FIELD OF THE INVENTION;
This invention relates to a plant bioreactor.
This invention further relates to a small scale plant bioreactor which
works as a dual phase reactor.
BACKGROUND OF THE INVENTION;
Plant bioreactors generally function in one of the two modes i.e.
temporary immersion system (e.g. RITA) or surface contact with medium
(Growtek). Various types of reactors exist in the market, few allow us to
monitor various parameters inside the reactor, few others are being
automated to reduce human intervention and thereby reducing the risk
of contamination.
For plant tissue culture in aqueous medium, it is essential that the
culture medium, vessel and plant be free from contamination either due
to improper handling or from the atmosphere. Further, it becomes
necessary to change the culture medium from time to time, to support
various stages of the culture process.

Therefore, there is an in increasing emphasis on reducing the
contamination by using disposable reactors or by reducing human
intervention. Further, the need exists, to enhance the yield of plant in a
bioreactor and to have a simple system, which can support all the
different stages of plant culture in a single vessel. It would also be
advantageous to have a bioreactor which can work in a number of
modes.
OBJECTS OF THE INVENTION;
It is therefore an object of this invention to propose a plant bioreactor
which enhances the yield of plant.
It is a further object of this invention to propose a plant bioreactor which
is cost effective and simple.
A still further object of this invention is to propose a plant bioreactor
which can work in a number of modes.
Another object of this invention is to propose a plant bioreactor which
can support all stages of plant culture in a single vessel.

Yet another object of this invention is to propose a plant bioreactor which
minimizes the risk of contamination due to human intervention.
It is to be understood that the ensuing description is only an exemplary
embodiment without implying any restriction on the scope of the
invention.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
Fig 1 shows a plan view of the bioreactor.
Fig 2 shows the components of the bioreactor.
Fig 3 shows the thin tube.
Fig 4 shows the floater a) from the top
b) from the side
Fig 5 shows the configuration of the bioreactor in the surface contact
phase.

Fig 6 shows the configuration of the bioreactor in the dry mode.
Fig 7 shows the configuration of the bioreactor in the submerged phase.
Reference is invited to Fig 1 of the accompanying drawings, which shows
the plant bioreactor. The container (1) is provided with a cap (2) which is
releaseably fitted to the container by means of threads which may be
continuous or discontinuous or by any press-fit means. The cap (2) of the
container (1) has a central opening (3) to accommodate the passage of a
thin tube (4). The thin tube passes into the container through the central
opening (3) of the cap (2) of the container. The tube is provided with a
groove (G) which corresponds to the central opening in the cap for press-
fitting the cap (2) over the tube. The thin tube is also provided with a
smaller cap (5) which is secured to the upper end (U) of the tube by
thread means or press -fit means. The caps are preferably screw fitted to
the container or the cap with a minimum of 3.5 threads, thereby
reducing the chance of contamination. The lower end (L) of the tube rests
over a first stopper (6) fixed to the base of the container. The first stopper
(6) is integral with a hollow support means moulded into the floor of the
container (1). In accordance with an embodiment, the lower end of the
tube slides through the first stopper (6) and is fixed to the support means
(7) by screws or rivets.

The container is provided with a second stopper (8) (Fig 2) slidably fixed
to the thin tube (4), above a floater (9). The second stopper (8) acts as a
restraint and prevents the floater (9) from going above the level of the
second stopper (8). The second stopper is preferably press-fitted into a
groove (10) on the thin tube (Fig 3). Use of stoppers allows the reactor to
be operated in a periodic submerges and dry conditions which has also
been found to very useful in certain species of plants. The thin tube
provides for monitoring the parameters like temperature, pH etc, by
using probes, and /or for changing the culture medium and also for
adding or draining out the culture medium, when required. As the thin
tube opening would mean less surface area to work with, it would hence
reduce the risk of contamination as compared to handling the similar
containers with a large opening. This necessarily helps in avoiding
contamination. The cap provided at the upper end (U) of the tube also
restricts the ingress of contaminants into the vessel. Further, change in
reactor medium and continuous monitoring allows enhanced
micropropagation and somatic embryogenesis. Temporary Immersion
System is very conductive for ornamental plants such as Orchids and
Anthurium andraeanum. The change of medium is done through the
center tube and this eliminates the need of any side tube or components
which project out of the system.

The container further houses a floater (9) which is cylindrical in shape
and having a diameter selected so as to freely slide inside the container.
Fig 4 shows (a) the floater from the top and (b) floater from the side. The
base (11) of the floater is provided with a concentric inner rim (12) to
define a groove. The groove accommodates the passage of the tube
therethrough and press-fit into a corresponding groove on the outer
surface of the tube. The wire mesh (13) is held in place by a plurality of
panels (14) extending radially outwards from the inner rim (12) and
terminating at the periphery (15) of the base. The panels are configured
to define a 30 to 120° angle between two neighbouring panels. Preferably,
the number of panels is four. The meshed base supports the plantlets
and simultaneously allows for absorption of the culture medium by the
plantlets. The medium is filled upto the required volume, depending on
the plant used. Fig 4a clearly illustrates the floater with the meshed
base. The floater also includes two holding members (16) (Fig 4b),
integral with and projecting upwards from the side walls of the floater.
Preferably such holding means are two in number and placed
diametrically opposite each other.

