Showing papers on "Bioreactor published in 2001"
TL;DR: The specific activity of the mesophilic granular sludge was improved under psychrophilic conditions, which indicates that there was growth and enrichment of methanogens and acetogens in the anaerobic system.
492 citations
TL;DR: Flow cytometric analysis revealed reduced damage with respect to cytoplasmic membrane potential and integrity in cells grown in the dynamic environments of the large scale reactor and the scale-down reactor.
443 citations
TL;DR: Investigation of the viability and synthetic function of rat hepatocytes cocultured with 3T3-J2 fibroblasts in a small-scale microchannel flat-plate bioreactor with and without an internal membrane oxygenator under flow showed that theBioreactor without the oxygenator resulted in significantly decreased viability and function of hepatocytes, whereas hepatocytes in the bioreactors with internal membranes oxygenator were able to maintain their viability andfunction.
Abstract: The goal of this study was to investigate the viability and synthetic function of rat hepatocytes cocultured with 3T3-J2 fibroblasts in a small-scale microchannel flat-plate bioreactor with and without an internal membrane oxygenator under flow. Bioreactor channel heights ranged between 85 and 500 microm and medium flow rates ranged between 0.06 and 4.18 mL/min. The results showed that the bioreactor without the oxygenator resulted in significantly decreased viability and function of hepatocytes, whereas hepatocytes in the bioreactor with internal membrane oxygenator were able to maintain their viability and function. The shear stress calculations showed that, at lower wall shear stresses (0.01 to 0.33 dyn/cm(2)), hepatocyte functions, measured as albumin and urea synthesis rates, were as much as 2.6- and 1.9-fold greater, respectively, than those at higher wall shear stresses (5 to 21 dyn/cm(2)). Stable albumin and urea synthesis rates for 10 days of perfusion were also demonstrated in the bioreactor with internal membrane oxygenator. These results are relevant in the design of hepatocyte bioreactors and the eventual scaling-up to clinical devices.
342 citations
TL;DR: The process was found more efficient as compared to other continuous hydrogen production processes using packed bed reactor and the maximum rate of hydrogen production was found to be 2.1 times higher than that of batch system.
308 citations
TL;DR: Characterized by an oxygen consumption rate, sludge specific activities both for organic decomposition and nitrification of ammonia nitrogen varied with SRT, but volumetric oxygen consumption rates of the membrane bioreactor, representing the whole ability of the process for decomposing pollutants, were enhanced as SRT increased.
210 citations
TL;DR: It was found that Pseudomonas putida was able to degrade compounds other than phenol, and the bioreactor showed phenol degradation efficiencies higher than 90%, even for a phenol loading rate of 0.5 g phenol/ld (corresponding to 0.54 g TOC/ld).
207 citations
TL;DR: Anaerobic treatability and methane generation potential of cheese whey were determined in batch reactors and nutrient and trace metal supplementation is vital for the anaerobic treatment of Cheese whey.
202 citations
TL;DR: In this article, a fixed-bed bioreactor, fed with an H 2 /CO 2 mixture, was used in conjunction with a gas stripping column to determine the maximum rate of hydrogen transfer.
156 citations
TL;DR: By using external loop bioreactor to immobilize the cells uniformly on the loofa sponge beds, efficient large scale ethanol production systems can be constructed.
156 citations
TL;DR: The bioreactor system could reduce initial and operational cost for micro Propagation, but further development of sophisticated technology might be needed to apply this system to plant micropropagation industries.
