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Attilio Converti - One of the best experts on this subject based on the ideXlab platform.
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effects of light intensity and Dilution Rate on the semicontinuous cultivation of arthrospira spirulina platensis a kinetic monod type approach
Bioresource Technology, 2011Co-Authors: Raquel Pedrosa Bezerra, João Carlos Monteiro De Carvalho, Sunao Sato, Attilio Converti, Patrizia Perego, Erika Yuliana Ortiz MontoyaAbstract:Abstract Semicontinuous cultures were carried out at different Dilution Rates (D) and light intensities (I) to determine the maximum productivity of Arthrospira platensis cultivated in helicoidal photobioreactor up to the achievement of pseudo-steady-state conditions. At I = 108 μmol photons m−2 s−1, the semicontinuous regime ensured the highest values of maximum cell concentration (Xm = 5772 ± 113 mg L−1) and productivity (PXS = 1319 ± 25 mg L−1 d−1) at the lowest (D = 0.1 day−1) and the highest (D = 0.3 day−1) Dilution Rates, respectively. A kinetic model derived from that of Monod was proposed to determine the relationship between the product of light intensity to Dilution Rate (ID) and the cell productivity, which were shown to exert a combined influence on this parameter. This result put into evidence that pseudo-steady-state conditions could be modified according to circumstances, conveniently varying one or other of the two independent variables.
Kenji Kida - One of the best experts on this subject based on the ideXlab platform.
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Microbial community of a mesophilic propionate-degrading methanogenic consortium in chemostat cultivation analyzed based on 16S rRNA and acetate kinase genes
Applied Microbiology and Biotechnology, 2006Co-Authors: Toru Shigematsu, Kana Ninomiya, Yukiko Kamegawa, Yuko Mizuno, Shigeru Morimura, Kenji KidaAbstract:We constructed a mesophilic anaerobic chemostat that was continuously fed with synthetic wastewater containing propionate as the sole source of carbon and energy. Steady-state conditions were achieved below the critical Dilution Rate of 0.3 d −1 with almost complete substRate degradation. The propionate-degrading methanogenic communities in the chemostat at Dilution Rates of 0.01, 0.08, and 0.3 d −1 were analyzed using molecular biological techniques. Fluorescence in situ hybridization with archaeal and bacterial domain-specific probes showed that archaeal cells predominated throughout the three Dilution Rates. Archaeal-16S rRNA gene clone library analysis and quantitative real-time polymerase chain reaction studies showed that hydrogenotrophic methanogen rRNA genes closely related to Methanoculleus was detected at a Dilution Rate of 0.01 d −1 , whereas rRNA genes closely related to the Methanoculleus and Methanospirillum genera were detected at Dilution Rates of 0.08 and 0.3 d −1 . The aceticlastic methanogen, Methanosaeta , was detected throughout the three Dilution Rates. Bacterial-rRNA gene clone library analysis and denaturing gradient gel electrophoresis demonstRated that rRNA genes affiliated with the genus Syntrophobacter predominated at the low Dilution Rate, whereas rRNA genes affiliated with the phylum Firmicutes predominated at the higher Dilution Rates. A significant number of rRNA genes affiliated with the genus Pelotomaculum were detected at Dilution Rate of 0.3 d −1 . The diversity of genes encoding acetate kinase agreed closely with the results of the rRNA gene analysis. The Dilution Rates significantly altered the archaeal and bacterial communities in the propionate-fed chemostat.
