Butanol production by Clostridium acetobutylicum in a continuous packed bed reactor (original) (raw)
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5.1 Butanol Production in a Continuous Packed Bed Reactor by Clostridium acetobutylicum
Butanol production was characterized in terms of concentration of free cells and metabolites. Results were worked out to assess the rate of ABE production. The yields of the carbon source in cells, acids and solvents were also assessed. The reactor was operated under continuous conditions for more than one month. The optimal performance of the reactor was recorded at dilution rate of 0.97 h-1: the butanol productivity was 4.6 g/Lh and the selectivity of solvent to butanol was 88% w.
Assessment of Kinetics for Butanol Production by Clostridium Acetobutylicum
Preliminary results of a research activity aiming at investigating the feasibility of the acetone-butanol-ethanol (ABE) production by Clostridium acetobutylicum ATCC824 are reported. The contribution regards the characterization of the kinetics related to the ABE production process by free C. acetobutylicum ATCC824. Lactose solutions were adopted as medium with the aim of emulating cheese whey. The conversion process is characterized in terms of cells, acids, solvents, pH and total organic compounds as a function of time. Tests carried out under batch conditions show that: i) cells growth is constant for lactose concentration (C L) smaller than 100 g/L; ii) the butanol specific production rate as a function of C L may be represented by a Monod-like kinetics; iii) the lactose conversion-measured at the end of the solventogenesis phase-decreases with C L ; iv) the selectivity of butanol with respect to total solvents increases with C L and stabilizes at about 72% W for C L larger than 30 g/L.
Biotechnology and Bioengineering, 1991
An integrated solvent (ABE) fermentation and product removal process was investigated. A stable solvent productivity of 3.5 g/L h was achieved by using cells of Clostridium acetobutylicum immobilized onto a packed bed of bonechar, coupled with continuous product removal by pervaporation. Using a concentrated feed solution containing lactose at 130 g/L, a lactose utilization value of 919% was observed. The integrated fermentation and product removal system, with recycling of the treated fermenter effluent containing only low amount of solvents (but lactose and acids), leads to only low acid losses. Therefore, most of the acids are converted to solvents, and this results in a high solvent yield of 0.39 g solvents/g lactose utilized. The pervaporation system provided a high product removal rate even at low solvent concentrations. A solvent membrane flux of 11 g/m* h with a selectivity of 5 was achieved during these investigations. The system proved to be very reliable.
Butanol production by fermentation of Clostridium acetobutylicum: Solventogenic kinetics
New Biotechnology, 2014
Acetone-Butanol-Etanol is typically produced during the second stage of batch fermentations of some Clostridium strains under selected operating conditions: acids are consumed along with the carbon source and pH increase The objective of this study was to establish a continuous butanol production system by means of Clostridium acetobutylicum, lactose as the sole carbon source, and cell recycling (CSTR equipped with a microfiltration unit). Continuous cultures were carried out under a wide interval of operating conditions (diluition rate and recycle flux) in order to characterize the fermentation process under solventogenesis phase.
2010
Bio-butanol Acetone-Butanol-Ethanol ABE) ABEfermentation Butyric acid Clostridium C. acetobutylicum ATCC 824 C. beijerinckii ATCC 55025 C. beijerinckii BA 101 C. beijerinckii NCIMB 8052 Fibrous-bed Bioreactor (FBB) Batch Suspended cell culture Immobilized cell system. DEDICATION I would like to dedicate this M.Sc. Thesis to my beloved Family for all their love and encouragement and for always been supportive of my choices. "I am among those who think that science has great beauty. A scientist in his laboratory is not only a technician: he is also a child placed before natural phenomena, which impress him like a fairy tale." − Marie Curie
Fuel Processing Technology, 2016
Butanol production by acetone-butanol-ethanol (ABE) fermentation is usually associated with Clostridium acetobutylicum. In this report, ABE fermentation using the little known, oxygen tolerant solventogenic strain, Clostridium pasteurianum NRRL B-598, in packed-bed continuous cultures is described and compared with suspended cells in continuous, batch and fed-batch processes. While the highest butanol and total ABE concentrations (8.3 and 12.3 g/L respectively), were obtained in fed-batch fermentation, the highest solvent yield and productivity (32% and 0.73 g/L/h), were achieved in packed-bed continuous fermentation at a dilution rate of 0.12 1/h. In these processes, the strain showed exceptional stability, as demonstrated not only by low deviations in process parameters in batch and fed-batch experiments but also long-term stability (over 700 h, or more than 35 bioreactor residence times) in continuous fermentations.
