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Joao Carlos Monteiro De Carvalho - One of the best experts on this subject based on the ideXlab platform.
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effects of photobioreactor configuration Nitrogen Source and light intensity on the fed batch cultivation of arthrospira spirulina platensis bioenergetic aspects
Biomass & Bioenergy, 2012Co-Authors: Marcelo Chuei Matsudo, Sunao Sato, Attilio Converti, Raquel Pedrosa Bezerra, Patrizia Perego, Joao Carlos Monteiro De CarvalhoAbstract:Bioenergetic analysis may be applied in order to predict microbial growth yields, based on the Gibbs energy dissipation and mass conservation principles of the overall growth reaction. The bioenergetics of the photoautotrophic growth of the cyanobacterium Arthrospira (Spirulina) platensis was investigated in different bioreactor configurations (tubular photobioreactor and open ponds) using different Nitrogen Sources (nitrate and urea) and under different light intensity conditions to determine the best growing conditions in terms of Gibbs energy dissipation, number of photons to sustain cell growth and phototrophic energy yields distribution in relation to the ATP and NADPH formation, and release of heat. Although an increase in the light intensity increased the Gibbs energy dissipated for cell growth and maintenance with both Nitrogen Sources, it did not exert any appreciable influence on the moles of photons absorbed by the system to produce one C-mol biomass. On the other hand, both bioenergetic parameters were higher in cultures with nitrate than with urea, likely because of the higher energy requirements needed to reduce the former Nitrogen Source to ammonia. They appreciably increased also when open ponds were substituted by the tubular photobioreactor, where a more efficient light distribution ensured a remarkably higher cell mass concentration. The estimated percentages of the energy absorbed by the cell showed that, compared with nitrate, the use of urea as Nitrogen Source allowed the system to address higher energy fractions to ATP production and light fixation by the photosynthetic apparatus, as well as a lower fraction released as heat. The best energy yields values on Gibbs energy necessary for cell growth and maintenance were achieved in up to 4–5 days of cultivation, indicating that it would be the optimum range to maintain cell growth. Thanks to this better bioenergetic situation, urea appears to be a quite promising low-cost, alternative Nitrogen Source for Arthrospira platensis cultures in photobioreactors.
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evaluation of the composition of continuously cultivated arthrospira spirulina platensis using ammonium chloride as Nitrogen Source
Biomass & Bioenergy, 2010Co-Authors: Carlos Eduardo Nascimento Sassano, Sunao Sato, Luiz Antonio Gioielli, Livia Seno Ferreira, Mayla Santos Rodrigues, Attilio Converti, Joao Carlos Monteiro De CarvalhoAbstract:Abstract This work is focused on the influence of dilution rate (0.08 ≤ D ≤ 0.32 d−1) on the continuous cultivation and biomass composition of Arthrospira (Spirulina) platensis using three different concentrations of ammonium chloride (cNo = 1.0, 5.0 and 10 mol m−3) as Nitrogen Source. At cNo = 1.0 and 5.0 mol m−3 the biomass protein content was an increasing function of D, whereas, when using cNo = 10 mol m−3, the highest protein content (72.5%) was obtained at D = 0.12 d−1. An overall evaluation of the process showed that biomass protein content increased with the rate of Nitrogen supply (D cNo) up to 72.5% at D cNo = 1.20 mol m−3 d−1. Biomass lipid content was an increasing function of D only when the Nitrogen Source was the limiting factor for the growth (D cNo ≤ 0.32 mol m−3 d−1), which occurred solely with cNo = 1.0 mol m−3. Under such conditions, A. platensis reduced its Nitrogen reserve in the form of proteins, while maintaining almost unvaried its lipid content. The latter was affected only when the concentration of Nitrogen was extremely low (cNo = 1.0 mol m−3). The most abundant fatty acids were the palmitic (45.8 ± 5.20%) and the γ-linolenic (20.1 ± 2.00%) ones. No significant alteration in the profiles either of saturated or unsaturated fatty acids was observed with cNo ≤ 5.0 mol m−3, prevailing those with 16 and 18 carbons.
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repeated fed batch cultivation of arthrospira spirulina platensis using urea as Nitrogen Source
Biochemical Engineering Journal, 2009Co-Authors: Marcelo Chuei Matsudo, Sunao Sato, Attilio Converti, Raquel Pedrosa Bezerra, Patrizia Perego, Joao Carlos Monteiro De CarvalhoAbstract:Abstract Arthrospira (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 of the ratio of renewed volume to total volume (R), the urea feeding time (tf) and the number of successive repeated fed-batch cycles on the maximum cell concentration (Xm), cell productivity (Px), Nitrogen-to-cell conversion yield (Yx/n), maximum specific growth rate (μm) and protein content of dry biomass. The experimental results demonstrated that R = 0.80 and tf = 6 d 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 (Xm = 2101 ± 113 mg L−1, Px = 219 ± 13 mg L−1 d−1 and Yx/n = 10.3 ± 0.8 g g−1).
