Дисертації з теми "Microalgae valorisation"
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Audoin, Coralie. "Valorisation de métabolites secondaires issus de micro-algues : approches métabolomiques, isolement et caractérisation structurale." Thesis, Nice, 2013. http://www.theses.fr/2013NICE4068.
Повний текст джерелаMicroalgae are present both in Oceans and freshwaters and could include more than 200 000 species. This diversity is a source of original specialized metabolites that can find a large array of applications. Pigments, lipids, proteins, polysaccharides and carotenoids are usual compounds produced by microalgae that have found commercial applications. A global vision of the metabolome of each species has showed promises to highlight the commercial value of this “microdiversity”. We then decided to assess the metabolome of several microalgae species grown at the Greensea company by using HPTLC, NMR and UHPLC-QTOF techniques for a rapid and global overview. A classification of the species according to their metabolomics similarities was obtained after statistics treatment of the data. A second part was dedicated to a phytochemical study of the extracts of selected strains and led to the isolation and characterization of several metabolites. Thus, in addition to known molecules, an original peptide substituted by an isoprenyl moiety and named cumbriamide has been characterized in Lyngbya sp and a first assessment of its therapeutical potential has been undertaken. Glycolipids have been identified as the major metabolites in the extracts of numerous strains and a UHPLC-QTOF method was developed for their identification. Finally, several applications of the metabolomics approaches were considered. Chemotaxonomic studies were first carried out and the influence of growth conditions on the metabolome of Nannochloropsis oculata was observed
Calabro, Kevin. "Valorisation dans le domaine de la cosmétique de métabolites produits par microalgues et cyanobactéries." Thesis, Université Côte d'Azur (ComUE), 2016. http://www.theses.fr/2016AZUR4100.
Повний текст джерелаThe sectors of fragrances and cosmetics play a prominent role in the modern society. During the last decades, several companies have been focusing on nature to provide innovative products. Plants have historically been considered the main raw material in the cosmetic field but, recently, microalgae have been identified as a worthy competitor due to the facility to obtain biomass. Thus, the company Cosmo International Ingredients supported this PhD. thesis to broaden their range of raw materials that can be used for the cosmetic industry. First, the phytochemical study of Peruvian microalgae allowed the isolation of a major family of metabolites: glycolipids. An environmentally-friendly, selective and low-cost method for their extraction from the biomass has been developed. Cyanobacteria known for their production of structurally diverse metabolites have been selected for culture following specific criteria; as a result 5 compounds have been isolated and fully characterized, 4 of which were peptides and one was an indole alkaloid. Finally, to optimize the production of the targeted bioactive peptides, a kinetic study was performed for 3 different temperatures and 3 different light intensities. These parameters were found to play a critical role for the peptide production
Zea, OBANDO Claudia Yamilet. "Caractérisation et valorisation de microalgues tropicales." Thesis, Lorient, 2015. http://www.theses.fr/2015LORIS385/document.
Повний текст джерелаBiomass of tropical microalgae have natural virtues that can be used in a wide range of bioproducts. Their valuation can enable sustainable and commercially viable production. Indeed, tropical microalgae represent a large biodiversity and benefit from favourable environmental conditions for large scale production. In this context, this thesis aims to explore new tropical strains to determine their potential development in the field of biotechnology, particularly in three areas: energy, nutraceutical and antifouling. This field is studied in the project ANR-CD2I "BIOPAINTROP" whose objective is the eco-responsible fight against biofouling. These works target biotechnological applications, but also development of new methods to characterize antifouling activity.Of the 50 strains studied, some have shown interest in the production of metabolites such as glycosyl glycerol, quality nutraceutical and lipids for biodiesel production. The Amphidinium sp. (P-43) stain led to a methanol extract having biological activity of interest. Its efficiency against biofilm was demonstrated. Moreover, the ecotoxicology study has suggested a low environmental impact
Avila, Cintia Romina. "Microalgae-based systems for micropollutants removal, resource recovery and bioenergy production towards a circular bioeconomy approach." Doctoral thesis, Universitat Autònoma de Barcelona, 2021. http://hdl.handle.net/10803/673680.
