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Showing papers on "Bioreactor published in 1994"


Patent
30 Nov 1994
TL;DR: A method and apparatus for converting waste gases from industrial processes such as oil refining, carbon black, coke, ammonia, and methanol production, into useful products is described in this article.
Abstract: A method and apparatus for converting waste gases from industrial processes such as oil refining, carbon black, coke, ammonia, and methanol production, into useful products. The method includes introducing the waste gases into a bioreactor where they are fermented to various organic acids or alcohols by anaerobic bacteria within the bioreactor. These valuable end products are then recovered, separated and purified. In an exemplary recovery process, the bioreactor raffinate is passed through an extraction chamber into which one or more non-inhibitory solvents are simultaneously introduced to extract the product. Then, the product is separated from the solvent by distillation. Gas conversion rates can be maximized by use of centrifuges, hollow fiber membranes, or other means of ultrafiltration to return entrained anaerobic bacteria from the bioreactor raffinate to the bioreactor itself, thus insuring the highest possible cell concentration.

201 citations


01 Jan 1994
TL;DR: In this article, the authors investigated the application of the conventional upflow anaerobic sludge blanket (UASB) and its modification, the expanded granular sludge bed (EGSB), for the treatment of low strength soluble wastewaters.
Abstract: Low strength soluble wastewaters with chemical oxygen demand (COD) of less than 2000 mg/I are mostly from food processing industries. They commonly contain simple substrates such as short- chain fatty acids, alcohols and carbohydrates. The application of anaerobic technology has been mostly directed towards the treatment of medium and high strength wastewaters rather than those of low strength. Problems limiting the treatment of dilute wastewaters are related to the wastewater and the reactor design. This dissertation investigates the application of the conventional upflow anaerobic sludge blanket (UASB) and its modification, the expanded granular sludge bed (EGSB), for the treatment of low strength soluble wastewaters. The main topics studied concern the wastewater related problems. Ile effect of dissolved oxygen on the methanogenic activity of granular sludges and the effect of low substrate levels inside reactors on the treatment performance were evaluated. Moreover, some aspects of reactor design related problems such as the retention of biomass and wastewaterbiomass contact were considered.Methanogens located in granular sludge have a high tolerance to oxygen. The concentration of oxygen found to cause 50% inhibition to methanogenic activity was between 7% and 41 % oxygen in the head space of flasks, which corresponded to 0.05 mg/ l and 6 mg/ l of dissolved oxygen prevailing in the media, respectively. The most important mechanism for the tolerance was the consumption of oxygen by facultative bacteria while metabolizing substrates. The most highly tolerant sludges had the highest respiration rates. The hypothesis considered is that anaerobic microenvironments are created inside granules protecting the methanogens. The absence of facultative substrate for respiring oxygen decreases the tolerance of methanognens to O 2 . The coexistence of methanogenic and facultative bacteria competing for substrate in one single bioreactor was explored under highly aerobic conditions, in order to verify the possible application of anaerobic-aerobic cocultures for the removal of recalcitrant pollutants. Simultaneous methane production and oxygen uptake occurred in an oxygen tolerant sludge while at least 2 mg/ l of dissolved oxygen was present in the media. The healthy co-culture was evident even after longer periods of oxygen exposure, when methane oxidizing bacteria eventually also developed.The feasibility of UASB and EGSB reactors at 30°C was demonstrated. In UASB reactors, COD removal efficiencies exceeded 95% at organic loading rates (OLR) up to 6.8 g COD/ l .d and influent COD concentrations (COD in ) ranging from 422 to 943 mg/ l , during the treatment of ethanol substrate. The efficiencies exceeded 86% at OLR up to 3.9 mg COD/ l .d when whey was used as a substrate. Below 630 mg COD/ l , acidification of whey instead of methanogenesis was the rate limiting step. The retention of biomass is not a problem in the UASB, but the mixing intensity is not high enough to decrease the biofilm diffusion limitation of substrate transport into granular biofilms. The EGSB was shown to have superior potentials compared with the UASB. COD removal efficiencies were above 80% at OLRs up to 12 g COD/ l .d with COD in as low as 100 to 200 mg/ l . The effect of low substrate levels was not significant in the EGSB due to the intense turbulent mixing regime obtained by applying high hydraulic and organic loads. The very low apparent K S value of 9.8 mg COD/ l found for the biofilms in the reactor, was comparable to the intrinsic K S values determined for the most predominant acetoclastic methanogen found in anaerobic bioreactors, Methanothrix soehngenii. This indicates that all transport limitations of substrate movement into the biofilms were overcome. Optimized operation without sludge washout is achieved when liquid upflow velocities (V up ) below 5.5 m/h are applied. The problem of sludge retention is also restricted when sludge flotation occurs due to the buoyancy forces of gas attached to biofilms. The required equilibrium between mixing intensity and sludge retention limits the operation of the EGSB to OLRs up to 7 g COD/ l .d and V up values ranging from 2.5 and 5.5 m/h. Both reactor studies confirmed that in practice dissolved oxygen does not constitute any detrimental effect on the treatment performance. Improved mixing intensity in the UASB and improved sludge retention in the EGSB will enable higher OLRs and lower COD in which can be tolerated, compared with those of this study.

