Showing papers on "Bioreactor published in 2002"
TL;DR: Treatment performance was very stable and on a high level and the COD was reduced by 95%.
330 citations
TL;DR: The immobilized-cells fermentation in the RFB gave a virtually cell-free fermentation broth and provided many advantages over conventional fermentation processes, especially those with freely suspended fungal cells.
Abstract: A rotating fibrous-bed bioreactor (RFB) was developed for fermentation to produce L(+)-lactic acid from glucose and cornstarch by Rhizopus oryzae. Fungal mycelia were immobilized on cotton cloth in the RFB for a prolonged period to study the fermentation kinetics and process stability. The pH and dissolved oxygen concentration (DO) were found to have significant effects on lactic acid productivity and yield, with pH 6 and 90% DO being the optimal conditions. A high lactic acid yield of 90% (w/w) and productivity of 2.5 g/L.h (467 g/h.m(2)) was obtained from glucose in fed-batch fermentation. When cornstarch was used as the substrate, the lactic acid yield was close to 100% (w/w) and the productivity was 1.65 g/L.h (300 g/h.m(2)). The highest concentration of lactic acid achieved in these fed-batch fermentations was 127 g/L. The immobilized-cells fermentation in the RFB gave a virtually cell-free fermentation broth and provided many advantages over conventional fermentation processes, especially those with freely suspended fungal cells. Without immobilization with the cotton cloth, mycelia grew everywhere in the fermentor and caused serious problems in reactor control and operation and consequently the fermentation was poor in lactic acid production. Oxygen transfer in the RFB was also studied and the volumetric oxygen transfer coefficients under various aeration and agitation conditions were determined and then used to estimate the oxygen transfer rate and uptake rate during the fermentation. The results showed that the oxygen uptake rate increased with increasing DO, indicating that oxygen transfer was limited by the diffusion inside the mycelial layer.
181 citations
TL;DR: Aerobic granules cultivated in two column-type sequential aerobic sludge blanket reactors fed with glucose and acetate have comparable characteristics in terms of settling velocity, size, shape, biomass density, hydrophobicity, physical strength, microbial activity and storage stability.
Abstract: Aerobic granules were cultivated in two column-type sequential aerobic sludge blanket reactors fed with glucose and acetate, respectively. The characteristics of aerobic granules were investigated. Results indicated that the glucose- and acetate-fed granules have comparable characteristics in terms of settling velocity, size, shape, biomass density, hydrophobicity, physical strength, microbial activity and storage stability. Substrate component does not seem to be a key factor on the formation of aerobic granules. However, microbial diversity of the granules is closely associated with the carbon sources supplied to the reactors. Compared with the conventional activated sludge flocs, aerobic granules exhibit excellent physical characteristics that would be essential for industrial application. This research provides a complete set of characteristics data of aerobic granules grown on glucose and acetate, which would be useful for further development of aerobic granules-based compact bioreactor for handling high strength organic wastewater.
171 citations
TL;DR: The FBB technology is suitable for producing value-added biochemicals directly from agricultural residues or commodities such as corn meal, suggesting that these carboxylic acids can be efficiently produced from direct fermentation of corn meal hydrolyzate.
157 citations
TL;DR: The feasibility of sulphate removal from sulphate-rich wastewater using an anaerobic fixed-bed reactor was investigated in this paper, where the bioreactor was installed at a chemical industry producing organic peroxides, which generate wastewater with sulphate concentrations ranging from 12,000 to 35,000 mg SO 4 2− l −1.
155 citations
TL;DR: It is suggested that bacteria present in the highly concentrated biomass of the membrane reactor use the energy supplied for their maintenance metabolism and were not in a physiological state characteristic for growth, which could explain the zero net biomass production observed in the reactor.
147 citations
TL;DR: A six phase anaerobic/aerobic sequencing laboratory scale batch reactor was developed to treat a synthetic textile effluent, and cultures were able to tolerate the oxygen and methane continued to be produced but there was a deterioration in settlement.
143 citations
TL;DR: Proper understanding and rigorous analysis of several engineering parameters would pave the way towards the successful commercialization of plant cell bioprocesses.
