A fermenter for cultivating of microorganisms has a container bounding
an inner chamber in which microorganisms are accommodated to be
cultivated, and at least one diaphragm filter unit which is introduced
into the inner chamber, so that the products of metabolism of the
microorganisms are continuously separated and withdrawn, simultaneously
with cultivation of the microorganisms and directly in the fermenter.
A plurality of the diaphragm filter units may be provided and located
in a guiding pipe which is arranged centrally of the container.
What is claimed as new and desired to be protected by Letters Patent
is set forth in the appended claims:
1. An improved fermenter for cultivating of microorganisms in a
substrate of the type in which a container bounds an inner chamber
in which microorganisms are accommodated and cultivated, said improvement
comprising substrate inlet means, discharge means and product collecting
means for the container, a double circumferential wall for the container
having inlet and outlet conduits for supplying and withdrawing of
heating or cooling medium through the interior of said double circumferential
wall; a guiding pipe located centrally of said container in said
inner chamber and having a conical bottom portion; at least one
diaphragm filter unit arranged in the interior of said guiding pipe
and operative for continuously separating and withdrawing the products
of metabolism of the microorganisms, simultaneously with cultivating
of the latter directly in the fermenter; a main aerating pipe running
from the top of said container through the central region of said
guiding pipe and extending into said conical bottom portion of said
guiding pipe, said main aerating pipe terminating in a distributing
member in said conical bottom portion of said guiding pipe; a rotary
turbine beneath said distributing member; and driving means for
said rotary turbine, whereby the aspirating action of said rotary
turbine provides a moderate pressure overcoming the pressure in
the interior of the fermenter and whereby air is entrained by the
substrate solution in the process of downward movement and whereby
air bubbles of said entrained air are comminuted by said rotary
turbine, thereby ensuring sufficient air supply for the microorganisms.
2. A fermenter as defined in claim 1, wherein a plurality of such
diaphragm filter units are located in said inner chamber of said
3. A fermenter as defined in claim 2, wherein each of said diaphragm
filter units is formed as a filtering tube.
4. A fermenter as defined in claim 3, wherein each of said filtering
tubes has a porous diaphragm with a plurality of pores each having
a diameter which does not exceed 0.01 micrometer.
5. A fermenter as defined in claim 4, wherein said container has
a circumferential wall, said diaphragm filter units being distributed
over said inner chamber and extending substantially parallel to
said circumferential wall of said container.
6. A fermenter as defined in claim 3; and further comprising a
plurality of air supply pipes each of which is open into a respective
one of said filtering tubes.
7. A fermenter as defined in claim 6; and further comprising an
air supply conduit extending into said inner chamber of said container,
said air supply pipes branching off from said main air supply conduit.
8. A fermenter as defined in claim 3; and further comprising a
collecting conduit communicating with said diaphragm filter units
and operative for collecting a permeate, said collecting conduit
being provided with a connecting line for flushing back said diaphragm
9. A fermenter as defined in claim 2, wherein each of said diaphragm
filter units has a longitudinal axis and is rotatable about said
10. A fermenter as defined in claim 2, wherein said diaphragm filter
units are replaceable without interruption of the cultivating process.
11. A fermenter as defined in claim 1; and further comprising an
exhaust conduit in said container and provided with a control valve
operative for controlling pressure in said inner chamber.
12. A fermenter as defined in claim 11; and further comprising
a foam breaking unit located in said container and provided with
said exhaust conduit.
BACKGROUND OF THE INVENTION
The present invention relates to a fermenter for cultivating of
microorganism. More particularly, it relates to a fermenter for
cultivating of microorganisms as well as separating and withdrawing
products of metabolism of microorganisms.
Products of metabolism of microorganisms are generally separated
after the fermentation for extraction of vinegar, wine and antibiotics.