Повний текст джерелаLas tecnologías basadas en microalgas ofrecen una solución prometedora para cambiar el foco desde el tratamiento de residuos y aguas hacia la recuperación de energía y recursos. Las microalgas eliminan nutrientes de las aguas residuales y producen oxígeno para que las bacterias biodegraden la materia orgánica. Estos procesos se implementaron con éxito en el tratamiento de aguas residuales urbanas, pero en las ciudades cada vez más industrializadas y en los entornos agrícolas, el reto es determinar si estos sistemas pueden degradar contaminantes orgánicos como los pesticidas. La biomasa algal puede valorizarse para producir biocombustibles y otros bio-productos. La digestión anaeróbica es una tecnología consolidada para convertir residuos orgánicos en energía renovable (biogás). La co-digestión anaerobia de dos o más residuos contribuye a superar los inconvenientes de la mono-digestión e impulsa la producción de energía. Esta tesis evalúa diferentes procesos incluidos en el concepto de biorrefinería de microalgas: utilización de las algas para degradar micro-contaminantes, producción de energía mediante la digestión anaerobia de algas, la co-digestión con otros residuos cercanos, y la utilización de flujos de residuos como fertilizantes. Primero, se estudió la degradación individual de tres pesticidas polares y tres pesticidas hidrofóbicos mediante un cultivo de microalgas y otros microorganismos. Se estudiaron diferentes condiciones para determinar los mecanismos de degradación. La biodegradación y la foto-degradación contribuyeron a la eliminación del propanil (100%), acetamiprid (100%), oxadiazon (55%), clorpirifós (35%) y la cipermetrina (14%). Más del 60% del clorpirifós y la cipermetrina se eliminaron por bio-sorción. Se identificaron los productos de transformación generados por las microalgas para el clorpirifós, el acetamiprid y el propanil. Se evaluó el rendimiento de un fotobiorreactor piloto de exterior operado a un TRH de 8 días en el tratamiento de aguas residuales sintéticas conteniendo una mezcla de pesticidas. Se evaluó la capacidad de degradación cuantificando la eliminación de nutrientes y pesticidas, y se detectaron los productos de transformación. Las eficiencias de eliminación de nitratos and ortofosfato fueron del 24 y 94%, respectivamente. El propanil y el acetamiprid se eliminaron eficazmente (99 y 71%, respectivamente), principalmente por biodegradación. La digestión anaeróbica de las algas no fue inhibida por los pesticidas retenidos. Para mejorar la solubilidad y la digestibilidad anaeróbica de la biomasa algal, se evaluaron diferentes pretratamientos energéticamente eficientes. Previamente, se estudió la cosecha de las microalgas mediante técnicas de bajo coste: sedimentación natural, coagulación-floculación y floculación inducida por pH. Los pretratamientos se aplicaron antes de la co-digestión anaeróbica de las microalgas con lodos activados. Se evaluó el efecto de los pretratamientos térmicos a baja temperatura para las mezclas de microalgas y lodos, y se investigó el efecto de los pretratamientos enzimáticos en la solubilización de la pared celular de las microalgas. En ambos casos, se comprobó el efecto del pretratamiento en el rendimiento de biogás. La solubilidad de las algas aumentó, incrementando el rendimiento de metano. Sin embargo, en la co-digestión de lodos y algas, incluso cuando la solubilidad aumentó tras el pretratamiento, la producción de biogás no incrementó. Además, esta tesis evalúa un caso de estudio para la integración de un sistema basado en microalgas en la planta de tratamiento de aguas residuales de una empresa vinícola para aplicar un enfoque circular en la recuperación de nutrientes y energía de sus aguas residuales y lodos. El tratamiento terciario de las aguas residuales mediante microalgas eliminó eficazmente el amonio (97%) y el ortofosfato (93%). La biomasa algal fue co-digerida en un digestor anaerobio piloto de 50 L con lodos produciendo 225.8 NL CH4 kg VS-1. Los digestatos de mono-digestión y co-digestión y la biomasa seca de algas mejoraron la acumulación de biomasa vegetal al usarlos como fertilizantes.