Abstract: Plant cell culture provides a viable alternative over whole plant cultivation for the production of secondary metabolites. In order to successfully cultivate the plant cells at large scale, several engineering parameters such as, cell aggregation, mixing, aeration, and shear sensitivity are taken into account for selection of a suitable bioreactor. The media ingredients, their concentrations and the environmental factors are optimized for maximal synthesis of a desired metabolite. Increased productivity in a bioreactor can be achieved by selection of a proper cultivation strategy (batch, fed-batch, two-stageetc.), feeding of metabolic precursors and extraction of intracellular metabolites. Proper understanding and rigorous analysis of these parameters would pave the way towards the successful commercialization of plant cell bioprocesses.
139 citations
Patent•
25 Feb 2002
TL;DR: In this paper, a vertical shaft bioreactor was proposed for enhanced secondary and/or tertiary treatment of wastewater, including residential, municipal and industrial wastewater, which achieved thermophilic aerobic digestion and pasteurization of sewage sludges.
Abstract: In a vertical shaft bioreactor, improved devices and methods are provided for enhanced secondary and/or tertiary treatment of wastewater, including residential, municipal and industrial wastewater. The devices and methods of the invention are useful for enhanced secondary wastewater treatment, including BOD and TSS removal. Tertiary treatment can alternately or additionally be achieved in the biorecator with nitrification of ammonia, with nitrification and denitrification, and with nitrification, denitrification, and chemical phosphorus removal. A vertical shaft bioreactor is also provided which achieves thermophilic aerobic digestion and pasteurization of sewage sludges, optionally to produce class A biosolids.
136 citations
TL;DR: Submerged cultivation of Podophyllum hexandrum for the production of podophyllotoxin was carried out in a 3l stirred tank bioreactor fitted with a low-shear Setric impeller and was found to be a combined growth-associated and non-growth associated process.
116 citations
TL;DR: The ability of the RDBR biofilm to aerobically mineralize an azo dye without exogenous carbon and nitrogen sources suggests that this approach could be used to remediate industrial wastewater contaminated with spent dye.
TL;DR: A co-culture of Pseudomonas putida and P. fluorescens immobilized in a fibrous-bed bioreactor was used to degrade benzene, toluene, ethylbenzene and xylenes, present as sole carbon sources in contaminated water, to achieve biodegradation rates as high as 600 mg/l/h at the highest BTEX loading rate, studied.
TL;DR: Initial results using wastewater from a dumpsite leachate plant indicate removal of more than 90% of nonylphenol (NP) and bisphenol (BPA) and no dependency on the contact angle was observed.
TL;DR: The running conditions of the MD process (such as elevated temperature, significant salt concentrations and low pH values) inhibited the growth of microorganism in the MD system.
TL;DR: In this paper, the results of organic wastes' bioconversion into hydrogen and of the respective H 2 /CO 2 gas mixtures' separation by using active membrane systems (membrane contactors) with moving liquid carriers are presented.
TL;DR: Aim: Statistical medium optimization for maximum production of a hyperthermostable lipase from Burkholderia cepacia and its validation in a bioreactor.
Abstract: Aim: Statistical medium optimization for maximum production of a hyperthermostable lipase from Burkholderia cepacia and its validation in a bioreactor.
Methods and Results:Burkholderia cepacia was grown in shake flasks containing 1% glucose, 0·1% KH2PO4, 0·5% NH4Cl, 0·24% (NH4)2HPO4, 0·01% MgSO4.7H2O and 1% emulsified palm oil, at 45 °C and pH 7·0, agitated at 250 rev min−1 with 6-h-old inoculum (2% v/v) for 20 h. A fourfold enhancement in lipase production (50 U ml−1) and an approximately three fold increase in specific activity (160 U mg−1) by B. cepacia was obtained in a 14 litre bioreactor within 15 h after statistical optimization following shake flask culture. The statistical model was obtained using face centred central composite design (FCCCD) with five variables: glucose, palm oil, incubation time, inoculum density and agitation. The model suggested no interactive effect of the five factors, although incubation period, inoculum and carbon concentration were the important variables.
Conclusions: The maximum lipase production was 50 U ml−1, with specific activity 160 U mg−1 protein, in a 14 litre bioreactor after 15 h in a medium obtained after statistical optimization in shake flasks. Further, the model predicted reduction in time for lipase production with reduction in total carbon supply.
Significance and Impact of the Study: Statistical optimization allows quick optimization of a large number of variables. It also provides a deep insight into the regulatory role of various parameters involved in enzyme production.
TL;DR: The results indicate the potential of the Cytopilot bioreactor culture system for the continuous production of a recombinant protein over several weeks.