This separation is performed by filtration through filters, with
the utilization of auxiliary filtering aids in alluvial filters
or application or precoating layers over drim rotary filters. Such
filtration can take place only in a batch process. At the same time,
the above-mentioned products of metabolism are discontinuously processed
during the fermentation.
It has been proposed to utilize ultrafiltration for separation
of products of fermentation, as disclosed, for example, in Michaels
"Ultrafiltration", Booklet No. 905, AMICON Corp., March
2968, p. 22. The U.S. Pat. No. 3,720,583 teaches continuous separation
of glucose from an enzymatic hydrolysis with the aid of an ultrafilter
which is connected in parallel with an enzyme reactor. In this construction
smaller molecules of glucose are separated by diaphragms and larger
active enzymes are recirculated.
The known apparatuses have many disadvantages. When the membrane
filter is located outside of the reaction container, additional
pumps, tubular conduits and armature are necessary. The required
pumps have the disadvantage that microorganisms, especially mushrooms,
are readily damaged in them. The pumps, as well as measuring probes
and pipe section in which they are mounted, are always sources of
contamination by external microorganisms. Susceptable microorganisms,
such as highly cultivated vinegar bacteriam which cannot tolerate
even a short interruption of air supply, must be additionally aerated
when they travel from the outlet of the fermenter to a further inlet,
so as to maintain the lowest possible level rate of perishing.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide
a fermenter for cultivating of microorganisms, which avoids the
disadvantages of the prior art.
More particularly it is an object of the present invention to provide
a fermenter which has a simple construction and reliably performs
the functions of cultivating of microorganisms.
In keeping with these objects and with others which will become
apparent hereinafter, one feature of the present invention resides,
briefly stated, in a fermenter in which one of several diaphragm
filter units are introduced directly in the fermenter, so as to
continuously perform separation and withdrawal of products of metabolism
of the microorganisms, simultaneously with cultivating of the same
and directly in the fermenter.
Such a fermenter has a simple construction and reliably performs
its functions. No additional pumps, conduits and armature which
otherwise would make the fermenter more complex and be sources of
contamination, are needed. The fermenter provides for conditions
which are optimum for cultivating of microorganisms and withdrawal
of products of their metabolism.
Another feature of the present invention is that the diaphragm
filter units may be located in the interior of a guiding pipe accommodated
in the inner chamber of the fermenter. The guiding pipe may be arranged
centrally of the inner chamber of the fermenter.
Still another feature of the present invention is that the filter
units may be formed by permeable pipes, and may have porous diaphragms
with pores whose diameter does not exceed 0.2 micrometer.
In accordance with a further feature of the present invention,
the diaphragm filter units may extend parallel to a wall of the
fermenter. An air supply conduit may be open into each of the diaphragm
filter units. It is also possible that each filter unit is mounted
rotatable about its longitudinal axis. Each filter unit may be replaceable
without interruption of the fermentation process.
The novel features which are considered as characteristic for the
invention are set forth in particular in the appended claims. The
invention itself, however, both as to its construction and its method
of operation, together with additional objects and advantages thereof
will be best understood from the following description of specific
embodiments when read in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a view showing a longitudinal section of a fermenter
with filter units mounted therein, in accordance with the present
FIG. 2 is a view showing a cross section of a central part of the
fermenter of FIG. 1;
FIG. 3 is a view showing a longitudinal section of a fermenter
in accordance with a further embodiment of the present invention;
FIG. 4 is a view showing a diaphragm filter unit located outside
of the fermenter and partially introduced in the interior of the
FIG. 5 is a view showing a bundle of the diaphragm filtering pipes;
FIG. 6 is a view showing an outlet portion of an air supply conduit
and an inlet portion of one of the diaphragm filter pipes, on an
enlarged scale; and
FIG. 7 is a view showing the filtering pipe in detail.
