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1
Tzeng, Jing-Wen. "Study of fluidized bed reactor : fluid dynamics and bioreactor applications /." The Ohio State University, 1991. http://rave.ohiolink.edu/etdc/view?acc_num=osu148775943632625.
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Heo, Jinseok. "Characterization and applications of microfluidic devices based on immobilized biomaterials." Texas A&M University, 2005. http://hdl.handle.net/1969.1/4688.
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Microfluidic biosensors and bioreactors based on
immobilized biomaterials are described in this dissertation.
Photocrosslinkable hydrogel or polymeric microbeads
were used as a supporting matrix for immobilizing E.coli or
enzymes in a microfluidic device. This dissertation covers
a microfluidic bioreactor based on hydrogel-entrapped
E.coli, a microfluidic biosensor based on an array of
hydrogel-entrapped enzymes, and a microfluidic bioreactor
based on microbead-immobilized enzymes.
Hydrogel micropatches containing E.coli were
fabricated within a microfluidic channel by in-situ
photopolymerization. The cells were viable in the hydrogel
micropatch and their membranes could be porated by lysating
agents. Entrapment of viable cells within hydrogels,
followed by lysis, could provide a convenient means for preparing biocatalysts without the need for enzyme
extraction and purification. Our results suggested that
hydrogel-entrapped cells, immobilized within microfluidic
channels, can act as sensors for small molecules and as
bioreactors for carrying out reactions.
A microfluidic biosensor based on an array of
hydrogel-entrapped enzymes could be used to simultaneously
detect different concentrations of the same analyte or
multiple analyte in real time. The concentration of an
enzyme inhibitor could be quantified using the same basic
approach. Isolations of the microchannels within different
microfluidic channels could eliminate the possibility of
cross talk between enzymes.
Finally, we characterized microfluidic bioreactors
packed with microbead-immobilized enzymes that can carry
out sequential, two-step enzyme-catalyzed reactions under
flow conditions. The overall efficiency of the reactors
depended on the spatial relationship of the two enzymes
immobilized on the beads. Digital simulations confirmed the
experimental results.
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Sun, Yang. "Engineering and Functionalization of Degradable Scaffolds for Medical Implant Applications." Doctoral thesis, KTH, Polymerteknologi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-152605.
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The treatment of bone defects is facing the situation of lacking donations for autotransplantation. As a valid approach, scaffold-based tissue engineering combines the construction of well-defined porous scaffolds with advanced cell culturing technology to guide tissue regeneration. The role for the scaffold is to provide a suitable environment with a sufficient mechanical stiffness, supports for cell attachment, migration, nutrients and metabolite transport and space for cell remodeling and tissue regeneration. The random copolymers poly(L-lactide-co-ɛ-caprolactone) (poly(LLA-co-CL)) and poly(L-lactide-co-1,5-dioxepan-2-one) (poly(LLA-co-DXO)) have been successfully incorporated into 3D porous scaffolds to induce specific interactions with cells and direct osteogenic cell differentiation. In this thesis, these scaffolds have been modified in chemical and physical ways to map and understand requirements for bone regeneration. Scaffold functionalities and properties, such as hydrophilicity, stiffness, size/shape, and reproducibility, were studied. The hydrophilicity was varied by adding 3–20 % (w/w) Tween 80 to poly(LLA-co-CL) and poly(LLA-co-DXO) respectively, which resulted in contact angles from 35° to 15°. With 3 % Tween 80, the resultant mechanical and thermal properties were similar to pristine polymer materials. Tween 80 did not significantly influence cell attachment or proliferation but did stimulate the mRNA expression of osteogenetic markers. The surface functionality and mechanical properties were altered by introducing nanodiamond particles (n-DP) into poly(LLA-co-CL) scaffolds by means of surface physisorption or hybrid blending. Scaffold with n-DP physisorbed showed improved cell attachment, differentiation, and bone reformation. Hybrid n-DP/poly(LLA-co-CL) composites were obtained by direct blending of polylactide modified n-DP (n-DP-PLA) with poly(LLA-coCL). The n-DP-PLA was prepared by sodium hydride-mediated anionic polymerization using n-DP as the initiator. Prepared n-DP-PLA could be dispersed homogenously in organic solvents and blended with poly(LLA-coCL) solution. The n-DP-PLA particles were homogenously distributed in the composite material, which significantly improved mechanical properties. For comparison, the addition of benzoquinone-modified n-DP (n-DP-BQ) did not reinforce poly(LLA-co-CL). This indicated the importance of specific surface grafting, which determined different particle-polymer interactions. For the treatment of critical size defects, a large porous poly(LLA-co-CL) scaffold (12.5 mm diameter × 25 mm thickness) was developed and produced by molding and salt-leaching methods. The large porous scaffolds were evaluated in a scaffold-customized perfusion-based bioreactor system. It was obvious that the scaffold could support improved cell distribution and support the stimulation of human mesenchymal stem cell (hMSC) especially with dynamic flow in a bioreactor. To improve the scaffolding technique, a three-dimensional fiber deposition (3DF) technique was employed to build layer-based scaffolds. Poly(LLA-coCL) scaffolds produced by the 3DF method showed enhanced mechanical properties and a homogeneous distribution of human osteoblasts (hOBs) in the scaffolds. Although poly(LLA-co-CL) was thermally degraded, the degradation did not influence the scaffold mechanical properties. Based on the computerized design, a 3DF scaffold of amorphous copolymer poly(LLAco-CL) provides high-precision control and reproducibility. In summary, the design of porous scaffolds is one of the essential factors in tissue engineering as to mimicking the intrinsic extracellular environment. For bone tissue engineering, an optimized scaffold can maintain a contact angle greater than 35 degrees. Pristine or modified n-DP, introduced as an additive by surface physisorption or direct blending, can improve scaffold mechanical properties and cell response. Various sizes of scaffolds can be easily produced by a mold-mediated salt-leaching method. However, when 100 % reproducibility is required, the 3DF method can be used to create customizable scaffolds.QC 20140929
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Odeleye, A. O. O. "Engineering characterisation of single-use bioreactor technology for mammalian cell culture applications." Thesis, University College London (University of London), 2015. http://discovery.ucl.ac.uk/1464038/.
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The thesis describes an experimental investigation of the fluid dynamics within novel single-use bioreactors (SUBs), including stirred, rocked and pneumatically driven mixing systems. Biological studies to ascertain the impact of hydrodynamic conditions within these systems, on the growth and protein productivity of a mammalian cell line, are also presented. Two-dimensional velocity measurements within different SU technology were acquired with the use of a whole flow field laser-based technique, Particle Image Velocimetry (PIV). Fluid dynamic characteristics including velocity, turbulence, turbulent kinetic energy and vorticity were determined from time-resolved and phase-resolved velocity measurements. Commercial bioreactor systems were modified, if needed, in order to perform experiments within bioreactors commonly used for cell culture experiments, in preference to using vessel mimics. The fluid flow characteristics in both the impeller region and bulk fluid of a single-impeller stirred bioreactor were investigated, facilitating an enhanced understanding of the spatial distribution of velocity and turbulence throughout the vessel. PIV was also used to study the flow in a dual-impeller stirred bioreactor, providing a rare examination of the interaction between the flow fields generated by two impellers. The whole flow field velocity and turbulence characteristics measured within a rocked bag and pneumatically driven vessel, allow a unique insight into the flow pattern and turbulence distribution within two novel cell culture systems. Cell viability, size, growth, protein productivity and metabolites concentration were monitored under different cell culture operating conditions. Cell culture experiments, combined with the hydrodynamic information acquired using PIV, offer an insight into the physiological response of the cells to highly disparate flow conditions. This information helped to understand how the hydrodynamics induced by novel commercially used mixing systems, can impact upon a mammalian cell line. Having implications for an augmented capacity for cross-compatibility, in addition to enhanced strategies for scale translation and optimal bioreactor design.
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Laing, Ruth Mary Louise. "Development of Rhodopseudomonas palustris as a chassis for biotechnological applications." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/283194.
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The recent surge in biodiesel production has resulted in a huge surplus of crude glycerol, a by-product of the process to the level of 10% by weight. This is turn has caused the price of glycerol to fall dramatically, and there are now few economically viable channels for using this resource: waste glycerol is usually combusted. Therefore, much interest has arisen in the possibility of making use of glycerol with biotechnology, as this would not only be a more efficient use of resources but also make biodiesel itself more commercially viable. The purple bacterium Rhodopseudomonas palustris is able to metabolize glycerol through photofermentation and thereby produce hydrogen, a commercially useful commodity. R. palustris is of particular interest for this purpose as, in contrast to many other species which have been investigated with a view to fermenting glycerol, it is highly tolerant of crude glycerol. The feedstock requires little purification or dilution to be made suitable for cultivation of R. palustris. Furthermore, the hydrogen gas produced by R. palustris when grown on glycerol is of high purity, and the organism's great metabolic diversity suggests it may be a useful strain for remediation of other waste materials. However, much groundwork is needed to establish R. palustris as a viable chassis organism for biotechnological purposes. This work sets out to establish optimal conditions for cultivating R. palustris in the laboratory, including the design of a suitable batch photobioreactor system. It also determines optimal conditions for electroporation of R. palustris for the purpose of knocking out endogenous genes or introducing heterologous genes. Furthermore, the introduction of heterologous genes is attempted in order to demonstrate the possibility of producing other high-value compounds with R. palustris, and several deletion strains with potential benefits for hydrogen production are created. Finally, several existing deletion strains are investigated to establish their suitability as chassis strains for further genetic manipulation.
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Price, Joshua Colm Felician Aeddan. "The development and validation of a hydrostatic pressure bioreactor for applications in bone tissue engineering." Thesis, Keele University, 2017. http://eprints.keele.ac.uk/2807/.