Abstract: The application of bioreactor culture techniques for plant micropropagation is regarded as one of the ways to reduce production cost by scaling-up and automation. Recent experiments are restricted to a small number of species that, however, demonstrate the feasibility of this technology. Periodic immersion liquid culture using ebb and flood system and column-type bubble bioreactors equipped with a raft support system to maintain plant tissues at the air and liquid interface were found to be suitable for micropropagation of plants via the organogenic pathway. Balloon-type bubble bioreactors proved to be fit for micropropagation via somatic embryogenesis with less shear stress on cultured cells. Several cultivars of Lilium were successfully propagated using a two-stage culture method in one bioreactor. A large number of small-scale segments were cultured for 4 wk with periodic immersion liquid culture to induce multiple bulblets from each segment, then the bulblet induction medium was changed into bulblet growth medium by employing a submerged liquid bioreactor system. This culture method resulted in a nearly 10-fold increase in bulblet growth compared to conventional culture with solid medium. About 20 000 cuttings of virus-free potato could be obtained from 120 singlenode explants in a 20-liter balloon-type bubble bioreactor after 8 wk of culture. The percentage of ex vitro survival and root induction of the cuttings was more than 95%. Other successful results were obtained from the micropropagation and transplant production of chrysanthemum, sweetpotato, Chinese foxglove. Propagation systems via somatic embryogenesis in Acanthopanax koreanum and thornless Aralia elata were established using a liquid suspension of embryogenic determined cells. More than 500 000 somatic embryos in different stages were harvested from a 10-liter balloon-type bubble bioreactor after a 6-wk culture. Further development of these embryos in solid medium and eventually in the field was successful. The bioreactor system could reduce initial and operational cost for micropropagation, but further development of sophisticated technology might be needed to apply this system to plant micropropagation industries.
143 citations
TL;DR: There was a distinctive difference in the production potential of cells (cell-density-related parameter in Luedeking-Piret equation) as lactic acid concentration increases over 55 g/L, and this finding led to a more precise estimation of bioreactor performance.
Abstract: It is important to produce L(+)-lactic acid at the lowest cost possible for lactic acid to become a candidate monomer material for promising biodegradable polylactic acid. In an effort to develop a high-rate bioreactor that provides high productivity along with a high concentration of lactic acid, the performance of membrane cell-recycle bioreactor (MCRB) was investigated via experimental studies and simulation optimization. Due to greatly increased cell density, high lactic acid productivity, 21.6 g L(-1) h(-1), was obtained in the reactor. The lactic acid concentration, however, could not be increased higher than 83 g/L. When an additional continuous stirred tank reactor (CSTR) was attached next to the MCRB a higher lactic acid concentration of 87 g/L was produced at significant productivity expense. When the two MCRBs were connected in series, 92 g/L lactic acid could be produced with a productivity of 57 g L(-1) h(-1), the highest productivity among the reports of L(+)-lactic acid that obtained lactic acid concentration higher than 85 g/L using glucose substrate. Additionally, the investigation of lactic acid fermentation kinetics resulted in a successful model that represents the characteristics of lactic acid fermentation by Lactobacillus rhamnosus. The model was found to be applicable to most of the existing data with MCRBs and was in good agreement with Levenspiel's product-inhibition model, and the Luedeking-Piret equation for product-formation kinetics appeared to be effective in representing the fermentation kinetics. There was a distinctive difference in the production potential of cells (cell-density-related parameter in Luedeking-Piret equation) as lactic acid concentration increases over 55 g/L, and this finding led to a more precise estimation of bioreactor performance.
Patent•
26 Jul 2001
TL;DR: In this article, a bioreactor is divided into a plurality of serially connected treatment zones (30, 32, 34, 36, 38, 38) and includes a wastewater inlet (18), a downstream aerobic zone /38), and an upstream aerobic zone (34) between the water inlet and the downstream aerator.
Abstract: An apparatus (10) and method using activated sludge for the removal of biological nutrients from a wastewater includes a bioreactor (12) for containing a mixture of wastewater under treatment and activated sludge. The bioreactor (12) is divided into a plurality of serially connected treatment zones (30, 32, 34, 36, 38) and includes a wastewater inlet (18), a downstream aerobic zone /38) and an upstream aerobic zone (34) between the wastewater inlet (18) and the downstream aerobic zone (38). A membrane filter is provided in the downstream aerobic zone so that it functions as an immersed membrane filter (56) with a bioreactor containing an operative volume of wastewater and activated sludge. The immersed membrane filter filters treated water flowing from the bioreactor through a first outlet (20). An aerator (58) is operative associated with the membrane filter (56) for purging solids from the membrane filter (56). A second outlet in the downstream aerobic zone (60) is connected to an inlet in the upstream aerobic zone for recycling activated sludge charged with oxygen from the downstream aerobic zone to the upstream aerobic zone.
TL;DR: Experimental values indicated that both bioreactors showed high phenol degradation efficiencies, higher than 90%, even for a phenol loading rate in the influent as high as 4 g phenol/l day.
