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Antonio Djalma Nunes Ferraz - One of the best experts on this subject based on the ideXlab platform.
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impact of organic loading rate on biohydrogen production in an up flow anaerobic packed bed reactor uanpbr
Bioresource Technology, 2014Co-Authors: Antonio Djalma Nunes Ferraz, Medhavi Gupta, Elsayed Elbeshbishy, Hisham Hafez, Marcelo Zaiat, George NakhlaAbstract:Abstract This study assesses the impact of organic loading rate on biohydrogen production from glucose in an up-flow anaerobic packed bed reactor (UAnPBR). Two mesophilic UAPBRs (UAnPBR1 and 2) were tested at organic loading rates (OLRs) ranging from 6.5 to 51.4 gCOD L −1 d −1 . To overcome biomass washout, design modifications were made in the UAnPBR2 to include a settling zone to capture the detached biomass. The design modifications in UAnPBR2 increased the average hydrogen yield from 0.98 to 2.0 mol-H 2 mol −1 -glucose at an OLR of 25.7 gCOD L −1 d −1 . Although, a maximum hydrogen production rate of 23.4 ± 0.9 L H 2 L −1 d −1 was achieved in the UAnPBR2 at an OLR of 51.4 gCOD L −1 d −1 , the hydrogen yield dropped by 50% to around 1 mol-H 2 mol −1 -glucose. The microbiological analysis (PCR/DGGE) showed that the biohydrogen production was due to the presence of the hydrogen and volatile acid producers such as Clostridium beijerinckii , Clostridium butyricum , Megasphaera elsdenii and Propionispira arboris .
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impact of organic loading rate on biohydrogen production in an up flow anaerobic packed bed reactor uanpbr
Bioresource Technology, 2014Co-Authors: Antonio Djalma Nunes Ferraz, Medhavi Gupta, Elsayed Elbeshbishy, Hisham Hafez, Marcelo Zaiat, George NakhlaAbstract:Abstract This study assesses the impact of organic loading rate on biohydrogen production from glucose in an up-flow anaerobic packed bed reactor (UAnPBR). Two mesophilic UAPBRs (UAnPBR1 and 2) were tested at organic loading rates (OLRs) ranging from 6.5 to 51.4 gCOD L −1 d −1 . To overcome biomass washout, design modifications were made in the UAnPBR2 to include a settling zone to capture the detached biomass. The design modifications in UAnPBR2 increased the average hydrogen yield from 0.98 to 2.0 mol-H 2 mol −1 -glucose at an OLR of 25.7 gCOD L −1 d −1 . Although, a maximum hydrogen production rate of 23.4 ± 0.9 L H 2 L −1 d −1 was achieved in the UAnPBR2 at an OLR of 51.4 gCOD L −1 d −1 , the hydrogen yield dropped by 50% to around 1 mol-H 2 mol −1 -glucose. The microbiological analysis (PCR/DGGE) showed that the biohydrogen production was due to the presence of the hydrogen and volatile acid producers such as Clostridium beijerinckii , Clostridium butyricum , Megasphaera elsdenii and Propionispira arboris .
George Nakhla - One of the best experts on this subject based on the ideXlab platform.
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impact of organic loading rate on biohydrogen production in an up flow anaerobic packed bed reactor uanpbr
Bioresource Technology, 2014Co-Authors: Antonio Djalma Nunes Ferraz, Medhavi Gupta, Elsayed Elbeshbishy, Hisham Hafez, Marcelo Zaiat, George NakhlaAbstract:Abstract This study assesses the impact of organic loading rate on biohydrogen production from glucose in an up-flow anaerobic packed bed reactor (UAnPBR). Two mesophilic UAPBRs (UAnPBR1 and 2) were tested at organic loading rates (OLRs) ranging from 6.5 to 51.4 gCOD L −1 d −1 . To overcome biomass washout, design modifications were made in the UAnPBR2 to include a settling zone to capture the detached biomass. The design modifications in UAnPBR2 increased the average hydrogen yield from 0.98 to 2.0 mol-H 2 mol −1 -glucose at an OLR of 25.7 gCOD L −1 d −1 . Although, a maximum hydrogen production rate of 23.4 ± 0.9 L H 2 L −1 d −1 was achieved in the UAnPBR2 at an OLR of 51.4 gCOD L −1 d −1 , the hydrogen yield dropped by 50% to around 1 mol-H 2 mol −1 -glucose. The microbiological analysis (PCR/DGGE) showed that the biohydrogen production was due to the presence of the hydrogen and volatile acid producers such as Clostridium beijerinckii , Clostridium butyricum , Megasphaera elsdenii and Propionispira arboris .