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Current orthopaedics treatments of bone defects often involve the use of implanted fixatives and/or autograft procedures to restore function to the afflicted area following injury. Fixatives and implants are usually temporary solutions, since they are intrinsically prone to failure. In addition to this, replacing implants involve expensive and invasive procedures that cause great hardship to patients. Whilst autografts can provide an excellent outcome in healing of the initial injury site, donor site morbidity from the autologous bone graft can lead to complications such as infection, chronic pain and an abnormal walking gait. Bone tissue engineering is a field of science aiming to address these limitations by providing in vitro manufactured bone to replace autografts, and also limit the use of temporary fixatives. Hydrostatic force bioreactors are currently being developed within this field to attempt improve the outcome of the tissue engineered bone by mimicking the forces typically experienced by cells in the native bone niche. Based on this principle, it is hoped that such systems will aid the translation of research in bone tissue engineering from the lab to the clinic. This research aims to investigate and validate the use of a hydrostatic force bioreactor for improving the outcome of in vitro manufactured bone using a clinically relative strategy employing human mesenchymal stem cells seeded in 3D scaffolds. The research first describes a validation process to determine the initial response of cells to hydrostatic pressure in monolayer cultures. The outcome of this study indicated that mechanical responsiveness in cells can vary according to cell phenotype and the integrity of the f-actin cytoskeleton. Next it was demonstrated that hydrostatic pressure can improve the outcome of in vitro bone formation by MG-63 human osteoblast like cells, validating the bioreactor as a potential preconditioning platform. Following this, a model of bone formation in hMSCs/collagen scaffolds was described, whereby a predictable rate of bone formation was determined by adjusting cellular distribution and protein concentration in collagen type-1 scaffolds. Finally, an organotypic fracture repair model was established using explanted embryonic chick femurs to test the hypothesis that hydrostatic preconditioning of hMSC/collagen hydrogels can improve the outcome of fracture repair. The results of this study showed that bioreactor stimulation could enhance the outcome of repair using a combination of undifferentiated hMSC/collagen type-1 scaffolds, and global mechanical signalling (stimulation of entire femur constructs). It was then shown that hydrostatic preconditioning of hMSC seeded hydrogels prior to implantation did not increase the rate of in vitro bone formation. Following implantation of the hydrogels into the fracture repair model, it was demonstrated that highly mineralised preconditioned implants actually inhibited the fracture repair process. In addition to this, it was shown that preconditioned implants with a lower level of mineralisation allowed invasion and bone formation by native cells from the host tissue. Collectively, the results implied that the outcome of repair using this model relied on three main factors: the presence of global hydrostatic stimulation; the lineage commitment of hMSCs in collagen scaffolds at the time of implantation; and the permeability and cell invasion capacity of the implant.
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Umstead, Russell Blake. "Development of Fungal Bioreactors for Water Related Treatment and Disinfection Applications." Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/72291.
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Wastewater, recycled irrigation water, and agricultural runoff can contain high levels of pathogenic bacteria, which pose a threat to human and ecosystem health. The use of a bioreactor containing mycelial mats of filamentous fungi is a novel treatment technology that incorporates physical, biological, and biochemical processes to remove bacterial pathogens from influent water. Although a relatively new concept, fungal bioreactors have demonstrated the ability to dramatically reduce fecal coliform bacteria in water, but no studies have attempted to explicitly identify the bacterial pathogen removal mechanisms exhibited by the fungi.
This study evaluated several different species of fungi for use in fungal bioreactor systems and aimed to identify the modes of action responsible for the removal of bacterial pathogens. The species evaluated were Daedaleopsis confragosa, Pleurotus eryngii, and Piptoporus betulinus. Experimental results showed that all species of fungi assessed were capable of removing E. coli in a synthetic water solution. Significant concentrations of hydrogen peroxide, an antiseptic, were produced by all species of fungi evaluated. The fungal bioreactors containing P. eryngii produced the highest concentrations of hydrogen peroxide, generating a maximum concentration of 30.5 mg/l or 0.896 mM. This maximum value exceeds reported minimum concentrations required to demonstrate bacteriostatic and bactericidal effects when continually applied, providing evidence that a major bacterial removal mode of action is the production of antimicrobial compounds. In addition to its promising application to improve water quality, fungal bioreactors are a low cost and passive treatment technology. The development a hyper-functional system could be a have a substantial impact on the use of recycled irrigation water and on the water/wastewater treatment industry, for both municipal and agricultural wastewater.Master of Science
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Gawande, Nitin A. "Modeling microbiological and chemical processes in municipal solid waste bioreactor development and applications of a three-phase numerical model BIOKEMOD-3P /." Orlando, Fla. : University of Central Florida, 2009. http://purl.fcla.edu/fcla/etd/CFE0002659.
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Gama, Repson. "A lignocellulolytic enzyme system for fruit waste degradation : commercial enzyme mixture synergy and bioreactor design." Thesis, Rhodes University, 2014. http://hdl.handle.net/10962/d1013073.
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Studies into sources of alternative liquid transport fuel energy have identified agro-industrial wastes, which are lignocellulosic in nature, as a potential feedstock for biofuel production against the background of depleting nonrenewable fossil fuels. In South Africa, large quantities of apple and other fruit wastes, called pomace, are generated from fruit and juice industries. Apple pomace is a rich source of cellulose, pectin and hemicellulose, making it a potential target for utilisation as a lignocellulosic feedstock for biofuel and biorefinery chemical production. Lignocellulosic biomass is recalcitrant in nature and therefore its degradation requires the synergistic action of a number of enzymes such as cellulases, hemicellulases, pectinases and ligninases. Commercial enzyme cocktails, containing some of these enzymes, are available and can be used for apple pomace degradation. In this study, the degradation of apple pomace using commercial enzyme cocktails was investigated. The main focus was the optimisation of the release of sugar monomers that could potentially be used for biofuel and biorefinery chemical production. There is no or little information reported in literature on the enzymatic degradation of fruit waste using commercial enzyme mixtures. This study first focused on the characterisation of the substrate (apple pomace) and the commercial enzyme cocktails. Apple pomace was found to contain mainly glucose, galacturonic acid, arabinose, galactose, lignin and low amounts of xylose and fructose. Three commercial enzyme cocktails were initially selected: Biocip Membrane, Viscozyme L (from Aspergillus aculeatus) and Celluclast 1.5L (a Trichoderma reesei ATCC 26921 cellulase preparation). The selection of the enzymes was based on activities declared by the manufacturers, cost and local availability. The enzymes were screened based on their synergistic cooperation in the degradation of apple pomace and the main enzymes present in each cocktail. Viscozyme L and Celluclast 1.5L, in a 50:50 ratio, resulted in the best degree of synergy (1.6) compared to any other combination. The enzyme ratios were determined on Viscozyme L and Celluclast 1.5L based on the protein ratio. Enzyme activity was determined as glucose equivalents using the dinitrosalicylic acid (DNS) method. Sugar monomers were determined using Megazyme assay kits. There is limited information available on the enzymes present in the commercial enzyme cocktails. Therefore, the main enzymes present in Viscozyme L and Celluclast 1.5L were identified using different substrates, each targeted for a specific enzyme and activity. Characterisation of the enzyme mixtures revealed a large number of enzymes required for apple pomace degradation and these included cellulases, pectinases, xylanases, arabinases and mannanases in different proportions. Viscozyme L contained mainly pectinases and hemicellulases, while Celluclast 1.5L displayed largely cellulase and xylanase activity, hence the high degree of synergy reported. The temperature optimum was 50ºC for both enzyme mixtures and pH optima were observed at pH 5.0 and pH 3.0 for Viscozyme L and Celluclast 1.5L, respectively. At 37ºC and pH 5.0, the enzymes retained more that 90% activity after 15 days of incubation, allowing the enzymes to be used together with less energy input. The enzymes were further characterised by determining the effect of various compounds, such as alcohols, sugars, phenolic compounds and metal ions at various concentrations on the activity of the enzymes during apple pomace hydrolysis. Apart from lignin, which had almost no effect on enzyme activity, all the compounds caused inhibition of the enzymes to varying degrees. The most inhibitory compounds were some organic acids and metal ions, as well as cellobiose and xylobiose. Using the best ratio for Viscozyme L and Celluclast 1.5L (50:50) for the hydrolysis of apple pomace, it was observed that synergy was highest at the initial stages of hydrolysis and decreased over time, though the sugar concentration increased. The type of synergy for optimal apple pomace hydrolysis was found to be simultaneous. There was no synergy observed between Viscozyme L and Celluclast 1.5L with ligninases - laccase, lignin peroxidase and manganese peroxidase. Hydrolysing apple pomace with ligninases prior to addition of Viscozyme L and Celluclast 1.5L did not improve degradation of the substrate. Immobilisation of the enzyme mixtures on different supports was performed with the aim of increasing stability and enabling reuse of the enzymes. Immobilisation methods were selected based on the chemical properties of the supports, availability, cost and applicability on heterogeneous and insoluble substrate like apple pomace. These methods included crosslinked enzyme aggregates (CLEAs), immobilisation on various supports such as nylon mesh, nylon beads, sodium alginate beads, chitin and silica gel beads. The immobilisation strategies were unsuccessful, mainly due to the low percentage of immobilisation of the enzyme on the matrix and loss of activity of the immobilised enzyme. Free enzymes were therefore used for the remainder of the study. Hydrolysis conditions for apple pomace degradation were optimised using different temperatures and buffer systems in 1 L volumes mixed with compressed air. Hydrolysis at room temperature, using an unbuffered system, gave a better performance as compared to a buffered system. Reactors operated in batch mode performed better (4.2 g/L (75% yield) glucose and 16.8 g/L (75%) reducing sugar) than fed-batch reactors (3.2 g/L (66%) glucose and 14.6 g/L (72.7% yield) reducing sugar) over 100 h using Viscozyme L and Celluclast 1.5L. Supplementation of β- glucosidase activity in Viscozyme L and Celluclast 1.5L with Novozyme 188 resulted in a doubling of the amount of glucose released. The main products released from apple pomace hydrolysis were galacturonic acid, glucose and arabinose and low amounts of galactose and xylose. These products are potential raw materials for biofuel and biorefinery chemical production. An artificial neural network (ANN) model was successfully developed and used for predicting the optimum conditions for apple pomace hydrolysis using Celluclast 1.5L, Viscozyme L and Novozyme 188. Four main conditions that affect apple pomace hydrolysis were selected, namely temperature, initial pH, enzyme loading and substrate loading, which were taken as inputs. The glucose and reducing sugars released as a result of each treatment and their combinations were taken as outputs for 1–100 h. An ANN with 20, 20 and 6 neurons in the first, second and third hidden layers, respectively, was constructed. The performance and predictive ability of the ANN was good, with a R² of 0.99 and a small mean square error (MSE). New data was successfully predicted and simulated. Optimal hydrolysis conditions predicted by ANN for apple pomace hydrolysis were at 30% substrate (wet w/v) and an enzyme loading of 0.5 mg/g and 0.2 mg/mL of substrate for glucose and reducing sugar, respectively, giving sugar concentrations of 6.5 mg/mL and 28.9 mg/mL for glucose and reducing sugar, respectively. ANN showed that enzyme and substrate loadings were the most important factors for the hydrolysis of apple pomace.
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Damen, Bas Stefaan, and bsdamen@hotmail com. "Design, Development, and Optimisation of a Culture Vessel System for Tissue Engineering Applications." Swinburne University of Technology. n/a, 2003. http://adt.lib.swin.edu.au./public/adt-VSWT20040512.125051.
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A Tissue Engineering (TE) approach to heart valve replacement has the aim of producing an implant that is identical to healthy tissue in morphology, function and immune recognition. The aim is to harvest tissue from a patient, establish cells in culture from this tissue and then use these cells to grow a new tissue in a desired shape for the implant. The scaffold material that supports the growth of cells into a desired shape may be composed of a biodegradable polymer that degrades over time, so that the final engineered implant is composed entirely of living tissue. The approach used at Swinburne University was to induce the desired mechanical and functional properties of tissue and is to be developed in an environment subjected to flow stresses that mimicked the haemodynamic forces that natural tissue experiences. The full attainment of natural biomechanical and morphological properties of a TE structure has not as yet been demonstrated.