157 citations


Journal ArticleDOI
TL;DR: A flow–through device which uses high frequency, low energy ultrasonic resonance fields to transiently aggregate hybridoma cells and return them by sedimentation to a perfusion bioreactor retained up to 99 percent of the inflowing viable cells with no measurable effect on viability.
Abstract: We have developed a flow–through device which uses high frequency, low energy ultrasonic resonance fields to transiently aggregate hybridoma cells and return them by sedimentation to a perfusion bioreactor. The system retained up to 99 percent of the inflowing viable cells with no measurable effect on viability. Viable cells were selectively retained at up to 3 percent higher efficiency than nonviable cells. A stirred tank bioreactor was operated for 700 hours with acoustic cell recycle. Concentrations greater than 5×107 cells/ml were attained with a 5–fold increase in antibody concentration and a 70–fold increase in volumetric productivity compared with batch culture.

152 citations


Patent
10 Jun 1994
TL;DR: A method and apparatus for converting waste gases from industrial processes such as oil refining, carbon black, coke, ammonia, and methanol production, into useful products is described in this paper.
Abstract: A method and apparatus for converting waste gases from industrial processes such as oil refining, carbon black, coke, ammonia, and methanol production, into useful products. The method includes introducing the waste gases into a bioreactor where they are fermented to various organic acids or alcohols by anaerobic bacteria within the bioreactor. These valuable end products are then recovered, separated and purified. In an exemplary recovery process, the bioreactor raffinate is passed through an extraction chamber into which one or more non-inhibitory solvents are simultaneously introduced to extract the product. Then, the product is separated from the solvent by distillation. Gas conversion rates can be maximized by use of centrifuges, hollow fiber membranes, or other means of ultrafiltration to return entrained anaerobic bacteria from the bioreactor raffinate to the bioreactor itself, thus insuring the highest possible cell concentration.

146 citations


Journal ArticleDOI
TL;DR: Compared to conventional batch fermentors, the new bioreactor offers many advantages for industrial fermentation, including a more than 10‐fold increase in productivity, acceptance of low‐nutrient feedstocks such as whey permeate, and resistance to contamination.
Abstract: Continuous production of propionate from whey lactose by Propionibacterium acidipropionici immobilized in a novel fibrous bed bioreactor was studied. In conventional batch propionic acid fermentation, whey permeate without nutrient supplementation was unable to support cell growth and failed to give satisfactory fermentation results for over 7 days. However, with the fibrous bed bioreactor, a high fermentation rate and high conversion were obtained with plain whey permeate and de-lactose whey permeate. About 2% (wt/vol) propionic acid was obtained from a 4.2% lactose feed at a retention time of 35 to 45 h. The propionic acid yield was approximately 46% (wt/vol) from lactose. The optimal pH for fementation was 6.5, and lower fermentation rates and yields were obtained at lower pH values. The optimal temperature was 30 degrees C, but the temperature effect was not dramatic in the range of 25 to 35 degrees C. Addition of yeast extract and trypticase to whey permeate hastened reactor startup and increased the fermentation rate and product yields, but the addition was not required for long-term reactor performance. The improved fermentation results with the immobilized cell bioreactor can be attributed to the high cell density, approximately 50 g/L, attained in the bioreactor, Cells were immobilized by loose attachement to fiber surfaces and entrapment in the void spaces within the fibrous matrix, thus allowing constant renewal of cells. Consequently, this bioreactor was able to operate continuously for 6 months without encountering any clogging, degeneration, or contamination problems. Compared to conventional batch fermentors, the new bioreactor offers many advantages for industrial fermentation, including a more than 10-fold increase in productivity, acceptance of low-nutrient feedstocks such as whey permeate, and resistance to contamination. (c) 1994 John Wiley & Sons, Inc.

129 citations


Journal ArticleDOI
TL;DR: In this paper, a hollow fibre membrane bioreactor with bubbleless membrane aeration was tested over 5 months for its ability to treat synthetic sewage and achieved 86% COD removal.

