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Acetone butanol ethanol (ABE) was produced in an integrated fed-batch fermentation-gas stripping product-recovery system using Clostridium beijerinckii BA101, with H2 and CO2 as the carrier gases. This technique was applied in order to eliminate the substrate and product inhibition that normally restricts ABE production and sugar utilization to less than 20 g l–1 and 60 g l–1, respectively. In the integrated fed-batch fermentation and product recovery system, solvent productivities were improved to 400% of the control batch fermentation productivities. In a control batch reactor, the culture used 45.4 g glucose l–1 and produced 17.6 g total solvents l–1 (yield 0.39 g g–1, productivity 0.29 g l–1 h–1). Using the integrated fermentation-gas stripping product-recovery system with CO2 and H2 as carrier gases, we carried out fed-batch fermentation experiments and measured various characteristics of the fermentation, including ABE production, selectivity, yield and productivity. The fed-batch reactor was operated for 201 h. At the end of the fermentation, an unusually high concentration of total acids (8.5 g l–1) was observed. A total of 500 g glucose was used to produce 232.8 g solvents (77.7 g acetone, 151.7 g butanol, 3.4 g ethanol) in 1 l culture broth. The average solvent yield and productivity were 0.47 g g–1 and 1.16 g l–1 h–1, respectively. 相似文献
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Use of starch solution as feed for butanol bioconversion processes employing Clostridium beijerinckii BA101 may have added economic advantage over the use of glucose. Acetone butanol ethanol (ABE) was produced from 30 gL(-1) starch solution using a continuous process. The bioreactor was fed at a dilution rate of 0.02 h(-1) and starch solution/feed volume (3 L) was replaced every 72 h. The continuous reactor fed with cornstarch solution (feed temperature 19 degrees C) produced approximately 6.0 gL(-1) total ABE. Increasing the feed storage temperature to 37 degrees C improved ABE production to 7.2 gL(-1) suggesting that retrogradation was occurring more rapidly at 19 degrees C. In both these cases the fermentation drifted toward acid production after approximately 260 h, consistent with the retrogradation of starch overtime. The use of soluble starch, which is less prone to retrogradation, resulted in the production of 9.9 gL(-1) ABE at 37 degrees C feed storage temperature, as compared to 7.2 gL(-1) ABE when cornstarch was used. It should be noted that gelatinized starch retrogradation takes place after sterilization and prior to use of the feed medium, and does not occur during long-term storage of the raw corn material in the months leading up to processing. The degree of hydrolysis of gelatinized starch decreased from 68.8 to 56.2% in 3 days when stored at 37 degrees C. Soluble starch which does not retrograde demonstrated no change in the degree of hydrolysis. 相似文献
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de Castro Assumpção Daniel Rivera Elmer Alberto Ccopa Tovar Laura Plazas Ezeji Thaddeus Chukwuemeka Filho Rubens Maciel Mariano Adriano Pinto 《Bioprocess and biosystems engineering》2018,41(11):1651-1663
Bioprocess and Biosystems Engineering - In flexible ethanol-butanol plants, low tolerance to butanol by solventogenic clostridia (and resulting dilute fermentation) results in considerable number... 相似文献
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Chidozie Victor Agu Victor Ujor Venkat Gopalan Thaddeus Chukwuemeka Ezeji 《Journal of industrial microbiology & biotechnology》2016,43(9):1215-1226
Lignocellulose-derived microbial inhibitors (LDMICs) prevent efficient fermentation of Miscanthus giganteus (MG) hydrolysates to fuels and chemicals. To address this problem, we explored detoxification of pretreated MG biomass by Cupriavidus basilensis ATCC®BAA-699 prior to enzymatic saccharification. We document three key findings from our test of this strategy to alleviate LDMIC-mediated toxicity on Clostridium beijerinckii NCIMB 8052 during fermentation of MG hydrolysates. First, we demonstrate that growth of C. basilensis is possible on furfural, 5-hydroxymethyfurfural, cinnamaldehyde, 4-hydroxybenzaldehyde, syringaldehyde, vanillin, and ferulic, p-coumaric, syringic and vanillic acid, as sole carbon sources. Second, we report that C. basilensis detoxified and metabolized ~98 % LDMICs present in dilute acid-pretreated MG hydrolysates. Last, this bioabatement resulted in significant payoffs during acetone-butanol-ethanol (ABE) fermentation by C. beijerinckii: 70, 50 and 73 % improvement in ABE concentration, yield and productivity, respectively. Together, our results show that biological detoxification of acid-pretreated MG hydrolysates prior to fermentation is feasible and beneficial. 相似文献
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Ezeji T.C. Qureshi N. Blaschek H.P. 《World journal of microbiology & biotechnology》2003,19(6):595-603