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impact of organic loading rate on biohydrogen production in an up flow anaerobic packed bed reactor uanpbr
Bioresource Technology, 2014Co-Authors: Antonio Djalma Nunes Ferraz, Medhavi Gupta, Elsayed Elbeshbishy, Hisham Hafez, Marcelo Zaiat, George NakhlaAbstract:Abstract This study assesses the impact of organic loading rate on biohydrogen production from glucose in an up-flow anaerobic packed bed reactor (UAnPBR). Two mesophilic UAPBRs (UAnPBR1 and 2) were tested at organic loading rates (OLRs) ranging from 6.5 to 51.4 gCOD L −1 d −1 . To overcome biomass washout, design modifications were made in the UAnPBR2 to include a settling zone to capture the detached biomass. The design modifications in UAnPBR2 increased the average hydrogen yield from 0.98 to 2.0 mol-H 2 mol −1 -glucose at an OLR of 25.7 gCOD L −1 d −1 . Although, a maximum hydrogen production rate of 23.4 ± 0.9 L H 2 L −1 d −1 was achieved in the UAnPBR2 at an OLR of 51.4 gCOD L −1 d −1 , the hydrogen yield dropped by 50% to around 1 mol-H 2 mol −1 -glucose. The microbiological analysis (PCR/DGGE) showed that the biohydrogen production was due to the presence of the hydrogen and volatile acid producers such as Clostridium beijerinckii , Clostridium butyricum , Megasphaera elsdenii and Propionispira arboris .
Paul J. Weimer - One of the best experts on this subject based on the ideXlab platform.
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fermentation of alfalfa wet fractionation liquids to volatile fatty acids by streptococcus bovis and Megasphaera elsdenii
Bioresource Technology, 2013Co-Authors: Paul J. Weimer, M F DigmanAbstract:Abstract “Green juice”, obtained by squeezing fresh alfalfa leaves inoculated with lactic acid bacteria, was fermented at room temperature for 7–21 d to obtain 12–47 g lactic acid L −1 . Inoculation of green juice with Streptococcus bovis and incubation at 39 °C reduced fermentation time to 8–12 h. The resulting “brown juice” from either fermentation had a pH of ∼4.5 and a protein precipitate. Upon adjustment to pH 5.2–6.8 and inoculation with Megasphaera elsdenii , brown juice was fermented within 48 h to up to 18 g of mixed volatile fatty acids (VFA) L −1 . Single-stage fermentation of green juice by both species in coculture typically resulted in overgrowth of S. bovis and acid inhibition of M. elsdenii , inhibiting VFA production. Because the juice fermentations are conducted without sterilization or supplemental nutrients, they can potentially contribute to an integrated process featuring protein recovery and fermentation of fractionated solids to VFA and other products.
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quantitative analysis of growth and volatile fatty acid production by the anaerobic ruminal bacterium Megasphaera elsdenii t81
Applied Microbiology and Biotechnology, 2013Co-Authors: Paul J. Weimer, G N MoenAbstract:Megasphaera elsdenii T81 grew on either DL-lactate or D-glucose at similar rates (0.85 h(-1)) but displayed major differences in the fermentation of these substrates. Lactate was fermented at up to 210-mM concentration to yield acetic, propionic, butyric, and valeric acids. The bacterium was able to grow at much higher concentrations of D-glucose (500 mM), but never removed more than 80 mM of glucose from the medium, and nearly 60 % the glucose removed was sequestered as intracellular glycogen, with low yields of even-carbon acids (acetate, butyrate, caproate). In the presence of both substrates, glucose was not used until lactate was nearly exhausted, even by cells pregrown on glucose. Glucose-grown cultures maintained only low extracellular concentrations of acetate, and addition of exogenous acetate increased yields of butyrate, but not caproate. By contrast, exogenous acetate had little effect on lactate fermentation. At pH 6.6, growth rate was halved by exogenous addition of 60 mM propionate, 69 mM butyrate, 44 mM valerate, or 33 mM caproate; at pH 5.9, these values were reduced to 49, 49, 18, and 22 mM, respectively. The results are consistent with this species' role as an effective ruminal lactate consumer and suggest that this organism may be useful for industrial production of volatile fatty acids from lactate if product tolerance could be improved. The poor fermentation of glucose and sensitivity to caproate suggests that this strain is not practical for industrial caproate production.