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effect of Dilution Rate on metabolic pathway shift between aceticlastic and nonaceticlastic methanogenesis in chemostat cultivation
Applied and Environmental Microbiology, 2004Co-Authors: Toru Shigematsu, Shigeru Morimura, Yueqin Tang, Hiromi Kawaguchi, Tsutomu Kobayashi, Kenji KidaAbstract:Acetate conversion pathways of methanogenic consortia in acetate-fed chemostats at Dilution Rates of 0.025 and 0.6 day−1 were investigated by using 13C-labeled acetates, followed by gas chromatography-mass spectrometry (GC-MS) analysis of the CH4 and CO2 produced. Nonaceticlastic syntrophic oxidation by acetate-oxidizing syntrophs and hydrogenotrophic methanogens was suggested to occupy a primary pathway (approximately 62 to 90%) in total methanogenesis at the low Dilution Rate. In contrast, aceticlastic cleavage of acetate by aceticlastic methanogens was suggested to occupy a primary pathway (approximately 95 to 99%) in total methanogenesis at the high Dilution Rate. Phylogenetic analyses of transcripts of the methyl coenzyme M reductase gene (mcrA) confirmed that a significant number of transcripts of the genera Methanoculleus (hydrogenotrophic methanogens) and Methanosarcina (aceticlastic methanogens) were present in the chemostats at the low and high Dilution Rates, respectively. The mcrA transcripts of the genus Methanosaeta (aceticlastic methanogens), which dominated the population in a previous study (T. Shigematsu, Y. Tang, H. Kawaguchi, K. Ninomiya, J. Kijima, T. Kobayashi, S. Morimura, and K. Kida, J. Biosci. Bioeng. 96:547-558, 2003), were poorly detected at both Dilution Rates due to the limited coverage of the primers used. These results demonstRated that the Dilution Rate could cause a shift in the primary pathway of acetate conversion to methane in acetate-fed chemostats.
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effect of Dilution Rate on structure of a mesophilic acetate degrading methanogenic community during continuous cultivation
Journal of Bioscience and Bioengineering, 2003Co-Authors: Toru Shigematsu, Kana Ninomiya, Shigeru Morimura, Yueqin Tang, Hiromi Kawaguchi, Junji Kijima, Tsutomu Kobayashi, Kenji KidaAbstract:The community structures of two mesophilic acetate-degrading methanogenic consortia enriched at Dilution Rates of 0.025 and 0.6 d−1 were analyzed by fluorescence in situ hybridization (FISH) and phylogenetic analyses based on 16S rDNA clonal sequences and quantitative real-time polymerase chain reaction (PCR). FISH experiments with archaeal and bacterial domain-specific probes showed that archaeal cells were predominant and only a small number of bacterial cells were detected at both Dilution Rates. In the domain Archaea, the number of cells closely related to Methanosarcina barkeri was shown to be greater at the high Dilution Rate using FISH with species-specific probes. Taxonomic analyses based on rDNA clonal sequences obtained at the low and high Dilution Rates showed that 43% of 100 clones and 72% of 92 clones, respectively, were affiliated with the domain Archaea and the remainders at each Dilution Rate were affiliated with the domain Bacteria. Within the domain Archaea, all rDNA clones at both Dilution Rates were affiliated with the genera Methanosaeta or Methanosarcina of the aceticlastic methanogens. Within the domain Bacteria, the rDNA clones obtained at the low Dilution Rate were affiliated with four phyla, Firmicutes (36%), Bacteroidetes (9%), Chloroflexi (6%) and candidate division OP12 (5%). The rDNA clones obtained at the high Dilution Rate were affiliated with four phyla, Firmicutes (16%), Bacteroidetes (8%), Proteobacteria (1%) and candidate division OP12 (3%). Real-time quantitative PCR experiments showed that the number of rDNA sequences affiliated with the genus Methanosarcina was greater at the high Dilution Rate. In addition, a significant number of rDNA sequences affiliated with the genus Methanoculleus were detected only at the low Dilution Rate. Detection of a hydrogenotrophic methanogen at the low Dilution Rate suggests that the syntrophic acetate oxidation by hydrogenotrophic methanogens and acetate-oxidizing bacteria could occur at the low Dilution Rate.