Chiming Che - One of the best experts on this subject based on the ideXlab platform.
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fe f20tpp cl catalyzed intramolecular c n bond formation for alkaloid synthesis using aryl azides as Nitrogen Source
ChemInform, 2011Co-Authors: Yungen Liu, Jinhu Wei, Chiming CheAbstract:The title porphyrin is an effective catalyst for preparing indole, indoline, tetrahydroquinoline, dihydroquinazolinone, and quinazolinone alkaloids via intramolecular amination of sp2 and sp3 C—H bonds using aryl azides as Nitrogen Source.
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feiii f20 tpp cl is an effective catalyst for nitrene transfer reactions and amination of saturated hydrocarbons with sulfonyl and aryl azides as Nitrogen Source under thermal and microwave assisted conditions
ChemInform, 2011Co-Authors: Yungen Liu, Chiming CheAbstract:The commercially available and air stable Fe-complex is a useful catalyst for aziridination of alkenes, sulfimidation of both alkyl and aryl sulfides, direct allylic amidation/amination of α-methylstyrenes, and amination of saturated C—H bonds including that of cycloalkanes with sulfonyl and aryl azides as the Nitrogen Source.
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fe f20tpp cl catalyzed intramolecular c n bond formation for alkaloid synthesis using aryl azides as Nitrogen Source
Chemical Communications, 2010Co-Authors: Yungen Liu, Jinhu Wei, Chiming CheAbstract:The syntheses of alkaloids including indoles, indolines, tetrahydroquinolines, dihydroquinazolinones and quinazolinones have been accomplished in moderate to excellent yields via [Fe(F20TPP)Cl] catalyzed intramolecular C–N bond formation using aryl azides as Nitrogen Source.
Attilio Converti - One of the best experts on this subject based on the ideXlab platform.
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effects of photobioreactor configuration Nitrogen Source and light intensity on the fed batch cultivation of arthrospira spirulina platensis bioenergetic aspects
Biomass & Bioenergy, 2012Co-Authors: Marcelo Chuei Matsudo, Sunao Sato, Attilio Converti, Raquel Pedrosa Bezerra, Patrizia Perego, Joao Carlos Monteiro De CarvalhoAbstract:Bioenergetic analysis may be applied in order to predict microbial growth yields, based on the Gibbs energy dissipation and mass conservation principles of the overall growth reaction. The bioenergetics of the photoautotrophic growth of the cyanobacterium Arthrospira (Spirulina) platensis was investigated in different bioreactor configurations (tubular photobioreactor and open ponds) using different Nitrogen Sources (nitrate and urea) and under different light intensity conditions to determine the best growing conditions in terms of Gibbs energy dissipation, number of photons to sustain cell growth and phototrophic energy yields distribution in relation to the ATP and NADPH formation, and release of heat. Although an increase in the light intensity increased the Gibbs energy dissipated for cell growth and maintenance with both Nitrogen Sources, it did not exert any appreciable influence on the moles of photons absorbed by the system to produce one C-mol biomass. On the other hand, both bioenergetic parameters were higher in cultures with nitrate than with urea, likely because of the higher energy requirements needed to reduce the former Nitrogen Source to ammonia. They appreciably increased also when open ponds were substituted by the tubular photobioreactor, where a more efficient light distribution ensured a remarkably higher cell mass concentration. The estimated percentages of the energy absorbed by the cell showed that, compared with nitrate, the use of urea as Nitrogen Source allowed the system to address higher energy fractions to ATP production and light fixation by the photosynthetic apparatus, as well as a lower fraction released as heat. The best energy yields values on Gibbs energy necessary for cell growth and maintenance were achieved in up to 4–5 days of cultivation, indicating that it would be the optimum range to maintain cell growth. Thanks to this better bioenergetic situation, urea appears to be a quite promising low-cost, alternative Nitrogen Source for Arthrospira platensis cultures in photobioreactors.