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dominance of prevotella and low abundance of classical ruminal bacterial species in the bovine rumen revealed by relative quantification real time pcr
Applied Microbiology and Biotechnology, 2007Co-Authors: David M Stevenson, Paul J. WeimerAbstract:Relative quantification real-time PCR was used to quantify several bacterial species in ruminal samples from two lactating cows, each sampled 3 h after feeding on two successive days. Abundance of each target taxon was calculated as a fraction of the total 16S rRNA gene copies in the samples, using taxon-specific and eubacterial domain-level primers. Bacterial populations showed a clear predominance of members of the genus Prevotella, which comprised 42% to 60% of the bacterial rRNA gene copies in the samples. However, only 2% to 4% of the bacterial rRNA gene copies were represented by the classical ruminal Prevotella species Prevotella bryantii, Prevotella ruminicola and Prevotella brevis. The proportion of rRNA gene copies attributable to Fibrobacter succinogenes, Ruminococcus flavefaciens, Selenomonas ruminantium and Succinivibrio dextrinosolvens were each generally in the 0.5% to 1% range. Proportions for Ruminobacter amylophilus and Eubacterium ruminantium were lower (0.1% to 0.2%), while Butyrivibrio fibrisolvens, Streptococcus bovis, Ruminococcus albus and Megasphaera elsdenii were even less abundant, each comprising <0.03% of the bacterial rRNA gene copies. The data suggest that the aggregate abundance of the most intensively studied ruminal bacterial species is relatively low and that a large fraction of the uncultured population represents a single bacterial genus.
Marcelo Zaiat - One of the best experts on this subject based on the ideXlab platform.
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impact of organic loading rate on biohydrogen production in an up flow anaerobic packed bed reactor uanpbr
Bioresource Technology, 2014Co-Authors: Antonio Djalma Nunes Ferraz, Medhavi Gupta, Elsayed Elbeshbishy, Hisham Hafez, Marcelo Zaiat, George NakhlaAbstract:Abstract This study assesses the impact of organic loading rate on biohydrogen production from glucose in an up-flow anaerobic packed bed reactor (UAnPBR). Two mesophilic UAPBRs (UAnPBR1 and 2) were tested at organic loading rates (OLRs) ranging from 6.5 to 51.4 gCOD L −1 d −1 . To overcome biomass washout, design modifications were made in the UAnPBR2 to include a settling zone to capture the detached biomass. The design modifications in UAnPBR2 increased the average hydrogen yield from 0.98 to 2.0 mol-H 2 mol −1 -glucose at an OLR of 25.7 gCOD L −1 d −1 . Although, a maximum hydrogen production rate of 23.4 ± 0.9 L H 2 L −1 d −1 was achieved in the UAnPBR2 at an OLR of 51.4 gCOD L −1 d −1 , the hydrogen yield dropped by 50% to around 1 mol-H 2 mol −1 -glucose. The microbiological analysis (PCR/DGGE) showed that the biohydrogen production was due to the presence of the hydrogen and volatile acid producers such as Clostridium beijerinckii , Clostridium butyricum , Megasphaera elsdenii and Propionispira arboris .