Microalgae-based technologies offer a promising solution to shift the focus from wastes and wastewater treatment, toward energy and resource recovery. In these systems, microalgae remove nutrients from wastewater and produce oxygen useful for bacteria to biodegrade organic matter. This has been fully demonstrated in urban wastewater treatment, but in increasingly industrialised cities and agricultural environments, the challenge is to determine if microalgae-based systems can degrade organic micropollutants such as pesticides. Microalgae biomass can be further valorised for the production of biofuels and valuable bioproducts. Anaerobic digestion is one of the most established technologies to convert organic wastes into renewable energy in the form of biogas. Another opportunity is the simultaneous anaerobic co-digestion of two or more bio-wastes, contributing to overcome the drawbacks of mono-digestion and boosting energy production in anaerobic digestion plants. Nonetheless, microalgae anaerobic digestion is generally hindered by the recalcitrancy of their cell walls, which lead to low methane potential. The present thesis assesses different processes included in the microalgal biorefinery concept: utilisation of algae for micropollutant degradation, energy production by algal anaerobic digestion, co-digestion with other nearby wastes, and utilisation of waste streams as fertilizers. First, it was studied the individual degradation of three polar and three hydrophobic pesticides frequently found in surface waters by a mixed-microalgae culture. Different conditions were studied to determine the main degradation mechanisms. Biodegradation plus photodegradation contributed to the removal of propanil (100%), acetamiprid (100%), oxadiazon (55%), chlorpyrifos (35%), and cypermethrin (14%) while more than 60% of chlorpyrifos and cypermethrin were removed by bio-sorption. Transformation products generated by the active microalgae were identified for chlorpyrifos, acetamiprid, and propanil. The performance of an outdoor pilot-photobioreactor operated at a HRT of 8 days in the treatment of synthetic wastewater containing a mixture of selected pesticides was assessed. During the steady-state, degradation capacity was evaluated by quantifying nutrients and pesticides removal, and transformation products were detected. Nitrate and ortophosphate removal efficiencies were 24 and 94%, respectively. Propanil and acetamiprid were effectively removed (99 and 71%, respectively) mainly by algal-mediated biodegradation as confirmed by the transformation products detected. The anaerobic digestion of the algal biomass was not inhibited by the retained pesticides. To enhance the solubility and the anaerobic digestibility of algal biomass, different mild pretreatments were assessed. Formerly, microalgal harvesting was tested by different cost-effective techniques: sedimentation, coagulation-flocculation, and pH-induced flocculation. The pretreatments were applied before the anaerobic co-digestion of microalgae with sludge. The effect of thermal pretreatments at low temperature were evaluated for microalgae and sludge mixtures. Additionally, the effect of enzymatic pretreatments on microalgae cell wall solubilisation was investigated. In both cases, the effect of the pretreatment in the biogas yield was tested. Results indicate that algal biomass solubility increased and led to a higher methane yield. Nonetheless, in the co-digestion of sludge and algal biomass, even when biomass solubility was enhanced after the pretreatment, biogas production did not increase. Furthermore, this thesis assesses a case study for the integration of a microalgae-based system into the industrial wastewater treatment plant of a winery company looking for a circular approach for nutrients and bioenergy recovery from wastewater and sludge. Tertiary wastewater treatment by microalgae efficiently removed ammonium (97%) and phosphate (93%). Algal biomass was co-digested in a 50 L pilot anaerobic digester with sludge obtaining a yield of 225.8 NL CH4 kg VS-1. The digester was operated in SBR mode showing adaptations to substrate variability over time. The valorisation of the generated bio-wastes for fertilization indicate that mono- and co-digestion digestates and dry algal biomass improved plant biomass accumulation (growth indexes of 163, 155 and 121% relative to those of the control -commercial amendment-).