Journal of Chemical Technology & Biotechnology, 2007
A jluidized bed reactor has been employed for the continuous production of solvents ffom whey permeate using cells of Clostridium acetobutylicum immobilized by adsorption onto bonechar. Substrate difision equations have been developed for the bioparticles, and a mathematical model has been advanced to describe the operation of the reactor. The model was fitted to the experimental data using the concept that not all of the biomass within the reactor was active in solvent production. On this basis, less than 5 % was 'active' biomass. NOTATION Cross-sectional area of reactor (m') Solvent concentration (kg m-3) Maximum solvent concentration (kg m-3) Effective diffusivity of lactose (m2 h-') Dilution rate, Fo/AH (h-') Feed rate of medium to reactor (m3 h-') Feed rate to the bed, Fo+Fr (m3 h-') Recycle rate (m3 h-') Height of reactor (m) 369 J. Chem. Tech. Biotechnol. 0268-2575/90/$03.50 0 1990 Society of Chemical Industry. Printed in Great Britain 370 N. Qureshi, I . S. Maddox Total height of reactor (m) Michaelis-Menten constant (kg m-') Ratio of solvent-producing biomass to total biomass, X J X , Radius of bioparticle (m) Radius of support particle (m) Rate of solvent production (kg m-' h-') Rate of lactose utilization in reactor (kg m -3 h-') External radius of bioparticle (m) Lactose concentration (kg m-3) Bulk lactose concentration, (Si +SJ2 (kg m-') Effluent lactose concentration (kg m-') Lactose concentration at inlet of bed (kg m-3) Minimum effluent lactose concentration (kg m-') Lactose concentration of feed medium (kg m-3) Time for a single recycle of liquid, (1 -E)V/'/F, (h) Residence time of feed in reactor, (1 -&)V/Fo (h) Rate of lactose utilization in bioparticle (kg m-' h-') Total reactor volume (m3) Maximum rate of lactose utilization (kg m-' h-') Maximum specific rate of solvent production (kg kg-' biomass h-') Dimensionless radius of bioparticle, r / R Dimensionless external radius of particle, ri/R Concentration of solvent-producing biomass (kg m -') Total concentration of biomass (kg m-') Dimensionless lactose concentration in bioparticle, S / S , Dimensionless lactose concentration inside reactor, S/Si Solvent yield, kg solvent/kg lactose utilized S b / K m S i I K m Solid volume fraction in reactor, bioparticle volume/total reactor volume Thiele modulus, dimensionless, R2 . Vrnax/De . K ,
Biotechnology and Bioengineering, 1990
Acetone–butanol–ethanol (ABE) fermentation was performed continuously in an immobilized cell, trickle bed reactor for 54 days without, degeneration by maintaining the pH above 4.3. Column clogging was minimized by structured packing of immobilization matrix. The reactor contained two serial glass columns packed with Clostridium acetobutylicum adsorbed on 12‐ and 20‐in.‐long polyester sponge strips at total flow rates between 38 and 98.7 mL/h. Cells were initially grown at 20 g/L glucose resulting in low butanol (1.15 g/L) production encouraging cell growth. After the initial cell growth phase a higher glucose concentration (38.7 g/L) improved solvent yield from 13.2 to 24.1 wt%, and butanol production rate was the best. Further improvement in solvent yield and butanol production rate was not observed with 60 g/L of glucose. However, when the fresh nutrient supply was limited to only the first column, solvent yield increased to 27.3 wt% and butanol selectivity was improved to 0.592 a...
Food and Bioproducts Processing, 2005
A cetone-butanol-ethanol (ABE) were produced from whey permeate medium, supplemented with lactose, in a batch reactor using Clostridium acetobutylicum P262, coupled with ABE removal by perstraction. ABE (98.97 gL 21) were produced from lactose (227 gL 21) at a yield of 0.44 and productivity of 0.21 gL 21 h 21. It should be noted that the ratio of acids to solvents was significantly lower in the perstraction experiment compared to the control batch process suggesting that acids were converted to solvents. The perstraction experiment results are superior to the control batch fermentation where 9.34 gL 21 ABE was produced. It was determined that lactose at 250 gL 21 was a strong inhibitor to the cell growth of C. acetobutylicum and fermentation. A membrane with an area of 0.1130 m 2 was used as the perstraction membrane while oleyl alcohol as the perstraction solvent. Removal of ABE by perstraction was faster than their production in the reactor, and the maximum concentration of ABE in the oleyl alcohol was 9.75 gL 21. It is viewed that recovery of ABE from oleyl alcohol (at this concentration) would be more economical than recovery from the fermentation broth. It is suggested that a new membrane be developed which can offer a higher ABE flux. Alternately, silicalite membranes that were successfully developed for pervaporation could be used for perstraction. Using such an integrated system would reduce process streams and save significant processing costs. It is also viewed that the process of concentrated lactose-whey permeate fermentation to butanol can be adapted in the existing solvent fermentation industries without making significant changes.