In this thesis a review of Tissue Engineering of Heart Valves (TEHVs) is presented followed by an assessment of biocompatible materials currently used for TEHVs. The thrust of the work was the design and development of a Bioreactor (BR) system, capable of simulating the corresponding haemodynamic forces in vitro so that long-term cultivation of TEHVs and/or other structures can be mimicked. A full description of the developed BR and the verification of its functionality under various physiological conditions using Laser Doppler Anemometry (LDA) are given. An analysis of the fluid flow and shear stress forces in and around a heart valve scaffold is also provided.
Finally, preliminary results related to a fabricated aortic TEHV-scaffold and the developed cell culture systems are presented and discussed. Attempts to establish viable cell lines from ovine cardiac tissue are also reported.
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Gawande, Nitin. "MODELING MICROBIOLOGICAL AND CHEMICAL PROCESSES IN MUNICIPAL SOLID WASTE BIOREACTOR: DEVELOPMENT AND APPLICATIONS OF A THREE-PHA." Doctoral diss., University of Central Florida, 2009. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3803.
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The numerical computer models that simulate municipal solid waste (MSW) bioreactor landfills have mainly two components--a biodegradation process module and a multi-phase flow module. The biodegradation model describes the chemical and microbiological processes of solid waste biodegradation. The models available to date include predefined solid waste biodegradation reactions and participating species. In a bioreactor landfill several processes, such as anaerobic and aerobic biodegradation, nitrogen and sulfate cycling, precipitation and dissolution of metals, and adsorption and gasification of various anthropogenic organic compounds, occur simultaneously. These processes may involve reactions of several species and the available biochemical models for solid waste biodegradation do not provide users with the flexibility to selectively simulate these processes. This research work includes the development of a generalized biochemical process model, BIOKEMOD-3P, which can accommodate a large number of species and process reactions. This model is able to simulate bioreactor landfill processes in a completely mixed condition; when coupled with a multi-phase model it will be able to simulate a full-scale bioreactor landfill. This generalized biochemical model can simulate laboratory and pilot-scale operations which are important to determine biochemical parameters important for simulation of full-scale operations. To illustrate application of BIOKEMOD-3P, two sets of laboratory MSW bioreactors were simulated in this research work. The first demonstrated simulation of data from anaerobic biodegradation of MSW in experimental bioreactors. In another application, simultaneous nitrification and denitrification processes in MSW bioreactors were simulated. The results from these simulations generated information about various modeling parameters that would help implement these processes in a full-scale bioreactor landfill operation.Ph.D.
Department of Civil and Environmental Engineering
Engineering and Computer Science
Environmental Engineering PhD
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Lenz, Jennifer. "Structuration d’électrode contrôlée pour des applications (bio)électrochimiques." Thesis, Bordeaux 1, 2011. http://www.theses.fr/2011BOR14305/document.
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Ce mémoire a été préparé dans le cadre du projet européen ERUDESP. Il décrit en détail les études qui ont été réalisées dans ce travail. Un bioréacteur sous forme d’une cellule bioélectrochimique à flux a été développé dans le but de servir pour la bioélectrosynthèse enantiopure. Le mémoire est consacré au design de cellules, screenings de différents médiateurs, au test de différentes réactions électroorganiques et électroenzymatiques à la fois dans une cellule électrochimique classique et dans une cellule électrochimique à flux. Un thème central de ce mémoire représente la synthèse d’électrodes macroporeuses tri-dimensionnelles. Grâce à cela, la surface active de l’électrode est augmentée de manière significative. Pour la préparation de ces électrodes une approche de template a été suivie. Des particules de polystyrène monodisperses ont été synthétisées de différentes manières et sont utilisées pour la synthèse des cristaux colloïdaux qui constituent les templates. Comme procédure de préparation contrôlée de ces templates, la technique de Langmuir-Blodgett et la méthode d’évaporation contrôlée, suivi par l’électrodéposition des métaux et des oxydes métalliques sont appliquées. Les diamètres des pores des matériaux macroporeux résultants sont parfaitement contrôlables par le diamètre des particules utilisées. La méthode de Langmuir-Blodgett a été étendue et appliquée pour la première fois à l’utilisation de particules de polystyrène. Le dépôt est réalisé dans les interstices des cristaux colloïdaux préparés préalablement, suivi par la dissolution des particules. De plus, des électrodes poreuses avec une grande surface de 6 x 6 cm2 ont été préparées. Les matériaux obtenus montrent une très bonne interconnéctivité avec une porosité ouverte et une surface active fortement augmentée ce qui se traduit électrochimiquement en une augmentation significative de la puissance du signal. Les matériaux poreux représentent un bénéfice non-seulement pour la (bio)électrosynthèse mais aussi dans le cadre de la (bio)électroanalyse. Dans ce mémoire, d’électrodes poreuses d’oxyde de ruthénium pour l’oxydation direct de NADH avec une surtension significativement améliorée ont été élaborée. La méthode de l’agrandissement de la surface est également appliquée et une meilleure densité de courant a été obtenue. Basé sur le projet ERUDESP, les méthodes apprises pour créer des électrodes poreuses à base de cristaux colloïdales ont dans la suite aussi été appliquées à d’autres domaines d’investigation. L’évolution méthodique de la technique de Langmuir-Blodgett a été utilisée pour le développement d’un système d’électrode renouvelable. Dans ce système, la surface peut être renouvelée sur commande par application d’un potentiel fixe (effet click).Les électrodes de l’oxyde de ruthénium ont non seulement été étudié dans le cadre du projet ERUDESP, mais la miniaturisation de ce matériau poreux et stable sous forme de microélectrodes a permis d’étudier une application comme capteur pH chimiquement et mécaniquement stable avec un meilleur ratio signal sur bruit. Dans ce cas le bruit thermique est diminué grâce à la porosité de l’électrode. Grâce à la technicité acquise par rapport à la synthèse des microélectrodes poreuses, des microélectrodes implantables pour les prothèses de main ont été aussi modifiées avec une couche macroporeuse pour augmenter la surface active et diminuer l’impédance de transition.Nous avons également exploré des couches multicatalyseurs macroporeuses de platine et nickel pour effectuer la génération d’hydrogène in-situ et l’hydrogénation simultanée dans un seul système catalytique.Comme dernière possibilité pour une structuration de surface contrôlée, des îlots de platine d’une étendue nanométrique furent examinées et biofonctionnalisées, ce qui résulte également en une augmentation significatif de la densité de courantThe present work has been prepared within the framework of the European project ERUDESP and describes the research that has been carried out during this work. A bioreactor as a bioelectrochemical flow-cell was designed and realized with the goal to serve for enantiopure bioelectrosynthesis. The work deals with the cell design and screening of different mediators in a batch-cell and multi-cells, the development of different electroorganic and electroenzymatic reactions in an electrochemical batch- and flow-cell. With respect to the flow-cell, the upscaling of electrochemical reactions was carried out in the present work not only for electroorganic but also for electroenzymatic reactions with regard to the final application. A main focus of the present work represents the synthesis of three-dimensional macroporous electrodes in order to increase significantly the active surface. These macroporous structures were obtained by using the template approach. For the preparation of the templates monodisperse polystyrene particles were synthesized in different ways, and then used for the preparation of colloidal crystals serving as templates. As controlled assembly procedures, the Langmuir-Blodgett technique and the controlled evaporation method with subsequent electrodeposition of metals and metal oxides were chosen. With the present process the pore diameter could be exactly controlled by the diameter of the used particles. The approach of the Langmuir-Blodgett technique has been extended and optimized. For the first time, the Langmuir-Blodgett technique could be used with polystyrene particles. The deposition took place in the interspaces of the prepared colloidal crystals and is followed by the dissolving of the particles. Furthermore, the size of the porous electrodes could be upscaled (6 x 6 cm2). The obtained materials showed a very good interconnectivity with an open porosity and a highly increased active surface, which led to an increased electrochemical signal. The prepared porous materials represent a great benefit not only for (bio)electrosynthesis but also in the field of (bio)electroanalysis. In the framework of this work, the use of porous ruthenium oxide electrodes for direct oxidation of NADH with a significantly improved overvoltage was studied. Also in this context the increase of the surface led to an improved current density. Based on the ERUDESP project, the studied techniques for preparing porous electrodes with colloidal crystals were used for further scientific studies. The new variant of the Langmuir-Blodgett technique has also been used for the elaboration of a renewable electrode system where the surface can be simply renewed by applying a positive potential to the porous multilayers (click effect). The porous ruthenium oxide electrodes have not only been studied with respect to the ERUDESP project, but it was also possible to miniaturize this stable porous material as microelectrodes and use them as chemically and mechanically stable pH sensor with an improved signal to noise ratio. In this case the thermal noise decreased due to the porosity of the electrode. Due to the acquired expertise in the field of the preparation of porous microelectrodes, implantable microelectrodes for hand prosthesis were modified with a porous layer on the surface for increasing the active surface and decreasing their impedance.In addition, macroporous multicatalyst layers of platinum and nickel were synthesized for the simultaneous in-situ generation of hydrogen and hydrogenation reaction in the same catalyst system.As a final example for controlled surface structuring, nanoscale platinum islands were in detail examined and biofunctionalized. This led also to a significant increase of the current density
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Halvarsson, Björn. "Interaction Analysis in Multivariable Control Systems : Applications to Bioreactors for Nitrogen Removal." Doctoral thesis, Uppsala universitet, Avdelningen för systemteknik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-122294.
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Many control systems of practical importance are multivariable. In such systems, each manipulated variable (input signal) may affect several controlled variables (output signals) causing interaction between the input/output loops. For this reason, control of multivariable systems is typically much more difficult compared to the single-input single-output case. It is therefore of great importance to quantify the degree of interaction so that proper input/output pairings that minimize the impact of the interaction can be formed. For this, dedicated interaction measures can be used. The first part of this thesis treats interaction measures. The commonly used Relative Gain Array (RGA) is compared with the Gramian-based interaction measures the Hankel Interaction Index Array (HIIA) and the Participation Matrix (PM) which consider controllability and observability to quantify the impact each input signal has on each output signal. A similar measure based on the
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Fotticchia, Andrea. "Design and development of anisotropic laminate scaffolds of electrospun polycaprolactone for annulus fibrosus tissue engineering applications." Thesis, Loughborough University, 2016. https://dspace.lboro.ac.uk/2134/21407.
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In several cases, current therapies available to treat a large number of musculoskeletal system diseases are unsatisfactory as they provide only temporary or partial restoration of the damaged or degenerated site. In an attempt to maintain a high standard of life quality and minimise the economic losses due to the treatments of these frequently occurring ailments and subsequent lost working days, alternative therapies are being explored. Contrary to the current treatments, tissue engineering aims to regenerate the impaired tissue rather than repair and alleviate the symptoms; thus offering a definitive solution. The annulus fibrosus (AF) of the intervertebral disc (IVD) is a musculoskeletal system component frequently subjected to degeneration and rupture, characterised by predominance of anisotropically arranged collagen fibres. In the present thesis, electrospinning technology is used to fabricate polycaprolactone (PCL) scaffolds intended to replicate the anisotropic structure of the AF.