Patent•
15 Feb 2001
TL;DR: A disposable bioreactor for perfusion cell culture is described in this article, where cells are grown in a plastic bag that is rocked and aerated on a mechanical platform, and a perfusion filter is constructed such that it can move freely on the liquid surface.
Abstract: A disposable bioreactor for perfusion cell culture. Cells are grown in a plastic bag that is rocked and aerated on a mechanical platform. The bioreactor bag contains a filter that allows liquid to be removed from the bioreactor-without losing cells. Nutrients may be added through another port. The perfusion filter is constructed such that it can move freely on the liquid surface. The filter is flicked rapidly across the surface as a result of the rocking motion of the bioreactor and this tangential motion of the filter keeps it from clogging. A weight-based control system regulates feed and harvest rates and allows weeks of continuous operation. This invention has numerous applications in biotechnology and medicine.
TL;DR: The present study demonstrated that SMPs contributed most to the organic matter in the effluent, and the results coincided well with the observations of many other researchers.
TL;DR: Two approaches were presented to make this anaerobic discontinuous process feasible for industrial application: optimization of the operating procedures in reactors containing self-immobilized sludge as granules, and design of bioreactors with inert support media for biomass immobilization.
Abstract: This paper describes and discusses the main problems related to anaerobic batch and fed-batch processes for wastewater treatment. A critical analysis of the literature evaluated the industrial application viability and proposed alternatives to improve operation and control of this system. Two approaches were presented in order to make this anaerobic discontinuous process feasible for industrial application: (1) optimization of the operating procedures in reactors containing self-immobilized sludge as granules, and (2) design of bioreactors with inert support media for biomass immobilization.
TL;DR: Results indicate that fungal bioreactors may be an effective alternative to conventional abatement technologies for treating high concentrations of pollutants in waste gas streams.
Abstract: Stricter regulations on volatile organic compounds and hazardous air pollutants have increased the demand for abatement technologies. Biofiltration, a process in which contaminated air is passed through a biologically active bed, can be used to remove these pollutants from air streams. In this study, a fungal vapor-phase bioreactor containing a strain of the dimorphic black yeast, Exophiala lecanii-corni, was used to treat a gas stream contaminated with toluene. The maximum toluene elimination capacity in short-term tests was 270 g m−3 h−1, which is 2 to 7 times greater than the toluene elimination capacities typically reported for bacterial systems. The fungal bioreactor also maintained toluene removal efficiencies of greater than 95% throughout the 175-day study. Harsh operating conditions such as low moisture content, acidic biofilms, and nitrogen limitation did not adversely affect performance. The fungal bioreactor also rapidly reestablished high toluene removal efficiencies after an 8-day shutdown period. These results indicate that fungal bioreactors may be an effective alternative to conventional abatement technologies for treating high concentrations of pollutants in waste gas streams.© 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 75: 550–558, 2001.
TL;DR: An agitated 12-well microtiter plate system with a working volume of 2ml was investigated for cell culture process development, which assures homogeneity in wells and enhances mass transfer between the gas and the liquid phase, thus improving maximum cell density and pH stability.
TL;DR: In this paper, the extraction of pure hydrogen from the fermentation of household waste by a mixed anaerobic bacterial flora was demonstrated, where simulated household waste (600 g) was fermented in a bioreactor.
TL;DR: A closed-loop, perfused bioreactor for long-term patch-tissue conditioning, which combines continuous, pulsatile perfusion and mechanical stimulation by periodically stretching the tissue-engineered patch constructs.
Abstract: To date, one approach to tissue engineering has been to develop in vitro conditions to ultimately fabricate functional cardiovascular structures prior to final implantation. In our current experiment, we developed a new pulsatile flow system that provides biochemical and biomechanical signals to regulate autologous patch-tissue development in vitro. The newly developed patch bioreactor is made of Plexiglas and is completely transparent (Mediport Kardiotechnik, Berlin). The bioreactor is connected to an air-driven respirator pump, and the cell culture medium continuously circulates through a closed-loop system. We thus developed a closed-loop, perfused bioreactor for long-term patch-tissue conditioning, which combines continuous, pulsatile perfusion and mechanical stimulation by periodically stretching the tissue-engineered patch constructs. By adjusting the stroke volume, the stroke rate, and the inspiration/expiration time of the ventilator, it allows various pulsatile flows and different levels of pressure. The whole system is a highly isolated cell culture setting, which provides a high level of sterility, gas supply, and fits into a standard humidified incubator. The bioreactor can be sterilized by ethylene oxide and assembled with a standard screwdriver. Our newly developed bioreactor provides optimal biomechanical and biodynamical stimuli for controlled tissue development and in vitro conditioning of an autologous tissue-engineered patch.
