Showing papers on "Bioreactor published in 1989"

Modeling phenol degradation in a fluidized-bed bioreactor

Abstract: A study was made of phenol degradation by bacteria immobilized onto particles of calcined diatomaceous earth in a draft-tube, three-phase fluidized-bed reactor. A mathematical model is used to describe simultaneous diffusion and reaction of oxygen and phenol in the reactor. Kinetic parameters for the growth of nonsupported cells were obtained in batch and chemostat experiments. Liquid-solid mass transfer coefficients were determined experimentally and showed good agreement with literature values for conventional three-phase fluidized beds. Experimental steady-state degradation data were used to calculate biofilm substrate diffusivities. These were found to decrease as the biofilm density increased. The transition from phenol to oxygen-limiting biofilm kinetics predicted by the model was shown to exist experimentally. A critical ratio of phenol/dissolved oxygen concentration was found at which this transition occurred. This provides a criterion for establishing whether increased aeration will increase the volumetric degradation rate.

Degradation of trichloroethylene and trans-1,2-dichloroethylene by a methanotrophic consortium in a fixed-film, packed-bed bioreactor

Abstract: We have constructed and operated a fixed-film packed-bed bioreactor to evaluate the technical feasibility of bioremediation of TCE-contaminated groundwater using methanotrophic microorganisms. The performance of our bench-scale bioreactor system and observations on the kinetics of degradation of TCE and DCE in the bioreactor are described in this report

High cell density culture of E. coli in a fed-batch system with dissolved oxygen as substrate feed indicator

Abstract: A fed batch system using the dissolved oxygen concentration as substrate feed indicator has been developed to perform high cell density E. coli culture. A cell density of about 110 g/l (dw) has been obtained within 12 hours with an overall growth yield of about 0.68 gX/gGlucose.

Membrane bioreactor system

Abstract: A bioreactor is disclosed in which cells are confined to a compartment formed by porous hydrophyllic sheet membranes through which a nutrient solution diffuses in and exocellular products and metabolic waste diffuse out. Adjacent gas compartments allow the flow of free oxygen into the cell compartment. Each cell compartment is configured to place cells within about 100-200 micrometers of the oxygen transport membrane.

Removal of hydrogen sulfide from biogas by chemoautotrophic fixed‐film bioreactor

Abstract: A variety of «retained biomass» bioreactors have been developed, particularly for anaerobic digestion of industrial wastes. The fixed-film bioreactors are found to be advantageous in many ways. Reported here is a fixed-film bioreactor for H 2 S removal from biogas employing chemoautotrophic bacteria

The effect of calcium on anaerobic digestion

Abstract: The ability of methanogenic bacteria to adapt to high concentrations of calcium was investigated using a 9 l Upflow Anaerobic Sludge Blanket (UASB) reactor fed semi-continuously with a synthetic waste. It was found that a calcium concentration of up to 7000 mg/l had no inhibitory effect on anaerobic digestion.

High pressure-temperature bioreactor: assays of thermostable hydrogenase with fiber optics.

Abstract: Enzymes from deep-sea thermophilezs should be useful models for studying the influence of pressure on enzyme activity and stability under extreme physical conditions. To demonstrate the features of the bioreactor described later, initial studies have focused on the enhancement by pressure of methyl viologen-reducing hydrogenase activity in crude extracts of M. jannaschii

Production of solvents (ABE fermentation) from whey permeate by continuous fermentation in a membrane bioreactor

Abstract: A continuous bioreactor where cells were recycled using a cross-flow microfiltration (CFM) membrane plant was investigated for the production of solvents (ABE fermentation) from whey permeate using Clostridium acetobutylicum P262. A tubular CFM membrane plant capable of being backflushed was used. The continuous fermentations were characterized by cyclic solventogenic and acidogenic behaviour, and ultimately degenerated to an acidogenic state. Steady-state solvent production was obtained for only short periods. This degeneration is attributed to the complex morphological behaviour of this strain of organism on this substrate. It is postulated that to achieve steady-state solvent production over extended periods of time, it is necessary to maintain a balance among the various morphological cell forms, i.e. acid-producing vegetative cells, solvent-producing clostridial cells, and inert forms, e.g. spores.

