited by nitrogen and phosphorus
Provedor de dados: 5
Autores: Bougaran, Gael; Bernard, Olivier; Sciandra, Antoine.
It is well documented that the combination of low nitrogen and phosphorus resources can lead to situations where colimitation of phytoplankton growth arises, yet the underlying mechanisms are not fully understood. Here, we propose a Droop-based model built on the idea that colimitation by nitrogen and phosphorus arises from the uptake of nitrogen. Indeed, since N-porters are active systems, they require energy that could be related to the phosphorus status of the cell. Therefore, we assumed that N uptake is enhanced by the P quota. Our model also accounts for the biological observations that uptake of a nutrient can be down-regulated by its own internal quota, and succeeds in describing the strong contrast for the non-limiting quotas under N-limited and...
Tipo: Text
Palavras-chave: Colimitation; Phytoplankton; Mathematical model; Quota.
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00011/12216/9060.pdf

A New Photobioreactor for Continuous Microalgal Production in Hatcheries Based on External-Loop Airlift and Swirling Flow
Provedor de dados: 5
Autores: Loubiere, K; Olivo, Erell; Bougaran, Gael; Pruvost, J; Robert, Rene; Legrand, J.
This study deals with the scale of a new photobioreactor for continuous microalgal production in hatcheries. The combination of the state-of-art with the constraints inherent to hatcheries has turned the design into a closed, artificially illuminated and external-loop airlift configuration based on a succession of elementary modules, each one being composed of two transparent vertical interconnected columns. The liquid circulation is ensured pneumatically (air injections) with respect to a swirling motion (tangential inlets). A single module of the whole photobioreactor was built-up to scale its geometry (diameter and length) and to optimize its design (air sparger, tangential inlets). The volumetric productivities were predicted by modeling radiative...
Tipo: Text
Palavras-chave: Isochrysis affinis galbana; Swirling flow; Airlift; Hatchery; Continuous photobioreactor.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/2009/publication-5288.pdf

Effects of growth phase and nitrogen limitation on biochemical composition of two strains of Tisochrysis lutea
Provedor de dados: 5
Autores: Da Costa, Fiz; Le Grand, Fabienne; Quere, Claudie; Bougaran, Gael; Cadoret, Jean-paul; Robert, Rene; Soudant, Philippe.
Standard and mutant Tisochrysis lutea strains were grown in batch culture for 10 days under nitrogen (N)-replete and N-reduced conditions to determine the effects of N supply in culture medium and growth phase on microalgal physiology and biochemistry. These two T. lutea strains were compared in terms of growth, morphology, associated free-living bacterial community, viability, intracellular lipid content (as measured by Bodipy staining), chlorophyll autofluorescence, and biochemical composition, with a focus on lipid class and fatty acid compositions. The standard strain (T) reached higher cell counts regardless of N supply in culture medium. In both T. lutea strains, microalgal final cell density was significantly lower in N-reduced medium. Carbohydrates...
Tipo: Text
Palavras-chave: Tisochrysis lutea; Nitrogen limitation; Growth phase; Flow cytometry; Fatty acids; Lipid classes.
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00399/51074/51936.pdf

Culture en continu de Isochrysis galbana affinis Tahiti
Provedor de dados: 5
Autores: Bougaran, Gael; Le Dean, Loic; Lukomska, Ewa; Picquet, Marie-lise; Kaas, Raymond; Muller-feuga, Arnaud.
La prymnésiophycée Isochrysis galbana affinis Tahiti (T -iso) est une micro algue marine classiquement utilisée comme nourriture de larves de mollusques et de proies vivantes de poissons d'aquaculture dans la plupart des écloseries produisant des juvéniles de ces espèces. Aujourd'hui, de nombreuses écloseries de mollusques et de poissons l'utilisent en association avec d'autres espèces telles que Pavlova lutheri, Chaetoceros calcitrans et Skeletonema costatum. Isolée à Tahiti par JL Martin en 1975 (comm. pers.), cette algue s'est rapidement imposée dans la nutrition larvaire des crevettes et des mollusques en raison de sa croissance rapide en conditions tropicales et de ses qualités nutritionnelles, en relation avec sa forte teneur en acides gras...
Tipo: Text
Ano: 2001
URL: http://archimer.ifremer.fr/doc/00304/41508/40716.pdf