122 citations


Journal ArticleDOI
TL;DR: In this work, the major pathways of glucose and glutamine metabolism were incorporated into the stoichiometric model and the formation of toxic byproducts, such as ammonia and lactate, was greatly reduced.
Abstract: In our previous work (Xie and Wang, 1994a), a simplified stoichiometric model on energy metabolism for animal cell cultivation was developed. Fed-batch experiments were performed in T-flasks using this model in supplemental medium design (Xie and Wang, 1994b). In this work, the major pathways of glucose and glutamine metabolism were incorporated into the stoichiometric model. Fed-batch culture was conducted in a 2-liter bioreactor with appropriate process control strategies. Nutrient concentrations, especially glucose and glutamine, were maintained at constant but low levels through the automated feeding of a supplemental medium formulated using the improved stoichiometric model. The formation of toxic byproducts, such as ammonia and lactate (Hassell et al., 1991), was greatly reduced. The specific lactate production rate was decreased by 62-fold compared with batch culture in bioreactor and by 8-fold compared to fed-batch culture in T-flask using the previous stoichiometric model. Ammonia formation was also decreased compared with both the batch and fed-batch cultures. Most importantly, the monoclonal antibody concentration reached 900 mg l-1, an increase of 17- and 1.6-fold compared with the batch and fed-batch cultures respectively.

120 citations


Journal ArticleDOI
TL;DR: A pH-controlled continuous lactic acid fermentation of whey permeate supplemented with yeast extract was carried out with Lactobacillus helveticus entrapped in κ-carrageenan-locust bean gum gel beads at various dilution rates and pH set points with low activity due to the presence of high inhibition in the central part of the beads.

107 citations


Book
17 Nov 1994
TL;DR: The design of a bioreactor system - overview shows the effect of microorganism type and culture characteristics onBioreactor design and operation design, formulation, and optimization of media.
Abstract: Design of a bioreactor system - overview Part 1 Biological systems and media design: organism selection bacterial, yeast, and fungal cultures - effect of microorganism type and culture characteristics on bioreactor design and operation design, formulation, and optimization of media Part 2 Bioreactor design: fundamentals of bioreactor design stirred tank bioreactors pneumatically agitated bioreactors membrane reactors immobilized microorganism bioreactors immobilized animal cell bioreactors plant cell bioreactors photobioreactors bioreactor operation modes bioreactor scale-up Part 3 Bioreactor support systems: sterilization and containment bioreactor system supplies

93 citations


Patent
09 Feb 1994
TL;DR: In this paper, a high performance hollow fiber bioreactor with concentric hollow fiber bundles is described, where the central hollow fiber bundle supplies culture medium while the outer hollow fibre bundle supplies oxygen needed for cell culture.
Abstract: A high performance hollow fiber bioreactor having concentric hollow fiber bundles (22, 23) is disclosed. The central hollow fiber bundle (23) supplies culture medium while the outer hollow fiber bundle (22) supplies oxygen needed for cell culture. Methods for use of the high performance bioreactor include, for example, to expand stem cells ex vivo are described.

92 citations


Journal ArticleDOI
TL;DR: The low-temperature-cultivations showed a lower growth rate and a lower glucose consumption rate and, therefore, less lactate production, while the maximum cell density and productivity seemed not to be affected by the temperature reduction.
Abstract: Adherent recombinant BHK cells were cultivated at temperatures between 30 and 37°C. Batch and repeated-batch-cultivations in a 2-litre bioreactor showed a significant influence on metabolism and cell growth. The low-temperature-cultivations showed a lower growth rate and a lower glucose consumption rate and, therefore, less lactate production. On the other hand, the maximum cell density and productivity seemed not to be affected by the temperature reduction.

Journal ArticleDOI
TL;DR: The temperature gradients caused by heat transfer resistances were reduced considerably with corresponding increases in enzyme activity and the problem of heat accumulation during the course of fermentation has been alleviated to a considerable extent using a packed-column bioreactor with forced aeration.

Journal ArticleDOI
TL;DR: Treatment of municipal wastewater on a semi-industrial aerobic pilot-scale MBR resulted in complete nitrification and from 93 to 99.9% removal of COD, N-NH 3 and suspended solids.

Journal ArticleDOI
TL;DR: Plant regenerated organs such as shoots, bulbs, microtubers, corms, embryos, etc. have been successfully proliferated in the bioreactor.
Abstract: Plant regenerated organs such as shoots, bulbs, microtubers, corms, embryos, etc. have been successfully proliferated in the bioreactor. The use of a bioreactor leads to the development of technology suitable for large scale plant propagation. The basic construction and characteristics of various types of bioreactor systems are reviewed in relation to shoot and embryo cultures. A pilot scale 500 liter bioreactor system was applied to the production of large scale Stevia rebaudiana shoots.