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Influence of Ni2+ and Co2+ on methanogenic activity and the amounts of coenzymes involved in methanogenesis
Journal of Bioscience and Bioengineering, 2002Co-Authors: Kenji Kida, Toru Shigematsu, Junji Kijima, Masami Numaguchi, Yoshitaka Mochinaga, Shigeru MorimuraAbstract:Abstract The requirement of Ni2+ and Co2+ addition on methanogenic activity and the coenzymes involved in methanogenesis were investigated in anaerobic continuous cultivation with synthetic wastewater using acetate as the sole carbon source. Addition of Ni2+ and Co2+ to the synthetic wastewater drastically increased the maximum Dilution Rate of the cultivation. The concentrations of coenzymes F430 and corrinoids in the biomass increased to 0.62 μmol-Ni/g-VSS and 0.67 μmol-Co/g-VSS, respectively with the increase of the Dilution Rate. Methanogenic activity of the culture broth also increased with an increase of Dilution Rate. However, without addition of Ni2+ and Co2+, F430 and corrinoids were not detected in the biomass and methanogenic activity was only a trace level at a Dilution Rate of 0.025 d−1. When the amounts of Ni2+ and Co2+ added at a Dilution Rate of 0.6 d−1 were lowered in steps, the concentrations of F430 and corrinoids in the biomass and methanogenic activity decreased with decreasing amounts of Ni2+ and Co2+ added. These results suggest that Ni2+ and Co2+ were required for the methane-producing reactions via increases of coenzymes F430 and corrinoids.
Tom Granstrom - One of the best experts on this subject based on the ideXlab platform.
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continuous lignocellulosic ethanol production using coleus forskohlii root hydrolysate
Fuel, 2014Co-Authors: Shirish M Harde, Sandip B Bankar, Heikki Ojamo, Tom Granstrom, Rekha S Singhal, Shrikant A SurvaseAbstract:Root biomass of Coleus forskohlii obtained after extraction of forskolin constitutes more than 90% of the raw material rich in carbohydRates that could be used as a substRate for the production of bioethanol. Ethanol production from this waste biomass was optimized in batch and continuous fermentation. The maximum ethanol concentration of 31.32 g/l was obtained with batch fermentation. Continuous production of ethanol was carried out using wood chips immobilized cells of Saccharomyces cerevisiae in packed bed reactor. The maximum ethanol concentration of 34.25 g/l was obtained with nitrogen supplement and aeration as compared to 33.57 g/l without supplement and aeration at 0.1 (1/h) Dilution Rate showing no effect of aeration and nitrogen at low Dilution Rate. The maximum ethanol productivity (15.88 g/l h) was obtained at a Dilution Rate of 1 (1/h) with nitrogen supplement and aeration whereas ethanol productivity (13.48 g/l h) was obtained at a Dilution Rate of 0.75 (1/h) without nitrogen supplement and aeration showing promising effect of nitrogen and aeration at high Dilution Rate. Immobilized column reactor was useful for the production of bioethanol, and also suggests efficient utilization of C. forskohlii root biomass for the production of bioethanol.
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continuous bio catalytic conversion of sugar mixture to acetone butanol ethanol by immobilized clostridium acetobutylicum dsm 792
Applied Microbiology and Biotechnology, 2012Co-Authors: Shrikant A Survase, Adriaan Van Heiningen, Tom GranstromAbstract:Continuous production of acetone, n-butanol, and ethanol (ABE) was carried out using immobilized cells of Clostridium acetobutylicum DSM 792 using glucose and sugar mixture as a substRate. Among various lignocellulosic materials screened as a support matrix, coconut fibers and wood pulp fibers were found to be promising in batch experiments. With a motive of promoting wood-based bio-refinery concept, wood pulp was used as a cell holding material. Glucose and sugar mixture (glucose, mannose, galactose, arabinose, and xylose) comparable to lignocellulose hydrolysate was used as a substRate for continuous production of ABE. We report the best solvent productivity among wild-type strains using column reactor. The maximum total solvent concentration of 14.32 g L−1 was obtained at a Dilution Rate of 0.22 h−1 with glucose as a substRate compared to 12.64 g L−1 at 0.5 h−1 Dilution Rate with sugar mixture. The maximum solvent productivity (13.66 g L−1 h−1) was obtained at a Dilution Rate of 1.9 h−1 with glucose as a substRate whereas solvent productivity (12.14 g L−1 h−1) was obtained at a Dilution Rate of 1.5 h−1 with sugar mixture. The immobilized column reactor with wood pulp can become an efficient technology to be integRated with existing pulp mills to convert them into wood-based bio-refineries.