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Miller, Richard Allen. "Computer simulation of continuous fermentation of glucose to ethanol with the use of an expert system for parameter calculations and applications for bioreactor control." Thesis, Virginia Tech, 1987. http://hdl.handle.net/10919/41545.
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Louis, Fiona. "Régulation de l'ostéo / adipogénèse par le Strontium pour des applications spatiales : implication des RhoGTPases." Thesis, Saint-Etienne, 2014. http://www.theses.fr/2014STET005T/document.
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En impesanteur réelle ou simulée, l'absence de gravité oriente les cellules souches multipotentes de la moelle osseuse à privilégier l’adipogénèse aux dépens de l’ostéogénèse. Ceci entraine une perte osseuse fréquemment rencontrée chez les astronautes lors des vols spatiaux. Parmi les traitements médicamenteux existants, le strontium possède une double action, à la fois activatrice de l'ostéogénèse et inhibitrice de l’adipogénèse. Dans ce contexte, l’objectif général de ce projet de thèse a été de démontrer que le strontium peut être un bon candidat pour contrecarrer les effets de l'impesanteur. Nous nous sommes particulièrement intéressés aux petites protéines Rho de la famille des GTPases, qui contrôlent le cytosquelette de la cellule, sa tension cellulaire ainsi que de nombreuses voies de signalisation. D'après la littérature, ces signalisations ont aussi été montrées comme étant liées aux voies du VEGF ou au statut oxydant des cellules, impliquées dans l’engagement des cellules souches multipotentes. La première partie de cette étude a permis de montrer l’effet antioxydant du strontium sur la lignée C3H10T1/2 en tant qu’activateur de la GTPase RhoA, permettant l’induction du gène clé de la réponse antioxydante, Nrf2, et par conséquent l’inhibition de l’adipogénèse. La deuxième partie a utilisé comme modèle des cultures 3D sur microbilles de polystyrène recouvertes de collagène pour la culture d'adipocytes, avec l'ajout de minéraux d’apatite pour la culture d'ostéoblastes. Ces billes ont été mises en culture dans un bioréacteur simulant l’impesanteur (Rotating Wall Vessel, RWV, NASA). Sous strontium, cette culture en RWV a favorisé l’ostéogenèse et limité l’adipogénèse, validant l'utilisation du strontium en tant que répresseur des effets délétères de l'impesanteur sur l’os. Nous avons montré que cet effet peut être expliqué d'une part par la stimulation des activités des deux GTPases RhoA et Rac1, et d'autre part par l’induction de l’isoforme matricielle du VEGF chez les ostéoblastes. En revanche, chez les adipocytes, les deux formes solubles et matricielles du VEGF étaient inhibées. De plus, le strontium a induit l'expression du récepteur Flt-1 qui favoriserait l’ostéogénèse. L’ensemble de ces données nous a permis de mieux comprendre les cinétiques de RhoA et Rac1 pendant l’ostéoblastogénèse et l’adipogénèse, ainsi que le rôle important des voies de signalisation du VEGF et du statut oxydant dans l’orientation de la différenciation des cellules multipotentes. Le strontium s’est révélé être un bon inducteur ostéogénique dont les applications fondamentales peuvent amener de nouvelles voies d’utilisationIn real or simulated microgravity, the absence of gravity directs multipotent stem cells from bone marrow to favor adipogenesis at the expense of osteogenesis. This causes a bone loss, commonly found in astronauts during spaceflight. Among existing drug therapies, strontium has a double action, both activating osteogenesis and inhibiting adipogenesis. In this context, the general objective of this project was to demonstrate that strontium may be a good candidate to counteract the microgravity effects. We were particularly interested in small proteins Rho of the GTPases family, which control cell cytoskeleton, cell tension and many signaling pathways. According to the literature, these pathways were also shown to be related to the VEGF singaling or the cell oxidative status, involved in the multipotent stem cells commitment. The first part of this study demonstrated the strontium antioxidant effect on the C3H10T1/2 line as an activator of the GTPase RhoA, allowing the induction of the key antioxidant response gene, Nrf2, and therefore inhibiting adipogenesis. The second part used a 3D cultures model on polystyrene microbeads coated with collagen for the adipocytes culture, and with mineral apatite added for osteoblasts culture. These beads were cultivated in a bioreactor simulating microgravity (Rotating Wall Vessel, RWV, NASA). With strontium, this RWV culture promoted osteogenesis and limited adipogenesis, validating the use of strontium as a repressor of the microgravity deleterious effects on bone. We have shown that this effect can be explained first by the stimulation of both GTPases RhoA and Rac1 activities, and secondly by the induction of the matrix-bound VEGF isoform in osteoblasts. In contrast, in adipocytes, both soluble and matrix-bound VEGF isoforms were inhibited. Moreover, strontium induced Flt-1 receptor expression, which would promote osteogenesis. All these data allowed us to better understand the RhoA and Rac1 kinetics during osteoblastogenesis and adipogenesis, and the important role of VEGF signaling pathways and oxidative status in directing multipotent cells differentiation. Strontium was found to be a good osteogenic inductor whose core applications can bring new ways of use
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Bhadra, Sharmistha. "Electrode-based wireless passive pH sensors with applications to bioprocess and food spoilage monitoring." IEEE, 2011. http://hdl.handle.net/1993/30366.
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This thesis purposes and develops inductively coupled LC (inductive-capacitive) pH sensors based on pH-sensitive electrode pair. The LC resonator circuit is based on a varactor and measures the low frequency potential difference. For wireless pH monitoring, the resonator circuit is integrated with a pH-sensitive electrode pair. This sensor demonstrates a linear response over 2 to 12 pH dynamic range, 0.1 pH accuracy and long-term stability. Accurate measurement of pH using electrode-based sensors is affected by temperature variation. A technique of simultaneously measuring two parameters, pH and temperature, with a single RLC resonator based sensor is presented. An algorithm is developed, which applies both pH and temperature measurement to incorporate temperature compensation in pH measurement. For in-fluid applications, an encapsulation method is applied to the LC resonator based sensor to reduce the influence of medium permittivity and conductivity on the sensor measurement. Non-invasive way to obtain reliable pH information from bacterial culture bioprocesses is demonstrated with the fluid embeddable sensor. The pH sensor is remodeled to an acidic and basic volatile sensor by embedding the electrodes in a hydrogel host electrolyte. Tests demonstrate that the volatile sensor has a detection limit of 1.5 ppm and 2 ppm for ammonia and acetic acid vapor, respectively. Application of the volatile sensor to fish spoilage monitoring shows that the sensor is capable of detecting the product rejection level with good sensitivity in real-time. It is important to develop low cost wireless passive pH sensor technologies for embedded applications such as bioprocess and food spoilage monitoring. The electrode-based passive LC sensor approach employed in this thesis overcomes drawbacks of some of the early developed passive pH sensors and can lead to an inexpensive implementation using printed electronics technology.
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Porter, Blaise Damian. "Development and application of a 3-D perfusion bioreactor cell culture system for bone tissue engineering." Diss., Available online, Georgia Institute of Technology, 2005, 2005. http://etd.gatech.edu/theses/available/etd-11222005-174526/.
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Thesis (Ph. D.)--Mechanical Engineering, Georgia Institute of Technology, 2006.Wick, Tim, Committee Member ; Neitzel, Paul, Committee Member ; Fyhrie, David, Committee Member ; Garcia, Andres, Committee Member ; Guldberg, Robert, Committee Chair. Vita.
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Lant, Paul Andrew. "Adaptive Inferential Estimation : application to an industrial bioreactor." Thesis, University of Newcastle Upon Tyne, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239732.
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Lucarini, Adriana Celia. "Hidrólise contínua de sacarose em um reator enzimático com membrana." Universidade de São Paulo, 2003. http://www.teses.usp.br/teses/disponiveis/9/9134/tde-09012015-161450/.
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Reatores enzimáticos com membrana (REM) combinam muitas das características desejáveis em um bioprocesso, tais como: reator de elevada produtividade, reprodutibilidade no tempo, fácil controle e automação, operação em regime contínuo, eficiente separação de biocatalisador, substratos e produtos, com a viabilidade do uso de enzimas sem necessidade de imobilização. Este estudo faz parte do desenvolvimento e otimização de um bioprocesso que utiliza um reator enzimático com membrana com a enzima invertase, que catalisa a hidrólise da sacarose produzindo uma mistura equimolar de glicose e frutose. Estudou-se a influência de algumas variáveis operacionais e de reação no comportamento do REM. Este reator consiste de um tanque agitado de 50 mL onde células de Saccharomyces cerevisiae, contendo a invertase, ficam retidas por meio de uma membrana (Øporo 0,45µm), disposta na parte inferior do sistema. A configuração deste é semelhante a um reator contínuo tipo tanque agitado (CSTR). Inicialmente, avaliou-se a influência das variáveis: concentração de sacarose e concentração de enzima, por meio de experimentos seriais, que possibilitaram fixar estas variáveis em níveis adequados, de 500 mM e 1 mg/mL, respectivamente, para a continuidade dos ensaios por meio de planejamentos experimentais fatoriais. Foi utilizado um planejamento experimental (23 + estrela) e a análise de superfície de resposta para avaliar a influência das variáveis: vazão de alimentação do substrato, temperatura e pH. Para a análise estatística dos resultados, utilizaram-se como respostas o grau de conversão da sacarose e a produtividade em frutose, determinadas em amostragens feitas durante o tempo de operação do reator, em média de 8 a 9 horas por condição avaliada. Dos resultados obtidos, mostraram-se significativos, com 95% de confiança, os efeitos lineares e quadráticos da vazão e temperatura. As condições ótimas encontradas foram: vazão de alimentação entre 0,4 e 1,0 mL/min e temperatura 51°C. O grau de conversão obtido foi de aproximadamente 95%, com as seguintes condições experimentais: concentração da suspensão de células de 1mg/mL, temperatura de 51°C, pH 5,5; concentrações de sacarose de 500 mM e vazão de alimentação de 1,0 mL/min. Para esta condição obteve-se uma produtividade da ordem de 0,6 mmol frutose/h.mg invertase. Os desvios entre os valores previstos pelo modelo estatístico e pelo modelo experimental foram da ordem de 3%. Em função dos resultados obtidos neste trabalho concluiu-se que esta concepção de reator é eficiente para a bioconversão da sacarose e, portanto, o processo contínuo com reator com membrana é promissor para o desenvolvimento de processos enzimáticos desta natureza.Enzymatic membrane reactors combine several desirable characteristics in a bioprocess, such as high productivity, reproducibility, easy control and automation, continuous operation, efficient separation of biocatalyst, substrate and products, and the use of enzymes without immobilization. This work is part of the development and optimization of a bioprocess using an enzymatic reactor which utilizes a membrane reactor for the enzymatic hydrolysis of sucrose in a solution of fructose and glucose, containing the enzyme invertase. The influence of some operational and reaction variables on the performance of the membrane reactor was studied. The bioreactor consisted of a 50 mL-stirred tank where intact cells of Saccharomyces cerevisiae, containing invertase in the cell wall, are retained inside the reactor by a microfiltration membrane (Øpore 0.45µm). The flat sheet membrane is fixed at the bottom of the device. The reactor configuration is similar to a continuous stirred tank reactor (CSTR). Initially, the influence of sucrose and enzyme concentration was evaluated through a series of experiments in order to determine the suitable levels of these variables. Sucrose was set to 500 mM and enzyme set to 1 mg/mL. This allowed the work to continue by means of experimental factorial designs. It was utilized a 23 full experimental design followed by a 2nd order statistical design and, the surface response methodology in order to evaluate the influence of volume feeding rate of the substrate, temperature and pH on fructose productivity and sucrose conversion. The values were obtained during the reactor operation. The average operation time was trom 8 to 9 hours for all evaluated conditions. From the statistical analysis, it was concluded that the linear and quadratic effects of temperature and flow rate on the results were the most significant with 95% of confidence. The optimum conditions found for this bioprocess were volume feeding rate between 0.4 and 1.0 mL/min and temperature of 51°C. The degree of conversion of sucrose obtained experimentally was 95%, in the following experimental conditions: cell concentration of 1mg/mL, temperature of 51°C, pH 5.5; sucrose concentration of 500 mM and feeding rate of 1.0 mL/min. For this operational condition it was obtained a productivity of about 0.6 mmol fructose/h.mg invertase. The deviation between the predicted values by the statistical model and the experimental data was 3%. Based on the results obtained in this work, it can be concluded that this conception of bioreactor is efficient for the bioconversion of sucrose and, a continuous membrane reactor process is very promising for the development of this kind of enzymatic process.