TL;DR: An autotrophic biological process was developed for the treatment of nitrate-contaminated drinking water and when detected in the effluent, the concentration of nitrite was low, even under conditions that resulted in the elution of very high concentrations of nitrates.
TL;DR: Hepatocytes with oxygen dependent functional heterogeneity may exhibit optimal function in the bioreactor with the internal membrane oxygenator and can avoid cell hypoxia by appropriate selection of membrane Sherwood number and/or the gas phase oxygen partial pressure, thus providing greater control of cell oxygenation.
Abstract: Oxygen transfer to cultured hepatocytes in microchannel parallel-plate bioreactors with and without an internal membrane oxygenator was investigated with a mathematical model and the results were corroborated with fluorescence imaging experiments. The consumption of oxygen by hepatocytes was assumed to follow Michaelis-Menten kinetics. Our simulations indicate that under conditions of low Peclet (Pe) number (<80) and fixed Damlkohler number (= 0.14, corresponding to rat hepatocytes) the cells are hypoxic in the bioreactor without an internal membrane oxygenator. Under the same conditions, the bioreactor with an internal membrane oxygenator can avoid cell hypoxia by appropriate selection of membrane Sherwood number and/or the gas phase oxygen partial pressure, thus providing greater control of cell oxygenation. At high Pe, both bioreactors are well oxygenated. Experimentally determined oxygen concentrations within the bioreactors were in good qualitative agreement with model predictions. At low Pe, cell surface oxygen depletion was predicted from analytically derived criteria. Hepatocytes with oxygen dependent functional heterogeneity may exhibit optimal function in the bioreactor with the internal membrane oxygenator.
TL;DR: This process is believed to be very practical for the treatment of high concentrations of gaseous pollutants, and represents an alternative to the use of biofilters.
Abstract: A novel, continuous bioreactor system combining a bubble column (absorption section) and a two-phase bioreactor (degradation section) has been designed to treat a gas stream containing benzene. The bubble column contained hexadecane as an absorbent for benzene, and was systemically chosen considering physical, biological, environmental, operational, and economic factors. This solvent has infinite solubility for benzene and very low volatility. After absorbing benzene in the bubble column, the hexadecane served as the organic phase of the two-phase partitioning bioreactor, transferring benzene into the aqueous phase where it was degraded by Alcaligenes xylosoxidans Y234. The hexadecane was then continuously recirculated back to the absorber section for the removal of additional benzene. All mass transfer and biodegradation characteristics in this system were investigated prior to operation of the integrated unit, and these included: the mass transfer rate of benzene in the absorption column; the mass transfer rate of benzene from the organic phase into the aqueous phase in the two-phase bioreactor; the stripping rate of benzene out of the two-phase bioreactor, etc. All of these parameters were incorporated into model equations, which were used to investigate the effects of operating conditions on the performance of the system. Finally, two experiments were conducted to show the feasibility of this system. Based on an aqueous bioreactor volume of 1 L, when the inlet gas flow and gaseous benzene concentration were 120 L/h and 4.2 mg/L, respectively, the benzene removal efficiency was 75% at steady state. This process is believed to be very practical for the treatment of high concentrations of gaseous pollutants, and represents an alternative to the use of biofilters.
TL;DR: The feasibility of using shake flasks to culture animal cells was evaluated and it was found that conditions can be optimized so that hybridoma, Chinese Hamster Ovary cells, and insect cells can be efficiently cultured in the shaking reactors to cell densities comparable to that obtained with stirred-jar bioreactors.
TL;DR: In this article, the effect of phosphate addition in drinking water was tested under static conditions as batch tests and under dynamic conditions using continuously fed reactors, and the results showed that phosphate supplements from 0.1 to 2 mg P-PO4 L(-1) did not show any relationship between bacterial growth and phosphate concentration.