Carbon Orientation in the Diatom Phaeodactylum tricornutum: The Effects of Carbon Limitation and Photon Flux Density
Provedor de dados: 5
Autores: Heydarizadeh, Parisa; Veidi, Brigitte; Huang, Bing; Lukomska, Ewa; Wielgosz-collin, Gaetane; Couzinet-mossion, Aurélie; Bougaran, Gael; Marchand, Justine; Schoefs, Benoit.
Diatoms adapt to changing environmental conditions in very efficient ways. Among the mechanisms that can be activated, the reorientation of carbon metabolism is crucial because it allows the storage of energy into energy-dense molecules, typically lipids. Beside their roles in physiology, lipids are commercially interesting compounds. Therefore studies dealing with this topic are relevant for both basic and applied science. Although the molecular mechanisms involved in the reorientation of carbon metabolism as a response to a deficiency in nutrients such as nitrogen or phosphorus has been partially elucidated, the impacts of carbon availability on the implementation of the reorientation mechanisms remain unclear. Indeed, it has not been determined if the...
Tipo: Text
Palavras-chave: Diatom; Carbon deficiency; Carbon metabolism; Stress; Light intensity; Regulation; Biotechnology; Phosphoenolpyruvate.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00489/60058/63338.pdf

Betaine lipid and neutral lipid production under nitrogen or phosphorus limitation in the marine microalga Tisochrysis lutea (Haptophyta)
Provedor de dados: 5
Autores: Huang, Bing; Marchand, Justine; Thiriet-rupert, Stanislas; Carrier, Gregory; Saint-jean, Bruno; Lukomska, Ewa; Moreau, Brigitte; Morant-manceau, Annick; Bougaran, Gael; Mimouni, Virginie.
Nitrogen (N) and phosphorus (P) limitations induce neutral lipid accumulation and membrane lipid remodeling in the domesticated oleaginous microalga Tisochrysis lutea. This study compared growth, photosynthetic activity, biochemical and transcriptional responses of T. lutea throughout batch cultures under N or P limitation compared with non-limiting nutrient condition (NP). The results show that, under N limitation, the breakdown and re-use of cellular N-containing compounds contributed to carbohydrates and further triacylglycerol (TAG) accumulation, where the accumulation of docosahexaenoic acid (DHA) in neutral lipids might mainly be derived from the recycling of membrane polar lipids. Conversely, P limitation did not hinder the photosynthetic capacity;...
Tipo: Text
Palavras-chave: Tisochrysis lutea; Phosphorus; Nitrogen; Lipid remodeling; Betaine lipid; Polyunsaturated fatty acid.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00492/60409/64776.pdf

Bio-physiological response of biofilter algal candidate Ulva sp. to different nitrogen forms and fluxes
Provedor de dados: 5
Autores: Moustafa, Yasser T. A.; Bougaran, Gael; Callier, Myriam; Blancheton, Jean-paul.
The present study was carried out to study the long term effect of different nitrogen forms and concentrations (14.3, 28.6 and 57.1 µM N-NH4 and 214, 2360 and 3700 µM N-NO3) on the photosynthesis and relative growth rate (RGR) of Ulva sp. for five weeks. Nutrient-enriched seawater was supplied at an exchange rate of between 12.6 and 14.4 volumes per day. Relative growth rate was determined weekly. Photosynthetic oxygen evolution response was measured using 20 - 25 mg fresh weight seaweed incubated in a DW3 measuring chamber for 56 min under different irradiances with light and dark periods alternating every seven minutes. Photosynthetic light-response curves were drawn using 15 photosynthetic oxygen evolution readings normalized to dry weight. Experimental...
Tipo: Text
Palavras-chave: Ulva sp.; Photosynthetic oxygen evolution; Relative growth rate; Nitrogen forms; Nutrients uptake.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00251/36259/34807.pdf

