JPH0256070B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fermentor for continuous circulation and aeration of growing cultures.

Successful commercial deployment of many fermentation methods developed over the past 20 years, particularly for the production of single-cell proteins, requires large-scale operations and the use of large-volume fermentors. In the production of suitable large fermenters, it has not been proven that it is possible to simply enlarge fermenters of conventional design, as the development of large fermenters has raised many unforeseen problems. do not have. Solving such problems requires significant changes in fermentor design. In developing successful methods for the production of single-cell proteins, the development of large fermentors with the appropriate combination of components that allow satisfactory control of the fermentation is critical.

According to the invention, the invention comprises a closed system formed by connecting an upflow tank (riser) and a downflow tank (downcomer) to each other and above their upper ends with a compartment; A fermenter apparatus for continuously circulating and aerating a culture, the closed system comprising: (a) piping means for introducing a liquid into the closed system and for sterilizing the liquid; (b) pipe means for removing liquid from a closed system, the pipe means having an outward direction of liquid sufficient to prevent the entry of organisms into the closed system along the pipe; (c) means for injecting the gas into the upflow vessel; (d) means including or in conjunction with a cyclone for directing the gas from the compartment; (e) means for removing one portion of the upflow tank volume occupied by the culture;
distribution means provided in the upflow tank for supplying growth-limiting nutrients to the culture in the upflow tank at an average of at least one location per cubic meter;
and (f) a plurality of buttfuls disposed within the upflow tank and spaced apart from each other in the vertical direction, wherein the solid portion of each buttful has an area of 30 to 80% of the internal cross-sectional area of the upflow tank. There is provided a fermenter device characterized in that it contains a combination of the following elements, accounting for %.

The gas injected into the upflow tank (riser) is
It can be used to generate circulation of the culture around the system. In this case, the gas is preferably injected into the lower part of the riser or, depending on the geometry of the system, below the lower end of the upflow tank or the upflow tank. and a downcomer. When this fermentor apparatus is used in an aerobic fermentation process, the gas injected into the system is an oxygen-containing gas such as air. In addition to the gas injected into or near the lower part of the upflow chamber as described above, in aerobic fermentation processes some gas is injected into the upper part of the downcomer. It is preferable to inject a gas of .

The shape and dimensions of the closed system of fermenters have many possible variations, for example British Patent No. 1353008,
There are those described in specifications No. 1417486 and No. 1417487. The present invention relates to the large-scale production of single-cell proteins [e.g., by the method of British Patent No. 1370892, in particular the production of Methylophilus methylotrophus sp., in a medium containing methanol as a carbon source;
It is particularly useful in connection with the large-scale production of proteins by growing a species of bacteria previously named Pseudomonas methylotropha.

The fermentor apparatus of the present invention has six major elements in combination that make the fermentor apparatus highly suitable for use in operating commercial processes for the production of single-cell proteins. These elements (a) to (f) already listed will be explained in more detail below.

(b) Piping means for introducing liquids into the closed system. A fermenter device comprises one or more pipes along which the nutrient-containing liquid(s) are introduced into the fermenter. It is adapted for continuous feeding to the culture, and one or more of the pipes is equipped with means for sterilizing the nutrient solution passing therethrough. Sterilization (which may be, for example, heat or oversterilization) is carried out to prevent the introduction of undesirable foreign organisms into the fermenter. Preferably, a steam sterilization method is used, and the arrangement is such that a valve, a steam container, a condensate removal device and a second valve are sequentially located in the middle of the pipe. Preferably, the valves are equipped with steam packing feet to prevent the entry of organisms through the valves. These pipes are used to supply inorganic nutrients such as nitrogen sources, magnesium sources, phosphorus sources, and other appropriate nutrients. A separate distribution device will normally be used to supply the carbon source, which is often considered a growth-limiting nutrient.

