This document discusses plant cell culture production in bioreactors. It describes various bioreactor types including mechanically agitated, bubble column, and airlift bioreactors. Mechanically agitated bioreactors employ impellers but can cause high shear stress on plant cells. Bubble column and airlift bioreactors have no moving parts, providing mixing through rising gas and liquid circulation with less shear stress, but have lower oxygen transfer rates than mechanically agitated bioreactors. The document compares these bioreactor types for oxygen transfer ability and low shear on plant cells.
this presentation cover the topics of cell biotechnology and plant tissue culture. the basic terms used in plant cell culture are used and then different types of culture media and methods are discussed including cell suspension and callus culture,
Mass multiplication procedure for tissue culture and PTC requirementDr. Deepak Sharma
This presentation include basic Micropropagation protocol: Application and advantages of mass multiplication. Beside this the requirement of tissue culture are there (Nutrient, gelling agent, energy source, vitamins and PGRs) are also included.
this presentation cover the topics of cell biotechnology and plant tissue culture. the basic terms used in plant cell culture are used and then different types of culture media and methods are discussed including cell suspension and callus culture,
Mass multiplication procedure for tissue culture and PTC requirementDr. Deepak Sharma
This presentation include basic Micropropagation protocol: Application and advantages of mass multiplication. Beside this the requirement of tissue culture are there (Nutrient, gelling agent, energy source, vitamins and PGRs) are also included.
It gives the general knowledge about plant tissue culture. As this topic is an important aspects of plant biotechnology, it will remind a brief idea about why it is necessary.
A growth medium or culture medium is a liquid or gel designated to support the growth of microorganisms,cells,or small plants.
Culture media generally comprise an appropriate sourcde of energy and compounds which regulate the cell cycle.
A typical culture media is composed of a complement of amino acids,vitamins,inorganic salts,glucose, and serum as a source of growth factors, hormones, and attachment factors.
In addition to nutrients, the medium also helps maintain pH and osmolarity.
Imporatant amino acids, trace elements, growth factor,hormone,transport protein and adhesion factor are added.
Adhesion factor added are main components of intercellular substance such as fibronectin,collagen and laminin.
Primary purpose of introducing SFM is to promote the specific growth of a particular type of cell.
Exapmple of one serum free media: DCMM-1 SFM. High protein serum free medium, designed for hybridoma cell growth and monoclonal antibody production.
Richard's aventures in two entangled wonderlandsRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
It gives the general knowledge about plant tissue culture. As this topic is an important aspects of plant biotechnology, it will remind a brief idea about why it is necessary.
A growth medium or culture medium is a liquid or gel designated to support the growth of microorganisms,cells,or small plants.
Culture media generally comprise an appropriate sourcde of energy and compounds which regulate the cell cycle.
A typical culture media is composed of a complement of amino acids,vitamins,inorganic salts,glucose, and serum as a source of growth factors, hormones, and attachment factors.
In addition to nutrients, the medium also helps maintain pH and osmolarity.
Imporatant amino acids, trace elements, growth factor,hormone,transport protein and adhesion factor are added.
Adhesion factor added are main components of intercellular substance such as fibronectin,collagen and laminin.
Primary purpose of introducing SFM is to promote the specific growth of a particular type of cell.
Exapmple of one serum free media: DCMM-1 SFM. High protein serum free medium, designed for hybridoma cell growth and monoclonal antibody production.
Richard's aventures in two entangled wonderlandsRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
What is greenhouse gasses and how many gasses are there to affect the Earth.moosaasad1975
What are greenhouse gasses how they affect the earth and its environment what is the future of the environment and earth how the weather and the climate effects.
The ability to recreate computational results with minimal effort and actionable metrics provides a solid foundation for scientific research and software development. When people can replicate an analysis at the touch of a button using open-source software, open data, and methods to assess and compare proposals, it significantly eases verification of results, engagement with a diverse range of contributors, and progress. However, we have yet to fully achieve this; there are still many sociotechnical frictions.
Inspired by David Donoho's vision, this talk aims to revisit the three crucial pillars of frictionless reproducibility (data sharing, code sharing, and competitive challenges) with the perspective of deep software variability.