Universitat Autònoma de Barcelona. Programa de Doctorat en Ciència i Tecnologia Ambientals
IASIMONE, Floriana. "Experimental studies on Microalgae cultivation in urban wastewater: nutrients removal, CO2 absorption, biomass harvesting and valorisation." Doctoral thesis, Università degli studi del Molise, 2018. http://hdl.handle.net/11695/84780.
Повний текст джерелаMicroalgal biotechnology has received more and more attention in recent years as an alternative method of conventional wastewater treatment process and as possible solution for carbon dioxide capture. Moreover, the algal biomass generated during wastewater treatment is regarded as exploitable resource. Although this technology is attractive, a number of obstacles need to be solved before large-scale applications. The main purpose of this work is to study some critical aspects linked to the sustainable microalgal production chain, such as biotic factors (light, nutrients supply), carbon dioxide utilization, lipids production and biomass harvest. A wastewater-autochthonous algal culture was used to treat raw urban wastewater in closed photobioreactors under different light intensities and nutrients supply. The best conditions for both biomass production and lipids accumulation resulted in low nutrients supply (~ 10 mg NH4+/L, ~ 6.5 mg PO43-/L) and high light intensity (100 µmol s-1m-2). The biomass autoflocculation was investigated at the end of the cultivation period, corresponding to the high pH values of the cultivation media. The highest biomass recovery of 72% was estimated for the lowest light intensity (20 µmol s-1m-2) and nutrients supply conditions. The same wastewater-autochthonous algal culture was further cultivated in an open system (200 L pilot-scale raceway pond), using urban wastewater as growth medium, to analyse its carbon dioxide capture potential, applying different gas input flowrates (0.2, 0.4 and 1.0 L/min). Biomass growth, inorganic carbon and nutrients absorption were also studied during the cultivation start-up and its semi-continuous feeding conditions. Low gas flowrates favoured the fixation of bio-available CO2, while higher gas flowrates favoured the CO2 absorption in the open system, corresponding also the highest microalgal productivity (28.3 g d-1m-2 at the gas flowrate of 1.0 L/min). The combined cultivation of microalgae and yeast was conducted in batch conditions and in the open system, with the final purpose of increase the total lipid concentration of the produced biomass. Urban wastewater was used as growth medium. Yeast growth was monitored only during the first days of the cultivation because of the low availability of easy assimilated organic substrates in the medium. Microalgae growth showed a 3 days long initial lag phase and a subsequent linear growth, during which nutrients were completely depleted with 2.9 mgN•L-1•d-1and 0.96 mgP•L-1•d-1 of removal rates. The cultivation induced a natural bactericidal and antifungal action at the end of the cultivation period (14 days). The highest lipids content was measured at the end of the cultivation (15% lipids/dry weight) and resulted mainly composed by arachidic acid. Bioflocculation was studied as harvesting technique since it is low cost and not toxic for the biomass. First, microalgae bioflocculation was studied through their interaction with filamentous cyanobacteria. The filamentous cyanobacteria were obtained by the cultivation of the wastewater-autochthonous algal culture in specific condition of light, temperature, growth media and cultivation mode. Microlagae and cyanobacteria were cultivated in synthetic media and in pre-filtered urban wastewater. Natural flocculation occurred for cyanobacteria and enhanced the microalgae harvesting which resulted trapped in cyanobacteria mats; anyway, the suspended microalgae limited the clarification of the growth media. Finally, the natural cyanobacteria flocculation-tendency was further investigated applying two different mixing systems (air bubbles and shaking moment) and different initial biomass concentrations. Results showed a better flocculation performance in case of air bubbles mixing and with high initial biomass concentration. Moreover, the best condition for the natural biomass settling corresponded to the end of the biomass exponential growth state.
