Consulta: creatorFacets:"Sciandra, Antoine"
Registros recuperados: 6
Data/hora: 10/06/2024 12:04:24

How do microalgae perceive light in a high-rate pond? Towards more realistic Lagrangian experiments
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Demory, David; Combe, Charlotte; Hartmann, Philipp; Talec, Amelle; Pruvost, Eric; Hamouda, Raouf; Souille, Fabien; Lamarea, Pierre-olivier; Bristeau, Marie-odile; Sainte-marie, Jacques; Rabouille, Sophie; Mairet, Francis; Sciandra, Antoine; Bernard, Olivier.
Hydrodynamics in a high-rate production reactor for microalgae cultivation affects the light history perceived by cells. The interplay between cell movement and medium turbidity leads to a complex light pattern, whose forcing effects on photosynthesis and photoacclimation dynamics are nontrivial. Hydrodynamics of high density algal ponds mixed by a paddle wheel has been studied recently, although the focus has never been on describing its impact on photosynthetic growth efficiency. In this multidisciplinary downscaling study, we first reconstructed single cell trajectories in an open raceway using an original hydrodynamical model offering a powerful discretization of the Navier-Stokes equations tailored to systems with free surfaces. The trajectory of a...
Tipo: Text
Palavras-chave: Photosynthesis; Hydrodynamics; Modelling; Photoacclimation; Dunaliella salina; Non-photochemical quenching.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00445/55692/57352.pdf

Modeling continuous cultures of microalgae colimited by nitrogen and phosphorus
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
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

Quantifying the potential of microalgae to remove nutrients from wastewater
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Martinez, Carlos; Mairet, Francis; Plaza, Luis; Sciandra, Antoine; Bernard, Olivier.
The main resources limiting microalgae growth are typically phosphorus, nitrogen, and light. Based on the theory of the light limited chemostat, the variable cell quota approach, and photoacclimation models, we build a mathematical model for describing microalgae growth under limitation by these resources. The model is calibrated with a data set from the literature. Then, by numerical simulations, we find that under constant operation of the culture and constant environmental conditions (illumination, temperature, pH, etc.), solutions of the model approach towards either a positive or an extinction steady state. Based on the positive steady state, and in the context of wastewater treatment, we evaluate the capacity of microalgae to remove contaminants. We...
Tipo: Text
Palavras-chave: Control; Biotechnology; Wastewater treatment; Microalgae; Cell quota model.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00600/71188/69541.pdf

The use of fluorescent Nile red and BODIPY for lipid measurement in microalgae
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
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

Phytoplankton growth formulation in marine ecosystem models: Should we take into account photo-acclimation and variable stoichiometry in oligotrophic areas?
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Ayata, S. -d.; Levy, Marina; Aumont, Olivier; Sciandra, Antoine; Sainte-marie, J.; Tagliabue, A.; Bernard, Olivier.
The aim of this study is to evaluate the consequences of accounting for variable Chl:C (chlorophyll:carbon) and C:N (carbon:nitrogen) ratios in the formulation of phytoplankton growth in biogeochemical models. We compare the qualitative behavior of a suite of phytoplankton growth formulations with increasing complexity: 1) a Redfield formulation (constant C:N ratio) without photo-acclimation (constant Chl:C ratio), 2) a Redfield formulation with diagnostic chlorophyll (variable and empirical Chl:C ratio), 3) a quota formulation (variable C:N ratio) with diagnostic chlorophyll, and 4) a quota formulation with prognostic chlorophyll (dynamic variable). These phytoplankton growth formulations are embedded in a simple marine ecosystem model in a 1D framework...
Tipo: Text
Palavras-chave: Biogeochemical modeling; Phytoplankton; Photo-acclimation; Redfield ratio; Internal quota; BATS; Optimization; Micro-genetic algorithm.
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00159/27071/25460.pdf

Continuous selection pressure to improve temperature acclimation of Tisochrysis lutea
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
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