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Ivanovic, Igor. "Application of biofilm membrane bioreactor (BF-MBR) for municipal wastewater treatment." Doctoral thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for vann- og miljøteknikk, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-13395.
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The biofilm membrane reactor (BF-MBR) is a wastewater treatment system that combines biological wastewater treatment with a biofilm process and with membrane separation for clarification and purification of biologically treated wastewater. Work in this thesis is experimentally based on laboratory pilot scale systems specially built, developed and modified for the research purposes in this thesis. The work in this thesis is presented through six main themes (research chapters (RC)): RC1: Overview of previous research on knowledge on particle separation in a movingbed-biofilm reactor (MBBR) process RC2: Overview of previous research on membrane bioreactors (MBR) based on attached (biofilm) growth. RC3: Results from empirical studies on the influence of aeration on membrane performances in the BF-MBR RC4: Results from mathematical and empirical studies on influence of membrane reactor design on membrane performances in the BF-MBR RC5: Results from empirical studies on influence of nitrogen removal on membrane performances in the BF-MBR RC6: Results from empirical studies on influence of coagulation and flocculation on overall performances in the BF-MBR The main contributions (C) are: C1: An overview of the research literature on empirical studies of knowledge on MBR with biofilm implementations and separation techniques in the movingbed-biofilm reactor C2: Proposing a method for defining optimum aeration rates for the membrane unit based on minimizing the amount of submicron particles. C3: Improvement in membrane performances by changing the membrane reactor geometry. C4: Demonstration of feasibility of sustainable operation of proposed system with biological nitrogen removal treatment configurations. C5: Improvement of membrane and overall process performance with addition of different additives. Results from the research work in this thesis are based on five main empirical studies using a pilot scale biofilm MBR (BF-MBR) setup where overall system performance and membrane performance has been studied. The thesis is structured as a paper collection based on seven papers, where the first two are review papers and other five are results of the original research. In addition, there are three publications based on original research from the study that were published during the early stages of the project studies, presented only with the references and abstracts as secondary papers.En biofilm membran reaktor (BF-MBR) er et rensesystem for avlopsvann som kombinerer biologisk rensing ved bruk av en biofilm prosess, og med membranseparasjon for filtrering og rensing av det biologisk renset avlopsvannet. Denne avhandlingen er basert pa eksperimentelle arbeider med pilot enheter og laboratoriesystemer som er spesielt bygd, utviklet og modifisert for forskningsformalene i dette studiet. Arbeidet i denne avhandlingen er presentert gjennom seks hovedtema (forskning kapitler (FK)): FK1: Oversikt over tidligere forskning og kunnskap om partikkelseparasjon i en moving-bed-biofilm reaktor (MBBR) prosess FK 2: Oversikt over tidligere forskning pa membran bioreaktorer (MBR) basert pa vekst av fastsittende biomasse (biofilm). FK 3: Resultater fra empiriske studier om hvordan lufting pavirker membranens prosessegenskaper i en BF-MBR FK 4: Resultater fra matematiske og empiriske studier om hvordan membranreaktor design pavirker membranens separasjonsegenskaper i en BF-MBR FK 5: Resultater fra empiriske studier om hvordan membranprosessen pavirkes av nitrogenfjerning i en BF-MBR FK 6: Resultater fra empiriske studier om hvordan koagulering og flokkulering pavirker den generelle prosessen i en BF-MBR De viktigste bidragene (B) er: B1: En oversikt over forskningslitteratur om empiriske studier og kunnskap om MBR med anvendelse av biofilm prosesser og separasjon teknikker brukt i en movingbed-biofilm reaktor B2: Foreslag pa en metode for a definere optimal lufting for membranenheten basert pa a minimere mengden av sub-mikron partikler. B3: Forbedring i membranens ytelsesevne ved a endre pa membranreaktorens geometri. B4: Demonstrasjon av mulighetene for en barekraftig drift av foreslatte system med konfigurasjoner av biologisk nitrogenfjerning. B5: Forbedring av bade membran og generelle prosessytelser ved bruk av forskjellige tilsetningsstoffer. Resultater fra forskningsarbeidet i denne avhandlingen er basert pa fem empiriske studier utfort med en pilot biofilm MBR (BF-MBR) apparatur, der generelle systemytelse og membranytelse er studert. Avhandlingen er strukturert som en samling av syv publikasjoner, der de to forste er ”review” artikler og folgende fem artikler er resultatene fra original forskningen. I tillegg er tre publikasjoner basert pa original forskning fra studiet som ble publisert i en tidlig fase av arbeidet presentert som sekundare artikler, kun angitt med referanser og sammendrag.
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Machado, Araujo Sonia Maria. "The application of model-based observer control to bioreactors." Thesis, University of Surrey, 1998. http://epubs.surrey.ac.uk/770/.
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Liu, Wenjun. "High strength industrial wastewater treatment using membrane bioreactors : a novel extractive membrane bioreactor for treating bio-refractory organic pollutants in the presence of high concentrations of inorganics: application to acidic effluents." Thesis, University of Bath, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369997.
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Lafforgue, Christine. "Fermentation alcoolique en bioreacteur a membranes." Toulouse, INSA, 1988. http://www.theses.fr/1988ISAT0024.
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Etude de la fermentation alcoolique continue couplee a la micropropagation tangentielle. La modelisation du procede permet de realiser des simulations previsionnelles et d'estimer le dimensionnement d'une installation pour une production determinee. L'application de cette technique a l'elaboration de boissons fermentees est envisagee
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De, Jager Debbie. "Membrane bioreactor application within the South African textile industry: pilot to full-scale." Thesis, Cape Peninsula University of Technology, 2013. http://hdl.handle.net/20.500.11838/926.
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Thesis submitted in the requirements for the degree
Doctor Technologiae: Chemical Engineering
in the Faculty of
Engineering
at the
CAPE PENINSULA UNIVERSITY OF TECHNOLOGY, 2013To date, limited information has been published on textile wastewater treatment, for re-use, in South Africa (SA), with treatment processes focusing on conventional wastewater treatment methods. A large contributor to the contamination of water within textile industries is from dyehouse processes. A major concern in textile wastewater treatment is the release of azo dyes and their metabolites, some of which are carcinogenic and mutanogenic, into the environment since they are xenobiotic and aerobically recalcitrant to biodegradation. A necessity therefore exists to find an effective treatment method capable of removing both the strong colour and the toxic organic compounds from textile wastewater. Membrane bioreactors (MBRs) are favoured when treating high-strength wastewater, since the membrane area is determined by the hydraulic throughput and not the biological load; no sludge is wasted and all bacteria are retained within the reactor, including specific bacteria capable of degrading the toxic, non-biodegradable constituents present in textile wastewater. MBR systems, using various configurations have been utilised extensively in the rest of the world to treat textile wastewater at both lab and pilot-scale. This DTech project formed part of a collaborative Water Research Commission (WRC) funded project K5/1900 - Pilot application of a dual-stage membrane bioreactor (dsMBR) for industrial wastewater treatment. The main purpose of this study was the on-site evaluation of a pilot-scale dsMBR incorporating two ultrafiltration (UF) sidestream membrane modules for the treatment, recovery and re-use of textile wastewater. The objectives of this project were to determine the treatment efficiency of the system; to evaluate the degree of colour removal from the textile wastewater; to improve residual colour removal within the system using treatment processes, such as NF and RO, as well as to propose a design and cost for a full-scale plant. A textile industry located in Bellville, Western Cape, was chosen as the industrial partner for the on-site evaluation of a semi-automated pilot wastewater treatment MBR plant using two 5.1 m2 Norit X-flow AirliftTM membrane modules. Since the wastewater treatment system was located on the premises, real continuously changing industrial wastewater was being treated. The industrial textile wastewater was treated in a series of tanks: 1) an anaerobic tank, which cleaved the azo bonds of the reactive dyes; 2) an anoxic tank containing reduced amounts of dissolved oxygen, in which denitrification occurred; and 3) an aerobic tank, in which i) nitrification, as well as ii) mineralisation of the aromatic amines occurred. The UF-membrane modules would account for the removal of any organic material. The wastewater stream was characterised by a chemical oxygen demand (COD) range of between 45 to 2,820 mg/L and an average biological oxygen demand (BOD) of 192.5 mg/L. The dsMBR achieved an average COD reduction of 75% with a maximum of 97% over the 220 day test period. The COD concentration obtained after dsMBR treatment averaged at 191 mg/L, which was well within the City of Cape Town industrial wastewater discharge standard. The average reduction in turbidity and TSS was 94% and 19.6%, respectively, during the UF-MBR stage of the system. Subsequent treatment of the UF permeate with nanofiltration (NF) for 4 days, alternated with reverse osmosis (RO) for 14 days removed both the residual colour and salt present in the UF permeate. A consistent reduction in the colour of the incoming wastewater was evident. The colour in the wastewater was reduced from an average of 659 ADMI units to ~12 ADMI units in the NF permeate, a lower American dye manufacturing index (ADMI) (i.e. method of colour representation) compared to the potable water (~17 ADMI units) utilised by the industrial partner in their dyeing processes. The colour was reduced from an average of 659 to ~20 ADMI units in the RO permeate, a lower ADMI and therefore colour when compared to the potable water. An average conductivity rejection of 91% was achieved with conductivity being reduced from an average of 7,700 to 693 μS/cm and the TDS reduced from an average of 5,700 to 473 mg/L, which facilitated an average TDS rejection of 92%. Based on the composition of the UF permeate fed to the RO membrane a maximum removal of 98.7% was achieved for both conductivity and total dissolved solids (TDS). The proposed full-scale plant would incorporate a UF-MBR system, followed by NF, RO, flocculation and a filter press. Therefore, the two waste products produced during operation of the proposed full-scale plant, would be the solid filter cakes and the liquid filtrate from the filter press. Implementing the proposed full-scale plant it would cost the industrial partner an operating cost of ZAR 113.85 and ZAR 3,415.49 to treat 97.1 m3 and 2,913 m3 of textile wastewater, respectively, per day and per month. This results in an annual saving of ZAR 845,848 on potable water expenses. This research, would provide SA textile industries, with an option to: 1) reduce their water consumption, thereby utilising less of a valuable decreasing commodity; 2) meet the SA government discharge standards and reduce their discharge costs; 3) reduce their carbon footprint (i.e. reduce their impact on the environment) by re-using their treated wastewater and therefore using less water from the municipality; and 4) decrease their annual expenditure on water, since the treated wastewater would be available for re-use.
