Abstrict
The invention relates to a solid-state fermenter for the cultivation
of micro-organisms on solid substrates, in particular for large
volumes. The field of application of the invention is the microbiological
industry. The solid-state fermenter according to the invention comprises
one or more air-proof and waterproof fermenter levels arranged on
top of one another, connected with the wall of the container in
such a way that neither air nor water can flow past laterally, with
a culture substrate to be found on the fermenter levels for the
micro-organisms to be cultivated, and wherein the cooling of the
fermenter material is done by cooling lances rising vertically from
the fermenter base and leading through the fermenter levels (4)
and a seal (6) is installed between the fermenter levels (4), which
is pressed against the inner wall of the fermenter by the mass of
the level above it (4).
Claims
1. Solid-state fermenter comprising one or more air-proof and waterproof
fermenter levels arranged above one another connected with the walls
of the container in such a way that neither air nor water can flow
past laterally, with a culture substrate to be found on the fermenter
levels for the micro-organisms to be cultivated, wherein the cooling
of the fermenter material is achieved by cooling lances (3) rising
from the fermenter base and leading through the fermenter levels
(4) and a seal (6) is installed between the fermenter levels, the
seal being pressed against the inner wall of the fermenter by the
mass of the level (4) above it.
2. Solid-state fermenter according to claim 1, wherein the cooling
lances (3) are positioned in a triangular arrangement to one another
and each cooling lance manifests the same distance form the closest
one.
3. Solid-state fermenter according to claim 1, wherein the cooling
lances (3) comprise an internal tube with a lower diameter, which
is used for the return of the coolant, and a tube with a larger
diameter, in which the first one is arranged centrally and which
is used for the feed of the coolant.
4. Solid-state fermenter according to claim 1, wherein the outer
tube has been provided with a circular cone shaped stopper at the
upper end and the inner tube preferably ends open 1-2 cm in front
of the stopper of the outer tube.
5. Solid-state fermenter according to claim 1, wherein the cooling
lances preferably manifest an outer diameter of 1-3 cm.
6. Solid-state fermenter according to claim 1, wherein the ratio
of the diameters of the two tubes to one another is preferably designed
in such a way that the flow velocity of the coolant in feeding is
equal to the flow velocity of the coolant in the return.
7. Solid-state fermenter according to claim 1, wherein the seal
comprises an elastic, heat-resistant material which is pressed against
the inner wall of the fermenter by the mass of the level above it
(4).
8. Solid-state fermenter according to claim 1, wherein the seal
comprises silicone.
9. Solid-state fermenter according to claims 1, wherein spacers
(6a) have been arranged between the levels (4).
10. Solid-state fermenter according to claims 1, wherein the seal
is installed either on the upper edge of the lower level (4) or
on the edge below the base of the upper level (4), e.g. with the
help of a groove.
11. Solid-state fermenter according to claims 1, wherein the bottom
fermenter level (4), which is mainly used to accommodate a moistening
medium, is positioned on a ring firmly installed in the fermenter
wall, the ring being positioned on a seal.
Description [0001] The invention relates to a solid-state fermenter for the
cultivation of micro-organisms on solid substrates, in particular
for large volumes. The field of application of the invention is
the microbiological industry.
[0002] WO 99/57239 has already manifested a solid-state fermenter
comprising at least two fermenter levels permeable to air and water
and arranged above one another, which are connected with the walls
of the container in such a way that neither air nor water can flow
past on the side, there being a culture substrate on the fermenter
levels for the micro-organisms to be cultivated and a cooling device
being fitted under each level.
[0003] In use, this fermenter manifests a number of disadvantages.
[0004] 1. The use of a cooling system in the form of cooling spirals
for each individual fermenter level, which run below the levels
and each have to be provided with a flow of coolant and with a coolant
discharge from the outside through the fermenter wall, results in
a high risk of contamination of the fermenter material with the
coolant used for cooling. This risk of contamination is in particular
to be put down to the fact that each cooling spiral must be connected
with the coolant feed and discharge tubes outside the fermenter
with the help of 2 connectors (for feed and discharge of the coolant).
Leaks can come about on these connectors. The risk of the occurrence
of said leaks increases as the number of fermenter levels increases.
As a result of the connection pieces of the cooling system protruding
into the fermenter from the outside (one feed and one discharge
per fermenter level), the insertion of the fermenter levels thereunder
is connected with difficulties. In insertion, they must either be
held at an angle or have been provided with a recess in order to
be lowered past the connections and into the lower part of the fermenter.
[0005] 2. A further problem with the solid state fermenter described
under WO 99/57239 is that the fermenter levels are placed on "rings
or otherwise shaped devices" (Claim 4). These "rings or
otherwise shaped devices" are provided with a heat-stable gasket.
This is to prevent water or air flowing past the fermenter levels.
However, these "rings or otherwise shaped devices" have
the effect that the insertion of the level underneath them is connected
with difficulties.
[0006] Therefore, the invention was based on the task of eliminating
the said disadvantages of the solid-state fermenter claimed in WO
99/57239 by constructive alterations and enabling the use of large
volumes.
