Transcript Plant Bioreactor Design

PLANT CULTURE
BIOREACTORS
Group Lysine
Noraini Abd. Rahman
Fan Chao Way
Nurirdayu Jantan
Nur Suhaili Mohd Yatim
Characteristic of Plant
Cell Suspension
Characteristic
Plant Cell Suspension
Size
10-200 micrometer
Individual Size
Aggregates up to 2mm
generally form
Slow, doubling time
2-5 day
High, 10%
Growth Rate
Inoculation Density
Shear Stress
Sensitivity
Aeration requirement
Sensitive and tolerant
Low
• Plant cell are often found in groups
which can alter in size during the cell
growth
• The large size, rigid cellulose based cell
wall, and large vacuole make the plant
sensitive to shear stress.
• Many of method of determining viability
in plant cell suspension depend upon the
membrane integrity measured by using
dyes such as fluorescein diacetate.
• One best method is of measuring
viability was determine weather growth
can occur after stressing.
• Plant cell suspension have very low
growth rate, with doubling of 2-6 days.
• Plant cell have a critical inoculation
density below which growth will not
occur.
• Along the slow growth rate, it have a
low oxygen requirement. (0.1-10mM)
PLANT CELL
BIOREACTOR
REQUIREMENTS
Table 11.4
Inoculation levels
• High inoculation levels required will not
affect bioreactor.
• Mean that the inoculation vessels will be
large and scale-up small.
• Owing to shear sensitivity and
aggregated nature of the cell
suspension, the connections between
vessels will have to be large and
transfer by gravity or air pressure.
Growth rate
• Low growth rate increase productivity
high biomass levels.
• At high cell densities the culture will be viscous
and difficult to mix in airlift bioreactor.
• However, for its particular nature, viscosity of
plant cell is low, and mixing in airlift BRs is not
greatly affected by biomass up to 40gl-1
• Formation of dead zones where conditions are
anoxic and cells settle out is a problem.
Temperature
• Plant cell suspensions grow normally
at 250C
• With the slow growth rate, heat
input and cooling requirements are
minimal.
Impeller
• In microbial BR, impeller is used:
-to mix the culture
-to break up and distribute air
bubble to
increase oxygen transfer. (main)
• With plant cell cultures, these roles
are reversed owing to low O2
requirements and high settling rates.
• Mixing achieved under the restraint
of shear sensitivity pf plant cells.
Impeller of Plant Cell BR
• Initially, low impeller speed(50-100rpm) is
used.
• For Panax ginseng in a 30L BR, angled disk gave
the best result compared to disk Rushton
turbine and anchor impeller (Furuya et al.)
• Coleus culture-turbine spiral most effective
compared to anchor impellers (Ulbrich et al.)
• Inclined impeller more effective than normal
Rushton turbine because it produces less shear
while still mixing well.
Type of impeller
Rushton turbine
Anchor Impeller
Spiral Impeller
Anchor and spiral impeller
• Cell –lift impeller proved to be better at
maintaining viability than flat-bladed
impeller (Treat et al.)
• Large flat-bladed impellers showed
considerable improvement than small
one. (Hooker et al.)
• For shear tolerance, low shear impellers
used at low impeller speed appear to be
overcomplicated as simple inclined
impeller run at 300 rpm or above give
adequate mixing at low enough shear.
Cell-lift impellers
Spin
Filter
with
impeller
Cell-Lift
impeller
DraftTube
Basket
Impeller
Pitched
Blade
Impeller
Marine
Blade
Impeller
• Spin Filter with impeller for suspension or
anchorage-dependent cells in perfusion.
• Patented double-screen Cell-Lift impeller for low
shear and high oxygenation maximizes yields in
microcarrier cultures. If foam accumulates it
coalesces in the screened-in foam-inhibitor
chamber at top of impeller and dissipates when
forced through the screen's pores.
• Patented low shear Draft-Tube Basket Impeller
(basket not shown) increases OTR in fibrous-bed
cultures.
• Pitched Blade Impeller for high aeration and low
shear in insect and other cell cultures.
• Marine Blade Impeller for the growth of insect
cells and other cultures
• Due to shear sensitive of the plant
cell culture, it is not suitable to use
the impellers.
• Another method that suitable for
mixing of plant culture is by using the
airlift method.
SIMPLE DESIGN
FOR PLANT
BIOREACTOR
In the early cultivation of plant cells,
stirred bioreactors were used with the
impellers run at low speed.
At 1970s, low shear airlift bioreactor
develop.
This was adopted as the bioreactor of
choice.
 However, the use of high gassing
rates to achieve good mixing can have
problems:
Plant cell suspensions sensitive to the
level of carbon dioxide.
Other essential volatiles such as
ethylene can be stripped off with
high aeration rates.
 Alternative designs to the airlift and
stirred tank bioreactor have been
used in the cultivation of plant cells
where mixing or aeration is achieved
at low shear rates.
 A bioreactor based on 2 concentric
rotating cylinders as been used to
grow Beta vulguris cells.
 Aeration is provided by inner cylinder
which was gas permeable.
 Mixing by vortices produced by
Taylor-Couette Flow.
Mixing Using Taylor-Couette Flow
 Another bioreactor is designed to
provide bubble-free aeration via
rotating coil of gas permeable
membranes.
Rotating drum Bioreactor
• Both roots and shoots can be grown
in liquid culture , and such organized
structures may be required to
stimulate the accumulation of certain
secondary product.
• These more organized and larger
structures more sensitive to shear
stress.
• Alteration in bioreactor design is
required.
Plant Bioreactor Design
Bioreactor for the cultivation of
plant organ cultures
• Suspension cultures can be induced
to undergo embryogenesis to form
small plants.
• Application of this technique at large
scale led to the consideration of
production of artificial seeds.
• Alternative design, Spin Filter
Bioreactor has been successfully
used for carrot embryogenesis
where;
Rotating filter mixed the culture
while allowing medium to be added or
removed from culture.
Spin Filter Bioreactor
Bubble Column
•
•
•
•
•
Cylindrical shape
Axial flow (Eddies)
Vertical baffle
Gas is sparged at the base
Movement of the liquid is caused by
the density differences
Internal device:
horizontal perforate
plate
Bubble Column
Schematic Diagram:
Bubble column
Airlift Bioreactor
• 2 internal zones
-riser
-downcomer
BUT only 1 zone is sparged with air
a)Draft-tube internal loop configuration
b)Split cylinder device
c)External loop system
Airlift Bioreactor
*THANKS 4 UR
ATTENTION