Showing papers on "Bioreactor published in 1999"
TL;DR: A novel bioreactor system for the cultivation of animal, insect, and plant cells using wave agitation induced by a rocking motion that provides good nutrient distribution, off-bottom suspension, and excellent oxygen transfer without damaging fluid shear or gas bubbles is described.
Abstract: This work describes a novel bioreactor system for the cultivation of animal, insect, and plant cells using wave agitation induced by a rocking motion. This agitation system provides good nutrient distribution, off-bottom suspension, and excellent oxygen transfer without damaging fluid shear or gas bubbles. Unlike other cell culture systems, such as spinners, hollow-fiber bioreactors, and roller bottles, scale-up is simple, and has been demonstrated up to 100 L of culture volume. The bioreactor is disposable, and therefore requires no cleaning or sterilization. Additions and sampling are possible without the need for a laminar flow cabinet. The unit can be placed in an incubator requiring minimal instrumentation. These features dramatically lower the purchase cost, and operating expenses of this laboratory/pilot scale cell cultivation system. Results are presented for various model systems: 1) recombinant NS0 cells in suspension; 2) adenovirus production using human 293 cells in suspension; 3) Sf9 insect cell/baculovirus system; and 4) human 293 cells on microcarrier. These examples show the general suitability of the system for cells in suspension, anchorage-dependent culture, and virus production in research and GMP applications.
292 citations
TL;DR: Cell metabolism and tissue composition were studied for engineered cartilage cultured for 5 weeks using bovine articular chondrocytes, polymer scaffolds, and rotating bioreactors to identify larger constructs containing higher amounts of cartilaginous tissue components, while anaerobic conditions suppressed chondrogenesis in 3D tissue constructs.
Abstract: Tissue engineered cartilage can be grown in vitro if the necessary physical and biochemical factors are present in the tissue culture environment. Cell me- tabolism and tissue composition were studied for engi- neered cartilage cultured for 5 weeks using bovine ar- ticular chondrocytes, polymer scaffolds (5 mm diameter ◊ 2 mm thick fibrous discs), and rotating bioreactors. Medium pH and concentrations of oxygen, carbon diox- ide, glucose, lactate, ammonia, and glycosoaminoglycan (GAG) were varied by altering the exchange rates of gas and medium in the bioreactors. Cell-polymer constructs were assessed with respect to histomorphology, bio- chemical composition and metabolic activity. Low oxy- gen tension (~40 mmHg) and low pH (~6.7) were associ- ated with anaerobic cell metabolism (yield of lactate on glucose, YL/G, of 2.2 mol/mol) while higher oxygen ten- sion (~80 mmHg) and higher pH (~7.0) were associated with more aerobic cell metabolism (YL/G of 1.65-1.79 mol/mol). Under conditions of infrequent medium re- placement (50% once per week), cells utilized more eco- nomical pathways such that glucose consumption and lactate production both decreased, cell metabolism re- mained relatively aerobic (YL/G of 1.67 mol/mol) and the resulting constructs were cartilaginous. More aerobic conditions generally resulted in larger constructs con- taining higher amounts of cartilaginous tissue compo- nents, while anaerobic conditions suppressed chondro- genesis in 3D tissue constructs. © 1999 John Wiley & Sons, Inc. Biotechnol Bioeng 63: 197-205, 1999.
244 citations
TL;DR: In this article, a wave agitation system for the cultivation of animal, insect, and plant cells using wave agitation induced by a rocking motion is described, which provides good nutrient distribution, off-bottom suspension, and excellent oxygen transfer without damaging fluid shear or gas bubbles.