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Jain, Pradeep. "Moisture addition at bioreactor landfills using vertical wells mathematical modeling and field application /." [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0010860.
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Zhang, Hu. "Application of computational fluid dynamics to micro-titre plate scale bioreactors." Thesis, University College London (University of London), 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.406632.
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Zhang, Hu. "Application of computational fluid dynamics to micro-titre plates scale bioreactors." Thesis, University College London (University of London), 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.405560.
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Picó, Marco Enrique. "Nonlinear robust control of biotechnological processes. Application to fed-batch bioreactors." Doctoral thesis, Universitat Politècnica de València, 2008. http://hdl.handle.net/10251/2901.
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La tesis está centrada en los biorreactores en "fed-batch", dada la importancia de estos reactores agitados de alta densidad para la producción industrial eficiente de proteinas, encimas,.... utilizando microorganismos modificados genéticamente. El problema real está caracterizado por la escasez de medidas en línea. Otros problemas importantes son la (fuerte) incertidumbre paramétrica y la presencia significativa de no linealidades. Además de los problemas comentados, en el caso de biorreactores en ``fed-batch'' es necesario tratar con equilibrios parciales, es decir, sólo respecto a una parte de las variables. Los objetivos principales de la tesis son:
- La búsqueda de un conjunto limitado de estructuras de modelos representando la mayor parte de los casos de interés industrial.
- La solución, como primer paso en una aproximación de ``abajo-arriba'', del problema de control para el caso de cultivos puros con un sólo substrato limitante y asumiendo el oxígeno está en exceso.
- El diseño de controladores para regular la tasa específica de crecimiento de los microorganismos. Utilizando solamente medidas en línea de biomasa y volumen, sin ninguna estimación de la tasa de crecimiento ni de ninguna otra variable. Y, finalmente, teniendo en cuenta las no linealidades del sistema, la incertidumbre y otros fenómenos.
- Tratar el problema citado anteriormente de estabilidad parcial.
El último punto ha marcado la elección de las posibles técnicas a estudiar para resolver el problema de control. En concreto:
- Técnicas de control geométrico(Fradkov et al.). El problema de control de biorreactores puede ser visto como uno de "control de coordinación". La solución está relacionada con algunas propiedades específicas de los
sistemas como la invarianza y la atractividad local de conjuntos no triviales en el espacio de estados.
- Flatness. Aunque comunmente asociada con la linealización exacta, un sistema puede ser plano dentro de un subconjunto del espacio de estados sin ......Picó Marco, E. (2004). Nonlinear robust control of biotechnological processes. Application to fed-batch bioreactors [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/2901
Palancia
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Seagle, Christopher M. Macdonald Jeffrey M. "Metabolomics footprinting of three dimensional bioreactors with applications to in-cell NMR." Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2007. http://dc.lib.unc.edu/u?/etd,1262.
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Thesis (Ph. D.)--University of North Carolina at Chapel Hill, 2007.Title from electronic title page (viewed Mar. 26, 2008). "... in partial fulfillment of the requirements for the degree of Doctorate in the department of Biomedical Engineering." Discipline: Biomedical Engineering; Department/School: Medicine.
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Cao, Keping. "Simultaneous Removal of Carbon and Nitrogen by Using a Single Bioreactor for Land Limited Application." Thesis, Water Resources Research Center, University of Hawaii at Manoa, 1998. http://hdl.handle.net/10125/22230.
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An Entrapped-Mixed-Microbial-Cell (EMMC) process was investigated for its simultaneous removal of carbon and nitrogen in a single bioreactor with the influent COD/N ratio varying from 4 to 15 and influent alkalinity of 140 mg CaCO3/L and 230 mg CaCO3/L. The reactor was operated with alternate schedules of intermittent aeration. Two different sizes of carriers (10 * 10 * 10 mm3 and 20 * 20 * 20 mm3) were studied.
The medium carrier (10 * 10 * 10 mm3) system presents higher nitrogen removal and COD removal compared to the large carrier system. The nitrogen removal efficiency is related to the ratio of COD/N in the influent. With the increase of the COD/N ration in the influent, the nitrogen removal efficiency is increased.
The average reductions of nitrogen were over 92% and the average reductions of SCOD and BOD5 are over 95% and 97%, respectively, in the medium carrier system. This is operated at the HRT of 12 hours and 0.5 hour aeration and 2 hours of non-aeration, and the COD/N ratio of 15 in the influent. Changing alkalinity from 140 to 230 mg CaCO3/L has no effect in both large and medium carriers for the nitrogen removal efficiency.
The pH, oxidation – reduction potential (ORP) and dissolved oxygen (DO) were used to monitor the biological nitrogen removal. It was found that the ORP (range from -100 to 300 mV) can be used to provide better effluent quality measured as total-nitrogen of less than 10 mg/L. Also, the impact of influent COD/N ratio on the effluent quality (measured as Inorg.-nitrogen) for the EMMC process is very important.
Compared to other two compact biological wastewater treatment processes, membrane bioreactor (MBR) and moving bed biofilm reactor (MBBR), the EMMC process with the intermittent aeration has higher removal efficiencies of carbon and nitrogen, easier operation, lower O&M cost, lower energy requirement, and more compact. The total cost requirement is less than $3.27 per 1000 gallons (3.785 m 3) of treated settled domestic sewage per day. It is apparent that the EMMC process is technically feasible for the simultaneous removal of carbon and nitrogen under the operation on a schedule of intermittent aeration and suitable to be used for replacement or upgrading of existing treatment plant at land limited area.
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MacNeil, Susan Lynne. "Bioremediation f C1 and C2 chlorinated aliphatic hydrocarbon contaminated groundwater : application of membrane bioreactor technology." Thesis, McGill University, 1997. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=27240.
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An extensive literature survey concerning C$ sb1$ and C$ sb2$ chlorinated aliphatic hydrocarbon (CAH) biodegradation is presented and membrane bioreactor (MBR) technology is exercised towards PCE bioremediation. A 108-day run was conducted utilizing a pilot-scale 20 L MBR comprising a methanol-fed mixed-methanogenic culture operating at a constant 1-day HRT and 36-day SRT. The MBR exhibited long-term (four months) PCE degradation activity at biomass concentrations of 0.61 to 1.45 g protein/L and contaminant loadings of 100 to 400 $ mu$mol PCE/L. The bacteria showed quick acclimation and improved PCE degradation with long-term PCE exposure. The maximum specific TCE formation rates were 50 to 80 $ mu$mol TCE produced/g protein day. In spite of a rapid permeate flux decline at the beginning of the run, the flux stabilized at a satisfactory level. A number suggestions to further enhance CAH biodegradation and issues concerning membrane fouling are described.
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Ewart, D. Keith. "Studies on a moderately thermophilic mixed culture of bacteria and its application to the biooxidation of gold-bearing minerals." Thesis, King's College London (University of London), 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389882.
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ZEIN, MAHER M. "MTBE BIODEGRADATION IN AN INNOVATIVE BIOMASS CONCENTRATOR REACTOR: THE EVOLUTION FROM LABORATORY TO FIELD APPLICATION." University of Cincinnati / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1140534772.
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Deladisma, Marnico David. "Accuracy and Enhancement of the Lattice Boltzmann Method for Application to a Cell-Polymer Bioreactor System." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/10546.
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Articular cartilage has a limited ability to heal due to its avascular, aneural, and alymphatic nature. Currently, there is a need for alternative therapies for diseases that affect articular cartilage such as osteoarthritis. Recently, it has been shown that tissue constructs, which resemble cartilage in structure and function, can be cultured in vitro in a cell-polymer bioreactor system. Bioreactors provide a three dimensional environment that promotes cell proliferation and matrix production. The primary objective of this study is to accurately simulate fluid mechanics using the lattice Boltzmann method for application to a cell-polymer bioreactor system.
Lattice Boltzmann (LB) is a flexible computation technique that will allow for the simulation of a moving construct under various bioreactor conditions. The method predicts macroscopic hydrodynamics by considering virtual particle interactions. Derived from the Lattice Gas Automata, lattice Boltzmann allows for mass transfer, complex geometries, and particle dynamics. A primary goal is to characterize the accuracy of the LB implementation and eventually the shear stresses felt by a tissue construct in this dynamic environment. This information is important since recent studies show that chondrocytic function may depend on the mechanical stimuli produced by fluid flow. Hence, shear stress may affect the final mechanical properties of tissue constructs. In this study, numerical simulations are done first in 2D and then extended to 3D to test the LB implementation. Simulations of the rotating wall vessel (RWV) bioreactor are then undertaken. The results are benchmarked against computations done with a commercial CFD package, FLUENT, and compared with analytic solutions and experimental data.
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Ronne, Luke John Thomas. "Design considerations and analysis of a bioreactor for application in a bio-artificial liver support system." Pretoria : [s.n.], 2006. http://upetd.up.ac.za/thesis/available/etd-04242008-093504/.
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Murakami, Yu. "Establishment of a practical gene knock-in system and its application in medaka." Kyoto University, 2020. http://hdl.handle.net/2433/253339.
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Kyoto University (京都大学)0048
新制・課程博士
博士(農学)
甲第22503号
農博第2407号
新制||農||1077(附属図書館)
学位論文||R2||N5283(農学部図書室)
京都大学大学院農学研究科応用生物科学専攻
(主査)教授 佐藤 健司, 教授 澤山 茂樹, 准教授 豊原 治彦
学位規則第4条第1項該当
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MacNeil, Susan Lynne. "Bioremediation of C¦1 and C¦2 chlorinated aliphatic hydrocarbon contaminated groundwater, application of membrane bioreactor technology." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ29613.pdf.
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Regestein, Lars [Verfasser]. "Design and application of calorimeters for monitoring biological processes in stirred tank bioreactors / Lars Regestein." Aachen : Hochschulbibliothek der Rheinisch-Westfälischen Technischen Hochschule Aachen, 2013. http://d-nb.info/1031109536/34.