The use of fluorescent Nile red and BODIPY for lipid measurement in microalgae
Provedor de dados: 5
Autores: Rumin, Judith; Bonnefond, Hubert; Saint-jean, Bruno; Rouxel, Catherine; Sciandra, Antoine; Bernard, Olivier; Cadoret, Jean-paul; Bougaran, Gael.
Microalgae are currently emerging as one of the most promising alternative sources for the next generation of food, feed, cosmetics and renewable energy in the form of biofuel. Microalgae constitute a diverse group of microorganisms with advantages like fast and efficient growth. In addition, they do not compete for arable land and offer very high lipid yield potential. Major challenges for the development of this resource are to select lipid-rich strains using high-throughput staining for neutral lipid content in microalgae species. For this purpose, the fluorescent dyes most commonly used to quantify lipids are Nile red and BODIPY 505/515. Their fluorescent staining for lipids offers a rapid and inexpensive analysis tool to measure neutral lipid content,...
Tipo: Text
Palavras-chave: Nile red; BODIPY 505/515; Microalgae; Neutral lipid; Fluorescence; Biodiesel.
Ano: 2015
URL: http://archimer.ifremer.fr/doc/00257/36823/35451.pdf

Use of a lipid rich strain reveals mechanisms of nitrogen limitation and carbon partitioning in the haptophyte Tisochrysis lutea
Provedor de dados: 5
Autores: Garnier, Matthieu; Bougaran, Gael; Pavlovic, Marija; Berard, Jean-baptiste; Carrier, Gregory; Charrier, Aurelie; Le Grand, Fabienne; Lukomska, Ewa; Rouxel, Catherine; Schreiber, Nathalie; Cadoret, Jean-paul; Rogniaux, Helene; Saint-jean, Bruno.
Haptophytes are a diverse monophyletic group with a worldwide distribution, known to be significantly involved in global climate regulation in their role as a carbon sink. Because nitrogen is a major limiting macronutrient for phytoplankton in oceans and for cultures of microalgae, understanding the involvement of nitrogen availability in haptophyte carbon partitioning is of global and biotechnological importance. Here, we made an ecophysiological study coupled with comprehensive large scale proteomic analysis to examine differences of behavior in reaction to nitrogen availability changes between a wild type strain of Tisochrysis lutea (WTc1) and a mutant strain (2Xc1) known to accumulate more storage lipids. Strains were grown in chemostats and studied...
Tipo: Text
Palavras-chave: Algae; Isochrysis; Lipids; Nitrogen; Reverse genomic: proteomic.
Ano: 2016
URL: https://archimer.ifremer.fr/doc/00356/46702/46904.pdf

Influence of temperature, irradiance and pH on the physiology of Teleaulax amphioxeia
Provedor de dados: 5
Autores: Gaillard, Sylvain; Charrier, Aurelie; Carpentier, Liliane; Malo, Florent; Bougaran, Gael; Hegaret, Helene; Hess, Philipp; Sechet, Veronique.
Tipo: Text
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00617/72958/71990.pdf

Transcription factors in microalgae: genome-wide prediction and comparative analysis
Provedor de dados: 5
Autores: Thiriet-rupert, Stanislas; Carrier, Gregory; Chenais, Benoit; Trottier, Camille; Bougaran, Gael; Cadoret, Jean-paul; Schoefs, Benoit; Saint-jean, Bruno.
Background: Studying transcription factors, which are some of the key players in gene expression, is of outstanding interest for the investigation of the evolutionary history of organisms through lineage-specific features. In this study we performed the first genome-wide TF identification and comparison between haptophytes and other algal lineages. Results: For TF identification and classification, we created a comprehensive pipeline using a combination of BLAST, HMMER and InterProScan software. The accuracy evaluation of the pipeline shows its applicability for every alga, plant and cyanobacterium, with very good PPV and sensitivity. This pipeline allowed us to identify and classified the transcription factor complement of the three haptophytes...
Tipo: Text
Palavras-chave: Algae; Endosymbiotic gene transfer; Haptophytes; Prediction pipeline; Stramenopiles; Tisochrysis lutea; Transcription factors.
Ano: 2016
URL: https://archimer.ifremer.fr/doc/00333/44403/44072.pdf