DESCRIPTION OF PREFERRED EMBODIMENTS
A fermenter for cultivating microorganisms shown in FIG. 1 has
a container 1 with a double circumferential wall 2 and conduits
3 and 4 for supplying and withdrawing, respectively, of heating
medium or cooling medium. A guiding pipe 5 is located in the interior
of the container 1, advantageously centrally of the latter. A bundle
of diaphragm filtering pipes 6 are accommodated in the interior
of the guiding pipe 5. P Intermediate spaces 6' between the diaphragm
filterng pipes 6 serve for admitting of a permeate, or, in other
words, a filtrate or an ultrafiltrate. The intermediate spaces 6'
have a single outlet formed by a collecting pipe 8 which extends
through the wall of the container 1. A substrate is supplied through
a conduit 7 in the top of the fermenter. A main aerating pipe 9
is located in the central region of the guiding pipe 5 and extends
into a conical portion 10 of the latter. The main aerating pipe
9 terminates in a distributing member 11. A discharge valve 12 is
located below a short pipe 13 arranged in the bottom of the container
1. A rotary turbine 14 is provided which is driven in rotation by
an electric motor 16 through a shaft 15.
A further air supply conduit 17 is arranged in an upper part of
the container 1. The air supply conduit 17 has branching off portions
18 which are open into the diaphragm filtering pipes 6. Each diaphragm
filtering pipe is provided with one branching off air supply portion
18. A mechanical foam-breaking device 19 is mounted in the upper
portion of the container 1. It is driven by an electric motor 20
and provided with an exhaust pipe 21. A control valve 22 is connected
with the fermenter through a manometer 23 in order to throttle the
exhaust gas and to increase the pressure in the inner chamber of
the container 1.
FIG. 5 shows a bundle of the diaphragm filtering pipes 6 with the
intermediate spaces 6' therebetween. FIG. 2 shows the cross section
of the diaphragm filtering pipes 6 and the guiding pipe 5 surrounding
the same. These Figures do not require additional explanation.
FIG. 3 shows a fermenter in which the inner chamber bounded by
the container 1 is filled by the diaphragm filtering pipes 6 to
a greater extent. In addition to the diaphragm filtering pipes 6
located in the interior of the guiding pipe 5, further diaphragm
filtering pipes are provided in the space between the guiding pipe
5 and the wall of the container 1. The diaphragm filter units extend
upwardly beyond the top of the container 1 and are open into the
collecting pipe 8 in the region above the top. The collecting pipe
8 is provided with a short pipe 24 and a valve 25 through which
the diaphragm filters can be cleaned by flushing back. During the
process of flushing back, an additional valve 26 is closed.
FIG. 4 shows a drive part of a rotatable diaphragm filter unit
6 with a diaphragm 6", which is guided in a housing 27. Sealing
of the diaphragm filter unit is performed by a two-stage axial slide
ring packing 28. The diaphragm filter unit is supported by an upper
ball bearing 30 and a lower ball bearing 29. The diaphragm filtering
unit can be driven in rotation by a not shown drive through a pulley
The diaphragm filter units may be formed as porous pipes whose
walls serve as diaphragms and have pores of a diameter not exceeding
0.2 micrometer. As shown in FIG. 6, each diaphragm filter unit may
be composed of a porous supporting part and a diaphragm shown by
The fermenter in accordance with the present invention operates
in the following manner. A substrate is supplied into the container
1 through the conduit 7 under the action of a moderate positive
pressure or the aspirating action of the rotary turbine 14 which
overcome the predetermined pressure in the interior of the fermenter.
