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| Registros recuperados: 11 | |
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| Anastassiadis,Savas; Rehm,Hans-Jürgen. |
| The effect of air saturation on citric acid production in batch, repeated batch and chemostat cultures has been studied. It was shown that, under continuous fermentation (chemostat mode), the highest concentration of citric acid equal of 98 g/l was produced at 20% of air saturation. In contrary to continuous fermentation, displaying an optimum at 20%, 80% air saturation yielded higher values in repeated batch fermentation process. 167 g/l citric acid were produced continuously with the fill and drain technique at 4.85 days, at 80% air saturation, compared with 157.6 g/l achieved within 5.4 days at 20%. Under repeated batch fermentation, the formation rate of the generic product (Rj) as well as the specific citric acid productivity (m p) reached a maximum... |
| Tipo: Journal article |
Palavras-chave: Air saturation influence; Chemostat; Citric acid; Citric acid fermentation; Repeated batch; Oxygen influence. |
| Ano: 2006 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582006000100005 |
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| Jauffrais, Thierry; Sechet, Veronique; Truquet, Philippe; Amzil, Zouher; Herrenknecht, Christine; Hess, Philipp. |
| Azadinium spinosum, a small dinoflagellate has recently been discovered and identified as the primary producer of azaspiracid-1 (AZA) and -2. Since AZA poisoning has been reported following consumption of contaminated shellfish it is important to have these toxins available for toxicological studies, and a sustainable production of AZAs as calibrants in monitoring programs without having to rely on natural events. In order to address this concern, continuous pilot scale cultures were carried out to evaluate the feasibility of AZA production from A. spinosum. Algae were cultured using two 100 L chemostats in series (R1 and R2), with agitation and pH control. Four different dilution rates were tested (0.15, 0.2, 0.25 and 0.3 day−1) to evaluate chemostat... |
| Tipo: Text |
Palavras-chave: Solid phase adsorption; Chemostat; Photobioreactor; Microalgae; LC-MS/MS; Tangential flow filtration. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00152/26349/24437.pdf |
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| 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 |
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| 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 |
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| Jauffrais, Thierry; Kilcoyne, Jane; Sechet, Veronique; Herrenknecht, Christine; Truquet, Philippe; Herve, Fabienne; Berard, Jean-baptiste; Nulty, Ciara; Taylor, Sarah; Tillmann, Urban; Miles, Christopher O.; Hess, Philipp. |
| Azaspiracid (AZA) poisoning has been reported following consumption of contaminated shellfish, and is of human health concern. Hence, it is important to have sustainable amounts of the causative toxins available for toxicological studies and for instrument calibration in monitoring programs, without having to rely on natural toxin events. Continuous pilot scale culturing was carried out to evaluate the feasibility of AZA production using Azadinium spinosum cultures. Algae were harvested using tangential flow filtration or continuous centrifugation. AZAs were extracted using solid phase extraction (SPE) procedures, and subsequently purified. When coupling two stirred photobioreactors in series, cell concentrations reached 190,000 and 210,000 cell·mL−1 at... |
| Tipo: Text |
Palavras-chave: Solid phase extraction; Photobioreactor; Chemostat; Dinoflagellate; Micro-algae; LC-MS/MS; Tangential flow filtration; Azaspiracid; HP-20. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00088/19875/17526.pdf |
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| 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 |
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| Jauffrais, Thierry; Sechet, Veronique; Herrenknecht, Christine; Truquet, Philippe; Savar, Veronique; Tillmann, Urban; Hess, Philipp. |
| Azadinium spinosum, a small dinoflagellate isolated from the North Sea, is a producer of azaspiracids (AZAs), a group of biotoxins associated with human illness following ingestion of contaminated shellfish. Using batch and continuous cultures of A. spinosum, the present study investigated the effects of different environmental and nutritional factors (salinity, temperature, photon flux density, aeration, culture media, nitrogen sources, phosphate source, and N/P ratios) on growth, maximum cell concentration, and AZA cell quota. Azadinium spinosum grew in a wide range of conditions; from 10 ̊C to 26 ̊C and salinities from 30 to 40, under irradiances ranging from 50 μmol m−2 s−1 to 250 μmol m−2 s−1, with or without aeration. Growth and maximum cell... |
| Tipo: Text |
Palavras-chave: AZA; Chemostat; Dinophyceae; Nutrients; N/P ratio; Photobioreactor. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00149/26054/24411.pdf |
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| Nef, Charlotte; Henry, Céline; Nicolau, Elodie; Bérard, Jean-baptiste; Hervé, Fabienne; Caruana, Amandine; Kaas, Raymond; Mairet, Francis; Garnier, Matthieu. |
| Cobalamin (vitamin B12) is a cobalt-containing enzymatic cofactor involved in methionine synthesis. Provided only by select bacteria and archaea in marine systems, this vitamin is known to limit primary production in different oceanic areas. Understanding the consequences of cobalamin limitation on phytoplankton physiology is of great interest, notably for cobalamin-dependent haptophytes that significantly contribute to oceanic carbon fixation and sulfur cycle through dimethyl sulfonio propionate (DMSP) synthesis. Here, the effect of cobalamin limitation was compared to nitrogen limitation on the model haptophyte Tisochrysis lutea grown in chemostats, combining comparative proteomics with the analysis of major macromolecules and specific osmolytes. Our... |
| Tipo: Text |
Palavras-chave: Cobalamin; Vitamin B-12; Haptophyte microalgae; Tisochrysis lutea; DMSP; Chemostat; Comparative proteomics; Metabolism. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00654/76575/77711.pdf |
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| Jacques, G.; De Billy, G.. |
| One approach to the problem of aquaculture consists in a simple acceleration of natural processes in extended areas of salt or brackish water. From this point of view, the authors have been interested in the effect of moderate fertilization on natural communities . A first series of experiments (8) was made in an external tank of 3000 liters. After fertilization, the development of flowering diatoms was obtained each time. The time of latency, the level of production reached, the composition of the final communities is to some extent variable, but bacterial development may be neglected. In contrast to earlier results, obtained in small volumes of water, these experiments have always led to simplified communities mostly dominated by the diatom... |
| Tipo: Text |
Palavras-chave: Phytoplancton; Fertilisation; Chémostat.; Phytoplankton; Nutrient; Enrichment; Chemostat. |
| Ano: 1979 |
URL: http://archimer.ifremer.fr/doc/00306/41688/40897.pdf |
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| Registros recuperados: 11 | |
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