Spelling suggestions: "subject:"bioreactors"" "subject:"bioreactores""
111 |
Biochemical and mechanical stimuli for improved material properties and preservation of tissue-engineered cartilageFarooque, Tanya Mahbuba. January 2008 (has links)
Thesis (Ph.D)--Chemical Engineering, Georgia Institute of Technology, 2009. / Committee Chair: Boyan, Barbara; Committee Chair: Wick, Timothy; Committee Member: Brockbank, Kelvin; Committee Member: Nenes, Athanasios; Committee Member: Sambanis, Athanassios. Part of the SMARTech Electronic Thesis and Dissertation Collection.
|
112 |
Control and measurement of oxygen in microfluidic bioreactors : a thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy, University of Canterbury, Christchurch, New Zealand /Nock, Volker. January 1900 (has links)
Thesis (Ph. D.)--University of Canterbury, 2009. / Typescript (photocopy). "January, 2009." Includes bibliographical references (p. 213-227). Also available via the World Wide Web.
|
113 |
Production of butyric acid and hydrogen by metabolically engineered mutants of Clostridium tyrobutyricumLiu, Xiaoguang, January 2005 (has links)
Thesis (Ph. D.)--Ohio State University, 2005. / Title from first page of PDF file. Document formatted into pages; contains xv, 220 p.; also includes graphics (some col.). Includes bibliographical references (p. 189-201). Available online via OhioLINK's ETD Center
|
114 |
Produção de celulases e xilanases por Penicillium echinulatum em biorreator com agitação mecânicaReis, Laísa dos 09 December 2011 (has links)
As celulases e as xilanases são enzimas que hidrolisam a celulose e a xilana, respectivamente,
contidas nos resíduos lignocelulósicos. A possibilidade de aplicar estas enzimas na produção de
etanol vem sendo objeto de diversos estudos. No entanto, ainda não há uma tecnologia
economicamente viável para a produção deste biocombustível a partir da biomassa
lignocelulósica. Entre os microrganismos que apresentam altos títulos para estas enzimas,
incluem-se linhagens de Penicillium echinulatum; porém, ainda faltam dados de sua fisiologia e
estudos da produção de enzimas em biorreator. Neste trabalho, empregou-se a linhagem mutante
celulolítica desreprimida S1M29 de P. echinulatum e o meio de cultivo foi composto por
celulose, sacarose, solução de sais, Tween 80, farelo trigo e farelo de soja. Avaliou-se o efeito de
diferentes temperaturas e pHs na produção das enzimas. O efeito da concentração da celulose
sobre as atividades enzimáticas foi avaliada em regime descontínuo (RD) e regime descontínuo
alimentado (RDA). Verificou-se que a temperatura mais apropriada para a produção de celulases
e xilanases é de 28ºC e dentre os valores de pHs avaliados, o pH 6,0 apresentou a maior produção
das enzimas. O aumento da concentração da celulose no RD proporcionou maiores atividades
para endoglicanases, porém o mesmo não foi obtido para xilanases. Para FPA (Filter Paper
Activity), aumentos proporcionais nas atividades foram obtidos somente com concentrações de
até 3% de celulose em RD, condição que também proporcionou as maiores atividades de -
glicosidases. O RDA incrementou as atividades de FPA, endoglicanases e xilanases, mas não de
-glicosidases. Estes resultados contribuem para a otimização de processos e para a produção
econômica de enzimas por P. echinulatum, visando o desenvolvimento de tecnologias
economicamente viáveis para produção de etanol a partir de materiais lignocelulósicos. / Submitted by Marcelo Teixeira (mvteixeira@ucs.br) on 2014-06-11T13:29:22Z
No. of bitstreams: 1
Dissertacao Laisa dos Reis.pdf: 1870988 bytes, checksum: 956ace97d10d44f22cb5eba7cea275d1 (MD5) / Made available in DSpace on 2014-06-11T13:29:23Z (GMT). No. of bitstreams: 1
Dissertacao Laisa dos Reis.pdf: 1870988 bytes, checksum: 956ace97d10d44f22cb5eba7cea275d1 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Cellulases and xylanases are enzymes that hydrolyze cellulose and xylan respectively, which are
found in lignocellulosic residues. Although the applicability of these enzymes in the ethanol
production has been the subject of several studies, an economically viable technology for the
production of biofuel from lignocellulosic biomass is currently not available. Strains of
Penicillium echinulatum are among the microorganisms that have high titers of these enzymes.