Bioreactor for mammalian cell culture.

Abstract: Purpose of this article is to review the current status of bioreactor design for mammalian cell culture. Morphological and biochemical features of two major mammalian cell groups, anchorage-dependent and independent cells are proposed as a basis for different behavior at their cultivation. Different bioreactor configurations are systematically discussed through enumerating elementary physical phenomena and through stressing their physiological significance. Special considerations are given to those areas which are inherent to mammalian cell bioreactor.

Performance of an external loop air-lift bioreactor for the production of monoclonal antibodies by immobilized hybridoma cells

Abstract: The performance of an external loop air-lift bioreactor was investigated by assessing the inter-relationships between various hydrodynamic properties and mass transfer. The feasibility of using this bioreactor for the production of monoclonal antibodies by mouse hybridoma cells immobilized in calcium alginate gel beads and alginate/poly-l-lysine microcapsules was also examined. When the superficial gas velocity, Vg, in the 300 ml reactor was varied from 2 to 36 cm/min, the average liquid velocity increased from 3 to 14 cm/sec, the gas hold-up rose from 0.2 to 3.0%, and the oxygen mass transfer coefficient, kLa, increased from 2.5 to 18.1 h-1. A minimum liquid velocity of 4 cm/s was required to maintain alginate gel beads (1000 μm diameter, occupying 3% of reactor volume) in suspension. Batch culture of hybridoma cells immobilized in alginate beads followed logarithmic growth, reaching a concentration of 4×107 cells/ml beads after 11 days. Significant antibody production did not occur until day 9 into the culture, reaching a value of 100 μg/ml of medium at day 11. On the other hand, bioreactor studies with encapsulated hybridoma cells gave monoclonal antibody concentrations of up to 800 μg/ml capsules (the antibody being retained within the semipermeable capsule) and maximum cell densities of 2×108 cells/ml capsule at day 11. The volumetric productivities of the alginate gel immobilized cell system and the encapsulated cell system were 9 and 3 μg antibody per ml of reactor volume per day, respectively. The main advantage of the bioreactor system is its simple design, since no mechanical input is required to vary the hydrodynamic properties.

Development of semi-continuous and continuous flow bioreactors for the high level production of chloroperoxidase

Abstract: Continuous and semi-continuous flow bioreactors have been developed for the production of chloroperoxidase, which is secreted by the fungusCaldariomyces fumago. The semi-continuous system facilitated the harvest of mycelium-free supernatant for 200 days from a single inoculum, with enzyme levels greater than 600 mg/l during the first 80 days. The continuous flow bioreactor yielded essentially pure enzyme at the rate of 117 mg/day.

Growth and biocatalytic activities of aerobic thermophilic populations in sewage sludge

Abstract: Enzymatic activities of aerobic thermophilic microorganisms are described and investigated for the development and control of sewage sludge treatment processes in batch and fed-batch cultures. Proteolytic activity is the main enzymatic activity in an aerobic thermophilic sewage sludge treatment process. It has an optimum at 80°C and can be found also during growth on synthetic media. The activity is correlated with the increase in ammonium in the particle-free fraction and the values of the respiratory quotients during cultivation either in sewage sludge or in a syntheticc medium. No other extracellular activities (lipase, amylase, pectinase and cellulase) were detected in the investigated sludge samples. Carbohydrates, lipids and other polymers were either not present in significant amounts or passed with only minor modifications through the treatment. Cultivations in sewage sludge were either oxygen or carbon limited. One strain able to excrete lysozyme was isolated. It might have a synergistic effect on the heat inactivation of pathogenic microorganisms (cryptic growth) although lytic activity remained very low. Two-thirds of the entire metabolic activity is due to degradation of insoluble matter. The utilization of particulate matter also has a positive influence on the efficiency of the process by reduction in dry matter and increase in water-removal properties. Even at extremely low aeration rates, the acidification effect was small. Only small amounts of isobutyrate, isovaleriate and 2-methylbutyrate were formed at extremely low aeration rates and caused an increase in the total volatile fatty acid content after 12 and 36 h cultivation time.