Abstract: A Chinese hamster ovary (CHO) cell line that expresses human erythropoietin (huEPO) was in a 2-L Cytopilot fluidized-bed bioreactor with 400 mL macroporous Cytoline-1 microcarriers and a variable perfusion rate of serum-free and protein-free medium for 48 days. The cell density increased to a maximum of 23 x 10(6) cells/mL, beads on day 27. The EPO concentration increased to 600 U/mL during the early part of the culture period (on day 24) and increased further to 980 U/mL following the addition of a higher concentration of glucose and the addition of sodium butyrate. The EPO concentration was significantly higher (at least 2x than that in a controlled stirred-tank bioreactor, in a spinner flask, or in a stationary T-flask culture. The EPO accumulated to a total production of 28,000 kUnits over the whole culture period. The molecular characteristics of EPO with respect to size and pattern of glycosylation did not change with scale up. The pattern of utilization and production of 18 amino acids was similar in the Cytopilot culture to that in a stationary batch culture in a T-flask. The concentration of ammonia was maintained at a low level (< 2 mM) over the entire culture period. The specific rate of consumption of glucose, as well as the specific rates of production of lactate and ammonia, were constant throughout the culture period indicating a consistent metabolic behavior of the cells in the bioreactor. These results indicate the potential of the Cytopilot bioreactor culture system for the continuous production of a recombinant protein over several weeks.
TL;DR: To investigate the applicability and characteristics of NF membrane, the membrane bioreactor (MBR) using the cellulose acetate NF membrane was performed to treat synthetic wastewater, and according to AFM investigation, the cellulOSE acetate membrane after 71 days has larger voids because of the biodegradation.
TL;DR: A correlation was found between the relative abundance of each strain and its specific denitrification activity.
Patent•
11 Dec 2002
TL;DR: In this article, a bioreactor system is described having an equalization system, a membrane bioreactors system, and a controller, as well as a rotary membrane ultrafilter.
Abstract: Methods and apparatus employing membrane filtration in biodegradation processes for treatment of wastewater are described. A bioreactor system is described having an equalization system, a membrane bioreactor system, and a controller. Aeration systems for a membrane bioreactor, such as a mixer, and an ultrafilter subsystem are also described, as is a rotary membrane ultrafilter.
TL;DR: A semi-continuous culture of Physcomitrella in a 5-l bioreactor grown at pH 4.5 yielded sufficient cell material for more than 100 transformations per day, and pH control reduced the protoplast yield compared to a culture without pH control to 11%.
TL;DR: Hydrogenotrophic denitrification of nitrate contaminated groundwater in a bench-scale microporous membrane bioreactor has been investigated and it was determined that the enrichment process selected for organisms belonging to the beta subclass of Proteobacteria.
TL;DR: It is demonstrated that this simple immobilization procedure was effective to maintain a 3-CA-degrading population within the activated sludge community.
Abstract: The survival and activity of microbial degradative inoculants in bioreactors is critical to obtain successful biodegradation of non- or slowly degradable pollutants. Achieving this in industrial wastewater reactors is technically challenging. We evaluated a strategy to obtain complete and stable bioaugmentation of activated sludge, which is used to treat a 3-chloroaniline (3-CA) contaminated wastewater in a lab-scale semi-continuous activated sludge system. A 3-CA metabolizing bacterium, Comamonas testosteroni strain I2, was mixed with molten agar and encapsulated in 4 mm diameter open-ended silicone tubes of 3 cm long. The tubes containing the immobilized bacteria represented about 1% of the volume of the mixed liquor. The bioaugmentation activity of a reactor containing the immobilized cells was compared with a reactor with suspended I2gfp cells. From day 25-30 after inoculation, the reactor with only suspended cells failed to completely degrade 3-CA because of a decrease in metabolic activity. In the reactors with immobilized cells, however, 3-CA continued to be removed. A mass balance indicated that ca. 10% of the degradation activity was due to the immobilized cells. Slow release of the growing embedded cells from the agar into the activated sludge medium, resulting in a higher number of active 3-CA-degrading I2 cells, was responsible for ca. 90% of the degradation. Our results demonstrate that this simple immobilization procedure was effective to maintain a 3-CA-degrading population within the activated sludge community.
TL;DR: In this article, a flat submerged membrane with a biological reactor was investigated for synthetic wastewater treatment of high concentration, and the increase of suction pressure as a result of fouling of the submerged membrane, nitrification and chemical oxygen demand (COD) removal efficiencies were monitored during 4-9 months operation.
TL;DR: Hydrogen production capability of Citrobacter sp.