However, data related to physiology and enzyme production in bioreactor for such strains are still
missing. A cellulolytic mutant strain of P. echinulatum S1M29 and a culture medium composed
of cellulose, sucrose, salt solution, Tween 80, wheat bran and soybean meal were used in this
study. The effect of different temperatures and pHs during the enzymes production was
evaluated. The effect of cellulose concentration in the enzymatic activity was evaluated in batch
cultivation (BC) and fed-batch cultivation (FBC). It was found that the appropriate temperature
for the production of cellulases and xylanases is 28°C, while the higher enzyme production
occurred at pH 6.0. The high cellulose concentration in BC provided the greatest activities for
endoglicanases, but the same result was not obtained for xylanases. For Filter Paper Activity
(FPA), proportional increases in activity were obtained only with concentrations up to 3% of
cellulose in BC, which is also linked to the highest activities for -glucosidases. FBC increased
the activities of FPA, endoglucanases and xylanases, but it did not increase the -glucosidases
activities. Such results contribute towards the optimization of enzyme production using P.
echinulatum and the development of economically viable technologies for the production of
ethanol from lignocellulosic materials.
|
115 |
Análise fluidodinâmica de biorreator destinado à produção de hidrogênio utilizando CFDMaurina, Guilherme Zanella 22 August 2014 (has links)
Devido à crescente preocupação com as questões ambientais envolvendo as emissões de gases que potencializam o efeito estufa e outros problemas associados aos combustíveis fósseis, o hidrogênio aparece como uma fonte de energia alternativa capaz de promover o desenvolvimento de forma sustentável. A produção de hidrogênio via fermentação anaeróbia é uma das rotas mais atraentes atualmente, envolvendo processos físicos, químicos e biológicos com inúmeras interações entre gases, líquidos e sólidos. No entanto, as pesquisas atuais têm dedicado especial atenção às características químicas e biológicas. Muitos reatores em escala real e de laboratório ainda são dimensionados por correlações empíricas, mas a compreensão dos fenômenos hidrodinâmicos envolvidos na produção de hidrogênio é um precursor necessário para a aplicação em projetos de escala industrial. Para otimizar o desempenho do reator, é essencial compreender a dinâmica das fases em seu interior. Neste contexto, o objetivo deste trabalho é empregar técnicas de fluidodinâmica computacional (CFD) para estudar e otimizar o comportamento fluidodinâmico de um reator anaeróbio sequencial em batelada (ASBR). Para tanto, foi adotada uma modelagem bifásica, tridimensional e turbulenta conduzida com o programa computacional OpenFOAM. Diferentes condições operacionais, configurações geométricas, bem como diferentes modelos, foram avaliados. Os resultados obtidos no estudo das forças interfaciais reforçam a importância e a necessidade de validar as simulações com dados experimentais, devido à grande variação nos resultados obtidos em cada caso simulado. Do ponto de vista das configurações geométricas e operacionais, observa-se que modificações na vazão e no sentido da recirculação, bem como alterações na geometria dos distribuidores afetam significativamente a velocidade de mistura e a energia cinética turbulenta no interior do reator. Estas modificações afetam a transferência de massa, a qual influencia diretamente na cinética das reações e possibilita uma maior produção e hidrogênio. Determinar o comportamento do reator de forma precisa é um precursor para propor alterações que melhorem a sua eficiência. / Submitted by Ana Guimarães Pereira (agpereir@ucs.br) on 2015-02-23T13:55:23Z
No. of bitstreams: 1
Dissertacao Guilherme Zanella Maurina.pdf: 2001909 bytes, checksum: f1de7c235fc3a85355a86042b3c96826 (MD5) / Made available in DSpace on 2015-02-23T13:55:23Z (GMT). No. of bitstreams: 1