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continuous acetone butanol ethanol fermentation using so2 ethanol water spent liquor from spruce
Bioresource Technology, 2011Co-Authors: Shrikant A Survase, Evangelos Sklavounos, German Jurgens, Adriaan Van Heiningen, Tom GranstromAbstract:SO2-ethanol-water (SEW) spent liquor from spruce chips was successfully used for batch and continuous production of acetone, butanol and ethanol (ABE). Initially, batch experiments were performed using spent liquor to check the suitability for production of ABE. Maximum concentration of total ABE was found to be 8.79 g/l using 4-fold diluted SEW liquor supplemented with 35 g/l of glucose. The effect of Dilution Rate on solvent production, productivity and yield was studied in column reactor consisting of immobilized Clostridium acetobutylicum DSM 792 on wood pulp. Total solvent concentration of 12 g/l was obtained at a Dilution Rate of 0.21 h(-1). The maximum solvent productivity (4.86 g/l h) with yield of 0.27 g/g was obtained at Dilution Rate of 0.64 h(-1). Further, to increase the solvent yield, the unutilized sugars were subjected to batch fermentation.
Hongwei Yen - One of the best experts on this subject based on the ideXlab platform.
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the effects of Dilution Rate and glucose concentration on continuous acetone butanol ethanol fermentation by clostridium acetobutylicum immobilized on bricks
Journal of Chemical Technology & Biotechnology, 2011Co-Authors: Hongwei YenAbstract:BACKGROUND: Owing to the rapid depletion of petroleum fuel, the production of butanol through biological routes has attracted increasing attention. However, low butanol productivity severely impedes its potential industrial production. It is known that the immobilization of whole cells can enhance productivity in the acetone-butanol-ethanol (ABE) continuous fermentation process. Therefore, the objective of this study was to develop a low-cost continuous operation for butanol production. RESULTS: Bricks were chosen as cell support because of their low cost and ease of use for immobilization. The solvent productivity for the bricks with immobilized cells was 0.7 g L−1 h−1, 1.89 times that of free cells (0.37 g L−1 h−1) at a Dilution Rate of 0.054 h−1. The productivity improvement can contribute to greater retention of biomass inside the reactor due to immobilization. The increase in glucose feed concentration raised total solvent production. However, it resulted in a decrease in yield (grams of solvents produced per gram of glucose introduced). Continuous operation with immobilized cells at a Dilution Rate of 0.107 h−1 resulted in a solvent productivity of 1.21 g L−1 h−1, 2.1 times that of the operation at 0.027 h−1. However, the yield (butanol produced per glucose consumed) was decreased to 0.19 from 0.29 under the same glucose feeding condition of 60 g L−1. CONCLUSION: The increase in Dilution Rate and feed glucose concentration enhanced productivity, but decreased the utilization of substRates and the final solvent concentration. Therefore, a balance between productivity and glucose utilization is required to ensure continuous process operation. Copyright © 2011 Society of Chemical Industry
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the development process for a continuous acetone butanol ethanol abe fermentation by immobilized clostridium acetobutylicum
Journal of The Taiwan Institute of Chemical Engineers, 2011Co-Authors: Hongwei YenAbstract:Abstract The low butanol productivity impedes acetone–butanol–ethanol (ABE) commercial production using Clostridium acetobutylicum . A continuous operation with cell immobilization could enhance efficiency and in turn, economic competitiveness. Among the three materials investigated in this study, bricks were determined to be the most suitable carrier for ABE fermentation. An immobilization ratio of 20% (the proportion of brick to the working volume) and a brick size of 0.15–2.4 mm were established as the most appropriate immobilization condition. After 6 cycles of repeated immobilized batch operation, the average butanol productivity amounted to 0.17 g/l/h. The continuous operation with cell immobilization resulted in a steady butanol production of 8.71 ± 0.69 g/l with an average productivity of 0.48 g/l/h for over 300 h, with a Dilution Rate of 0.054/h. However, when the Dilution Rate was increased to 0.108/h, butanol production decreased to 6.95 ± 0.53 g/l while productivity increased to 0.71 g/l/h. These results indicate that a high Dilution Rate leads to a low butanol concentration, but creates high levels of butanol productivity. Both the simplicity of the immobilization process and the economic benefits derived from the reduction in time and labor makes the use of bricks as carriers a very attractive option.
Shrikant A Survase - One of the best experts on this subject based on the ideXlab platform.