Journal ArticleDOI
Ho Nam Chang1, Ik-Keun Yoo1, Beom Soo Kim1
TL;DR: In this paper, the authors compared membrane-based cell recycle operation with other such high density cell culture systems as immobilized cell reactors and reactors with cell recycle by centrifugation or gravity sedimentation.

Journal ArticleDOI
TL;DR: A new hybrid process has been developed and tested for the treatment of dumpsite leachate, a highly contaminated multicomponent waste water, and is convinced that this new process is not confined to thereatment of leachates but is applicable for a variety of industrial waste waters.

Book
01 Jan 1994
TL;DR: Chairman's statement Making and selecting recombinant cell lines cell line characterisation complex media formulations Protein and / or serum free cultures.
Abstract: Chairman's statement Making and selecting recombinant cell lines cell line characterisation complex media formulations Protein and / or serum free cultures Ammonia/ Glutamine and other inhibitors Apoptosis and cell biology Perfusion cultures and segregation methods Fixed and Fluidized beds Porus microcarriers hollow fibre bioreactors Novel bioreactors Bioreactor comparisons Novel measurements and assays Physical factors in bioreactors bioreactor operation strategies Kinetics and modelling Downstream processing Products from animal cells in culture Post translational modifications Cells in culture for toxicology studies Product safety and consistency testing.

Journal ArticleDOI
TL;DR: The available data suggest that Type-Z biocarriers represent an immobilization medium that provides an amenable environment for microbial growth and has the potential for improving the reliability of fixed-film biotreatment processes.
Abstract: Inorganic matrices were developed for fixed-film bioreactors affording protection to microorganisms and preventing loss of bioreactor productivity during system upsets. These biocarriers, designated Type-Z, contain ion-exchange properties and possess high porosity and a high level of surface area, which provide a suitable medium for microbial colonization. Viable cell populations of 10/g were attainable, and scanning electron micrographs revealed extensive external colonization and moderate internal colonization with aerobic microorganisms. Laboratory-scale bioreactors were established with various biocarriers and colonized with Pseudomonas aeruginosa, and comparative studies were performed. The data indicated that bioreactors containing the Type-Z biocarriers were more proficient at removing phenol (1,000 ppm) than bioreactors established with Flexirings (plastic) and Celite R635 (diatomaceous earth) biocarriers. More significantly, these biocarriers were shown to moderate system upsets that affect operation of full-scale biotreatment processes. For example, subjecting the Type-Z bioreactor to an influent phenol feed at pH 2 for periods of 24 h did not decrease the effluent pH or reactor performance. In contrast, bioreactors containing either Celite or Flexirings demonstrated an effluent pH drop to approximately 2.5 and a reduction in reactor performance by 75 to 82%. The Celite reactor recovered after 5 days, whereas the bioreactors containing Flexirings did not recover. Similar advantages were noted during either nutrient or oxygen deprivation experiments as well as alkali and organic system shocks. The available data suggest that Type-Z biocarriers represent an immobilization medium that provides an amenable environment for microbial growth and has the potential for improving the reliability of fixed-film biotreatment processes.

Journal ArticleDOI
TL;DR: The continuous production of nisin, an antibiotic polypeptide, by Lactococcus lactis in a bioreactor system coupled to a microfiltration module is described and productivity with respect to both cultivation time and quantity of glucose consumed was enhanced by maintaining a low concentration of lactic acid in the broth.

Proceedings ArticleDOI
01 Jun 1994
TL;DR: Three Intermediate-Scale Aerobic Bioreactors utilized mixed microbial communities to bio-degrade plant residues to regenerate a wheat hydroponic nutrient solution and recovered and recycled over 80% of available potassium, calcium, and other minerals.
Abstract: Three Intermediate-Scale Aerobic Bioreactors were designed, fabricated, and operated. They utilized mixed microbial communities to bio-degrade plant residues. The continuously stirred tank reactors operated at a working volume of 8 L, and the average oxygen mass transfer coefficient, k(sub L)a, was 0.01 s(exp -1). Mixing time was 35 s. An experiment using inedible wheat residues, a replenishment rate of 0.125/day, and a solids loading rate of 20 gdw/day yielded a 48% reduction in biomass. Bioreactor effluent was successfully used to regenerate a wheat hydroponic nutrient solution. Over 80% of available potassium, calcium, and other minerals were recovered and recycled in the 76-day wheat growth experiment.