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Ishola, Mofoluwake M. "Novel application of membrane bioreactors in lignocellulosic ethanol production : simultaneous saccharification, filtration and fermentation (SSFF)." Doctoral thesis, Högskolan i Borås, Institutionen Ingenjörshögskolan, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-3705.
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Biofuels production and utilisation can reduce the emission of greenhouse gases, dependence on fossil fuels and also improve energy security. Ethanol is the most important biofuel in the transportation sector; however, its production from lignocelluloses faces some challenges. Conventionally, lignocellulosic hydrolysis and fermentation has mostly been performed by separate hydrolysis and fermentation (SHF) or simultaneous saccharification and fermentation (SSF). SHF results in product inhibition during enzymatic hydrolysis and increased contamination risk. During SSF, suboptimal conditions are used and the fermenting organism cannot be reused. Bacterial contamination is another major concern in ethanol production, which usually results in low ethanol yield. In these studies, the above-mentioned challenges have been addressed. A novel method for lignocellulosic ethanol production ‘Simultaneous saccharification filtration and fermentation (SSFF)’ was developed. It circumvents the disadvantages of SSF and SHF; specifically, it uses a membrane for filtration and allows both the hydrolysis and fermentation to be carried out at different optimum conditions. SSFF also offers the possibility of cell reuse for several cultivations. The method was initially applied to pretreated spruce, with a flocculating strain of yeast Saccharomyces cerevisiae. SSFF was further developed and applied to pretreated wheat straw, a xylose rich lignocellulosic material, using encapsulated xylose fermenting strain of S. cerevisiae. High solids loading of 12% suspended solids (SS) was used to combat bacterial contamination and improve ethanol yield. Oil palm empty fruit bunch (OPEFB) was pretreated with fungal and phosphoric acid in order to improve its ethanol yield. An evaluation of biofuel production in Nigeria was also carried out. SSFF resulted in ethanol yield of 85% of the theoretical yield from pretreated spruce with the flocculating strain. Combination of SSFF with encapsulated xylose fermenting strain facilitated simultaneous glucose and xylose utilisation when applied to pretreated wheat straw; this resulted in complete glucose consumption and 80% xylose utilisation and consequently, 90% ethanol yield of the theoretical level. High solids loading of 12% SS of pretreated birch resulted in 47.2 g/L ethanol concentration and kept bacterial infection under control; only 2.9 g/L of lactic acid was produced at the end of fermentation, which lasted for 160 h while high lactic acid concentrations of 42.6 g/L and 35.5 g/L were produced from 10% SS and 8% SS, respectively. Phosphoric acid pretreatment as well as combination of fungal and phosphoric pretreatment improved the ethanol yield of raw OPEFB from 15% to 89% and 63% of the theoretical value, respectively. In conclusion, these studies show that SSFF can potentially replace the conventional methods of lignocellulosic ethanol production and that high solids loading can be used to suppress bacterial infections during ethanol productions, as well as that phosphoric acid pretreatment can improve ethanol yield from lignocellulosic biomass.Thesis for the degree of Doctor of Philosophy at the University of Borås to be publicly defended on 31 October 2014, 10.00 a. m. in room E310, University of Borås, Allégatan 1, Borås.
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Nguyen, Anh-Long. "Application of self-cycling fermentation to a fixed-film reactor for the treatment of brewery wastewater." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0007/MQ44230.pdf.
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Leow, Aaron S. "Analysis of an aerobic membrane bioreactor with the application of event detection software and variable operational filtration modes." University of Cincinnati / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1447070203.
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Canales, Angel. "Croissance cryptique en bioreacteur a membrane : application au traitement des eaux residuaires urbaines." Toulouse, INSA, 1991. http://www.theses.fr/1991ISAT0013.
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Les procedes classiques de traitement aerobie des eaux usees domestiques transforment la matiere organique en co2 et biomasse. S'ils utilisent le recyclage des cellules pour augmenter les cinetiques de degradation, ils sont limites par la clarification de l'effluent traite et le probleme de traitement de boues. Un procede nouveau, associant un fermenteur et un module de filtration, par procede membranaire a ete mis en uvre. Il permet de travailler a forte charge volumique, mais a faible charge massique par minimisation des boues d'un facteur 3 a 5. Cette minimisation de la production des boues resulte de l'amplification et de la maitrise des phenomenes de lyse cellulaire et de la croissance cryptique. Les cinetiques biologiques sont quantifiees grace a la caracterisation, en terme d'activite, des differentes populations dans la culture, et confrontees au concept general de maintenance. Un modele global est construit qui considere deux types de biomasse, l'une active l'autre morte, differentiees par leur activite respiratoire. Les predictions du modele sont en accord avec les resultats experimentaux. Le modele peut etre facilement transposable a la gestion du fonctionnement d'un procede d'epuration type boues activees et reste generalisable a d'autres reactions biologiques mettant en jeu des microorganismes en limitation de substrat
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Holanda, Roseanne. "A study of novel acidophilic Firmicutes and their potential applications in biohydrometallurgy." Thesis, Bangor University, 2018. https://research.bangor.ac.uk/portal/en/theses/a-study-of-novel-acidophilic-firmicutes-and-their-potential-applications-in-biohydrometallurgy(50564a50-13ed-4663-bec0-efa149957493).html.
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The application of biotechnologies in the mining sector has intensified over the last 30 years, driven by the increasing demand for metals associated with the rise in energy costs and the awareness for environmentally responsible mining practices. Acidophilic prokaryotes play an important role in biohydrometallurgy, facilitating the solubilisation and recovery of base metals from ores and waste materials. The potential of novel acidophiles of the phylum Firmicutes for applications in biohydrometallurgical processes is examined in this thesis. Eight strains of extremely acidophilic bacteria were studied and shown to belong to the proposed novel genus “Acidibacillus”. These had been isolated previously from several distinct global locations and were shown to be obligately heterotrophic bacteria with potential to carry out tasks critical to biomining such as regenerating ferric iron (by catalysing the dissimilatory oxidation of ferrous iron), generating sulfuric acid (by the oxidation of zero-valent sulfur and tetrathionate; two strains only), and removing potentially inhibitory dissolved organic carbon. These isolates also demonstrated the ability to catalyse the dissimilatory reduction of ferric iron in anaerobic conditions. Results obtained during this study provide the basis for future research to assess their potential roles in microbial consortia applied in the bio-processing of metal ores. A novel obligately anaerobic acidophilic Firmicute (strain I2511) isolated from sediment obtained from an abandoned copper mine, was characterised in terms of its phylogeny and physiology. This isolate formed a separated clade within the Firmicutes, and was considered to represent a novel candidate genus. It also displayed a unique set of physiological traits, distinct from currently validated species of acidophilic Firmicutes. The isolate was an obligate anaerobe that grew via zero-valent sulfur (ZVS) respiration, generating H2S over a wide pH range (1.8 - 5.0), and also catalysed the dissimilatory reduction of ferric iron. Strains of acidophilic sulfatereducing bacteria (aSRB), also Firmicutes, were shown to reduce ZVS at pH as low as 3. These aSRB, together with isolate I2511, populated a novel variant of a low pH sulfidogenic bioreactor. The “hybrid sulfidogenic bioreactor” (HSB) operated using both sulfate and ZVS as electron acceptors, and glycerol as electron donor. The bioreactor successfully remediated and recovered zinc from circum-neutral pH mine-impacted waters with distinct chemical composition collected from two abandoned lead/zinc mines in the U.K. The microbial consortium used in this system proved to be robust, in which the HSB generated H2S consistently under a wide pH range (2 – 7). Experiments demonstrated that H2S could also be generated abiotically in a non-inoculated low pH reactor, by the chemical reaction of ZVS and zero-valent iron to form iron sulfide, and the consequent acid dissolution of the latter. Operational costs and the advantages of biogenic and abiotic generation of H2S for recovery of transition metals from mine waters are discussed.
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Irfan, Kerem. "Carbon dioxide control in bioreactors and the application of principal component analysis to cell culture process data." Thesis, University of Newcastle upon Tyne, 2017. http://hdl.handle.net/10443/3776.
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Carbon dioxide levels can vary with bioreactor scale in mammalian cell cultures but its effects on cell culture process is poorly understood. Varied results have been presented in the literature on the effects of pCO2 on the process performance of mammalian cell cultures. If pCO2 control can be demonstrated to show that it has the potential to effect or improve cell culture performance then the control at production scale and during scale-up would be beneficial. The primary objective of the research was to examine the effect of carbon dioxide concentration (pCO2) on a monoclonal antibody (mAb) producing Chinese Hamster Ovary (CHO) cell line in order to assess if pCO2 is a critical process parameter. During the research investigations, increasing pCO2 control resulted in an associated increase in osmolality; therefore, the role of the osmolality increase was also investigated. The main process responses examined were the productivity and product quality of a cell culture process, as well as the effect of pCO2 on the cell metabolism. The effect of pCO2 control from low to high (20 to 100 mmHg) and at elevated levels (140 mmHg) was examined and compared to a baseline condition (no pCO2 control). Results indicated that both increasing pCO2 and osmolality level independently led to increased product titre. Operation at low to high pCO2 gave reduced product quality attributes, compared to the baseline. Elevated pCO2 control resulted in equivalent product quality attributes compared to the baseline. Carbon dioxide level had the greatest impact on the product quality attributes, with osmolality playing little or no role. In summary, pCO2 control level was shown to be a critical process parameter and should be considered in quality by design, small scale optimisation and scale-up studies. The current research results disagreed with a selection of the varied results reported in the literature, on the effect on pCO2/osmolality on a mammalian cell culture process. In previous studies non-optimised process controls and conditions were used, such as the use of unrepresentative reactor vessels (e.g. T-flasks). This would lead to interacting effects from other process parameters. The majority of studies of studies on the effects of pCO2/osmolality carried out were conducted over 10 years ago. Since then, advances in process monitoring and control, media formulation, cell lines, analytical techniques and large increases in product titres, have occurred. Principal component analysis (PCA) was applied, with the aim of extracting further understanding from the data set generated in the pCO2 study. PCA models demonstrated grouping of pCO2 control and osmolality levels due to differences in process variables, relating to the control of pCO2. Overall, the PCA results statistically confirmed that pCO2 control leads to operational differences in the cell culture performance.
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Trollberg, Olle. "On Real-Time Optimization using Extremum Seeking Control and Economic Model Predictive Control : With Applications to Bioreactors and Paper Machines." Doctoral thesis, KTH, Reglerteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-213022.