Shifts in methanogenic subpopulations measured with antibody probes in a fixed-bed loop anaerobic bioreactor treating sulfite evaporator condensate.

Abstract: A fixed-bed loop, high-rate anaerobic bioreactor treating sulfite evaporator condensate was sampled when it reached steady state and afterwards following perturbations during a 14-month period. By using immunotechnology, it was observed that shifts in methanogenic subpopulations occurred in association with perturbations, such as restarting and relocating the biomass into a different tank. Methanogens related to Methanobacterium bryantii MoHG and Methanobrevibacter smithii ALI were numerous throughout the observation period, while Methanosarcina mazei S6 and Methanosarcina thermophila TM1 were found in the early and late samples, respectively. Also, Methanobacterium formicicum was more numerous at the top portion of the bioreactor, while Methanobrevibacter arboriphilus AZ and DC were at the bottom. Sample formalinization required for prolonged storage proved suitable for antigen preservation.

Method of processing biodegradable organic material

Abstract: An improved method and apparatus for treating a biodegradable organic material in an aqueous medium to produce methane gas is disclosed. The method involves flowing the aqueous medium under pressure through a hydrolytic-redox, immobilized microbe bioreactor to form a reaction product and then continuing the flow of the reaction product through an anaerobic, immobilized microbe bioreactor whereby methane gas is evolved. The aqueous medium is flowed in a downward direction counter to the flow of the gaseous carbon dioxide given off during the reaction and the aqueous medium may be recycled.

Semicontinuous cultivation of Digitalis lanata cells: production of beta-methyldigoxin in a 300-L airlift bioreactor

Abstract: Selected Digitalis lanata cell lines cultivated in 1-L shake flasks or 20-L airlift bioreactors converted beta-methyldigitoxin into beta-methyldigoxin with almost no side reactions. This biotransformation process was optimized with regard to substrate supply and culture medium composition, and was then scaled up to a volume of 210 L using a 300-L airlift bioreactor. A semicontinuous process was developed in which 513.3 g beta-methyldigoxin were produced after 89 days of cultivation.

Hydantoinase activity of immobilized non-growing Pseudomonas putida cells

Abstract: Hydantoinase (dihydropyrimidinase E.C. 3.5.2.2) activity of Pseudomonas putida DSM 84 was evaluated using cells immobilized in alginate beads and in a microporous hollow fibre bioreactor. Conversion of dihydrouracil into N-carbamyl-β-alanine was most efficient with alginate-immobilized cells. A 40 to 45% conversion was obtained in shake flasks and in continuous mode with packed bed columns. The highest volumetric productivity was obtained with a packed bed column operated at a dilution rate of 0.5 h-1 (99 μg of product. 100 μl-1 per hour). After 96 h the alginate beads began to swell and break apart; no free cells were detected however. Despite some initial loss of cells from the microporous hollow fibre bioreactor, a steady state was later established and maintained for 400 h at dilution rates of 0.1 and 0.25 h-1.

A Multistage Bioreactor with Replaceable Bioplates for Continuous Wine Fermentation

Abstract: A horizontal multistage bioreactor with replaceable immobilized plates (bioplates) was constructed for continuous wine fermentation. The bioplates were prepared by immobilizing viable cells in the form of membranes onto sintered glass plates, using calcium alginate as the carrier. Five bioplates were inserted vertically along a rectangular frame constructed from acrylic sheets, thus separating it into six compartments. The residence time distribution curve of the bioreactor approximated that of the six tanks in a series model (j = 5.61). The bioreactor was used for the continuous fermentation of Koshu grape must. During the steady state, axial sugar and ethanol concentration gradients existed from the first to the last compartment. The steady state was maintained for more than 42 days. Also, application of this bioreactor for continuous wine fermentation with simultaneous deacidification of a Muscat Bailey A grape must was carried out. Two bioplates of Schizosaccharomyces pombe O-77 and five bioplates of Saccharomyces cerevisiae 2HY-1 were used to separate the reactor into eight compartments. In this system, the total acidity of the wine during the steady state was reduced by 17% to 38% and the L-malic acid concentration by 58% to 76%. The L-lactic acid concentration remained more or less constant throughout the process.