Abstract: This work describes a novel bioreactor system for the cultivation of animal, insect, and plant cells using wave agitation induced by a rocking motion. This agitation system provides good nutrient distribution, off-bottom suspension, and excellent oxygen transfer without damaging fluid shear or gas bubbles. Unlike other cell culture systems, such as spinners, hollow-fiber bioreactors, and roller bottles, scale-up is simple, and has been demonstrated up to 100 L of culture volume. The bioreactor is disposable, and therefore requires no cleaning or sterilization. Additions and sampling are possible without the need for a laminar flow cabinet. The unit can be placed in an incubator requiring minimal instrumentation. These features dramatically lower the purchase cost, and operating expenses of this laboratory/pilot scale cell cultivation system. Results are presented for various model systems: 1) recombinant NS0 cells in suspension; 2) adenovirus production using human 293 cells in suspension; 3) Sf9 insect cell/baculovirus system; and 4) human 293 cells on microcarrier. These examples show the general suitability of the system for cells in suspension, anchorage-dependent culture, and virus production in research and GMP applications.
241 citations
TL;DR: To the authors' knowledge, these values represent the highest solvent and butanol concentrations produced by a solventogenic Clostridium strain when grown in batch culture.
Abstract: Addition of sodium acetate to chemically defined MP2 medium was found to increase and stabilize solvent production by Clostridium beijerinckii BA101, a solvent-hyperproducing mutant derived from C. beijerinckii NCIMB 8052. C. beijerinckii BA101 demonstrated a greater increase in solvent production than C. beijerinckii NCIMB 8052 when sodium acetate was added to MP2 medium. In 1-l batch fermentations, C. beijerinckii BA101 produced 32.6 g/l total solvents, with butanol at 20.9 g/l, when grown in MP2 medium containing 60 mM sodium acetate and 8% glucose. To our knowledge, these values represent the highest solvent and butanol concentrations produced by a solventogenic Clostridium strain when grown in batch culture.
198 citations
TL;DR: 2,4,6-TCP was successfully and completely degraded in a two-stage anaerobic–aerobic biological process in which the initial step was conducted anaerobically, resulting in the reductive dechlorination of the target compound to 2,4-dichlorophenol, and then 4-chlorophenol (4-CP).
187 citations
TL;DR: It is suggested that repeated excretion and re-assimilation of mixed-acid products contribute to the reduced yield during scale-up and that formate analysis is useful for detecting local oxygen deficiency in large-scale E. coli processes.
Abstract: Industrial 20-m3-scale and laboratory-scale aerobic fed-batch processes with Escherichia coli were compared. In the large-scale process the observed overall biomass yield was reduced by 12% at a cell density of 33 g/l and formate accumulated to 50 mg/l during the later constant-feeding stage of the process. Though the dissolved oxygen signal did not show any oxygen limitation, it is proposed that the lowered yield and the formate accumulation are caused by mixed-acid fermentation in local zones where a high glucose concentration induced oxygen limitation. The hypothesis was further investigated in a scale-down reactor with a controlled oxygen-limitation compartment. In this scaledown reactor similar results were obtained: i.e. an observed yield lowered by 12% and formate accumulation to 238 mg/l. The dynamics of glucose uptake and mixed-acid product formation (acetate, formate, D-lactate, succinate and ethanol) were investigated within the 54 s of passage time through the oxygen-limited compartment. Of these, all except succinate and ethanol were formed; however, the products were re-assimilated in the oxygen-sufficient reactor compartment. Formate was less readily assimilated, which accounts for its accumulation. The total volume of the induced-oxygen-limited zones was estimated to be 10% of the whole liquid volume in the large bioreactor. It is also suggested that repeated excretion and re-assimilation of mixed-acid products contribute to the reduced yield during scale-up and that formate analysis is useful for detecting local oxygen deficiency in large-scale E. coli processes.
183 citations
TL;DR: A fibrous-bed bioreactor containing the coculture of Pseudomonas putida and P. fluorescens immobilized in a fibrous matrix was developed to degrade benzene, toluene, ethylbenzene, and o-xylene in synthetic waste streams and was relatively insensitive to benzene toxicity.
164 citations
TL;DR: Three different reactor configurations were designed and tested for decolorization of an azo dye, Orange II, with white rot fungus and all the bioreactors showed high and stableDecolorization activity in long-term operation.