Our observation is that multiple layers — hardware, operating systems, third-party libraries, software versions, input data, compile-time options, and parameters — are subject to variability that exacerbates frictions but is also essential for achieving robust, generalizable results and fostering innovation. I will first review the literature, providing evidence of how the complex variability interactions across these layers affect qualitative and quantitative software properties, thereby complicating the reproduction and replication of scientific studies in various fields.
I will then present some software engineering and AI techniques that can support the strategic exploration of variability spaces. These include the use of abstractions and models (e.g., feature models), sampling strategies (e.g., uniform, random), cost-effective measurements (e.g., incremental build of software configurations), and dimensionality reduction methods (e.g., transfer learning, feature selection, software debloating).
I will finally argue that deep variability is both the problem and solution of frictionless reproducibility, calling the software science community to develop new methods and tools to manage variability and foster reproducibility in software systems.
Exposé invité Journées Nationales du GDR GPL 2024
Toxic effects of heavy metals : Lead and Arsenicsanjana502982
Heavy metals are naturally occuring metallic chemical elements that have relatively high density, and are toxic at even low concentrations. All toxic metals are termed as heavy metals irrespective of their atomic mass and density, eg. arsenic, lead, mercury, cadmium, thallium, chromium, etc.
Slide 1: Title Slide
Extrachromosomal Inheritance
Slide 2: Introduction to Extrachromosomal Inheritance
Definition: Extrachromosomal inheritance refers to the transmission of genetic material that is not found within the nucleus.
Key Components: Involves genes located in mitochondria, chloroplasts, and plasmids.
Slide 3: Mitochondrial Inheritance
Mitochondria: Organelles responsible for energy production.
Mitochondrial DNA (mtDNA): Circular DNA molecule found in mitochondria.
Inheritance Pattern: Maternally inherited, meaning it is passed from mothers to all their offspring.
Diseases: Examples include Leber’s hereditary optic neuropathy (LHON) and mitochondrial myopathy.
Slide 4: Chloroplast Inheritance
Chloroplasts: Organelles responsible for photosynthesis in plants.
Chloroplast DNA (cpDNA): Circular DNA molecule found in chloroplasts.
Inheritance Pattern: Often maternally inherited in most plants, but can vary in some species.
Examples: Variegation in plants, where leaf color patterns are determined by chloroplast DNA.
Slide 5: Plasmid Inheritance
Plasmids: Small, circular DNA molecules found in bacteria and some eukaryotes.
Features: Can carry antibiotic resistance genes and can be transferred between cells through processes like conjugation.
Significance: Important in biotechnology for gene cloning and genetic engineering.
Slide 6: Mechanisms of Extrachromosomal Inheritance
Non-Mendelian Patterns: Do not follow Mendel’s laws of inheritance.
Cytoplasmic Segregation: During cell division, organelles like mitochondria and chloroplasts are randomly distributed to daughter cells.
Heteroplasmy: Presence of more than one type of organellar genome within a cell, leading to variation in expression.
Slide 7: Examples of Extrachromosomal Inheritance
Four O’clock Plant (Mirabilis jalapa): Shows variegated leaves due to different cpDNA in leaf cells.
Petite Mutants in Yeast: Result from mutations in mitochondrial DNA affecting respiration.
Slide 8: Importance of Extrachromosomal Inheritance
Evolution: Provides insight into the evolution of eukaryotic cells.
Medicine: Understanding mitochondrial inheritance helps in diagnosing and treating mitochondrial diseases.
Agriculture: Chloroplast inheritance can be used in plant breeding and genetic modification.
Slide 9: Recent Research and Advances
Gene Editing: Techniques like CRISPR-Cas9 are being used to edit mitochondrial and chloroplast DNA.
Therapies: Development of mitochondrial replacement therapy (MRT) for preventing mitochondrial diseases.
Slide 10: Conclusion
Summary: Extrachromosomal inheritance involves the transmission of genetic material outside the nucleus and plays a crucial role in genetics, medicine, and biotechnology.
Future Directions: Continued research and technological advancements hold promise for new treatments and applications.
Slide 11: Questions and Discussion
Invite Audience: Open the floor for any questions or further discussion on the topic.
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
Spectroscopy is a branch of science dealing the study of interaction of electromagnetic radiation with matter.