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continuous lignocellulosic ethanol production using coleus forskohlii root hydrolysate
Fuel, 2014Co-Authors: Shirish M Harde, Sandip B Bankar, Heikki Ojamo, Tom Granstrom, Rekha S Singhal, Shrikant A SurvaseAbstract:Root biomass of Coleus forskohlii obtained after extraction of forskolin constitutes more than 90% of the raw material rich in carbohydRates that could be used as a substRate for the production of bioethanol. Ethanol production from this waste biomass was optimized in batch and continuous fermentation. The maximum ethanol concentration of 31.32 g/l was obtained with batch fermentation. Continuous production of ethanol was carried out using wood chips immobilized cells of Saccharomyces cerevisiae in packed bed reactor. The maximum ethanol concentration of 34.25 g/l was obtained with nitrogen supplement and aeration as compared to 33.57 g/l without supplement and aeration at 0.1 (1/h) Dilution Rate showing no effect of aeration and nitrogen at low Dilution Rate. The maximum ethanol productivity (15.88 g/l h) was obtained at a Dilution Rate of 1 (1/h) with nitrogen supplement and aeration whereas ethanol productivity (13.48 g/l h) was obtained at a Dilution Rate of 0.75 (1/h) without nitrogen supplement and aeration showing promising effect of nitrogen and aeration at high Dilution Rate. Immobilized column reactor was useful for the production of bioethanol, and also suggests efficient utilization of C. forskohlii root biomass for the production of bioethanol.
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continuous bio catalytic conversion of sugar mixture to acetone butanol ethanol by immobilized clostridium acetobutylicum dsm 792
Applied Microbiology and Biotechnology, 2012Co-Authors: Shrikant A Survase, Adriaan Van Heiningen, Tom GranstromAbstract:Continuous production of acetone, n-butanol, and ethanol (ABE) was carried out using immobilized cells of Clostridium acetobutylicum DSM 792 using glucose and sugar mixture as a substRate. Among various lignocellulosic materials screened as a support matrix, coconut fibers and wood pulp fibers were found to be promising in batch experiments. With a motive of promoting wood-based bio-refinery concept, wood pulp was used as a cell holding material. Glucose and sugar mixture (glucose, mannose, galactose, arabinose, and xylose) comparable to lignocellulose hydrolysate was used as a substRate for continuous production of ABE. We report the best solvent productivity among wild-type strains using column reactor. The maximum total solvent concentration of 14.32 g L−1 was obtained at a Dilution Rate of 0.22 h−1 with glucose as a substRate compared to 12.64 g L−1 at 0.5 h−1 Dilution Rate with sugar mixture. The maximum solvent productivity (13.66 g L−1 h−1) was obtained at a Dilution Rate of 1.9 h−1 with glucose as a substRate whereas solvent productivity (12.14 g L−1 h−1) was obtained at a Dilution Rate of 1.5 h−1 with sugar mixture. The immobilized column reactor with wood pulp can become an efficient technology to be integRated with existing pulp mills to convert them into wood-based bio-refineries.
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continuous acetone butanol ethanol fermentation using so2 ethanol water spent liquor from spruce
Bioresource Technology, 2011Co-Authors: Shrikant A Survase, Evangelos Sklavounos, German Jurgens, Adriaan Van Heiningen, Tom GranstromAbstract:SO2-ethanol-water (SEW) spent liquor from spruce chips was successfully used for batch and continuous production of acetone, butanol and ethanol (ABE). Initially, batch experiments were performed using spent liquor to check the suitability for production of ABE. Maximum concentration of total ABE was found to be 8.79 g/l using 4-fold diluted SEW liquor supplemented with 35 g/l of glucose. The effect of Dilution Rate on solvent production, productivity and yield was studied in column reactor consisting of immobilized Clostridium acetobutylicum DSM 792 on wood pulp. Total solvent concentration of 12 g/l was obtained at a Dilution Rate of 0.21 h(-1). The maximum solvent productivity (4.86 g/l h) with yield of 0.27 g/g was obtained at Dilution Rate of 0.64 h(-1). Further, to increase the solvent yield, the unutilized sugars were subjected to batch fermentation.