The floater (9) is slidably fitted on the tube, between the first stopper (6)
and second stopper (8). It is press-fitted into a grooved structure (10)
provided on the surface of the thin tube. The floater (9) allows the surface
contact of plants with the medium which is very conducive to plant
growth (Fig 5).
The first stopper (6) is permanently fixed on the support (7) near the
base, at a predetermined height, preferably 2 cm, above the base. This
prevents the floater from going below this level and allows the user to
operate the bioreactor in dry mode (Fig 6). Vitrification, a condition which
leads to hyperhydric malformation of invitro grown plantlets can be
reversed by operating the bioreactor in dry mode. On the other hand, the
second stopper (8), fitted on to the tube above the floater prevents the
floater from rising upwards beyond the level of the second stopper and
allows the user to operate the bioreactor in the submerged mode (Fig 7).
It may also be necessary to monitor the medium parameters such as
temperature, pH etc. In the bioreactor such a monitoring system can be
introduced by inserting probes through the thin tube. The medium can

also be changed in between the plant cycle through the middle tube so as
to induce and study various morphological changes in the plant without
risking the contamination and damage to the plant. Further, the change
of medium allows different stages to be performed in the same reactor.
The cap (2) of the container is provided with an inner face sloping
radially inwards and downwards (SL), to define a cone with a dipped
down tip. It is important to note that such a shape ensures that all the
medium which gets evaporated and condenses on the inner surface of
the container cap, drips down from the middle of the cap into the
container. This necessarily avoids condensed droplets from getting
arrested along the joint between the walls of the container and the cap,
or dripping down along the walls of the container and prevents
peripheral contamination.
The container, center tube, floater, caps etc. which are shown to be
cylindrical shaped, as in the accompanying drawings, may be of any
other shape and configuration such as triangular, oval, square,
rectangular and polygonal. The container is made of strong autoclavable
material. The material is also transparent to allow plants to carry out

photosynthesis. Such a material may be selected from polycarbonates.
The caps are also made from autoclavable material such as
polypropylene. The wire mesh is constructed from polymeric material or
non-corrosive metallic composite materials such as stainless steel. The
wire mesh is integral with the floater rim. As no media solidifier (usually
agarose) is required, cost of media is reduced by about 75% and ensures
homogenous growth. The whole bioreactors is quiet robust and can take
the stress applied on the reactor during transportation and handling in
industries and laboratories.
While the foregoing details describe the bioreactor in general, it is
possible to make obvious modifications in the reactor without departing
from the scope of the invention.

WE CLAIM;
1. A plant bioreactor comprising a container with a releasably
fitted cap having an opening therein, a thin tube releasably
suspended, through the opening in the cap, said thin tube
being provided with a smaller releasably fitted cap, a floater
held to the thin tube and adapted to fit in said container,
a first stopper fixed at a predetermined height from the base, a
second stopper releasably fitted to said thin tube above the
floater.
2. The bioreactor as claimed in claim 1, wherein said container,
thin tube and floater member is selected to have a cylindrical,
rectangular, square, oval or any polygonal shape.
3. The bioreactor as claimed in claim 1, wherein the container,
floater and thin tube are cylindrically shaped.
4. The bioreactor as claimed in claim 1, wherein said cap for the
container is provided with an inner face sloping radially inwards
and, downwards so as to be configured as a cone with a dipped
down tip.

5. The bioreactor as claimed in claim 1, wherein said caps for the
container and the thin tube are releaseably fitted to the
container and the tube respectively, in a press fit or screw fit
mode.
6. The bioreactor as claimed in claim 1, wherein said float member
is cylindrical in shape having a base provided with a mesh and
solid side wall, said side wall being provided with two
diametrically oppositely placed holding members.
7. The bioreactor as claimed in claim 1, wherein said first stopper
is placed on a support means integrally formed with the base of
the container.
8. The bioreactor as claimed in claim 1, wherein the lower end of
the thin tube is fixed to the support means by screws or rivets.
9. The bioreactor as claimed in claim 1, wherein the cap press-fits
into a groove on the thin tube.

A plant bioreactor comprising a container with a releasably fitted cap
having an opening therein, a thin tube releasably suspended, through
the opening in the cap, said thin tube being provided with a smaller
releasably fitted cap, a floater held to the thin tube and adapted to fit
in said container, a first stopper fixed at a predetermined height from
the base, a second stopper releasably fitted to said thin tube above
the floater.