Etude d'une méthode d'échantillonnage des populations de chevrettes (Macrobrachium lar. et M. australe) des rivières de Nuku Hiva (Marquises, Polynésie française)

Une méthode d'échantillonnage des #Macrobrachium, macrocrustacés dulçaquicoles, est étudiée dans le cadre d'un suivi de la faune non cible aux traitements des rivières de l'île de Nuku-Hiva (Marquises) visant l'éradication du "nono noir des vallées" (#Simulim buissoni). Plusieurs engins de pêche ont été étudiés dont de petites nasses fabriquées à l'aide de bouteilles plastiques. Le "comportement" de ces bouteilles en regard des captures échantillonnées est abordé par comparaison avec les captures d'autres types de pièges (grandes nasses et pêche électrique), divers types de bouteilles (appâtées, colorées), et différentes orientations des bouteilles dans la rivière. L'abondance des captures est analysée en fonction de l'échappement et des fluctuations de l'effort d'échantillonnage (nombre de bouteilles/unité de surface). L'efficacité des bouteilles transparentes quant à l'abondance des prises est étudiée après des estimations du nombre total de chevrettes dans le milieu résultant d'opérations de marquage-recapture et de comptages visuels de nuit. Enfin, une interprétation de l'abondance et de la densité des chevrettes par des variables écologiques descriptives du milieu est proposée. (Résumé d'auteur

Biodiversity as a tool for waste phycoremediation and biomass production

International audienc

Revisited phytoplanktonic carbon dependency of heterotrophic bacteria in freshwaters, transitional, coastal and oceanic waters

International audienc

Complementary support for the new ecological concept of ‘bacterial independence on contemporary phytoplankton production’ in oceanic waters

International audienc

About frame estimation of growth functions and robust prediction in bioprocess modeling

We address the problem of determining functional framing from experimental data points in view of robust time-varying predictions, which is of crucial importance in bioprocess monitoring. We propose a method that provides guaranteed functional bounds, instead of sets of parameters values for growth functions such as the classical Monod or Haldane functions commonly used in bioprocess modeling. We illustrate the applicability of the method with bioreactor simulations in batch and continuous mode, as well as on real data. We also present two extensions of the method adding flexibility in its application, and discuss its efficiency in providing guaranteed state estimations

Étude et prédiction des interactions en coculture algale

Séminaire TREASURE 2018, Dec 2018, Hammamet, Tunisi

Growth of Chlorella sorokiniana on a mixture of volatile fatty acids: The effects of light and temperature

International audienceThis study investigated the influence of light and temperature on Chlorella sorokiniana grown on a mixture of acetate and butyrate, two of the volatile fatty acids produced by dark fermentation. Exposure to light caused autotrophic biomass production (56% of the final biomass) and reduced the time to reach butyrate exhaustion to 7 days at 25°C from 10 days in the dark. For growth on acetate at the optimum temperature (35°C), the presence of butyrate reduced the growth rate (by 46%) and the carbon yield (by 36%). For successful microalgae growth on dark fermentation effluent, butyrate inhibition may be reduced by setting the temperature to 30°C and providing light

Potentialities of dark fermentation effluent as substrates for microalgae growth: A review

In recent years, coupling bacterial dark fermentation (DF) and heterotrophic cultivation of microalgae (HCM) has been pointed out as a promising sustainable approach for producing both gaseous and liquid biofuels. Complex organic waste and effluents that are not susceptible to be directly degraded by microalgae are first converted into volatile fatty acids (VFAs) and hydrogen by DF. In this work, the feasibility of using DF effluents to sustain has been thoroughly reviewed and evaluated. Promising perspectives in terms of microalgae biomass and lipids production are proposed and can be extended as guidelines to promote HCM whatever the organic waste used. Abiotic and biotic factors from DF effluents that promote or inhibit microalgae growth are discussed as well as the use of unsterile DF effluents. Overall, the microalgae growth is favored on effluents containing high acetate concentration (> 3 g L−1), with a high acetate:butyrate ratio (> 2.5), and when pH is strictly controlled. At a low acetate:butyrate ratio (<1) and/or high total metabolites concentrations (>10 g L−1), a low substrate:microalgae ratio and the presence of light appear to enhance microalgae growth. Butyrate content appears to be a key factor when coupling DF/HCM since high butyrate concentration inhibits the microalgae growth