144 citations
TL;DR: In this article, the performance of a submerged membrane bioreactor with gravitational filtration was evaluated using a pilot-scale plant and raw domestic wastewater, where treated water was filtered through flat microfiltration membrane modules (polyethylene; pore size 0.4μm) by the pressure head of bulk solution.
123 citations
TL;DR: In this paper, a laboratory scale anaerobic bioreactor coupled with a membrane filtration device was investigated for treating domestic wastewater at ambient temperature, achieving over 97% chemical oxygen demand (COD) removal with effluent of COD less than 20 mg l−1 on the average at volumetric organic loadings ranging from 0.5 to 12.5 kg m−3 d−1, and had a strong tolerance to wastewater temperature variation.
120 citations
TL;DR: Immobilization of pollutant-degrading microorganisms on oxygen-permeable membranes provides a novel method of increasing the oxidation capacity of wastewater treatment bioreactors as well as offering the further advantage of close to 100% oxygen conversion efficiencies for the treatment of high-strength wastewaters.
Abstract: Immobilization of pollutant-degrading microorganisms on oxygen-permeable membranes provides a novel method of increasing the oxidation capacity of wastewater treatment bioreactors. Oxygen mass transfer characteristics during continuous-flow steady-state experiments were investigated for biofilms supported on tubular silicone membranes. An analysis of oxygen mass transport and reaction using an established mathematical model for dual-substrate limitation supported the experimental results reported. In thick biofilms, an active layer of biomass where both carbon substrate and oxygen are available was found to exist. The location of this active layer varies depending on the ratio of the carbon substrate loading rate to the intramembrane oxygen pressure. The thickness of a carbon- substrate-starved layer was found to greatly influence the mass transport of oxygen into the active biomass layer, which was located close to, but not in contact with, the biofilm-liquid interface. The experimental results demonstrated that oxygen uptake rates as high as 20 g m -2 d -1 bar-' can be achieved, and the model predicts that, for an optimized biofilm thickness, oxygen uptake rates of more than 30 g m -2 d -1 bar-' should be possible. This would allow membrane-aerated biofilm reactors to operate with much greater thicknesses of active biomass than can conventional biofilm reactors as well as offering the further advantage of close to 100% oxygen conversion efficiencies for the treatment of high-strength wastewaters. In the case of dual- substrate-limited biofilms, the potential to increase the oxygen flux does not necessarily increase the substrate (acetate) removal rate.
TL;DR: The general performance of anaerobic digesters and the diversity of wastes that these can treat have been increasing steadily during the last decade as a result of new reactor designs, operating conditions, or the use of specialized microbial consortia.
Abstract: The general performance of anaerobic digesters and the diversity of wastes that these can treat have been increasing steadily during the last decade as a result of new reactor designs, operating conditions, or the use of specialized microbial consortia. This article illustrates a few examples of new or broader applications of anaerobic digestion to the treatment of sewage, slurries, industrial wastewater, and solid wastes. In the case of domestic sewage, the sustainability of the overall process is much improved by the adoption of an anaerobic pretreatment step, for example, an upflow sludge blanket (USB) reactor. New methods for nutrient removal need to be coupled with anaerobic digestion. These may include, for example, anaerobic ammonium oxidation (anammox) and chemical P precipitation. In terms of industrial wastewaters, new additives are being developed that help the anaerobic sludge deal with unbalanced or toxic wastewaters. Engineering of anaerobic sludge granules is a new area of research that ser...
TL;DR: The process using an air lift bioreactor was successfully carried out in a batch system without sterilization and/or preliminary hydrolysis of SPW, and the removal of 95% COD and total suspended solids would lead to a potential benefit to the environment.
TL;DR: The effect of powdered activated carbon addition on the performance of a membrane-coupled anaerobic bioreactor (MCAB) was investigated in terms of membrane filterability and treatabilty through a series of batch and continuous microfiltration experiments.
