|
The role of the
Microbes
Immobilization Reactor in a bioprocess driven by any
form of heterogeneous bioreactor:
Packed Bed Bioreactor or
in-fluid suspended-beads
Heterogeneous Bioreactor is that of a mission-critical support.
Hence, rational analysis of the development or engineering of such
bioreactors based on the methods of pure sciences for undertaking
the immobilization need to undertaken. Although the immobilization
addressing
colony-biofilm formation is very interesting and is being
extensively studied, the entrapment immobilization method is the
object of analysis here, given that the use of entrapment
immobilization has been incorporated in the analyses of
heterogeneous
bioreactor and
multi-packed bed bioreactor,
the analysis of which therefore is expanded by the analysis of the
entrapment method of
microbes
immobilization.
Noteworthy in the analyses,
noted above, adopting the entrapment immobilization of microbes, the
method of the pure sciences by which the entrapment is accomplished
is as detailed in
Immobilized Cells
Reactor, ICR, in the study of S. Cerevisiae. Specifically, the
method entails the squirting of a solution-mixture of Sodium
Alginate and S Cerevisiae from a pipette into a solution of Calcium
Chloride. The droplets falling into the Calcium Chloride solution
then undergoes an interfacial reaction with the host solution. The
droplet surface Sodium ion of the Sodium Alginate droplet then
undergoes ion-exchange reaction with the Calcium ions of the Calcium
Chloride host solution. The reaction is fast but yet of perceptible
time span, and so worthy of reaction kinetic analysis, though one is
not conducted in the experimental studies. The Sodium Alginate
solution is of higher density and so falls down the host solution,
and continues to fall even after the surface sodium ions have been
exchanged with host solution calcium ions. Incorporating this
science into the process engineering of a Bioprocess clearly
requires a bioreactor, the Microbes Immobilization Bioreactor,
within which the Calcium ions Sodium ions exchange reaction
can optimally occur.
The engineering of the
Immobilization Bioreactor of course, requires detailed information
about the entire science, such as the rate of reaction of the ion
exchange reaction, the physicochemical properties of the Sodium
Alginate solution impacting the size of the beads at squirting into
the Calcium Chloride solution, the impact of the squirting device on
the size of the beads as industrial operation will not use pipettes
for that
purpose, the impact of the
size of squirts on the sphericity of the beads. These considerations
over the size of and shape of the beads has as the object, the
formation of beads of |
virtually the same
size and sphericity as to support the uniform application of
the analysis of the
reaction
dynamics of beads and of the related
single
body problem. The reaction rate is required to allow the
determination of the reaction time for the formation and hardening
of the container-wall of the beads; the reaction time is often
generalized as the bead-particle minimum required residence time in
the bioreactor for the preferred state of the beads to obtain.
Generally, the size of a
droplet from an opening to a reservoir is impacted by the
physiochemical properties of the solution forming the droplet and
the physiochemical properties of the environment into which the
droplet was being formed. A significant property in this regards is
the surface tension property of the two fluids. The perspective
taken here is one of direct formation of the droplet in the host
fluid though the experimental studies was imprecise about whether or
not the droplets were formed in the air and then fell into the
Calcium Chloride host solution. This is not the assumed approach of
forming the droplet rather the approach is the direct immersed
"injection" or "squirting" or "sparging" into the host solution. An experimental
determination of the surface tension changes with solution
concentration mix changes, and the changes in bead size must be
made. A theoretical computational evaluation of this relation should
made and incorporated into the reactor design equations.
The determination of the
reaction mechanism and kinetics for constructing the reaction rate
equations as a task requires specially designed experiment. The
studies should aim to determine the mechanism of exchange and the
depth of penetration into the Sodium Alginate solution into which
the Calcium ions diffuse and reacts with the Sodium. The
interactions, if any, between the alginate components in evolving
the mechanism should also be determined. The dependence of depth of
penetration, or reaction band, on the concentration changes of the
two alginate solutions is also of viable consideration as such
should impact the toughness of the spherical shell of the beads.
With the availability of the
requisite data for the design of the bioreactor, then the design can
begin in earnest. Of primary considerations in the design of the
reactor is the type of reactor to adopt from the several basic of
types; in this context, there does not seem to be any preferred type
except that the vessel must be such as to allow the droplet to
suffer the least amount of rotation as that should cause a
distortion of the shape of the beads and so deform the beads from the preferred
sphere
shape. Then |
comes the
consideration of the specialization required to embody the squirting
dynamics of the bead formation method. The specifics of the design
of course simply depends on whether the host solution is stagnant or
flowing. In the former case the design consideration is confined to
the shape of the tip from which the microbe solution is squirted.
However, in the latter case, the consideration extends to include
the impact of the velocity of flow of the host solution during the
squirting and then interaction between the size of the
squirt-orifice and the fluid dynamics and the sphericity of the
beads.
Evidently, the design of the
fermentation
bioreactor is intimately dependent on the performance of the
immobilization bioreactor, and as such the design of the latter
should and ought be paid just as much attention as the former. |