(b) Pipe means for removing liquid from a closed system It is possible for organisms to move along a pipe against the unidirectional flow of liquid in a pipe. Therefore, pipes for transporting liquid (in particular product culture) from the fermenter (and preferably also pipes transporting gas)
to prevent the flow rate of the fluid (liquid or gas) from exceeding a certain minimum value in at least a portion of the line of the pipe and the movement of the symptomatic organisms toward the closed system against the flow of the fluid in the pipe. Designed according to speed requirements to ensure This can be done in various ways, for example by suitably narrowing a section of the pipe line, or by inserting a flow restriction device, such as a contoured piece, into the pipe. This prevents the ingress of undesirable organisms into the closed system along the inner walls of outlet pipes, such as product removal pipes, gas discharge pipes and sampling device pipes.

(c) Means for injecting gas into the upflow tank The fermentation tank is provided with means (suitably a sparger having a plurality of holes) for injecting gas into the upflow tank as described above. In the case of aerobic fermentation, the gas is suitably air.
Suitably, in addition to aerating the culture, the gas is sufficient to cause a circulating flow of the culture due to the difference in porosity (volume fraction of air bubbles in the liquid) that occurs between the upflow tank and the downflow tank. Injected in quantity and pressure.

(d) Means for removing gas from the compartment The waste gas from the fermentation process is removed from the compartment along a pipe. For foam suppression and droplet separation purposes, one or more cyclones are placed in the compartment and/or in the waste gas discharge pipe.

(e) Distribution means for supplying growth-limiting nutrients Growth-limiting nutrients are usually carbon sources and are cultivated in amounts that are limiting to the growth (proliferation) of the culture with respect to other components in the medium. supplied to things. The fermenter according to the invention provides a distribution device within the effective fluid volume part of the fermenter (in particular (in the upflow tank, but also in other parts). Preferably, the limiting nutrient is supplied at more than 1 location per cubic meter, in particular from 10 to 10 000 locations. The purpose of the distribution device is to provide a good distribution of the limiting nutrient throughout the culture in the fermenter and to prevent local over-concentration of the limiting nutrient (this is caused by the addition of another nutrient, e.g. oxygen, to the limiting nutrient). The aim is to ensure that such problems do not occur. In the production of single-cell proteins, high yields of product can be achieved with a dispensing device.

(F) Multiple buttfuls arranged in an upflow tank In order to promote good mixing of gas and liquid, a plurality of buttfuls are arranged in an upflow tank and separated from each other at intervals in the vertical direction. Leave it there.
The solid part of each buttful (the part without holes)
occupies 30-80%, preferably 50-60% of the internal cross-sectional area of the upflow tank. Preferably they are arranged within the upflow tank at regular intervals along the height of the upflow tank. Suitably, the baffles are arranged within the upflow tank at intervals of D/4 to D, where D is the diameter of the upflow tank. Therefore, for example, a diameter of 4 m
And in an upward flow tank with a height of 50m, Batsuful is
It is appropriate to arrange them at intervals of 1.2m or more.
Buzzfuls can be formed in a variety of ways. A crossful is a plate with one or more orifices, a single straight member, a plurality of straight members forming a grid (which may or may not include intersecting straight members), and It's fine. When forming the grid from a plurality of straight members, it is preferred that the straight members are contoured beams (horizontal members) for reasons of rigidity and ease of installation.
For example, a beam of T-shaped or I-shaped cross section is preferred. A baffle can be made from a certain number of groups of T or I beams, forming narrow slots between the individual beams of each group. The beams (horizontal members) themselves may have holes in their horizontal parts.
The baffle can be attached to the wall of the upflow tank by conventional means (eg, bolted or welded).

In addition to the above elements (a) to (f), the fermenter is preferably equipped with other suitable devices to facilitate control of fermentation. Such other suitable devices include pressure measuring devices, devices for measuring enzyme concentration, and instruments for measuring and controlling pH. These other devices and appliances can be placed in the upflow tank and/or downflow tank, or in the case of pH measurement and control equipment, pipes entering or exiting the closed system of the fermenter. It can be provided in the pipe.