Nitrogen and phosphorus limitations induce carbon partitioning and membrane lipid remodelling in the marine diatom Phaeodactylum tricornutum
Provedor de dados: 5
Autores: Huang, Bing; Marchand, Justine; Blanckaert, Vincent; Lukomska, Ewa; Ulmann, Lionel; Wielgosz-collin, Gaëtane; Rabesaotra, Vony; Moreau, Brigitte; Bougaran, Gael; Mimouni, Virginie; Morant-manceau, Annick.
Nitrogen (N) and phosphorus (P) limitations induce triacylglycerol (TAG) accumulation and membrane lipid remodelling in the marine diatom Phaeodactylum tricornutum. However, a clear understanding of the metabolic reorientation is still lacking. Carbon partitioning is of great interest because this microalga produces various highly valuable molecules such as lipids and polyunsaturated fatty acids. This study compared growth, photosynthetic activity, biochemical and transcriptional responses of P. tricornutum throughout batch culture under N or P limitation. The integrated results show that the photosynthetic intensity was greatly reduced under N or P limitation. Under N limitation, the degradation and re-use of cellular N-containing compounds contributed to...
Tipo: Text
Palavras-chave: Betaine lipid; Lipid remodelling; Microalga; Nitrogen; Phosphorus; Polyunsaturated fatty acid.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00491/60249/63861.pdf

Transient initial phase in continuous culture of Isochrysis galbana affinis Tahiti
Provedor de dados: 5
Autores: Bougaran, Gael; Le Dean, Loic; Lukomska, Ewa; Kaas, Raymond; Baron, Regis.
Starting microalgae continuous culture generally includes a preliminary batch culture to obtain sufficient cell density. It is possible to apply continuous regime from the beginning of the culture (IC mode) rather than to begin by an initial batch (IB mode). It is our purpose to check that both initial modes lead to identical steady-state cell characteristics. The microalga Isochrysis galbana affinis Tahiti was used for this comparative study. With an initial cell density of 5 x 10(5) cell ml(-1) and a dilution rate of about 1.0 d(-1), both IB and IC modes led to identical cell density once steady-state is reached between 6 and 8 d after inoculation in the two cases. Cell concentration of chlorophyll a and pheopigment a were found to be similar for IB and...
Tipo: Text
Palavras-chave: Isochrysis; Cell quota; Photosynthesis; Steady state; Continuous culture.
Ano: 2003
URL: http://archimer.ifremer.fr/doc/2003/publication-597.pdf

Carbon conversion efficiency and population dynamics of a marine algae–bacteria consortium growing on simplified synthetic digestate: First step in a bioprocess coupling algal production and anaerobic digestion
Provedor de dados: 5
Autores: Vasseur, Christophe; Bougaran, Gael; Garnier, Matthieu; Hamelin, Jérôme; Leboulanger, Christophe; Le Chevanton, Myriam; Mostajir, Behzad; Sialve, Bruno; Steyer, Jean-philippe; Fouilland, Eric.
Association of microalgae culture and anaerobic digestion seems a promising technology for sustainable algal biomass and biogas production. The use of digestates for sustaining the growth of microalgae reduces the costs and the environmental impacts associated with the substantial algal nutrient requirements. A natural marine algae–bacteria consortium was selected by growing on a medium containing macro nutrients (ammonia, phosphate and acetate) specific of a digestate, and was submitted to a factorial experimental design with different levels of temperature, light and pH. The microalgal consortium reached a maximum C conversion efficiency (i.e. ratio between carbon content produced and carbon supplied through light photosynthetic C conversion and acetate)...
Tipo: Text
Palavras-chave: Optimization; Nannochloris; Heterotrophic bacteria; Anaerobic digestion; Bioenergy.
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00085/19642/17419.pdf