We examined the effect of gas-stripping on the in situ removal of acetone, butanol, and ethanol (ABE) from batch reactor fermentation broth. The mutant strain (Clostridium beijerinckii BA101) was not affected adversely by gas stripping. The presence of cells in the fermentation broth affected the selectivities of ABE. A considerable improvement in the productivity and yield was recorded in this work in comparison with the non-integrated process. In an integrated process of ABE fermentation-recovery using C. beijerinckii BA101, ABE productivities and yield were improved up to 200 and 118%, respectively, as compared to control batch fermentation data. In a batch reactor C. beijerinckii BA101 utilized 45.4 g glucose l–1 and produced 17.7 g total ABE l–1, while in the integrated process it utilized 161.7 g glucose l–1 and produced total ABE of 75.9 g l–1. In the integrated process, acids were completely converted to solvents when compared to the non-integrated process (batch fermentation) which contained residual acids at the end of fermentation. In situ removal of ABE by gas stripping has been reported to be one of the most important techniques of solvent removal. During these studies we were able to maintain the ABE concentration in the fermentation broth below toxic levels. 相似文献
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Development of a butanologenic strain with high selectivity for butanol production is often proposed as a possible route for
improving the economics of biobutanol production by solventogenic Clostridium species. The acetoacetate decarboxylase (aadc) gene encoding acetoacetate decarboxylase (AADC), which catalyzes the decarboxylation of acetoacetate into acetone and CO2, was successfully disrupted by homologous recombination in solventogenic Clostridium beijerinckii NCIMB 8052 to generate an aadc
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mutant. Our fermentation studies revealed that this mutant produces a maximum acetone concentration of 3 g/L (in P2 medium),
a value comparable to that produced by wild-type C. beijerinckii 8052. Therefore, we postulated that AADC-catalyzed decarboxylation of acetoacetate is not the sole means for acetone generation.
Our subsequent finding that non-enzymatic decarboxylation of acetoacetate in vitro, under conditions similar to in vivo acetone–butanol–ethanol
(ABE) fermentation, produces 1.3 to 5.2 g/L acetone between pH 6.5 and 4 helps rationalize why various knock-out and knock-down
strategies designed to disrupt aadc in solventogenic Clostridium species did not eliminate acetone production during ABE fermentation. Based on these results, we discuss alternatives to
enhance selectivity for butanol production. 相似文献
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Production of butanol from starch-based waste packing peanuts and agricultural waste 总被引:3,自引:0,他引:3
Jesse TW Ezeji TC Qureshi N Blaschek HP 《Journal of industrial microbiology & biotechnology》2002,29(3):117-123
We examined the fermentation of starch-based packing peanuts and agricultural wastes as a source of fermentable carbohydrates
using Clostridium beijerinckii BA101. Using semidefined P2 medium containing packing peanuts and agricultural wastes, instead of glucose as a carbohydrate
source, we measured characteristics of the fermentation including solvent production, productivity, and yield. With starch
as substrate (control), the culture produced 24.7 g l−1 acetone–butanol–ethanol (ABE), while with packing peanuts it produced 21.7 g l−1 total ABE with a productivity of 0.20 g l−1 h−1 and a solvent (ABE) yield of 0.37. Cell growth in starch, packing peanuts, and agricultural wastes medium was different,
possibly due to the different nature of these substrates. Using model agricultural waste, 20.3g l−1 ABE was produced; when using actual waste, 14.8 g l−1 ABE was produced. The use of inexpensive substrates will increase the economic viability of the conversion of biomass to
butanol, and can provide new markets for these waste streams. Journal of Industrial Microbiology & Biotechnology (2002) 29, 117–123 doi: 10.1038/sj.jim.7000285
Received 14 November 2001/ Accepted in revised form 07 June 2002 相似文献
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Nasib?QureshiEmail author Bassam?A?Annous Thaddeus?C?Ezeji Patrick?Karcher Ian?S?Maddox 《Microbial cell factories》2005,4(1):24
This article describes the use of biofilm reactors for the production of various chemicals by fermentation and wastewater
treatment. Biofilm formation is a natural process where microbial cells attach to the support (adsorbent) or form flocs/aggregates
(also called granules) without use of chemicals and form thick layers of cells known as "biofilms." As a result of biofilm
formation, cell densities in the reactor increase and cell concentrations as high as 74 gL-1 can be achieved. The reactor configurations can be as simple as a batch reactor, continuous stirred tank reactor (CSTR),
packed bed reactor (PBR), fluidized bed reactor (FBR), airlift reactor (ALR), upflow anaerobic sludge blanket (UASB) reactor,
or any other suitable configuration. In UASB granular biofilm particles are used. This article demonstrates that reactor productivities
in these reactors have been superior to any other reactor types. This article describes production of ethanol, butanol, lactic
acid, acetic acid/vinegar, succinic acid, and fumaric acid in addition to wastewater treatment in the biofilm reactors. As
the title suggests, biofilm reactors have high potential to be employed in biotechnology/bioconversion industry for viable
economic reasons. In this article, various reactor types have been compared for the above bioconversion processes. 相似文献