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evaluation of the composition of continuously cultivated arthrospira spirulina platensis using ammonium chloride as Nitrogen Source
Biomass & Bioenergy, 2010Co-Authors: Carlos Eduardo Nascimento Sassano, Sunao Sato, Luiz Antonio Gioielli, Livia Seno Ferreira, Mayla Santos Rodrigues, Attilio Converti, Joao Carlos Monteiro De CarvalhoAbstract:Abstract This work is focused on the influence of dilution rate (0.08 ≤ D ≤ 0.32 d−1) on the continuous cultivation and biomass composition of Arthrospira (Spirulina) platensis using three different concentrations of ammonium chloride (cNo = 1.0, 5.0 and 10 mol m−3) as Nitrogen Source. At cNo = 1.0 and 5.0 mol m−3 the biomass protein content was an increasing function of D, whereas, when using cNo = 10 mol m−3, the highest protein content (72.5%) was obtained at D = 0.12 d−1. An overall evaluation of the process showed that biomass protein content increased with the rate of Nitrogen supply (D cNo) up to 72.5% at D cNo = 1.20 mol m−3 d−1. Biomass lipid content was an increasing function of D only when the Nitrogen Source was the limiting factor for the growth (D cNo ≤ 0.32 mol m−3 d−1), which occurred solely with cNo = 1.0 mol m−3. Under such conditions, A. platensis reduced its Nitrogen reserve in the form of proteins, while maintaining almost unvaried its lipid content. The latter was affected only when the concentration of Nitrogen was extremely low (cNo = 1.0 mol m−3). The most abundant fatty acids were the palmitic (45.8 ± 5.20%) and the γ-linolenic (20.1 ± 2.00%) ones. No significant alteration in the profiles either of saturated or unsaturated fatty acids was observed with cNo ≤ 5.0 mol m−3, prevailing those with 16 and 18 carbons.
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repeated fed batch cultivation of arthrospira spirulina platensis using urea as Nitrogen Source
Biochemical Engineering Journal, 2009Co-Authors: Marcelo Chuei Matsudo, Sunao Sato, Attilio Converti, Raquel Pedrosa Bezerra, Patrizia Perego, Joao Carlos Monteiro De CarvalhoAbstract:Abstract Arthrospira (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 of the ratio of renewed volume to total volume (R), the urea feeding time (tf) and the number of successive repeated fed-batch cycles on the maximum cell concentration (Xm), cell productivity (Px), Nitrogen-to-cell conversion yield (Yx/n), maximum specific growth rate (μm) and protein content of dry biomass. The experimental results demonstrated that R = 0.80 and tf = 6 d 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 (Xm = 2101 ± 113 mg L−1, Px = 219 ± 13 mg L−1 d−1 and Yx/n = 10.3 ± 0.8 g g−1).
Virginia E Armbrust - One of the best experts on this subject based on the ideXlab platform.
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coupled effects of light and Nitrogen Source on the urea cycle and Nitrogen metabolism over a diel cycle in the marine diatom thalassiosira pseudonana
Protist, 2012Co-Authors: Sara J Bender, Micaela S Parker, Virginia E ArmbrustAbstract:Diatoms are photoautotrophic organisms capable of growing on a variety of inorganic and organic Nitrogen Sources. Discovery of a complete urea cycle in diatoms was surprising, as this pathway commonly functions in heterotrophic organisms to rid cells of waste Nitrogen. To determine how the urea cycle is integrated into cellular Nitrogen metabolism and energy management, the centric diatom Thalassiosira pseudonana was maintained in semi-continuous batch cultures on nitrate, ammonium, or urea as the sole Nitrogen Source, under a 16: 8 light: dark cycle and at light intensities that were low, saturating, or high for growth. Steady-state transcript levels were determined for genes encoding enzymes linked to the urea cycle, urea hydrolysis, glutamine synthesis, pyrimidine synthesis, photorespiration, and energy storage. Transcript abundances were significantly affected by Nitrogen Source, light intensity and a diel cycle. The impact of N Source on differential transcript accumulation was most apparent under the highest light intensity. Models of cellular metabolism under high light were developed based on changes in transcript abundance and predicted enzyme localizations. We hypothesize that the urea cycle is integrated into Nitrogen metabolism through its connection to glutamine and in the eventual production of urea. These findings have important implications for Nitrogen flow in the cell over diel cycles at surface ocean irradiances.