Response of CO2-starved diatom Phaeodactylum tricornutum to light intensity transition
Provedor de dados: 5
Autores: Heydarizadeh, Parisa; Boureba, Wafaa; Zahedi, Morteza; Huang, Bing; Moreau, Brigitte; Lukomska, Ewa; Couzinet-mossion, Aurelie; Wielgosz-collin, Gaetane; Martin-jezequel, Veronique; Bougaran, Gael; Marchand, Justine; Schoefs, Benoit.
In this study, we investigated the responses of Phaeodactylum tricornutum cells acclimated to 300 mu mol m(-2) s(-1) photon flux density to an increase (1000 mmol m(-2) s(-1)) or decrease (30 mmol m(-2)s(-1)) in photon flux densities. The light shift occurred abruptly after 5 days of growth and the acclimation to new conditions was followed during the next 6 days at the physiological and molecular levels. The molecular data reflect a rearrangement of carbon metabolism towards the production of phosphoenolpyruvic acid (PEP) and/or pyruvate. These intermediates were used differently by the cell as a function of the photon flux density: under low light, photosynthesis was depressed while respiration was increased. Under high light, lipids and proteins...
Tipo: Text
Palavras-chave: Phaeodactylum tricornutum; Carbon metabolism; Light regulation; Photosynthesis; Chlorophyll fluorescence; Pyruvate hub.
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00395/50620/52341.pdf

Optimizing conditions for the continuous culture of Isochrysis affinis galbana relevant to commercial hatcheries
Provedor de dados: 5
Autores: Marchetti, Julie; Bougaran, Gael; Le Dean, Loic; Megrier, Cyril; Lukomska, Ewa; Kaas, Raymond; Olivo, Erell; Baron, Regis; Robert, Rene; Cadoret, Jean-paul.
Optimal culture conditions were investigated for the continuous culture of Isochrysis affinis galbana (T-Iso) by assessing the effects of irradiance, temperature, pH and nitrogen and phosphorus requirements. Assessment of the growth rate-irradiance relationship in a turbidostat experiment highlighted that an optimum irradiance efficiency for growth (E-mu) occurred at irradiance much lower than the saturating level. Furthermore, our modeling approach for productivity pointed out that an optimal set of irradiance and dilution rate could be achieved in order to maximize irradiance efficiency. Optimal conditions for growth were assessed for temperature, pH and irradiance by means of a factorial design experiment. The resulting model predicted that optimal...
Tipo: Text
Palavras-chave: Isochrysis affinis galbana; Irradiance efficiency; Factor interaction; Nutrient limitation; Microalgae cultures.
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00076/18736/16465.pdf

Influence of one selected Tisochrysis lutea strain rich in lipids on Crassostrea gigas larval development and biochemical composition
Provedor de dados: 5
Autores: Da Costa, F.; Petton, Bruno; Mingant, Christian; Bougaran, Gael; Rouxel, Catherine; Quere, Claudie; Wikfors, G. H.; Soudant, P.; Robert, Rene.
Effects of a remarkably high overall lipid Tisochrysis lutea strain (T+) upon gross biochemical composition, fatty acid (FA), sterol and lipid class composition of Crassostrea gigas larvae were evaluated and compared with a normal strain of Tisochrysis lutea (T) and the diatom Chaetoceros neogracile (Cg). In a first experiment, the influence of different single diets (T, T+ and Cg) and a bispecific diet (TCg) was studied, whereas, effects of monospecific diets (T and T+) and bispecific diets (TCg and T+Cg) were evaluated in a second experiment. The strain T+ was very rich in triglycerides (TAG: 93–95% of total neutral lipids), saturated FA (45%), monounsaturated FA (31–33%) and total fatty acids (4.0–4.7 pg cell−1). Larval oyster survival and growth rate...
Tipo: Text
Palavras-chave: Larvae; Lipids; Oyster; Tisochrysis lutea.
Ano: 2016
URL: https://archimer.ifremer.fr/doc/00251/36258/36063.pdf