Filali, Rayen. "Estimation et commande robustes de culture de microalgues pour la valorisation biologique de CO2." Phd thesis, Supélec, 2012. http://tel.archives-ouvertes.fr/tel-00765421.
Повний текст джерелаMarcilhac, Cyril. "Étude des conditions de culture d'un écosystème complexe microalgues / bactéries : application au développement d'un procédé d'extraction-valorisation des nutriments issus des digestats." Thesis, Rennes 1, 2014. http://www.theses.fr/2014REN1S078/document.
Повний текст джерелаThe culture conditions of autotrophic microalgae in open system associating microalgae/bacteria were studied in this thesis. The objective was to develop a process to valorize nutrients (N, P) contained in the liquid phase of digestate coming from agricultural methanization. First, a synthesis of anaerobic digestion process followed by a state of art on microalgae and their culture conditions allowed to highlight the main parameters specific to the studied influent, such as coloration, and the interactions with nitrification-denitrification processes. To better understand the mechanisms and study the impact of the main parameters, a laboratory-scale pilot composed of six 2.5L-reactors was designed and specific analyses were developed at the laboratory. With the help of those tools, effects of color and light on light penetration and on microalgae growth were quantified. Then, the study of the N:P ratio of the medium allowed to highlight the phosphorus storage by microalgae, allowing them to continue their growth while the phosphorus of the medium was depleted. Thereafter, the carbon dioxide transfer and its impact on microalgae growth were studied. The algal productivity is a function of the quantity of provided CO2 into the culture and fall to zero without injection. Finally, the study of solid retention time and extraction rate revealed that nitrification-denitrification is an important mechanism for nitrogen removal in a continuous algae culture in open system. This mechanism may even be predominant compared to nitrogen assimilation by microalgae under certain conditions. The proportion of each of these processes may still be controlled by these parameters. These experiments have also provided insight into the interactions between microalgae and nitrifying bacteria and the predominance of algae genera depending on culture conditions. Microalgae are better competitors on phosphorus than nitrifying bacteria. Furthermore, in non-limiting phosphorus conditions, nitrification is reduced in proportion to algal productivity. Scenedesmus and Chlorella proved to be dominant respectively when phosphorus and light are limiting. The experimental trials were completed by the development or the adaptation of biokinetic models able to represent quite accurately microalgae growth and nitrogen removal. From this model, different configurations were simulated to design high rate algal pond and assess the feasibility of the algal culture to extract nutrients from digestate
Hourizadeh, Nicolas. "Valorisation du traitement d'eaux usées à partir de piles à combustibles microbiennes benthiques." Thesis, Antilles, 2015. http://www.theses.fr/2015ANTI0142/document.
Повний текст джерелаThe work described in this document is oriented to enhancing the treatment of wastewater from benthic microbial fuel cell (BMFC) for electricity production. This technology allows the production of electricity from electro-active (EA) microorganisms and carbonated substrate which may be the wastewater.Four types of wastewater from human activity are selected. The presence of EA microorganisms is highlighted by two electrochemical methods. In real conditions, the lagoon environment has the best electrical performance (6.6 mW/m²).The lagoon environment offers the most favorable environment for installation BMFC in-situ. The results show a strong influence of microalgae on the EA biofilms activities and thus on the production of electricity. In lagoon conditions, with a day/night cycle, this production varies according to the lighting cycles. Microalgae bring oxygen necessary for cathode reactions at lower cost. BMFC also improve the consumption of pollutants including organics.Electrical supply by small devices such as sensors necessarily requires an increase of the voltage delivered by BMFC. The different voltage boosting techniques such as series and parallel connections of several units or the use of DC/DC converters are performed and analyzed. A temperature and humidity sensor worked for more than fifteen hours directly powered by a BMFC with a power of 328 µW. Its output voltage is increased by a flyback type DC/DC converter, from 560 mV to more than 5.5 V. The use of PCM in-situ in the lagoon can be an alternative to the power generation and the treatment of wastewater
Ligorini, Viviana. "Trajectoires d’évolution des communautés phytoplanctoniques et des lagunes côtières du littoral corse et applications." Electronic Thesis or Diss., Corte, 2023. http://www.theses.fr/2023CORT0005.