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impact of organic loading rate on biohydrogen production in an up flow anaerobic packed bed reactor uanpbr
Bioresource Technology, 2014Co-Authors: Antonio Djalma Nunes Ferraz, Medhavi Gupta, Elsayed Elbeshbishy, Hisham Hafez, Marcelo Zaiat, George NakhlaAbstract:Abstract This study assesses the impact of organic loading rate on biohydrogen production from glucose in an up-flow anaerobic packed bed reactor (UAnPBR). Two mesophilic UAPBRs (UAnPBR1 and 2) were tested at organic loading rates (OLRs) ranging from 6.5 to 51.4 gCOD L −1 d −1 . To overcome biomass washout, design modifications were made in the UAnPBR2 to include a settling zone to capture the detached biomass. The design modifications in UAnPBR2 increased the average hydrogen yield from 0.98 to 2.0 mol-H 2 mol −1 -glucose at an OLR of 25.7 gCOD L −1 d −1 . Although, a maximum hydrogen production rate of 23.4 ± 0.9 L H 2 L −1 d −1 was achieved in the UAnPBR2 at an OLR of 51.4 gCOD L −1 d −1 , the hydrogen yield dropped by 50% to around 1 mol-H 2 mol −1 -glucose. The microbiological analysis (PCR/DGGE) showed that the biohydrogen production was due to the presence of the hydrogen and volatile acid producers such as Clostridium beijerinckii , Clostridium butyricum , Megasphaera elsdenii and Propionispira arboris .
Hisham Hafez - One of the best experts on this subject based on the ideXlab platform.
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impact of organic loading rate on biohydrogen production in an up flow anaerobic packed bed reactor uanpbr
Bioresource Technology, 2014Co-Authors: Antonio Djalma Nunes Ferraz, Medhavi Gupta, Elsayed Elbeshbishy, Hisham Hafez, Marcelo Zaiat, George NakhlaAbstract:Abstract This study assesses the impact of organic loading rate on biohydrogen production from glucose in an up-flow anaerobic packed bed reactor (UAnPBR). Two mesophilic UAPBRs (UAnPBR1 and 2) were tested at organic loading rates (OLRs) ranging from 6.5 to 51.4 gCOD L −1 d −1 . To overcome biomass washout, design modifications were made in the UAnPBR2 to include a settling zone to capture the detached biomass. The design modifications in UAnPBR2 increased the average hydrogen yield from 0.98 to 2.0 mol-H 2 mol −1 -glucose at an OLR of 25.7 gCOD L −1 d −1 . Although, a maximum hydrogen production rate of 23.4 ± 0.9 L H 2 L −1 d −1 was achieved in the UAnPBR2 at an OLR of 51.4 gCOD L −1 d −1 , the hydrogen yield dropped by 50% to around 1 mol-H 2 mol −1 -glucose. The microbiological analysis (PCR/DGGE) showed that the biohydrogen production was due to the presence of the hydrogen and volatile acid producers such as Clostridium beijerinckii , Clostridium butyricum , Megasphaera elsdenii and Propionispira arboris .
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impact of organic loading rate on biohydrogen production in an up flow anaerobic packed bed reactor uanpbr
Bioresource Technology, 2014Co-Authors: Antonio Djalma Nunes Ferraz, Medhavi Gupta, Elsayed Elbeshbishy, Hisham Hafez, Marcelo Zaiat, George NakhlaAbstract:Abstract This study assesses the impact of organic loading rate on biohydrogen production from glucose in an up-flow anaerobic packed bed reactor (UAnPBR). Two mesophilic UAPBRs (UAnPBR1 and 2) were tested at organic loading rates (OLRs) ranging from 6.5 to 51.4 gCOD L −1 d −1 . To overcome biomass washout, design modifications were made in the UAnPBR2 to include a settling zone to capture the detached biomass. The design modifications in UAnPBR2 increased the average hydrogen yield from 0.98 to 2.0 mol-H 2 mol −1 -glucose at an OLR of 25.7 gCOD L −1 d −1 . Although, a maximum hydrogen production rate of 23.4 ± 0.9 L H 2 L −1 d −1 was achieved in the UAnPBR2 at an OLR of 51.4 gCOD L −1 d −1 , the hydrogen yield dropped by 50% to around 1 mol-H 2 mol −1 -glucose. The microbiological analysis (PCR/DGGE) showed that the biohydrogen production was due to the presence of the hydrogen and volatile acid producers such as Clostridium beijerinckii , Clostridium butyricum , Megasphaera elsdenii and Propionispira arboris .