TL;DR: Changes in the pH of the semi-continuous bioreactor culture medium between pH 4.5 and pH 7.0 influenced protonema differentiation; however it did not negatively affect the growth rate compared to uncontrolled pH.
Abstract: The use of the moss Physcomitrella patens as a production system for heterologous proteins requires highly standardised culture conditions. For this purpose a semi-continuous photoautotrophic bioreactor culture of Physcomitrella was established. This culture grew stably for 7 weeks in a 5-l bioreactor with a dilution rate of 0.22/day. Enrichment of the air for aeration in a batch bioreactor culture with 2% (v/v) CO 2 resulted in an in- crease in the specific growth rate to 0.57/day. Changes in the pH of the semi-continuous bioreactor culture medi- um between pH 4.5 and pH 7.0 influenced protonema differentiation; however it did not negatively affect the growth rate compared to uncontrolled pH. The advanta- ges of Physcomitrella as a system for the production of heterologous proteins in plants are discussed.
TL;DR: In order to understand the bioreactor operation, cellular metabolism must be considered together with the flow profile and the mass transfer characteristics of theBioreactor.
Abstract: Analysis of bioreactors is central for successful design and operation of biotechnical processes. The bioreactor should provide optimum conditions, with respect to temperature, pH and substrate condition, for example, besides its basic function of containment. The ability to control the substrate concentration is an important function of the bioreactor. The substrate concentration can be subject to spatial variation – advertently or inadvertently – and may also change with time in batch or fed-batch operation. The cellular metabolism will depend on local concentrations in the reactor, as well as on the physiological status of the cell. In order to understand the bioreactor operation, cellular metabolism must be considered together with the flow profile and the mass transfer characteristics of the bioreactor. Some fundamental aspects of bioreactor operation for yeast and bacterial cultivations are discussed in this short review.
TL;DR: Three bench-scale bioreactors were operated and the use of mites as fungal predators improved performance by increasing the overall mineralization of toluene to CO2, and by dislodging biomass along the bioreactor.
Abstract: Recent studies have focused on using vapor-phase bioreactors for the treatment of volatile organic compounds from contaminated air streams. Although high removal capacities have been achieved in many studies, long-term operation is often unstable at high pollutant loadings due to biomass accumulation and drying of the packing medium. In this study, three bench-scale bioreactors were operated to determine the effect of packing material and fungal predation on toluene removal efficiency and pressure drop. Toluene elimination capacities (mass toluene removed per unit packing per unit time) above 100 g m–3 h–1 were obtained in the fungal bioreactors packed with light-weight, artificial medium, and submersion of the packing in mineral medium once per week was found to provide sufficient moisture and nutrients to the biofilm. The use of mites as fungal predators improved performance by increasing the overall mineralization of toluene to CO2, and by dislodging biomass along the bioreactor.
Patent•
08 Jan 2002
TL;DR: In this paper, the authors present an apparatus for delivering activated microorganisms to an environment to be treated, where the controller maintains the conditions of the bioreactor so as to maintain the microorganisms in the exponential phase of growth.
Abstract: The invention is directed to an apparatus for delivering activated microorganisms to an environment to be treated. The apparatus has a bioreactor containing microorganisms, a supply of organic and inorganic nutrients and a controller. The controller maintains the conditions of the bioreactor so as to maintain the microorganisms in the exponential phase of growth. Although the apparatus is continuous, the controller also doses a portion of the fluid in the bioreactor to the environment to be treated. The invention also provides a method for the biological treatment of wastes and an organic and inorganic nutrient composition used to feed the microorganisms in the bioreactor.
Patent•
17 Dec 2002TL;DR: In this article, a method for hydrogen production from biodegradable feedstocks was proposed, in which a feedstock having at least one biodesgradable solid is introduced into a first stage anaerobic bioreactor operating at thermophilic conditions to form a liquid effluent which includes fatty acids.
Abstract: A method for hydrogen production from biodegradable feedstocks in which a feedstock having at least one biodegradable solid is introduced into a first stage anaerobic bioreactor operating at thermophilic conditions to form a liquid effluent which includes fatty acids. The liquid effluent is transferred through a plurality of hollow semipermeable fibers disposed in a second stage anaerobic bioreactor having a light transmitting wall, which hollow semipermeable fibers have an outer surface coated with a biofilm of photosynthetic bacteria, which photosynthetic bacteria, using the nutrients in the hollow fibers and the incoming light, generates hydrogen.