Abstract: The effect of powdered activated carbon (PAC) addition on the performance of a membrane-coupled anaerobic bioreactor (MCAB) was investigated in terms of membrane filterability and treatabilty through a series of batch and continuous microfiltration (MF) experiments. In both batch and continuous MF of the digestion broth, a flux improvement with PAC addition was achieved, especially when a higher shear rate and/or a higher PAC dose were applied. Both the fouling and cake layer resistances decreased continuously with increasing the PAC dose up to 5 g/L. PAC played an important role in subtantially reducing the biomass cake resistance due to its incompressible nature and higher backtransport velocities. PAC might have a scouring effect for removing the deposited biomass cake from the membrane surface while sorbing and/or coagulating dissolved organics and colloidal particles in the broth. The chemical oxygen demand and color in the effluent were much removed with PAC addition, and the system was also more st...
TL;DR: Almost complete removal of the colored quinones and associated polymers from the permeate was observed and this membrane allows greater flux and was shown to facilitate high efficiency in removal of reaction products from the reactor.
TL;DR: In this article, the concentration of BrO 3 − was reduced in a denitrifying bioreactor supplemented with ethanol, when NO 3 − − was almost completely removed.
Patent•
15 Oct 1999TL;DR: In this paper, an improved solid state fermentation device that combines all of the operations of microorganism cultivation (sterilization, inoculation, cultivation, extraction, and post extraction treatment) is presented.
Abstract: The present invention provides an improved solid state fermentation device that combines all of the operations of microorganism cultivation (sterilization, inoculation, cultivation, extraction, and post extraction treatment). This solid state fermentation device is modular in nature and operates in a contained manner so that the live microorganisms from the reactor cannot come into contact with the environment and pollute the environment and also so that the environment inside the bioreactor is aseptic. Another aspect of this invention allows fermentation of microorganisms without inhibiting the growth of the microorganism. Specifically, the bioreactor is designed to remove heat that accumulates inside the bioreactor during fermentation by conduction. Additionally, there is a mechanism to add fluid to the interior of the bioreactor that permits equal distribution and precise control of a variety of environmental parameters. For example, the bioreactor of the present invention provides a means to add nutritive media to the microorganisms at any time during the fermentation process without disturbing the fermenting microorganisms. Furthermore, the bioreactor of the present invention provides a mechanism to mix the contents of the bioreactor at any time and for any duration during the fermentation process. Finally, the present bioreactor provides a means of extracting desired microbial products from the bioreactor without opening the bioreactor.
TL;DR: Different nutritional and process parameters influencing lactic acid production by Lactobacillus casei, adsorbed to Poraver beads in a recycle batch reactor system, were studied in an attempt to set up a system having a long operational lifetime and permitting use of high substrate concentrations for maximal conversion to the product.
TL;DR: In this article, a laboratory scale membrane aeration bioreactor (MABR) with a void volume of 1.35 l was tested for its ability to treat synthetic wastewater, and the ability of the reactor to operate under plug flow conditions demonstrated that the biofilm plays a significant role in oxygen mass transfer.
TL;DR: Results from these experiments indicated that the lower biomass yield and higher acetate formation obtained on a large scale compared to homogeneous small-scale cultivations were not directly caused by the cell response to the glucose oscillation, and conclusions are drawn concerning the design of the scale-down reactor.