[0007] This task is solved according to the invention described
below. The essential features of the invention area
[0008] a new kind of cooling of the fermenter material and
[0009] a new kind of sealing of the fermenter levels to the fermenter
wall.
[0010] 1. Cooling of the Fermenter Material
[0011] The cooling of the fermenter material is assured by cooling
lances (FIG. 1/3) rising vertically from the base of the fermenter.
The distance of the cooling lances is based on the quantity of heat
produced by the cultivated micro-organisms. The cooling lances are
fitted in a triangular arrangement to one another (FIG. 2) with
the result that each cooling lance manifests the same distance from
the closest one. The cooling lances comprise an interior tube with
a lower diameter, which is used for the return of the coolant, and
a tube with a larger diameter, in which the first one is arranged
centrally, which is used for the feeding of the coolant (FIG. 3).
In the cross-section, the cooling lances display an annulus. The
tube is provided with a circular cone shaped stopper at the upper
end. Preferably, the interior tube ends open 1-2 cm in front of
the stopper of the outer tube. The cooling lances have an outer
diameter of preferably 1-3 cm. The ratio of the diameters of the
two tubes to one another should preferably be designed in such a
way that the flow velocity of the coolant in feeding is equal to
the flow velocity of the coolant in the return.
[0012] As shown in FIG. 1, the cooling lances are connected underneath
the lowest fermenter level with 2 tubes penetrating into the fermenter,
one used for the feed and the other used for the return of the coolant.
In this way, the outer wall of the fermenter, which is designed
as a pressure vessel, need only be broken through at 2 places for
the purpose of the cooling of the fermenter material.
[0013] The bases of the fermenter levels have been provided with
holes. The holes have a diameter which is approx. 1 mm larger than
the outer diameter of the cooling lances. They can be provided with
lids which open in an upward direction, i.e. into the culture substrate.
When fermenter levels are inserted into the fermenter from above,
these lids are opened by the cooling lances and thus open the path
for the same. Thanks to the circular cone shaped tip, the cooling
lances can penetrate the culture substrate in the insertion of the
fermenter levels into the fermenter without problems. As a result
of the volume occupied by the cooling lances, a fermenter level
may only be filled with culture substrate before insertion into
the fermenter to such an extent that there is sufficient space in
the fermenter level following insertion into the fermenter.
[0014] However, the filling of the fermenter levels can also be
done after the level in question has been inserted into the fermenter
in such a way that the level is just underneath the fermenter opening
and the cooling lances have penetrated the base of the fermenter
up to the intended height of the culture substrate. In this kind
of filling, no lids are necessary to stop the holes in the fermenter
levels. The levels are up to the intended height and inserted into
the fermenter until they have contact to the fermenter base underneath.
[0015] In a special case, the described fermenter can be operated
with only one level filled with the culture substrate. This is in
particular possible if the granular culture substrate manifests
a very stable structure and there is no risk that the culture substrate
compresses during the sterilisation or the fermentation or alters
its features in a different way to the detriment of the culture
process.
[0016] 2. Sealing of the Fermenter Levels to the Fermenter Wall
[0017] For the fermentation or culture of an aerobic micro-organism,
a continuous feed of oxygen to the culture substrate on which the
micro-organism develops is necessary. Therefore, air is guided through
the culture substrate according to the invention claimed under WO
99/57239. However, this is only possible if the fermenter levels
are sealed towards the walls of the fermenter. Otherwise, the air
would flow past the levels due to the lower resistance and the culture
substrate would not be sufficiently supplied with oxygen. A sealing
of the fermenter levels towards the walls of the fermenter is additionally
necessary for the inoculation of the fermenter. The inoculation
is done according to the invention claimed under WO 99/57239 by
the fermenter being banked to above the top fermenter level with
sterile water. The inoculum, which distributes in the water, is
then inserted via a hole in the lid. An even inoculation of all
the fermenter levels is subsequently reached by the water being
discharged from the fermenter again through a discharge in the base.
In this way, there is an even flow through all the fermenter levels
and simultaneous contamination with the inoculum. However, this
is only possible if the water does not flow past the fermenter levels
at the side.
[0018] The air-proof and waterproof seal is achieved in the invention
by a seal which is installed between the fermenter levels and is
pressed together by the mass of the level positioned above it (FIGS.
1/6 and 1/6a). The seal comprises an elastic, heat-stable material
(e.g. silicone). When the seal is pushed together, it expands to
the side and is pressed against the inner wall of the fermenter.
This then ensures the necessary air-proof and waterproof lock. In
order to prevent the seal from being pressed together too strongly,
the upper fermenter level is positioned on the one underneath it.
This can be achieved, for example, by spacers (FIG. 1/6a), which
result in the space for the seal pressed together being equal between
all the levels. The seal can be installed either on the top edge
of the lower level or on the edge below the base of the upper level,
e.g. with the help of a groove.
[0019] Merely the lowest fermenter level, which is mainly used
to accommodate a moistening medium, is positioned on a ring, which
is firmly installed on the fermenter wall (FIG. 1) and on which
a seal is positioned.
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