Ultraviolet-visible spectroscopy refers to absorption spectroscopy or reflect spectroscopy in the UV-VIS spectral region.
Ultraviolet-visible spectroscopy is an analytical method that can measure the amount of light received by the analyte.
DERIVATION OF MODIFIED BERNOULLI EQUATION WITH VISCOUS EFFECTS AND TERMINAL V...Wasswaderrick3
In this book, we use conservation of energy techniques on a fluid element to derive the Modified Bernoulli equation of flow with viscous or friction effects. We derive the general equation of flow/ velocity and then from this we derive the Pouiselle flow equation, the transition flow equation and the turbulent flow equation. In the situations where there are no viscous effects , the equation reduces to the Bernoulli equation. From experimental results, we are able to include other terms in the Bernoulli equation. We also look at cases where pressure gradients exist. We use the Modified Bernoulli equation to derive equations of flow rate for pipes of different cross sectional areas connected together. We also extend our techniques of energy conservation to a sphere falling in a viscous medium under the effect of gravity. We demonstrate Stokes equation of terminal velocity and turbulent flow equation. We look at a way of calculating the time taken for a body to fall in a viscous medium. We also look at the general equation of terminal velocity.
Nutraceutical market, scope and growth: Herbal drug technologyLokesh Patil
As consumer awareness of health and wellness rises, the nutraceutical market—which includes goods like functional meals, drinks, and dietary supplements that provide health advantages beyond basic nutrition—is growing significantly. As healthcare expenses rise, the population ages, and people want natural and preventative health solutions more and more, this industry is increasing quickly. Further driving market expansion are product formulation innovations and the use of cutting-edge technology for customized nutrition. With its worldwide reach, the nutraceutical industry is expected to keep growing and provide significant chances for research and investment in a number of categories, including vitamins, minerals, probiotics, and herbal supplements.
This presentation explores a brief idea about the structural and functional attributes of nucleotides, the structure and function of genetic materials along with the impact of UV rays and pH upon them.
9. Shikonin
Dye
Medicine – to treat fungal, bacterial or viral infections
Produced via continuous-flow reactor
cells retained by membrane / periodic harvesting
4000 L system
Ginseng
Health food
20 000 L system
Sanguinarine
• Produced from Papaver somniferum
• Dental care – treatment for gum disease (gingivitis)
10. Eukaryotes
Prokaryotes do not have nucleus, no internal
organs
Animal cell – do not have chloroplasts, may or
may not have cilia, no cell wall
Plant cell – have LARGE vacuoles, cell wall,
chloroplast, lack of lysosomes, centrioles,
pseudopods and flagella and cillia.
12. 1. The Quest for Commercial Production of Biochemicals
from Plant Cell Culture.
1.1 WHY PLANT? WHY PLANT CELL CULTURE?
Aphrodisiac
Anxiety
Malaria
Cancer
Fever
Parasitic infection
Testosterone increase
Ulcers
Male infertility
Analgesic
Hypertension
CUT
EXTINCT!!
Eurycoma longifolia
13. Industrial Chemical Sectors to Which Plant Products
Contribute
1) Medicinals
- 25% of prescribed drugs include compounds
from plants.
The Ten Most Prescribed Medicinals from Plant Sources
Medicinal agent Activity Plant Source
Steroids from diosgenin Anti-fertility agents Dioscorea deltoidea
Codeine Analgesic Papaver somniferum
Atropine Anticholinergic Atropa belladonna L.
Reserpine Antihypertensive Rauwolfia serpentina L.
Hycoscyamine Anticholinergic Hyoscyamus niger L.
Digoxin Cardiatonic Digitalis lanata L.
Scopolamine Anticholinergic Datura metel L.
Digitoxin Cardiovascular Digitalis purpurea L.
Pilocarpine Cholinergic Pilocarpus jabonandi
Quinidine Antimalarial Chinchona ledgeriana
from M.W.Fowler (1982)p.3 In PlantBiotech.(Mantel &Smith, ed.)