Abstract: A large bioreactor is heterogeneous with respect to concentration gradients of substrates fed to the reactor such as oxygen and growth limiting carbon source. Gradient formation will highly depend on the fluid dynamics and mass transfer capacity of the reactor, especially in the area in which the substrate is added. In this study, some production-scale (12 m3 bioreactor) conditions of a recombinant Escherichia coli process were imitated on a laboratory scale. From the large-scale cultivations, it was shown that locally high concentration of the limiting substrate fed to the process, in this case glucose, existed at the level of the feedpoint. The large-scale process was scaled down from: (i) mixing time experiments performed in the large-scale bioreactor in order to identify and describe the oscillating environment and (ii) identification of two distinct glucose concentration zones in the reactor. An important parameter obtained from mixing time experiments was the residence time in the feed zone of about 10 seconds. The size of the feed zone was estimated to 10%. Based on these observations the scale-down reactor with two compartments was designed. It was composed of one stirred tank reactor and an aerated plug flow reactor, in which the effect of oscillating glucose concentration on biomass yield and acetate formation was studied. Results from these experiments indicated that the lower biomass yield and higher acetate formation obtained on a large scale compared to homogeneous small-scale cultivations were not directly caused by the cell response to the glucose oscillation. This was concluded since no acetate was accumulated during scale-down experiments. An explanation for the differences in results between the two reactor scales may be a secondary effect of high glucose concentration resulting in an increased glucose metabolism causing an oxygen consumption rate locally exceeding the transfer rate. The results from pulse response experiments and glucose concentration measurements, at different locations in the reactor, showed a great consistency for the two feeding/pulse positions used in the large-scale bioreactor. Furthermore, measured periodicity from mixing data agrees well with expected circulation times for each impeller volume. Conclusions are drawn concerning the design of the scale-down reactor.
TL;DR: Significantly shortened fermentation times demonstrate the feasibility of immobilized yeast bioreactors for beer production and showed similar kinetics of extract consumption, and therefore similar volumetric productivity.
Abstract: Two different types of immobilized yeast bioreactors were examined for continuous fermentation of high-gravity worts One of these is a fluidized bed reactor (FBR) that employs porous glass beads for yeast immobilization The second system is a loop reactor containing a porous silicon carbide cartridge (SCCR) for immobilizing the yeast cells Although there was some residual fermentable sugar in the SCCR system product, nearly complete attenuation of the wort sugars was achieved in either of the systems when operated as a two-stage process Fermentation could be completed in these systems in only half the time required for a conventional batch process Both the systems showed similar kinetics of extract consumption, and therefore similar volumetric productivity As compared to the batch fermentation, total fusel alcohols were lower; total esters, while variable, were generally higher The yeast biomass production was similar to that in a conventional fermentation process As would be expected in an accelerated fermentation system, the levels of vicinal diketones (VDKs) were higher To remove the VDKs, the young beer was heat-treated to convert the VDK precursors and processed through a packed bed immobilized yeast bioreactor for VDK assimilation The finished product from the FBR system was found to be quite acceptable from a flavor perspective, albeit different from the product from a conventional batch process Significantly shortened fermentation times demonstrate the feasibility of this technology for beer production
TL;DR: Based on virus yields, ease of operation and linear scalability, large-scale adenovirus production seems feasible using 293 cells (adapted to suspension/serum free medium or on microcarriers in serum containing medium) in a stirred tank bioreactor.
Abstract: We have compared three different production methods, which may be suitable for the large scale production of adenovirus vectors for human clinical trials. The procedures compared 293 cells adapted to suspension growth in serum-free medium in a stirred tank bioreactor, 293 cells on microcarriers in serum-containing medium in a stirred tank bioreactor, and 293 cells grown in standard tissue culture plasticware. With a given virus, yields varied between 2000 and 10,000 infectious units/cell. The stirred tank bioreactor routinely produced between 4000 and 7000 infectious units/cell when 293 cells were grown on microcarriers. The 293 cells adapted to suspension growth in serum-free medium in the same stirred tank bioreactor yielded between 2000 and 7000 infectious units/cell. Yields obtained from standard tissue culture plasticware were up to 10,000 infectious units/cell. Cell culture conditions were monitored for glucose consumption, lactate production, and ammonia accumulation. Glucose consumption and lactate accumulation correlated well with the cell growth parameters. Ammonia production does not appear to be significant. Based on virus yields, ease of operation and linear scalability, large-scale adenovirus production seems feasible using 293 cells (adapted to suspension/serum free medium or on microcarriers in serum containing medium) in a stirred tank bioreactor.