Повний текст джерелаCoastal lagoons are of high ecological, economic and social importance. Nevertheless, they are particularly vulnerable to anthropogenic pressure and climate change, especially in the Mediterranean region. Lagoons’ conservation is hence fundamental for the protection of littoral systems and the well-being of human populations. This thesis aims to provide support for public policies for the restoration and conservation of coastal lagoons, but also to look for potential resources’ valorisation. The works aim to deepen knowledge on the evolution trajectories of phytoplankton communities and coastal lagoons of the Corsican coast, (i) by questioning the evolutions of seasonal variations linked to abiotic factors, but also the impact of salinity variations, particularly in the context of climate change, on large and/or small lagoons, and (ii) by testing different integrated approaches taking into account the human impact, from the watershed to the sea.Phytoplankton communities of six Corsican lagoons (Diana, Urbino, Biguglia, Arasu, Santa Giulia, Balistra) are studied in this framework. Analysis of long term historical datasets available, in situ monitoring and experimental essays performed allowed the identification of marked seasonal dynamics of phytoplankton communities and central elements for coastal lagoons’ management. The trend towards the dominance of dinoflagellates, the emergence of stress-tolerant (e.g. extreme salinities), sometimes potentially toxic, the increase in phytoplankton blooms as well as changes in the seasonal cycles have been highlighted in large and small sized lagoons. These phenomena are mainly linked to anthropogenic impacts (pollution, urban wastewater, water use, tourism…), hydrogeological alterations caused by human interventions, and climate change.The study of other biotic and abiotic compartments of the ecosystem, like biological invasion, fish production or hydrogeological functioning, has confirmed the need to apply an ecosystem-based approach, from the watershed to the sea, in order to understand the overall functioning of the system. The consideration of Humans in the study of ecological trajectories has also been highlighted, emphasizing that lagoons should be considered as social-ecological systems. This holistic vision is fundamental to consider an optimal integrated management of the complexity of the system.Moreover, this thesis provides a new perspective on small surfaced lagoons on the Mediterranean coast scale, which are very reactive to change and can thus be considered as sentinels of climate change.At the same time, the study of a diatom strain from the Diana lagoon has demonstrated promising ecophysiological and chemical characteristics for potential biotechnological applications in the aquaculture domain, due to its lagoon origin.The overall results on the past and future evolution trajectories have highlighted the complexity and vulnerability of coastal lagoons (and those of small surface areas in particular) in the face of growing threats and some questions about their future. This work provides hence some supporting elements for the lagoon management and the valorisation of resources linked to these environments, by proposing an integrated and interdisciplinary management for the sustainable conservation of these ecosystems and of the services provided, particularly in the climate change context
Jubeau, Sébastien. "Application du concept de bioraffinerie à la valorisation de la microalgue Porphyridium cruentum." Nantes, 2012. http://www.theses.fr/2012NANT2105.