14. 2) Agrochemicals
eg: Insect repellence from Cymbopogun nardus
3) Fine Chemicals
- including perfumes, flavours, aromas, colorants and food
materials, for example quinine alkaloid (bittering agent),
chalcone (non-nutritive sweetener), Jasmine (perfume)
15. Factors that determine the in-vitro growth and
development of plant are:
◦ Nutrients
◦ Physical factors
◦ Some organic substances
16. Water
◦ Necessary constituent of all living plant cell and tissue
◦ As biochemical medium and solvent
◦ A chemical reactant or product in many metabolic
processes, including photosynthesis
◦ Responsible for cell turgor
◦ Responsible for the function of the stomata
◦ Acts as a coolant and temperature buffer
17. Macro-elements
◦ Used in large amounts
◦ Carbon, hydrogen, oxygen, nitrogen, phosphorus,
potassium
◦ Eg; deficiency of nitrogen cause stunted growth,
yellow lower leaves, spindly stalk and pale green color
◦ Deficiency of phosphorus cause purplish color in lower
leaves and stems, dead spots on leaves and fruits
◦ Secondary nutrient – calcium ,magnesium and sulfur
18. Micro-elements
◦ Required in small quantities
◦ Boron, chlorine, copper, iron, manganese, molybdenum,
zinc
Sugar
◦ Since plants or parts of plants in tissue culture condition
are not completely autotrophic carbon source is needed
19. Light
◦ Plant contain pigment chlorophyll that traps light
energy and change it to chemical energy called ATP
(adenosine triphosphate),
◦ a compound used by cells for energy storage.
◦ This chemical is made of the nucleotide adenine
bonded to a ribose sugar, and that is bonded to three
phosphate groups.
◦ The dark reaction converts CO2 to sugar and ATP
◦ Light stimulated secondary metabolite
21. Vary in their ability to tolerate
Eg: Snapdragon grow best at 12oC but Nicotiana sp at
22oC
Effects many essential plant growth processes
(biological reaction in plant)
17-25oC is normally used for induction of callus
Callus Nicotiana tabacum
22. Normally adjusted to between 5 to 6 before
autoclaving
◦ ~ pH 5.8
◦ pH control equipment if use bioreactor
Why need oxygen?
◦ Remember that they are not Autotrophic
23. Plant growth regulators (PGRs)
◦ Hormones are produced naturally by plants, while
plant growth regulators are applied to plants by
humans.
◦ PGR may be synthetic compounds (e.g., IBA and
Cycocel) that mimic naturally occurring plant
hormones, or they may be natural hormones that were
extracted from plant tissue (e.g., IAA).
◦ (PGRs are chemicals that are designed to affect plant
growth and/or development.
◦ They are applied for specific purposes to affect specific
plant responses.
24. Eg: auxin, gibberellin (GA), cytokinin, ethylene, and
abscisic acid (ABA)
Auxin - is the active ingredient in most rooting
compounds in which cuttings are dipped during
vegetative propagation
Ex: Auxin (e.g IBA): 0.01-0.5-5.0 mg/l
Cytokinin (e.g BA): 0.01-0.5-5 mg/l
Cytokinins - stimulate cell division and often are included
in the sterile media used for growing plants from tissue
culture.
If a medium's mix of growth-regulating compounds is
high in cytokinins and low in auxin, the tissue culture
explant (small plant part) will produce numerous
shoots.
25. Ethylene - found only in the gaseous form
◦ It induces ripening, causes leaves to droop (epinasty)
and drop (abscission), and promotes senescence.
◦ Plants often increase ethylene production in response
to stress, and ethylene often is found in high
concentrations within cells at the end of a plant's life
◦ The increased ethylene in leaf tissue in the fall is part
of the reason leaves fall off trees. Ethylene also is
used to ripen fruit (e.g., green bananas).
26. Abscisic acid (ABA) - induces dormancy and
prevents seeds from germinating; causes
abscission of leaves, fruits, and flowers; and
causes stomata to close
◦ Eg; High concentrations of ABA in guard cells during
periods of drought stress probably play a role in stomatal
closure.
27. The internal culture conditions
◦ media components
◦ precursors and elicitors
◦ Aeration
◦ culture pH
The external culture conditions
◦ Light
◦ Temperature
◦ Culture agitation
28. Suspension culture
Root culture
Shoot culture
Seed culture
◦ Eg: orchid seed (because during in vivo seeds do not
germinate well)
◦ Sugar is extremely important as energy source
Embryo culture
◦ Is the sterile isolation and growth of an immature or mature
embryo in vitro, with the goal of obtaining a viable plant.