Dissertacao Guilherme Zanella Maurina.pdf: 2001909 bytes, checksum: f1de7c235fc3a85355a86042b3c96826 (MD5) / PETROBRAS, Brasil / Due to the growing concern with environmental issues involving the emission of gases that enhance the greenhouse effect and other problems associated with fossil fuels, hydrogen arises as an alternative source of energy capable of promoting development on a sustainable manner. Hydrogen production via anaerobic fermentation is currently one of the most attractive routes, involving physical, chemical and biological processes with numerous interactions between gas, liquid and solid. However, current research has devoted special attention to chemical and biological characteristics. Many full-scale and laboratory-scale reactors are still dimensioned using empirical correlations, but the understanding of hydrodynamic phenomena involved in the production of hydrogen is a necessary precursor for the application in industrial scale projects. To optimize the performance of the reactor, it is critical to understand the dynamics of the phases inside. In this context, the aim of this work is to employ computational fluid dynamics (CFD) techniques to study and optimize the fluid dynamic behavior of an anaerobic sequential batch reactor (ASBR). Thus, a two-phase, threedimensional and turbulent modeling was adopted, and simulations were conducted with the computer program OpenFOAM. Different operating conditions, geometric configurations and different models were evaluated. The results obtained in the study of interfacial forces reinforce the importance and the need to validate the simulations with experimental data, due to the large variation in the results obtained in each simulated case. Concerning geometric and operational settings, it was observed that changes in flow direction and recirculation, as well as changes in the geometry of distributors, affect significantly the velocity and the turbulent kinetic energy inside the reactor. These changes affect the mass transfer, which directly influences the reaction kinetics and enables greater production of hydrogen. The accurate establishment of the reactor behavior is a precur or to propose changes in order to improve its efficiency.
|
116 |
Hidrólise enzimática de diferentes acessos de capim-elefante (Pennisetum purpureum Schum.) in natura em reator rotativo e posterior fermentação dos açúcares liberados a etanolMenegol, Daiane 28 September 2017 (has links)
Submitted by cmquadros@ucs.br (cmquadros@ucs.br) on 2018-02-16T14:24:13Z
No. of bitstreams: 1
Tese Daiane Menegol.pdf: 963846 bytes, checksum: d798670f46321405c1e8f239c00c4831 (MD5) / Made available in DSpace on 2018-02-16T14:24:13Z (GMT). No. of bitstreams: 1
Tese Daiane Menegol.pdf: 963846 bytes, checksum: d798670f46321405c1e8f239c00c4831 (MD5)
Previous issue date: 2018-02-16 / Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul, FAPERGS
|
117 |
Momentum transfer inside a single fibre capillary membrane bioreactorGodongwana, Buntu January 2007 (has links)
Thesis (MTech (Chemical Engineering))--Cape Peninsula University of Technology, 2007. / Innovation in biotechnology research has resulted in a number of fungi being identified for
diverse industrial applications. One such fungus, which is the subject of this study and has been
one of the most intensively studied, is Phanerochaete chrysosporium. Much research has been
done in developing optimized membrane bioreactor systems for the cultivation of these fungi
because of their potent industrial applications. This research, however, has been hampered by the
lack of a thorough understanding of the kinematics of flow, as well as the dynamics of the flow
through these devices. Previous analyses of momentum transfer in membrane bioreactors have
been entirely based on horizontally orientated bioreactor systems, and ignored the different
modes of operations of membrane bioreactors. These models also ignored the osmotic pressure
effects brought about by the retention of solutes on the membrane surface.
In this study, analytical and numerical solutions to the Navier-Stokes equations for the
description of pressure, velocity, and volumetric flow profiles in a single fibre capillary
membrane bioreactor (SFCMBR) were developed. These profiles were developed for the lumen
and shell sides of the SFCMBR, taking into account osmotic pressure effects, as well as gel
and/or cake formation on the lumen surface of the membrane. The analytical models developed
are applicable to horizontal and vertical systems, as well as dead-end, continuous open shell,
closed-shell, and shell side crossflow modes.
|
118 |
Membrane bioreactor production of lignin and manganese peroxidaseSolomon, MS January 2001 (has links)
Thesis (M.Tech-Chemical Engineering)--Cape Technikon, Cape Town, 2001 / The white-rot fungus (WRF), Phanerochaete chrysosporium, is a well known microorganism
which produces ligninolytic enzymes. These enzymes can play a major role in
the bioremediation of a diverse range of environmental aromatic pollutants present in
industrial effluents. Bioremediation of aromatic pollutants using ligninolytic enzymes
has been extensively researched by academic, industrial and government institutions,
and has been shown to have considerable potential for industrial applications.