TL;DR: The immobilized biomass in a continuous reactor was found to have the capacity to sustain this removal efficiency continuously for a 4-month period, whereas the batch liquid culture systems remained active for approximately 8–15 days, after which cultures were no longer viable.
TL;DR: Anaerobic/aerobic batch experiments were conducted with a variety of volatile fatty (VFAs) and amino acids on two sequencing batch reactor populations displaying enhanced biological phosphorus removal, and it was hypothesized that 3HB resulted in greater P-uptake than other PHA forms such as 3HV.
TL;DR: The degradation of synthetic wastewater at short hydraulic retention times down to 1.5 h has been studied and at steady state a high quality filtrate could be obtained at different operating conditions.
Patent•
23 Jan 2001TL;DR: In this paper, a process for treating industrial wastewater that substantially eliminates the generation of excess solids in the system requiring mechanical removal is provided, where the wastewater is separated by gravity in a clarifying step to separate the wastewater into a liquid phase and a semi-solid phase.
Abstract: There is provided a process for treating industrial wastewater that substantially eliminates the generation of excess solids in the system requiring mechanical removal. The wastewater undergoes an equalization step wherein hydraulic flow is smoothed and the pH of the wastewater is adjusted to near neutral pH conditions. The equalized wastewater is then transferred to aeration tanks where the organic process wastes are absorbed, metabolized, or otherwise biodegraded by the microorganisms in the mixed liquor in the aeration tanks. After the aeration step, the wastewater is separated by gravity in a clarifying step to separate the wastewater into a liquid phase and a semi-solid phase. The clarified liquid phase is withdrawn from the clarifier and discharged, while the semi-solid phase is transferred either directly back to the aeration/biological treatment step, as recycle-activated sludge, or into a bioreactor as waste-activated sludge. In the bioreactor the semi-solid phase is subjected to active aeration. The aerated waste-activated sludge is then batch-recycled to the equalization tank discharging to the aeration step where it is mixed into newly introduced untreated wastewater and undergoes a new cycle of biological treatment. As a result of the indirect batch-recycling of bioreactor waste-activated sludge into the mixed liquor (biomass containing waste sludge) under aeration, which is also receiving recycle-activated sludge and enzymes, the excess solids generated in this process virtually eliminated.
TL;DR: Increased anaerobic acetate uptake was observed during recycle, which was sustained when the system was returned to flow-through mode and was related to increased cellular lipid inclusions by flow cytometry and electron microscopy, which may represent adaptation of cells to aerobic–anaerobic cycling with aerobic carbon/energy limitation.
Abstract: A strain of polyphosphate-synthesizing, phosphate-releasing Acinetobacter johnsonii was isolated from a wastewater treatment plant operating enhanced biological phosphate removal (EBPR) and was used to remove La(3+) from solution via precipitation of cell-bound LaPO(4). The effect of repeated aerobic-anaerobic cycles on the carbon and phosphate metabolism of the organism was studied in attempts to promote increased phosphate flux using a three-stage, continuous bioreactor comprising aerobic, anaerobic and settling vessels. The bioreactor was operated in two modes: In flow-through mode, cells were grown aerobically with acetate as the sole carbon source, promoting excess phosphate uptake (up to 5.0 mmol/l=3.0 mmol/g protein). Cells were diluted into the anaerobic vessel where phosphate was released (up to 1.0 mmol/l=0.3 mmol/g protein), and thence to waste. The system was initially operated to steady state in flow-through mode, then switched to recycle mode. Here the anaerobic vessel output passed to a settling vessel from which settled cells were returned to the aerobic vessel. Carbon source (acetate) was supplied only to the anaerobic vessel; increased anaerobic acetate uptake was observed during recycle, which was sustained when the system was returned to flow-through mode and was related to increased cellular lipid inclusions by flow cytometry and electron microscopy. These phenomena may represent adaptation of cells to aerobic-anaerobic cycling with aerobic carbon/energy limitation. Addition of La(3+) to the anaerobic vessel during recycle mode promoted removal of 95% of the La(3+) from a 0.1 to 0.3 mM (14-42 ppm) solution at the expense of biogenic phosphate.