29. Callus culture
◦ Culture of non-organized tumor tissue, which arise on
wounds of differentiated tissues and organs
◦ Takes place under the influence of exogenously supplied
growth regulators present in the nutrient medium. Auxin
alone or cytokinin alone or both auxin and cytokinin
30. Organ culture
◦ It is an isolated organ grown in vitro
Cell culture
◦ The growing of individual cells that have been obtained
from an explant tissue or callus or it is refer to as cell
suspension culture
Protoplast culture
◦ Culture of cells without cell wall
31. A cell suspension culture consists of cell aggregates
dispersed and growing in moving liquid media.
Initiated by transferring pieces of undifferentiated and
friable calli to a liquid medium
Platform (orbital) shakers are widely used for the
initiation and serial propagation of plant cell suspension
culture. With variable speed control (30- 150 rpm).
Agitation serves 2 purposes: 1. it exerts a mild pressure
on cell aggregates, breaking them in to smaller clumps
and single cell. 2. maintains uniform distribution of cell
and cell clumps in the medium.
Movement of the medium provides good gaseous
exchange between the culture medium and air.
Volume of the culture should be 20 ml for 100ml flask or
70 ml for 250 ml flask.
32. Batch culture
◦ A cell suspension culture grown in a fixed volume of
nutrient culture medium.
◦ Cell suspension increases in biomass by cell division and
cell growth until a factor in the culture environment
(nutrient or oxygen availability) becomes limiting and the
growth ceases.
33. The cells exhibit the following five phases of a growth
cycle
◦ 1. Lag phase, where cells prepare to divide
◦ 2. Exponential phase, where the rate of cell division is highest
◦ 3. Linear phase, where cell division slows but the rate of cells
expansion increases
◦ 4. Deceleration phase, where the rates of cell division and
elongation decreases
◦ 5. Stationary phase, where the number and size of cells remain
constant
The cell generation time (doubling time) in suspension
culture varies from 24 to 48 h in well established cell
cultures.
Doubling time (td) is the time required for the concentration of
biomass of a population of cell to double.
34. Continuous culture
◦ A culture is continuously supplied with nutrient by the
inflow of fresh medium but the culture volume is
normally constant.
◦ 2 types:
Open continuous culture
The inflow of fresh medium is balanced by outflow of corresponding
volumes of culture including harvest of cells
The rate of inflow of medium and culture harvest are adjusted so
that the cultures are maintained indefinitely at a steady state, the
rate of cells washout equals the rate of formation of new cells in the
system.
A situation of balanced growth is achieved; i.e. majority of cells in
the culture are in a similar metabolic state
The growth rate and cell density are held constant by a fixed rate of
input of growth limiting nutrients and removal of cells and
spend medium.
35. 1. Chemostates – growth rate and cell density are held
constant by a fixed rate of input of a growth limiting nutrient
medium (nitrogen, phosphorus or glucose). In such a medium,
all the constituents other than growth limiting nutrients are
present at concentrations higher than that required to maintain
the desired rate of cell growth. The growth limiting substances is
so adjusted that its increase or decrease is reflected by a
corresponding increase or decrease in the growth rate of cells.
2. Turbidostates- fresh medium flows in response to increase
in turbidity so as to maintain the culture at a fixed optical density
of suspension. A pre-selected biomass density is maintained by
the washout of cells.
36. Cells are retained and inflow of fresh medium is balanced
by outflow of corresponding volumes of spent medium only.
◦ The cells from the out-flowing medium are separated
mechanically and added back to the culture. So cell
biomass continues to increase as the growth proceeds
◦ It has potential value in studies on cytodifferentiation,
where it may be important to grow cells under a particular
regulated environment and then maintain them for a
considerable period in a non-dividing but viable state.
◦ It can also be used in cases where secondary products
produced by cell suspension cultures have been shown
to be released in significant amounts into their culture
medium. In such cases, a maintenance culture in a
closed continuous system should enable the chemical
product to be continuously harvested from a fixed culture
biomass.
37. The inflow of fresh medium is manually
controlled at infrequent intervals by a “drain and
refill” process, such that the volume of culture
removed is always replaced by an equivalent
volume of fresh medium.