Carbon partitioning and lipid remodeling during phosphorus and nitrogen starvation in the marine microalga   Diacronema lutheri   (Haptophyta)
Provedor de dados: 5
Autores: Huang, Bing; Mimouni, Virginie; Lukomska, Ewa; Morant-manceau, Annick; Bougaran, Gael.
The domesticated marine microalga Diacronema lutheri is of great interest for producing various highly valuable molecules like lipids, particularly long‐chain polyunsaturated fatty acids (LC‐PUFA). In this study, we investigated the impact of phosphorus (P) and nitrogen (N) starvation on growth, carbon fixation (photosynthetic activity) and partitioning, and membrane lipid remodeling in this alga during batch culture. Our results show that the photosynthetic machinery was similarly affected by P and N stress. Under N starvation, we observed a much lower photosynthetic rate and biomass productivity. The degradation and re‐use of cellular N‐containing compounds contributed to triacylglycerol (TAG) accumulation. On the other hand, P‐starved cells maintained...
Tipo: Text
Palavras-chave: Carbon partitioning; Diacronema lutheri; Nitrogen; Phosphorus; Polyunsaturated fatty acid.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00619/73071/72204.pdf

High-affinity nitrate/nitrite transporter genes (Nrt2) in Tisochrysis lutea: identification and expression analyses reveal some interesting specificities of Haptophyta microalgae
Provedor de dados: 5
Autores: Charrier, Aurelie Georgette; Berard, Jean-baptiste; Bougaran, Gael; Carrier, Gregory; Lukomska, Ewa; Schreiber, Nathalie; Fournier, Flora; Charrier, Aurelie; Rouxel, Catherine; Garnier, Matthieu; Cadoret, Jean-paul; Saint-jean, Bruno.
Microalgae have a diversity of industrial applications such as feed, food ingredients, depuration processes and energy. However, microalgal production costs could be substantially improved by controlling nutrient intake. Accordingly, a better understanding of microalgal nitrogen metabolism is essential. Using in silico analysis from transcriptomic data concerning the microalgae Tisochrysis lutea, four genes encoding putative high-affinity nitrate/nitrite transporters (TlNrt2) were identified. Unlike most of the land plants and microalgae, cloning of genomic sequences and their alignment with complementary DNA (cDNA) sequences did not reveal the presence of introns in all TlNrt2 genes. The deduced TlNRT2 protein sequences showed similarities to NRT2...
Tipo: Text
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00253/36467/35044.pdf

The combined effects of blue light and dilution rate on lipid class and fatty acid composition of Tisochrysis lutea
Provedor de dados: 5
Autores: Marchetti, Julie; Da Costa, Fiz; Bougaran, Gael; Quere, Claudie; Soudant, Philippe; Robert, Rene.
The lipid class and the fatty acid compositions of microalgae highly influence bivalve larval and post-larval development. Light is an essential environmental factor for microalgal culture, and quantity and quality of light may induce changes in the biochemical composition of the algae. The objective of this study was to investigate the effect of light spectrum (blue vs. white light) on lipid class and fatty acid compositions of Tisochrysis lutea cultured in a chemostat. Two different dilution rates (D) were assayed for each light spectrum: 0.2 and 0.7 day−1. Triacylglycerol (TAG), sterol, and hydrocarbon (HC) content increased sharply at low D. The proportion of alkenones was significantly reduced under blue light. Polyunsaturated fatty acids (PUFA), and...
Tipo: Text
Palavras-chave: Tisochrysis lutea; Blue light; Dilution rate; Lipid classes; Fatty acids; Chemostat.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00412/52299/53355.pdf

