63,196 research outputs found
Carbon dioxide from alcoholic fermentation as a carbon source for fed-batch cultivation of Arthrospira platensis
No full textWorld’s production of ethanol has increased dramatically in recent years. Brazil is the world’s largest exporter of bioethanol and second-largest producer after the United States. Considering the increasing demand for this fuel and the fact that alcoholic fermentation is responsible for a CO2 release, on weight basis, almost coincident with ethanol production, it would be interesting to develop a process for CO2 fixation able to turn it into a useful product. Photosynthetic microorganisms can fix CO2 efficiently producing biomass that contains high-value bioactive products and may provide a very promising alternative for the current CO2 mitigation strategies. Nowadays, there are numerous commercial applications of Arthrospira platensis biomass such as the enhancement of the nutritional value of foods and animal feed, bioremediation, and use in cosmetics. The objective of this work was to evaluate the Arthrospira platensis cultivation using CO2 from alcoholic fermentation and either urea or nitrate as nitrogen source at different light intensities (60 ≤ I ≤ 240 μmol photons m-2 s-1). The CO2 source (pure CO2 or from alcoholic fermentation) did not influence the maximum cell concentration (Xm), cell productivity (PX) and nitrogen-to-cell conversion factor (YX/N). On the other hand, the use of urea instead of nitrate led to higher YX/N values. Xm and PX increased when I was increased from 60 to 120-240 μmol photons m-2 s-1. Using CO2 from alcoholic fermentation, the best performance (Xm = 2952 ± 35 mg L-1, PX = 425 ± 5.9 mg L-1 d-1 and YX/N = 15 ± 0.20 mg mg-1) was obtained at I = 120 μmol photons m-2 s-1 with urea. The results obtained in this work demonstrate that urea and CO2 from alcoholic fermentation could be simultaneously used in large-scale cultivations to reduce the environmental impact associated to the release of this greenhouse gas as well as to decrease the production cost of this cyanobacterium
Repeated fed-batch cultivation of Arthrospira (Spirulina) platensis using urea as nitrogen source
No full textArthospira (Spirulina) platensis (Nordstedt) Gomont was autotrophically cultivated for biomass production in repeated fed-batch process using urea as nitrogen source, with the aim of making large-scale production easier, increasing cell productivity and then reducing the production costs. It was investigated the influence or the ratio of renewed volume to total volume (R), the Urea feeding time (t(f)) and the number of successive repealed fed-batch cycles on the maximum cell concentration (X(m)), cell productivity (P(x)), nitrogen-to-cell conversion yield (Y(x/n)), maximum specific growth rate (mu(m)) and protein content of, dry biomass. The experimental results demonstrated chat R=0.80 and t(f) = 6d were the best cultivation conditions, being able to simultaneously ensure, throughout the three fed-batch cycles, the highest average values of three of the five responses (X(m) = 2101 +/- 113 mg L(-1), P(x) = 219 +/- 13 mg L(-1) d(-1) and Y(x/n) = 10.3 +/- 0.8,g g(-1)). (C) 2008 Elsevier B.V. All rights reserved.FAPESP, Brazil[04/04004-1]FAPESP, Brazil[04/04012-4
Fed-Batch Cultivation of Arthrospira platensis Using Carbon Dioxide from Alcoholic Fermentation and Urea as Carbon and Nitrogen Sources
No full textIt was evaluated the Arthrospira platensis cultivation using CO2 from alcoholic fermentation and either urea or nitrate as nitrogen source at different light intensities (60 ≤ I ≤ 240 μmol photons m-2 s-1). Whereas the CO2 source (pure CO2 or from alcoholic fermentation) did not influence the maximum cell concentration (Xm), cell productivity (PX) and nitrogen-to-cell conversion factor (YX/N), the use of urea instead of nitrate led to higher YX/N values. Xm and PX increased when I was increased from 60 to 120-240 μmol photons m-2 s-1. Using CO2 from alcoholic fermentation, the best performance (Xm = 2952 ± 35 mg L-1, PX = 425 ± 5.9 mg L-1 d-1 and YX/N = 15 ± 0.20 mg mg-1) was obtained at I = 120 μmol photons m-2 s-1 with urea. The results obtained in this work demonstrate that urea and CO2 from alcoholic fermentation could be simultaneously used in large-scale cultivations to reduce the environmental impact associated to the release of this greenhouse gas as well as the production cost of cyanobacteria