TL;DR: The overall performance of the bioreactor was promising for further investigation, and high levels of cellulolytic and hemicellulolytic activities were obtained.
TL;DR: The membrane‐aeration bioreactor is a small footprint modular process, suited to on‐site treatment of high‐organic‐strength industrial wastewater, and biodegradation of organic matter within the wastewater was almost exclusively carried out within the biofilm.
Abstract: The membrane-aeration bioreactor is a small footprint modular process, suited to on-site treatment of high-organic-strength industrial wastewater. A pilot-plant membrane-aeration bioreactor was operated under completely mixed, low-flow, and plug-flow conditions during treatment of a high-strength brewery wastewater. Hydrophobic dead-end hollow fibers supplied pure oxygen in a bubbleless form to a biofilm attached to the shell side of the fibers. Biofilm development was rapid and fibers were cleaned regularly to control excessive growth and sloughing. Organic removal rates of 27 kg total chemical oxygen demand/ m 3 .d and removal efficiencies of 81% were achieved during plug-flow operation. Biodegradation of organic matter within the wastewater was almost exclusively (99.8%) carried out within the biofilm.
TL;DR: In this paper, two bench-scale completely mixed bioreactors were used to investigate the effect of potato-processing industrial wastewater on the acidogenesis of primary sludge and found that the addition of the starch-rich potato processing wastewater considerably improved the performance of the system, resulting in an increase in the net VFA and soluble chemical oxygen demand (COD) concentrations and corresponding specific production rates.
TL;DR: A municipal wastewater biosludge was acclimated to the degradation of 4-nitroaniline (4-NA), and batch tests showed, that 3-NA can serve as the sole source of carbon, nitrogen and energy.
TL;DR: In this paper, three denitrifying bacteria were isolated from rice paddy sediment in central Taiwan, and they were found capable of obtaining energy by converting nitrates to nitrogen gas under either aerobic or anaerobic conditions.
TL;DR: A batch reactor model was developed to predict a critical cell density at which photosynthetic biomass production switches from a rate-limited process to a CO 2 delivery limited process, and the model predicts that the tubular recycle photobioreactor is operating at saturation growth kinetics with respect to light.
TL;DR: Under certain conditions, microbial activity was even observed in the presence of alkylbenzenes down to pH 2.5 with mixed cultures, which is quite unusual and explains the ability of the present biocatalyst to remove alky lbenzene vapors with high efficiency in biofilters under acidic conditions.
Abstract: A biofilter treating alkylbenzene vapors was characterized for its optimal running conditions and kinetic parame-ters. Kinetics of the continuous biofilter were compared to batch kinetic data obtained with biofilm samples as well as with defined microbial consortia and with pure culture isolates from the biofilter. Both bacteria and fungi were present in the bioreactor. Five strains were isolated. Two bacteria, Bacillus and Pseudomonas, were shown to be dominant, as well as a Trichosporon strain which could, however, hardly grow on alkylbenzenes in pure culture. The remaining two strains were most often overgrown by the other three organisms in liquid phase batch cultures μ
max, KS, KI values and biodegradation rates were calculated and compared for the difterent mixed and pure cultures. Since filter bed acidification was observed during biofiltration studies reaching a pH of about 4, experiments were also undertaken to study the influence of pH on performance of the different cultures. Biodegradation and growth were possible in all cases, over the pH range 3.5–7.0 at appreciable rates, both with mixed cultures and with pure bacterial cultures. Under certain conditions, microbial activity was even observed in the presence of alkylbenzenes down to pH 2.5 with mixed cultures, which is quite unusual and explains the ability of the present biocatalyst to remove alkylbenzenes with high efficiency in biofilters under acidic conditions.
TL;DR: The results suggest that co-substrates stimulate oxygen respiration, which lowers oxygen penetration into the biofilm and thereby creates anaerobic microniches where azo dye reduction can occur.