The invention will be further explained below with reference to the accompanying drawings.

The fermenter device shown in the accompanying figures has a shell consisting of two cylindrical parts with different cross-sectional areas and topped with a dome. The cross-sectional area of the upper part of these two parts is larger than that of the lower part. The lower part is divided into an upward flow tank 2 and a downward flow tank 1 by a pair of partition walls parallel to the axis.
The downflow tank is actually divided into two zones.

The upper part of the shell and the dome surround the compartment 3. To the compartment 3 gases produced during fermentation are released from the culture in the fermenter. Air is injected through the sparger 4 into the lower part of the upflow tank 2, and the gas passes from the culture in the fermenter through the liquid surface B-B in the upflow tank 2 and downflow tank 1. released into the gas space of compartment 3;
From there the gas leaves the fermenter via the gas discharge pipe 5. Foaming in the compartment 3 is carried out by a cyclone 6 having a gas introduction slot 28 located in the compartment.
suppressed by

The majority of the inorganic nutrients are fed into the fermenter via a nutrient feed pipe 7 equipped with steam sterilization means. Details of one typical pipe are shown in FIG. Steam sterilization means include a sterilizer 8 (which can be heated with steam or hot water);
The storage container 9, the main pipe valves 10 and 11, the steam inlet 12 and the condensate outlet 13 are connected to the system sterilization valve 14 for steam and the system sterilization valve 1 for condensate.
5. Nutrients are fed into the nutrient feed pipe 7 at its end 16 and pass into the fermenter from the other end of the pipe. Combinations of several nutrients whose physical and chemical properties are compatible can be fed to the fermenter via the same sterile pipe 7. Steam sterilization of nutrient supply pipes such as No. 7 is performed in the following operating sequence.

First, the portion of the pipe 7 adjacent to the fermenter is sterilized with steam. To do this, valves 10 and 11
is closed, while both the steam inlet 12 and condensate outlet 13 valves are opened, thus sterilizing the portion of the pipe 7 between the valves 10 and 11. System sterilization valve 14
and 15 are opened, and the piping and storage container 9 between them are sterilized. The nutrient solution is then fed into the sterilizer 8 through the end 16 of the pipe 7 and the system sterilization valves 14 and 15 are closed. After a time has elapsed for suitable pressure to develop in the system, both valves at the steam inlet 12 and condensate outlet 13 are closed and the main pipe valves 10 and 11 are opened to transfer the sterilized nutrients to the end 17. Then put it into the fermenter. Preferably, each valve in the system is provided with steam to prevent the entry of undesirable organisms through the valve stem.
Equipped with a packing foot.

Other nutrient supply pipes 18 are used to supply nutrients such as filter sterilizable methanol, ammonia and oxygen to the fermenter. Details of one typical pipe 18 are shown in FIG.
Nutrients are passed along pipe 18 from end 19 to end 2.
0 prefilter 21 and sterilization filter 2
2 to the fermenter. Prefilter 2
1 typically has filter particles down to 1-2 microns in size and is included in the system to extend the usable life of the sterilizing filter 22. The sterilization filter 22 is equipped with steam sterilization means (not shown in FIG. 4).

The product (culture) exits the fermenter along a product discharge pipe 23, which discharge pipe 23 is located at position 2.
4 includes a flow limiting device that creates an outward fluid flow velocity at location 24 of sufficient magnitude to prevent the entry of organisms beyond 24 into the system; It is. Furthermore, along the pipe 23 in the direction outward from the fermenter there are arranged means for sterilizing the pipe (but this sterilization means is not shown in FIG. 1). The degree of pipe narrowing at 24 performed by the flow limiting device depends on the velocity requirements for the system under consideration, and whether the flow is single-phase or two-phase. It depends on whether there is one or three phases.