Patent
03 Oct 1994
TL;DR: In this paper, an integrated synchronous aerobic/anaerobic bioreactor is described for treating waste liquids, such as pulp and paper waste water, and to methods of treating such waste liquid.
Abstract: An integrated synchronous aerobic/anaerobic bioreactor is disclosed for treating waste liquids, such as pulp and paper waste water, and to methods of treating such waste liquid. The apparatus includes a bioreactor and an external aerator for injecting a controlled amount of an oxygen-containing gas into the waste liquid as it is cycled through the apparatus. An aerobic/anaerobic biofilm is provided in the reactor, having a decreasing gradient of oxygen concentration toward its core.

Journal ArticleDOI
TL;DR: In this article, a membrane recycle bioreactor (MRB) using Lactobacillus amylovorus was used for fermentation of lactic acid directly from starch, and the maximum productivity of 25 g litre−1 h−1 was obtained at 0·5 h− 1.

Journal ArticleDOI
TL;DR: Optimal growth was found at an oxygen concentration of 70% air saturation, resulting in a prolonged exponential growth phase that could be maintained for more than 16 days, and a maximum cell density of 5.5 x 10(7) viable cells ml-1 was achieved.

Journal ArticleDOI
TL;DR: The membrane bioreactor configuration described offers a range of advantages over conventional bioreactors due to the fact that there is no direct contact between the wastewater and the microorganisms.

Journal ArticleDOI
TL;DR: A mathematical model is developed for the titrant requirement as a function of the cell growth rate, the gas transfer properties of the bioreactor and the culture pH that predicts that bicarbonate accumulation affects the stoichiometry between titrant and biomass but does not prevent determination of growth rate constants.
Abstract: Recording the amount of titrant required to maintain constant pH in a bioreactor where cell metabolism causes acidity changes allows on-line determinations of growth kinetics in computer-controlled batch cultures. A system for making such measurements is described and its performance is investigated. Transient bicarbonate accumulation occurs if the culture produces CO2 at high pH values and low gas transfer rates. We have developed a mathematical model for the titrant requirement as a function of the cell growth rate, the gas transfer properties of the bioreactor and the culture pH. According to this model, bicarbonate accumulation affects the stoichiometry between titrant and biomass but does not prevent determination of growth rate constants. These predictions are confirmed using model experiments and measurements during batch growth of microbial cultures.

Journal ArticleDOI
TL;DR: Continuous fermentation with a membrane bioreactor allows the production of high-quality propionic acid with a volumetric productivity of 1 g l-1 h-1.

Journal ArticleDOI
TL;DR: Embryogenic cultures of a transformed Eschscholtzia californica cell line were carried out in a 11‐L helical ribbon impeller bioreactor operated under various conditions to evaluate the performance of this equipment for somatic embryo (SE) production.
Abstract: Embryogenic cultures of a transformed Eschscholtzia californica cell line were carried out in a 11-L helical ribbon impeller bioreactor operated under various conditions to evaluate the performance of this equipment for somatic embryo (SE) production. All bioreactor cultures produced SE suspensions with maximum concentrations at least comparable to those obtained from flask control cultures (∼8–13 SE · mL−;1). However, an increase of the mixingspeed, from 60 to 100 rpm, and low sparging rate (∼0.05 VVM, kL a ∼ 6.1 h−;1) for dissolved oxygen concentration (DO) control yielded poorer quality embryogenic cultures. The negative effects on SE production were attributed mainly to the low but excessive shear experienced by the embryogenic cells and/or embryoforming aggregates. High DO (∼60% of air saturation) conditions favored undifferentrated biomass production and high nutrient uptake rates at the expense of the slower SE differentiation process in both flask and bioreactor cultures. Too low DO (−5–10%) inhibited biomass and SE production. The best production of SE (∼44 SE · mL−1 or ∼757 SE · g dw−1 · d−1) was achieved by operating the bioreactor at 60 rpm while controlling DO at ∼20%by surface oxygenation only (0.05 VVM, kL a ∼ 1.4 h−;1). This production was found to be a biomass production/growth-associated process and was mainly limited by the availability of extracellular phosphate, magnesium, nitrogen salts, and carbohydrates. © 1994 John Wiley & Sons, Inc.

Journal ArticleDOI
TL;DR: A mutant strain of Clostridium thermoaceticum was studied in a cell-recycle membrane bioreactor for production of acetate from glucose, which resulted in a productivity 10-fold higher than that of the batch fermenter.

Journal ArticleDOI
TL;DR: Large-scale cultivation of cell suspension was performed in a 20-l airlift bioreactor under controlled conditions and an ajmalicine production of 315 micrograms g-1 dry weight was achieved in theBioreactor after 14 d of cultivation.