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Process optimization is used to improve the utility and the economic performance of industrial processes, and is as such central in most automation strategies. In this thesis, two feedback-based methods for online process optimization are considered: Extremum seeking control (ESC), a classic model-free method used for steady-state optimization which dates back to the early 1900's, and economic model predictive control (EMPC), a more recent method which utilizes a model to dynamically optimize the closed-loop process economics in real time. Part I of the thesis concerns ESC. Due to a well known result by Krsti\'c and Wang, it is known that the classic ESC-loop will possess a stable stationary solution in a neighborhood of the optimum when applied to dynamic plants. However, existence and stability of an optimal solution alone are not sufficient to guarantee that the ESC-loop will converge to the optimum; uniqueness also has to be considered. In this thesis, it is shown that the near-optimal solution is not necessarily unique, not even in cases where the objective, i.e., the steady-state input-output map, is convex. The stationary solutions to the loop are shown to be characterized by a condition on the local plant phase-lag, and for a biochemical reactor it is found that this condition can be satisfied not only locally at the optimum but also at arbitrary points away from the optimum. Bifurcation theory is used to show that the observed solution multiplicity may be explained by existence of fold bifurcation points, and conditions for existence of such points are given. The phase-lag condition for stationarity combined with the result by Krsti\'c and Wang suggest that the process phase-lag is connected to steady-state optimality. In this thesis, it is shown that the steady-state optimum corresponds to a bifurcation of the plant zero dynamics which is reflected in large local phase-lag variations. This explains why the classical ESC method will have a near-optimal stationary solution when applied to dynamic plants, and it also shows that a steady-state optimum may be located using only phase information. Finally, we introduce greedy ESC which is applicable to plants where the dynamics may be separated into different time-scales. By optimizing only the fast plant-dynamics, significant performance improvements may be achieved. Part II of this thesis concerns EMPC. The method is first evaluated for optimization of a paper-making process by means of simulations. These reveal several important properties of EMPC, e.g., that EMPC in the presence of excessive degrees of freedom automatically selects the inputs which are currently most efficient, and that EMPC effectively plans ahead which leads to significantly improved performance during grade changes. However, it is also observed that EMPC often operates with constraints active since economic objectives frequently are monotone, and this may lead to issues with robustness. To avoid active constraints, constraint margins are introduced to force the closed-loop to operate in the interior of the feasible set. The margins affect the economic performance significantly and the optimal choice is dependent on the uncertainty present in the problem. To avoid modeling of the uncertainty, it is suggested that the margins are adapted based on feedback from the realized closed-loop economic performance.QC 20180829
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Bhola, Sumita. "Effects of solute polarization on the hydrodynamics within membrane-fluid-solute systems, with special application to hollow fiber bioreactors." Thesis, University of Ottawa (Canada), 1994. http://hdl.handle.net/10393/6716.
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The primary objective of this study was to assess the influence of osmotically active macromolecules on the hydrodynamics of hollow fiber membrane systems which, in turn, influences solute distributions within these bioreactors. This included verifying the phenomenon of concentration polarization of bovine serum albumin (BSA) in a rectilinear flow cell designed to incorporate the salient features of the hollow fiber bioreactor. Following characterization of the membrane used in the study, experimentally determined concentration profiles of BSA were compared with those predicted from theoretical analysis. The membrane characterization revealed local variability in the permeability of the membrane: L$\rm \sb{p}/\mu$ was found to vary between 2.80 $\times$ 10$\sp{-11}$ and 8.19 $\times$ 10$\sp{-11}$ m$\sp2$s/kg. The membrane permeability did not exhibit hysteresis effects due to pressure nor were there substantial changes in the permeability as a result of membrane aging. The permeability of the membrane decreased by approximately 30% following conditioning with a solution of BSA and was successful at retaining the protein. Transient BSA polarization was observed in the extra-luminal space of the rectilinear flow cell after 12, 24 and 36 hours of operation. The theoretical concentration profiles of BSA over predicted the experimental concentration profiles when assuming a membrane permeability equal to the average of the membrane coupon measurements. Further experiments consisted of examining possible dilution of the BSA samples obtained from the flow cell as well as investigating the theoretical assumption of a one-dimensional model. Sedimentation experiments showed that settling of the protein was not responsible for diluting the BSA samples. The local variability in the membrane permeability is thought to contribute to the discrepancy between the theoretical and experimental concentration profiles, as well as transverse concentration gradients not considered by the model. (Abstract shortened by UMI.)
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Fillis, Vernon William. "Design of a packed-bed fungal bioreactor : the application of enzymes in the bioremediation of organo-pollutants present in soils and industrial effluent." Thesis, Peninsula Technikon, 2001. http://hdl.handle.net/20.500.11838/910.
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Thesis (MTech (Chemical Engineering))--Peninsula Technikon, 2001Certain fungi have been shown to excrete extracellular enzymes, including peroxidases, laccases, etc. These enzymes are useful for bioremediation of aromatic pollutants present in industrial effluents (Leukes, 1999; Navotny et aI, 1999). Leukes (1999) made recent significant development in the form of a capillary membrane gradostat (fungal) bioreactor that offers optimal conditions for the production of these enzymes in high concentrations. This system also offers the possibility for the polluted effluent to be treated directly in the bioreactor. Some operating problems relating to continuous production of the enzymes and scale-up of the capillary modules, were, however, indentified. In an attempt to solve the above-mentioned identified problems the research group at Peninsula Technikon considered a number of alternative bioreactor configurations. A pulsed packed bed bioreactor concept suggested by Moreira et at. (1997) was selected for further study. Their reactor used polyurethane pellets as the support medium for the fungal biofilm and relied upon pulsing of the oxygen supply and recycle of nutrient solution in order to control biomass accumulation. These authors reported accumulation due to the recycle of proteases that were believed to destroy the desired ligninases. We experimented with a similar concept without recycle to avoid backrnixing and thereby overcome protease accumulation. In our work, a maximum enzyme productivity of 456 Units.L1day·1 was attained. Since this was significantly greater than the maximum reported by Moreira et aI, 1997 (202 Units.L-1day-I) it appeared that the elimination of recycle had significant benefits. In addition to eliminating recycle we also used a length / diameter (L / D) ratio of 14: 1 (compared with 2.5: 1 used by Moreira et aI, 1997) in order to further reduce backrnixing. Residence time distributions were investigated to gain insight into mechanisms of dispersion in the reactor. It was found that the pulsed packed bed concept presented problems with regard to blockage by excess biomass. This led us to consider the advantages of a fluidized bed using resin beads. Accordingly, growth of fungi on resin beads in shake flasks was investigated with favorable results. An experimental program is proposed to further investigate the fluidized bed concept with a view to extending the operation time of the bioreactor. From our literature survey to date, packed bed fungal bioreactors are still the best reactor configuration for continuous production ofligninolytic enzymes. An interesting study of the application of laccases to the degradation of naphthalene and MTBE is described in an addendum to this thesis.
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Jackson, Vanessa Angela. "Investigation into the metal contamination of three rivers in the Western Cape and the subsequent application of a bioreactor system as remediation technology." Thesis, [S.l. : s.n.], 2008. http://dk.cput.ac.za/cgi/viewcontent.cgi?article=1023&context=td_cput.
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Champavert, Joffrey. "Développement d'électrodes modifiées et d'un bioréacteur électrochimique à flux continu pour une application aux biopiles microbiennes." Thesis, Montpellier, 2016. http://www.theses.fr/2016MONTT205/document.
Full textAbstract:
Les biopiles microbiennes sont des sources d’énergies renouvelables utilisant des bactéries qui convertissent une énergie chimique en électricité. Pour cela, l’anode doit collecter les électrons issus des microorganismes. La sélection d’un matériau d’anode possédant de grandes performances est d’une importance cruciale dans la construction d’une biopile microbienne. Le graphène est considéré comme un matériau prometteur avec de grandes possibilités d’application dans de nombreux domaines tels que les batteries Li-ion, les cellules photovoltaïques et les super condensateurs électrochimiques en raison de sa structure nanométrique. Ainsi, la modification de surface par de l’oxyde de graphène réduit a été appliquée à la construction d’anodes pour biopiles microbiennes. La cathode abiotique a aussi été étudiée puisqu’elle présente souvent une limitation cinétique vis-à-vis de la réduction de l’oxygène. Les potentialités des complexes organométalliques, et en particulier les phthalocyanines de nickel, ont été étudiés et appliquées à la construction d’une cathode pour biopile. Ainsi, une biopile hybride à deux compartiments a été construite en combinant une bioanode en mousse d’acier inoxydable modifiée par de l’oxyde de graphène réduite et une cathode en feutre de carbone modifiée avec de la phthalocyanine de nickel. La biopile microbienne ainsi construite utilise du lixiviat de terreau, comme source de microorganismes, pour le développement d’un biofilm électroactif à l’anode et présente une bonne stabilité dans le temps. Le graphène a permis d’obtenir une densité de puissance stable pendant une période 40 jours (24.8 mW/m² en présence d’oxygène pur). La cathode présentée dans ce travail a permis d’obtenir une densité de puissance supérieure à une cathode de platine (7.5 fois supérieur). Par ailleurs, un nouveau design de biopile à deux compartiments a été construit, afin de produire de l’électricité à partir d’une souche pure : Pseudomonas aeruginosa qui est connu pour la formation de biofilm électroactive. Un nouveau design a été proposé, permettant de travailler à alimentation constante et non plus en batch comme cela se fait de manière classique. Cette configuration permet de ne plus avoir de diminution de courant liée à un manque d’apport en carburant. Différents paramètres ont ainsi été explorés tel que le débit d’alimentation, la consommation en glucose dans le compartiment anodique, la variation de pH au cours du temps ainsi que l’évolution de la biomasse. Une première approche d’étude de corrélation de ces différents paramètres est proposéeMicrobial fuel cell (MFC) has been considered as a renewable energy source which uses bacteria to convert chemical energy into electricity. Since the anode, as the electron acceptor for the electroactive bacteria, directly interacts with microorganisms, the selection of high performance anode materials is of crucial importance in the design of a MFC. Recently, graphene has been considered as the intriguing material, attracting strong scientific and technological interest with great application potentials in various fields, such as lithium ion batteries, solar cells and electrochemical super-capacitors, for its unique nanostructure and extraordinary properties. Therefore, surface modification using reduced graphene oxide has been investigated for the construction of anodes. An abiotic cathode has also been investigated since it often has a kinetic limitation regarding the oxygen reduction reaction. The potential of the use of organometallics complexes, and more particularly nickel phthalocyanines (poly-NiTSPc), has been studied and applied to the fabrication of cathodes for biofuel cells applications. Thereby, a dual chamber hybrid MFC has been constructed combining a reduced graphene oxide modified bioanode with a chemical poly-NiTSPc modified carbon felt. This MFC uses compost garden leachate, as source of microorganisms, for the growth of an electroactive biofilm onto the anode and presents an excellent lifetime. Indeed, graphene allowed to obtain a power density stable for 40 fays (24.8 mW/m² with pure oxygen). When the modified carbon felt was used as cathode, the power densities obtained were 7.5 higher than the use of platinum cathode. Furthermore, a new design of a dual chamber MFC has been built up in order to work with a constant flow, to supply continuously substrates to the biofilm formed onto the anode from a pure strain, Pseudomonas aeruginosa, and to avoid to work in a batch as it is usually done. The interest of this configuration is to prevent any current loss due to a lack in supply of substrates. Using this bioreactor as a MFC, different parameters have been explored such as the feed rate and the glucose consumption in the anodic compartment, the evolution of the pH as well as the biomass between the entrance and the exit of the chamber. A first study of the correlation between all these parameters has been proposed