The upflow tank 2 includes a series of buffles 25 formed from contoured beams arranged in groups, the buffles being vertically spaced apart from each other as shown. The upward flow tank 2 is
Also included is a distribution device for supplying growth-limiting nutrients to the culture throughout the up-flow tank. The limiting nutrients are contained in many orifices.
It is fed through a number of pipe grids such as 26 with 27. An example of a typical pipe grid is shown in detail in FIG. The limiting nutrients are supplied to the pipe 26 via a manifold (not shown) and the entire distribution device is interposed between the baffles 25.

The fermenter shown in the accompanying diagram is particularly
1370892, in which bacteria of the species Methylophilus methylotrophus are cultured in a medium containing methanol as the limiting nutrient carbon source, and the carbon The source is pipe 2 of the distribution device
6 to the culture. The culture is continuously removed from the fermenter along the discharge pipe 23,
The cells are successively isolated from the removed culture and dried to obtain a single-cell protein product, which is a useful ingredient in animal feed. When the fermentor apparatus of the present invention is used in such a method for producing single-cell proteins, there are the following advantages.

(1) High oxygen transfer rates into the culture are achieved, with associated good distribution of the limiting nutrient (methanol), high productivity of symbiotic organisms, and high substrate utilization.

(2) Since there are no moving parts in the fermenter, the energy input per unit of production is lower than in conventional fermenters, and sterility can be easily maintained.

(3) The size of the fermenter equipment can be easily increased.

(4) With the fermenter apparatus of the present invention, it is possible to produce extremely homogeneous products.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of an example of a fermenter apparatus according to the present invention. FIG. 2 is a cross-sectional view taken along line A--A in FIG. 1. FIG. 3 is a schematic diagram showing details of an example of pipe means for introducing nutrients with steam sterilization means. FIG. 4 is a schematic diagram showing details of an example of pipe means for introducing nutrients with filter sterilization means. FIG. 5 is a side view showing details of an example of a growth-limiting nutrient distribution device. 1: Downward flow tank, 2: Upward flow tank, 3: Compartment chamber,
4: Gas injection means, 5: Gas removal pipe, 6: Cyclone, 7: Liquid introduction pipe means, 8: Sterilizer, 23: Liquid extraction pipe means, 24: Symptom invasion prevention device, 25: Batsuful, 26: Growth Limited nutrient distribution means, B-B: liquid level.

Claims (1)

[Scope of Claims] 1. A closed system formed by communicating an upflow tank and a downflow tank with each other and with a compartment above their upper ends, for continuously growing a growing culture. A fermenter device for circulation and aeration, the closed system of which is (a) pipe means for introducing a liquid into the closed system, the pipe being provided with means for sterilizing the liquid; (b) Piping means for removing liquid from a closed system having velocity requirements to produce an outward liquid flow velocity sufficient to inhibit the entry of microorganisms along the pipe into the closed system. (c) means for injecting the gas into the upflow vessel; (d) means including or in conjunction with a cyclone for removing gas from the compartment; e) 1 of the upflow tank volume occupied by the culture.
distribution means provided in the upflow tank for supplying growth-limiting nutrients to the culture in the upflow tank at an average of at least one location per cubic meter;
and (f) a plurality of buttfuls disposed within the upflow tank and spaced apart from each other in the vertical direction, wherein the solid portion of each buttful has an area of 30 to 80% of the internal cross-sectional area of the upflow tank. The above-mentioned fermenter apparatus is characterized in that it contains a combination of the following elements, accounting for % of the above. 2. Claims characterized in that the distribution means in the upflow tank supply growth-limiting nutrients to the culture at an average of at least 10 locations per cubic meter of upflow tank volume occupied by the culture. Range 1
Fermentation equipment described in section. 3. The fermentation apparatus according to claim 1 or 2, characterized in that the solid portion of each buffle in the upflow tank occupies 50 to 60% of the internal cross-sectional area of the upflow tank. 4. Apparatus according to any one of claims 1 to 3, characterized in that the butthole in the upward sulfur tank is formed by a perforated, contoured horizontal member.