Continuous selection pressure to improve temperature acclimation of Tisochrysis lutea
Provedor de dados: 5
Autores: Bonnefond, Hubert; Grimaud, Ghjuvan; Rumin, Judith; Bougaran, Gael; Talec, Amelie; Gachelin, Manon; Boutoute, Marc; Pruvost, Eric; Bernard, Olivier; Sciandra, Antoine.
Temperature plays a key role in outdoor industrial cultivation of microalgae. Improving the thermal tolerance of microalgae to both daily and seasonal temperature fluctuations can thus contribute to increase their annual productivity. A long term selection experiment was carried out to increase the thermal niche (temperature range for which the growth is possible) of a neutral lipid overproducing strain of Tisochrysis lutea. The experimental protocol consisted to submit cells to daily variations of temperature for 7 months. The stress intensity, defined as the amplitude of daily temperature variations, was progressively increased along successive selection cycles. Only the amplitude of the temperature variations were increased, the daily average...
Tipo: Text
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00404/51506/52107.pdf

Getting the most out of it: Optimal experiments for parameter estimation of microalgae growth models
Provedor de dados: 5
Autores: Munoz-tamayo, Rafael; Martinon, Pierre; Bougaran, Gael; Mairet, Francis; Bernard, Olivier.
Mathematical models are expected to play a pivotal role for driving microalgal production towards a profitable process of renewable energy generation. To render models of microalgae growth useful tools for prediction and process optimization, reliable parameters need to be provided. This reliability implies a careful design of experiments that can be exploited for parameter estimation. In this paper, we provide guidelines for the design of experiments with high informative content based on optimal experiment techniques to attain an accurate parameter estimation. We study a real experimental device devoted to evaluate the effect of temperature and light on microalgae growth. On the basis of a mathematical model of the experimental system, the optimal...
Tipo: Text
Palavras-chave: Biofuel; Biological processes; Modelling; Parameter identification; Optimal experiment design.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00191/30252/28684.pdf

Identification of transcription factors involved in the phenotype of a domesticated oleaginous microalgae strain of Tisochrysis lutea
Provedor de dados: 5
Autores: Thiriet-rupert, Stanislas; Carrier, Gregory; Trottier, Camille; Eveillard, D.; Schoefs, B.; Bougaran, Gael; Cadoret, Jean-paul; Chenais, B.; Saint-jean, Bruno.
Microalgae are an outstanding source of high value products with applications in food, feed or biofuel production. Among these promising organisms, the haptophyte Tisochrysis lutea is commonly used as a feed for shellfish and shrimps in aquaculture. Its capacity to produce high amounts of docosahexanoic acid and storage lipids is also of economic interest for nutrition and energy production. Consequently, understanding its lipid accumulation under nitrogen deprivation is of major interest. Here, we aimed to identify Transcription Factors (TFs) involved in the establishment of the mutant phenotype of the 2Xc1 strain of T. lutea, which accumulates double the quantity of storage lipids under nitrogen deprivation than the wild type strain (WTc1). Strains were...
Tipo: Text
Palavras-chave: Algae; Carbohydrates; Gene co-expression network; Lipids; Transcription factor; Tisochrysis lutea.
Ano: 2018
URL: http://archimer.ifremer.fr/doc/00418/52973/53901.pdf

Enhancement of neutral lipid productivity in the microalga Isochrysis affinis Galbana (T-Iso) by a mutation-selection procedure
Provedor de dados: 5
Autores: Bougaran, Gael; Rouxel, Catherine; Dubois, Nolwenn; Kaas, Raymond; Grouas, Sophie; Lukomska, Ewa; Le Coz, Jean-rene; Cadoret, Jean-paul.
Microalgae offer a high potential for energetic lipid storage as well as high growth rates. They are therefore considered promising candidates for biofuel production, with the selection of high lipid-producing strains a major objective in projects on the development of this technology. We developed a mutation-selection method aimed at increasing microalgae neutral lipid productivity. A two step method, based on UVc irradiation followed by flow cytometry selection, was applied to a set of strains that had an initial high lipid content and improvement was assessed by means of Nile-red fluorescence measurements. The method was first tested on Isochrysis affinis galbana (T-Iso). (...)
Tipo: Text
Palavras-chave: Strain selection; Isochrysis; Neutral lipid; Ultra violet; Flux cytometry; Biofuel.
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00085/19643/17418.pdf