Arthrospira platensis cultivated with CO2 from alcoholic fermentation and urea at differents light intensities
No full textThe aim of this study was to investigate the influence of different CO2 and nitrogen sources under different light intensities on the maximum cell concentration of Arthrospira (Spirulina) platensis, cell productivity and nitrogen-to-cell conversion yield
Cultivo descontínuo alimentado de Arthrospira platensis em fotobioreator tubular usando uréia como fonte de nitrogênio em diferentes intensidades luminosas
No full textThe aim of this work was the evaluation of the kinetic parameters of biomass growth in Arthrospira platensis cultures in tubular photobioreactor fed with pure CO2 for the pH control under different light intensities and nitrogen sourced supplied by the fed-batch process
Avaliação de diferentes tempos de alimentação e ciclos em processo descontínuo alimentado repetitivo, em cultivo de Spirulina platensis, empregando uréia como fonte de nitrogênio
No full textSpecific growth rate and photosynthetic efficiency of Arthrospira platensis cultivations at different times of ammonium chloride feeding and light intensities
No full textThe objective of this study was to evaluate the influence of light intensity and time of ammonium chloride feeding on the maximum specific growth rate and photosynthetic efficiency of Arthrospira platensis during fed-batch cultivations
Efeito da intensidade luminosa e da uréia como fonte de nitrogênio na composição centesimal da Arthrospira platensis cultivada em fotobioreator tubular
No full textThe aim of this work was to investigate the influence of the light intensity and of the use of urea as nitrogen source in fed-batch process on the contents of chlorophyll, lipids, proteins, carbohydrates and ash of Arthrospira platensis biomass
Influence of ammonium chloride feeding time and light intensity on the cultivation of Spirulina (Arthrospira) platensis
No full textThis study dealt with the influence of both the feeding time and light intensity on the fed-batch culture of the cyanobacterium Spirulina (Arthrospira) platensis using ammonium chloride as a nitrogen source. For this purpose, a 2 2 plus star central composite experimental design combined with response surface methodology was employed, and the maximum cell concentration (X-m), the cell productivity (P-X), and the yield of biomass on nitrogen (Y-X/N) were selected as the response variables. The optimum values of X-m (1,833 mgL(-1)) and Y-X/N (5.9 gg(-1)) estimated by the model at light intensity of 13 klux and feeding time of 17.2 days were very close to those obtained experimentally under these conditions (X-m = 1,771 +/- 41 mg L-1; Y-X/N = 5.7 +/- 0.17 gg(-1)). The cell productivity was a decreasing function of the ammonium chloride feeding time and a quadratic function of the light intensity. The protein and lipid contents of dry biomass collected at the end of cultivations were shown to decrease with increasing light intensity
Simultaneous use of urea and potassium nitrate for Arthrospira (Spirulina) platensis cultivation
No full textUrea has been considered as a promising alternative nitrogen source for the cultivation of Arthrospira platensis if it is possible to avoid ammonia toxicity; however, this procedure can lead to periods of nitrogen shortage. This study shows that the addition of potassium nitrate, which acts as a nitrogen reservoir, to cultivations carried out with urea in a fed-batch process can increase the maximum cell concentration (Xm) and also cell productivity (PX). Using response surface methodology, the model indicates that the estimated optimum Xm can be achieved with 17.3 mM potassium nitrate and 8.9 mM urea. Under this condition an Xm of 6077 +/- 199 mg/L and a PX of 341.5 +/- 19.1 mg L1day1 were obtained.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (Fapesp) [2005/52255-6, 2005/52269-7
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