Previously the production of these enzymes was done using batch cultures. However,
this resulted in low yields of enzyme production and therefore an alternative method
had to be developed. Little success on scale-up and industrialisation of conventional
bioreactor systems has been attained due to problems associated with the continuous
production of the pollutant degrading enzymes. It was proposed to construct an
effective capillary membrane bioreactor, which would provide an ideal growing
environment to continuously culture an immobilised biofilm of P; chrysosporium
(Strain BKMF-1767) for the continuous production of the ligninolytic enzymes,
Lignin(LiP) and Manganese(MnP) Peroridase. A novel membrane gradostat reactor
(MGR) was shown to be superior to more conventional systems of laboratory scale
enzyme production (Leukes et.al., 1996 and Leukes, 1999). This concept was based on
simulating the native state ofthe WRF, which has evolved on a wood-air interface and
involved irnmobilisng the fungus onto an externally skinless ultrafiltration membrane.
The MGR however, was not subjected to optimisation on a laboratory scale.
The gradostat reactor and concept was used in this work and was operated in the deadend
filtration mode. The viability of the polysulphone membrane for cultivation of the
fungus was investigated. The suitability of the membrane bioreactor for enzyme
production was evaluated. The effect of microbial growth on membrane pressure and
permeability was monitored. A possible procedure for scaling up from a single fibre
membrane bioreactor to a multi-capillary system was evaluated.
Results indicated that the polysulphone membrane was ideal for the cultivation of P
chrysosporium, as the micro-organism was successfully immobi1ised in the macrovoids
of the membrane resulting in uniform biofilm growth along the outside of the
membrane. The production of Lignin and Manganese Peroxidase was demonstrated.
The enzyme was secreted and then transported into the permeate without a rapid decline
in activity. Growth within the relatively confined macrovoids of the membrane
contributed to the loss of membrane permeability. A modified Bruining Model was
successfully applied in the prediction of pressure and permeability along the membrane
The study also evaluated the effect of potential1y important parameters on the
production of the enzymes within the membrane bioreactor. These parameters include
air flow (Ch concentration), temperature, nutrient flow, relative redox potential and
nutrient concentrations
A sensitivity analyses was performed on temperature and Ch concentration. The
bioreactor was exposed to normal room temperature and a controlled temperature at
37°C. The reactors were then exposed to different O2 concentration between 21% and
99"10. It was found that the optimum temperature fur enzymes production is 3TJC.
When oxygen was used instead of air, there was an increase in enzyme activity. From
the results obtained, it was clear that unique culture conditions are required for the
production of LiP and MnP from Phanerochaete chrysosporium. These culture
conditions are essential fur the optimisation and stability of the bioreactor.
|
119 |
Design of a packed-bed fungal bioreactor : the application of enzymes in the bioremediation of organo-pollutants present in soils and industrial effluentFillis, Vernon William January 2001 (has links)
Thesis (MTech (Chemical Engineering))--Peninsula Technikon, 2001 / Certain 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.
|
120 |
Bio-oxidation of ferrous iron at low temperature conditions in a packed bed column bioreactorsChukwuchendo, Emmanuel Chukwunonso January 2016 (has links)
Thesis (MTech (Chemical Engineering))--Cape Peninsula University of Technology, 2016. / The oxidation of microbial ferrous iron is an important sub-process in the bioleaching process. Several studies focussing on microbial ferrous iron oxidation have been investigated and reported in various studies. These studies were carried out using stirred tank bioreactors and shake flasks at optimum conditions. However, these studies could not describe the context of heap bioleach system. Packed column system may describe heap bioleaching, and most studies on microbial ferrous iron oxidation were performed under flooded conditions, which do not represent solution flow dynamics in a heap situation.
Biooxidation of ferrous iron oxidation kinetics of Acidiobacillus ferrooxidans was studied in a packed-bed bioreactor to investigate the kinetics in a system that mimics the solution flow dynamic of a heap bioleach operation at low-temperature conditions. This was done in a batch mode operation, with glass marble (15 mm) as reactor packing. The pH of the bioreactor was maintained at pH 1.35 ± 0.05 and aeration at 500 ml/min. Unstructured models known as Monod and Hansford were used to describe the experimental data in determining the kinetics of bio-oxidation.
|
Page generated in 0.0355 seconds