Although the number of cell increases
exponentially, the cell density is maintained
within fixed limits by the periodic replacement of
harvested culture by fresh medium
38. Disadvantages
◦ Productivity decrease – genetic alteration
◦ Slow growth, have to maintain for several week
◦ Shear effect size of plant aggregate than effect
performance
◦ Separate media for growth and secondary
metabolite
Advantages
◦ Better control
◦ Able to reproduce condition in large scale
39. Gas-liquid mass transfer
◦ Plant cell have lower respiration rate-oxygen transfer
requirements are less
◦ Plant cell bioreactor typically operated at KLa (oxygen
transfer coefficient) values of 10 – 30 hr-1
◦ High KLa results in poor plant cell growth
Increase shear
CO2 stripping from the liquid
◦ Bioreactor is equipped with a dissolved oxygen probe
and KLa is characteristic of the bioreactor system
40. Shear
◦ Plant cells are shear sensitive
◦ Shear refer to forces exerted on the surface of a body
in a directional parallel to the surface
◦ Turbulent Eddy Theory
Agitation system –
impart energy into the liquid-
transfer from larger to smaller eddies-
so the power input can be related to the size of the smallest
eddies-
the greater the power added the smaller is the size of the
smallest eddies-when the size of aggregate is small relative to
the size of the smallest eddy –
41. then it is carried around with the fluid in the eddy and is
probably undamaged-
however, when the size of aggregate is larger or same size of
the smallest eddy-
then it can be caught between eddies such that the dissipation
of energy occurs at the surface of the cell.
42. Important Implication of theory
◦ Shear forces may act on aggregates such that the
aggregates size is reduced at increased turbulent
◦ Plant cell enlarge as they age, they will also become
more shear sensitive (eg secondary metabolite
produce during stationary phase, reduce productivity)
Other report suggested that cell damage may
caused by cell-cell and cell-impeller collisions,
Also by gas sparging (even in the absent of
mechanical agitation)
43. Mixing – refer to the convective transport of
matter (eg: the transfer of solute associated with
bulk fluid motion)
Problem
◦ Large size of plant cell or cell aggregate-lead to
settling at the bottom of bioreactor (then settle into
dead zone or unmixed region of the bioreactor)-dead
zone can depleted of nutrient (eg dissolved oxygen)
◦ Attachment of cells onto surface above the level of the
liquid- cell not bathed in liquid media-deprived of
nutrient
44. Mechanically Agitated Bioreactor
◦ Employ impellers and mechanical energy for gas-liquid mass
transfer and mixing
◦ Eg: flat-blade turbine impeller- provide radial fluid mixing-but plant
cell can not tolerate high-shear condition- so marine propellor has
been used (low-shear mixing)-axial fluid mixing
◦ Disadvantage- Because of shear sensitivity-agitation speeds
appropriate for plant cell cultivation are insufficient to break the
incoming gas stream into small bubbles ----
◦ Obtaining sufficient oxygen transfer require that the incorporating
gas stream be dispersed as fine bubbles by using appropriate gas
distributor.
45. Pneumatically Agitated Bioreactor
◦ Motion of the rising gas stream should capable of
providing the energy for fluid mixing
◦ Different by
No impeller
Tall and thin (high-to-diameter ratio is 10)
◦ Advantage- no moving parts
46. ◦ 2 type
Bubble column-eg (picture from text books)
Airlift
Provide for liquid circulation
Promote better top-to-bottom mixing
Baffle use to separate the two sections
Advantage in suspending cells and clumps
Disadvantage – little oxygen transfer occurs in the downcomer
section
48. Refer to how the nutrient and product streams
are supplied or removed with respect to the time
Determination of suitable operating mode need
◦ Identification of timing of product synthesis to growth
Growth-associated production
Non-growth-associated production
◦ Where does the product have been secreted
Extracellular
Intracellular
49. Type of operating mode
◦ Batch-when all the nutrients the culture requires are
supplied initially
◦ Fed Batch
◦ Repeated Fed Batch
◦ Two-stage Batch operation
◦ Continuous Cultivation – chemostat
◦ Continuous Cultivation-perfusion Operating mode