Повний текст джерелаBiorefinery is the same methodology used in oil industry to separate each component of a biomass and to transform them into high value products. The microalga Porphyridium curentum is well referenced in the literature as a producer of many metabolites of interest like pigments (B-Phycoerythrin, zeaxanthin), ω3 and ω6 fatty acids and exopolysaccharides (EPS). We propose to apply the concept of biorefinery to P. Cruentum in order to produce different extracts of interest and so to make the biomass production profitable. We experimentally developed a process to produce and to separate the different fractions of P. Cruentum made of 4 main steps: cultivation and harvesting of the algae, cell disruption, separation of each biochemical family and purification of the latter. The optimization of culture conditions leads to a production of microalgae at the concentration of 2. 7g. L-1. Different cell destruction techniques have been tested such as high pressure cell disruption and freezing/thawing. Their impact on the molecules extracted has also been studied. A selective two-steps process has been developed to obtain pre-purified B-phycoerythrin extract. The purification of the latter has been tested by two different methods: the selective precipitation using ammonium sulfate and the tangential filtration on membrane. High purity levels (IP=3) have been reached using a filtration on polyethersulfone membrane (30kDa). 3 protocols have been developed and tested to promote the whole biomass
Devos, Marie. "Application des lipases pour la valorisation de l'acide docosahexaènoïque de la microalgue Isochrysis galbana." Le Mans, 2005. http://cyberdoc.univ-lemans.fr/theses/2005/2005LEMA1007.pdf.
Повний текст джерелаMarine microalgae represent a source of DHA (docosahexaenoic acid, C22 :6 3) which is not widely used. This study deals with enzymatic DHA enrichment of phospholipids from the microalga Isochrysis galbana. Analysis of microalgal lipids showed that 75 % of total DHA is carried by the phospholipids, representing 50% of phospholipid fatty acids. Moreover, it has been shown that DHA is mainly located at the sn-2 position of phospholipids. Among 19 lipase preparations tested, 3 have been selected according to their ability to discriminate against DHA during phospholipid hydrolysis, i. E. They liberate efficiently all fatty acids except DHA. They are Rhizopus oryzae and Mucor javanicus lipases from Amano Enzymes Inc. , U. K. As well as Rhizopus oryzae lipase from DSM, Netherlands. The best results have been obtained with the first 2 lipases: a DHA ratio of 71% was reached after 5 minutes of reaction and DHA yields of 98. 9% and 92. 1% were obtained for these two lipases, respectively. A reaction time of 3 hours allows the maximal DHA ratio of 77%, which is detrimental to the DHA yield. In a second part, it has been demonstrated, thanks to an original enzymatic approach, that acyl migration from sn-2 position to sn-1 position occurred in significant amounts during phospholipid hydrolysis. These results lead to the conclusion that the lipase ability to discriminate against DHA under our reaction conditions is due to a typoselectivity against this fatty acid and not to a regioselectivity towards the sn-1 position of phospholipids. At last, this study clearly shows the presence of an endogenous lipolytic activity in Isochrysis galbana. It is mainly active on phospholipids and DHA is the fatty acid the most widely liberated during hydrolysis of endogenous lipids. Therefore, it can be suggested that this activity comes from a phospholipase A2
Sialve, Bruno. "Couplage des cultures de microalgues avec la méthanisation : Traitement et valorisation de la matière et de l’énergie dans le cadre de la bioraffinerie environnementale." Thesis, Lyon, INSA, 2013. http://www.theses.fr/2013ISAL0062.
Повний текст джерелаIn recent years, there has been an explosion of interest in the use of microalgae as a source of bioenergy. Mass cultivation of microalgae for bioenergy production promises several advantages compared to first and second generation biofuels. However, similar difficulties in terms of nutrient requirements and an unfavourable energy balance are faced. As a consequence, achieving the sustainable levels of microalgal culture required to implement this strategy in the longer term appears problematic. The work presented in this thesis focuses on anaerobic digestion; a solution which allows both recycling of nutrients and supply of energy to the production and downstream processes. In particular, the studies presented here have been directed towards the integration of microalgal culture and methanisation, at both the laboratory and pilot scale. The guiding principle used is conversion of biomass and provision of nutrients to the culture. We first identified the constraints and potential strategies associated with the aerobic biodegradability of microalgae. Next, we demonstrated that the energetic potential of cells is limited by their quality as well as their level of resistance to biological degradation. We have shown that it is possible to optimise the conversion step, increasing energy yields and nutrient mineralisation via a strategy of thermal pretreatment The use of a natural microalgae-bacteria ecosystem which uses a synthetic digestate as culture media, revealed a key role for bacterial flora interacting with microalgae. These results were further tested in a pilot-level production system specifically designed to address these questions. The evidence suggests that the characteristics of the culture pond determine both the hydrodynamic behaviour of the culture and the physical and ecological behaviour of the phytoplanktonic population. A study of the dynamics of the microbial, eukaryotic and prokaryotic communities suggests the presence of a resilient and complex ecosystem, which is influenced by variations in its environment. The results of this work provide opportunities for management and optimisation of processes integrating microalgae cultivation and methanisation beyond bioenergy production, for example liquid wastes treatment and production of high-value byproducts
DAURINCHE, ISABELLE. "Valorisation des microalgues : culture en bassin; teneurs en lipides; influence des facteurs de l'environnement." Caen, 1991. http://www.theses.fr/1991CAEN2032.