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synergistic effects of light temperature and Nitrogen Source on transcription of genes for carbon and Nitrogen metabolism in the centric diatom thalassiosira pseudonana bacillariophyceae 1
Journal of Phycology, 2005Co-Authors: Micaela S Parker, Virginia E ArmbrustAbstract:The effects of Nitrogen Source, temperature, and light level on transcription of five genes from three pathways of carbon and Nitrogen metabolism were determined for the centric diatom Thalassiosira pseudonana (Hustedt) Hasle et Heimdal. The targeted genes were NR (nitrate reductase) and GSII (glutamine synthetase II), both required for nitrate utilization; PGP (phosphoglycolate phosphatase) and GDCT (glycine decarboxylase T-protein), both required for photorespiration; and SBP (sedoheptulose 1,7-bisphosphatase), required for carbon fixation (Calvin cycle). Quantitative reverse transcriptase PCR was used to compare transcript abundances for these genes from T. pseudonana cells grown at two light intensities (50 or 300 μmol photons·m -2 ·s -1 ), at two temperatures (12 or 22° C), and on two different Nitrogen Sources (nitrate or ammonium). Transcript abundance (normalized to 18S rRNA) was higher for all five genes at the higher light intensity. At 12° C, fewer transcripts were detected for the Calvin cycle gene, whereas more transcripts were detected for the photorespiration and nitrate utilization genes. Nitrogen Source affected transcript accumulation of the photorespiration and nitrate utilization genes but not the Calvin cycle gene. Extracellular concentrations of glycolate, a photorespiratory-specific product, were determined under the high light conditions and were found to decrease at 12° C and when cells were grown on ammonium. A hypothetical model is presented to explain the patterns of transcript accumulation and glycolate release in terms of energy balance within the cell.
Raquel Pedrosa Bezerra - One of the best experts on this subject based on the ideXlab platform.
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effects of photobioreactor configuration Nitrogen Source and light intensity on the fed batch cultivation of arthrospira spirulina platensis bioenergetic aspects
Biomass & Bioenergy, 2012Co-Authors: Marcelo Chuei Matsudo, Sunao Sato, Attilio Converti, Raquel Pedrosa Bezerra, Patrizia Perego, Joao Carlos Monteiro De CarvalhoAbstract:Bioenergetic analysis may be applied in order to predict microbial growth yields, based on the Gibbs energy dissipation and mass conservation principles of the overall growth reaction. The bioenergetics of the photoautotrophic growth of the cyanobacterium Arthrospira (Spirulina) platensis was investigated in different bioreactor configurations (tubular photobioreactor and open ponds) using different Nitrogen Sources (nitrate and urea) and under different light intensity conditions to determine the best growing conditions in terms of Gibbs energy dissipation, number of photons to sustain cell growth and phototrophic energy yields distribution in relation to the ATP and NADPH formation, and release of heat. Although an increase in the light intensity increased the Gibbs energy dissipated for cell growth and maintenance with both Nitrogen Sources, it did not exert any appreciable influence on the moles of photons absorbed by the system to produce one C-mol biomass. On the other hand, both bioenergetic parameters were higher in cultures with nitrate than with urea, likely because of the higher energy requirements needed to reduce the former Nitrogen Source to ammonia. They appreciably increased also when open ponds were substituted by the tubular photobioreactor, where a more efficient light distribution ensured a remarkably higher cell mass concentration. The estimated percentages of the energy absorbed by the cell showed that, compared with nitrate, the use of urea as Nitrogen Source allowed the system to address higher energy fractions to ATP production and light fixation by the photosynthetic apparatus, as well as a lower fraction released as heat. The best energy yields values on Gibbs energy necessary for cell growth and maintenance were achieved in up to 4–5 days of cultivation, indicating that it would be the optimum range to maintain cell growth. Thanks to this better bioenergetic situation, urea appears to be a quite promising low-cost, alternative Nitrogen Source for Arthrospira platensis cultures in photobioreactors.
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repeated fed batch cultivation of arthrospira spirulina platensis using urea as Nitrogen Source
Biochemical Engineering Journal, 2009Co-Authors: Marcelo Chuei Matsudo, Sunao Sato, Attilio Converti, Raquel Pedrosa Bezerra, Patrizia Perego, Joao Carlos Monteiro De CarvalhoAbstract:Abstract Arthrospira (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 of the ratio of renewed volume to total volume (R), the urea feeding time (tf) and the number of successive repeated fed-batch cycles on the maximum cell concentration (Xm), cell productivity (Px), Nitrogen-to-cell conversion yield (Yx/n), maximum specific growth rate (μm) and protein content of dry biomass. The experimental results demonstrated that R = 0.80 and tf = 6 d 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 (Xm = 2101 ± 113 mg L−1, Px = 219 ± 13 mg L−1 d−1 and Yx/n = 10.3 ± 0.8 g g−1).