The major part of the required aeration air is supplied through
the conduit 9 and the distributing member 11 directly to the rotary
turbine 14 which is driven by the electric motor 16 through the
shaft 15. Simultaneously with the supply of the substrate, plain
air or oxygen-containing air is uninterruptedly introduced through
the conduit 17 and the portions 18 into the pipes 6 of the diaphragm
filters. The nutrient substrate solution which contains microorganisms
performing the process of metabolism, is aspirated by the rotary
turbine 14, and the air is entrained by the solution in the process
of downward movement, whereby sufficient aeration of the solution
during this movement is guaranteed. Air bubbles contained in the
downward flow are comminuted by the rotary turbine 14 in known manner
and, together with the air from the distributing member 11, provide
for intensive aeration of the substrate and thereby sufficient air
supply to the microorganisms. The diaphragms 6" have a pore
diameter which is smaller than the dimension of the smallest microorganisms
taking part in the process of metabolism. Thereby, the desired product
flows through the diaphragms 6" whereas the microorganisms
cannot penetrate through the latter. The permeate is collected in
the intermediate spaces 6' of the diaphragm filtering pipes 6 and
leave the fermenter through the collecting conduit 8. The fermenter
is provided with means for controlling the pressure which includes
the above-mentioned contact manometer 23 controlling the valve 22,
so that the upper portion of the container 1 is always subjected
to a constant positive pressure. Thereby the flow rate of the substrate
through the diaphragm filtering pipes is reliably adjusted in order
to satisfy the necessary biological requirements. The control valve
22 is mounted in the exhaust conduit 21 of the mechanical foam-breaking
device 19 driven by the electric motor 20. It is also possible to
provide weight controlling means which is not shown in the drawing
and may serve for controlling the relation between recirculated
microorganisms and the required optimum concentration. The collecting
valve mounted in the short pipe 13 serves the discharge purposes
in the case of undesirable increase in the concentration of microorganisms.
The rotatable diaphragm filter makes possible to prevent formation
of deposits on the diaphragms 6", with the aid of intermittent
rotation of the filters. The diaphragms 6" can also be cleaned
by flushing back of the same through the conduit 24, when the valve
25 is open and the valve 24 is closed. The flushing back may also
be performed by the permeate during the fermentation process, in
required time periods.
The filtering pipes can be removed during the fermentation. As
shown in FIG. 7, the filtering pipe 6 is sealed by two O-rings 33.
A ball valve 34 is arranged in the housing 27 and can close the
same when the filtering pipe is withdrawn into the position shown
in dotted lines. The exchange of the filtering pipes is performed
by withdrawing the filtering tube to the above-mentioned position
identified by reference numeral 35, closing the housing by the valve
34, and thereafter completely withdrawing the filtering pipe. A
new sterile filtering pipe can be inserted into the housing 27 in
An especial advantage of the present invention is that the mounting
of the diaphragm filter units in the interior of the fermenter guarantees
an uninterrupted process of cultivation of microorganisms in sterile
condition. In addition to elimination of the damaging action of
the above-mentioned pumps, tubular conduits, measuring probes in
the case of providing an external system of filtering, no additional
expenditures for these structural parts are needed in the inventive
A further advantage of the present invention is that it is no longer
necessary to provide cooling means of a conventional diaphragm filter
system in which the liberated heat must be withdrawn from the required
rotary pump of an external diaphragm filter.
A decisive advantage of the inventive fermenter is revealed in
the process of fermentation of microorganisms which cannot tolerate
shortage of oxygen. Such microorganisms can be effectively cultivated
in the inventive fermenter in which the microorganisms, in condition
of separation of products of metabolism, can be uninterruptedly
supplied with air. As a result of this, microorganisms in all stages
of cultivation are not withdrawn from the environment in which they
Advantageous fields of application of the inventive fermenter is
the manufacture of vinegar, alcohol, antibiotics, organic acids,
especially citric acid.
It will be understood that each of the elements described above,
or two or more together, may also find a useful application in other
types of constructions differing from the types described above.
While the invention has been illustrated and described as embodied
in a fermenter it is not intended to be limited to the details shown,
since various modifications and structural changes may be made without
departing in any way from the spirit of the present invention.
Without further analysis, the foregoing will so fully reveal the
gist of the present invention that others can, by applying current
knowledge, readily adapt it for various applications without omitting
features that, from the standpoint of prior art, fairly constitute
essential characteristics of the generic or specific aspects of