High-rate acetic acid production in a shallow flow bioreactor

Abstract: The production of acetic acid in a new type of bioreactor was investigated. The bioreactor featured a shallow, horizontal flow of medium under a bacterial film of Acetobacter aceti M7. The volumetric productivity increased with increase in the specific liquid surface area. The maximum productivity was 31.7 g acetic acid·l-1 per hour for a specific liquid surface area of 10.7 cm-1 and the exit acetic acid concentration of 57.6 g·l-1. The productivity was considerably higher than values surveyed in the literature regarding the acetic acid concentration of normal vinegar (about 45 g·l-1).

Process development for anaerobic waste water treatment using porous carriers for microbial colonization

Abstract: A chemostat is well known to be a tool for selecting microorganisms with minimum doubling times during continuous fermentation, which is of special importance for slowly growing microorganisms like those used in anaerobic digestion. By set point control (SPC) of the operation parameters — especially of residence time τ — by means of a process computer, the selection stress can be optimized. A continuous operation very close to wash-out conditions is possible in spite of the microorganisms population changing properties. For anaerobic digestion of acid, a biomass was obtained that could reduce the chemical oxygen demand (COD) by more than 20 kg per kg dry biomass per d. For a high space-time yield, not only a high biomass activity but also a high biomass concentration is needed; therefore, methods for biomass retention or recycling have been developed. A porous glass sponge with free permeable macropores that can be colonized by anaerobic microorganisms proved to be especially useful. Raschig ring-shaped particles of this material were used in fixed-bed loop reactors for the anaerobic digestion of organically high polluted effluents.

Monoclonal antibody production in hollow fiber bioreactors using serum-free medium.

Abstract: Murine hybridoma cells that produce monoclonal antibody directed against human fibronectin have been cultured in VITAFIBER II and VITAFIBER V hollow fiber bioreactors using defined, serum-free WRC 935 medium. During a two-week growth period, following inoculation of the bioreactors, the cells proliferated to an extent where the bioreactor was filled with cultured cells. Using a 5 sq. ft. VITAFIBER V bioreactor, over 15 grams of antibody were produced during the 40 days of the experiment. This antibody was greater than 95% IgG. During the production period, this packed mass of cells produced 579 +/- 15 mg IgG per day. Because the medium is formulated for air equilibration and high cell densities, WRC 935 medium is especially useful for production of gram quantities of monoclonal antibodies using continuous feed hollow fiber bioreactor cell culture systems.

A fluidized-bed continuous bioreactor for lactic acid production

Abstract: A laboratory bioreactor consists of a fluidized bed of monosized activated carbon coated with a biofilm of the homolactic fermentative organismStreptococcus thermophilus. Biofilm growth moves the carbon beads through the bed, and adsorption of substrate and product at the bottom and top of the bed, respectively, reduces their inhibitory effects on the organism. Theory shows that high reactor productivity and rapid recirculation of carbon through the bed require a biofilm thickness of 25–45% of the carbon particle radius on particles fed into the base of the bed. This could not be achieved in practice owing to the fragility of the biofilm. A productivity of 12 gm/L h was achieved without any pH control and the outlet product concentration was higher than the completely-inhibiting concentration (found from batch experiments) at the outlet pH. This is possible because it is the undissociated form of the acid that both inhibits metabolism and adsorbs on activated carbon.

Plant cell immobilization in a dual hollow fiber bioreactor

Abstract: Lithospermumerythrorhizon was immobilized in a dual hollow fiber bioreactor (DHFBR) to maintain high cell density and to operate continuously. The cells grew well and its dry biomass density was 325 g/L of the void volume for the cell growth. Volumetric and specific productivities of phenolics were 221 mg/L.day and 0.68 mg/g.dry wt.day, respectively, which are 58 and 2 times of those of shake flask cultures.