Повний текст джерелаGargouch, Nesrine. "Caractérisation de la microalgue rouge Porphyridium marinum sous différentes conditions de culture et valorisation de ces métabolites." Thesis, Université Clermont Auvergne (2017-2020), 2018. http://www.theses.fr/2018CLFAC095/document.
Повний текст джерелаThe present study investigates the effect of a selected organic carbon source on the growth and production of metabolites of the red microalga Porphyridium marinum. The latter has been unable to multiply in heterotrophy, in total absence of light. However, in mixotrophic condition the productions of biomass, lipids and phycobiliproteins by P. marinum have been improved in comparison with the autotrophic condition. The contents of exopolysaccharide were almost similar under both conditions. In order to valorize these metabolites, the antioxidant, antibacterial, antibiofilm and anticancer effect were tested. The exopolysaccharide of P. marinum as well as its low molecular weight derivatives (EPS-2P and EPS-5P) have all exhibited antibacterial and antibiofilm activities at different concentrations. However, EPS-2P and EPS-5P were found to be more effective for anti-cancer activity against breast cancer cells. On the other hand, the production of the majority pigment of red microalgae, B-phycoerythrin (B-PE), has been optimized by means of adapted experimental plans. A content of 40 mg/g DW was obtained by varying the concentration of NaNO3, K2HPO4 and metal solution as well as the light intensity. After purification, the optimized molecule showed antioxidant activity in terms of free radical scavenging DPPH, chelation and reduction of iron ions and β-carotene bleachinginhibition. Our data suggest that the metabolites produced by the red microalga P. marinum may be potentially used in several applications namely cosmetic and pharmaceutical
Bélair, Viviane. "Développement de nouvelles techniques d’extraction des lipides à partir des microalgues en vue de leur valorisation en biocarburant." Thesis, Université Laval, 2012. http://www.theses.ulaval.ca/2012/28924/28924.pdf.
Повний текст джерелаVandanjon, Laurent. "Etude d'un procede de valorisation d'une microalgue marine : concentration et purification par techniques a membranes d'un pigment naturel produit par la diatomee haslea ostrearia." Nantes, 1997. http://www.theses.fr/1997NANT2050.
Повний текст джерелаPoisson, Laurent. "Valorisation enzymatique de lipides : synthèse de cires à partir de la matière grasse laitière : production et traitements d'acides gras polyinsaturés de microalgues." Le Mans, 1999. http://www.theses.fr/1999LEMAA002.
Повний текст джерелаDERRIEN, ANNE. "Etude par chromatographie liquide de la composition en acides amines libres des principales microalgues fourrageres utilisees en aquaculture en vue de leur valorisation cosmetique." Nantes, 1996. http://www.theses.fr/1996NANT2023.
Повний текст джерелаGifuni, Imma. "Valorisation of starch production in microalgae biorefinery." Tesi di dottorato, 2017. http://www.fedoa.unina.it/12265/7/gifuni_imma_30_COMPLETA.pdf.
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