JPH03990B2 - - Google Patents

Abstract

PURPOSE:To keep a high fermentation yield for a long period, by attaching a plurality of disks composed of laminated porous sheets containing interconnected cells perpendicularly to the horizontal rotary shaft of a fermentation tank for the cultivation of various microbial cells, and rotating the disks. CONSTITUTION:A horizontal rotary shaft 6 is placed in the fermentation tank 1, and plural disks 9 are attached perpendicularly to the shaft 6 interposing nearly equal distances between the disks. Both surfaces of the disk 9 are laminated with flexible porous sheets 10 having interconnected cells having a pore size of 1-1,000mum (e.g. sponge), and the volume ratio of the porous sheet in the liquid contained in the fermentation tank is adjusted to 10-70%. The stock solution is poured into the fermentation tank 1 through the feed port 3, and the cells held in the pore of the porous sheet 10 are cultured by slowly rotating the rotary shaft 6. The microbial cells can be kept in the fermentation tank 1 in high density and a high fermentation yield can be achieved by this process.

Description

[Detailed description of the invention]

The present invention relates to a fermenter for culturing various types of bacterial cells,
More specifically, the present invention relates to a fermenter having a porous support for holding bacterial cells. In methane fermentation, alcohol fermentation, etc., in order to increase the bacterial cell concentration in the fermenter and improve the fermentation rate, fermenters have been developed in which the bacterial cells are immobilized on various carriers. In conventional packed bed fermenters using gel-like substances with immobilized bacterial cells, when there is a lot of scum or suspended matter in the raw material liquid, such as in methane fermentation or alcohol fermentation of starch raw materials, these The carrier holding the bacterial cells is coated with the suspension, which significantly reduces reaction efficiency and tends to cause clogging. For this reason, it is necessary to separate the raw material liquid into solid-liquid in advance, and the resulting high cost hinders its practical application. When using a carrier with immobilized bacterial cells as a fluidized bed to prevent clogging, the strength of the carrier becomes an issue. A method has also been proposed in which a raw material liquid flows between the two. Depending on how it is used, membranes with immobilized bacteria either have reinforcements or are made of a specific polymer with a certain strength, and the raw material liquid flows parallel to the surface of the membrane, so bacteria cannot be easily absorbed. The efficiency of contact with the body is not necessarily good. JP-A-55-111785 discloses a method of rotating a perforated plate for fixing bacterial cells in a culture tank. The perforated plate used in this method is a stainless steel mesh, a perforated glass plate, ceramic, or the like, and the bacterial cells are fixed at a high density on the surface, and the action of the bacterial cells is limited to the surface of the rotating plate. The present invention provides a fermenter particularly suitable for continuous fermentation, which allows bacterial cells to exist at a high density in the fermenter, does not cause inhibition by suspended matter in the raw material solution, and has excellent volumetric efficiency. . That is, the present invention provides a fermentation tank characterized in that a plurality of discs each having open-cell porous sheets laminated on the plate surface are arranged in parallel perpendicularly to the horizontal rotation axis in the tank. It is. DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below based on figures showing one embodiment. FIG. 1 is a sectional view along the rotation axis of an embodiment of the fermenter of the present invention, and FIG. 2 is a sectional view taken along the line AA in FIG. 1. A fermentation tank 1 made of stainless steel is sealed with a lid 2, and the raw material liquid is supplied into the tank from a supply port 3, and in the case of continuous fermentation, the fermentation liquid 4 is extracted from an extraction port 5 in an amount commensurate with the supply amount. Extracted. Extraction port 5
The position can be set at an appropriate position depending on the liquid level in the fermenter. Inside the fermenter 1, a rotating shaft 6 is provided horizontally with both ends supported.
A bar magnet 7 attached to the end of the tank is rotated by the rotation of a strong magnet 8 outside the tank, and applies rotational force to the rotating shaft 6. A plurality of discs 9 are arranged perpendicularly to the rotating shaft 6 at approximately equal intervals. This disk 9 may be made of any material, such as metal, ceramic, or plastic, as long as it is corrosion resistant to the liquid and bacteria in the fermenter and does not inhibit the growth of bacteria. A porous sheet 10 is laminated on at least one surface, usually both surfaces, of the disk 9. This porous sheet is open-celled, and the diameter of its pores is larger than the bacterial cells cultured in the fermenter, usually 1 to 1000 μm.
A material having many pores of 20 to 200 μm is used. The thickness of the laminated porous sheets is approximately 1 to 100 mm, depending on the size of the fermenter.
Usually, a diameter of about 2 to 100 mm is used. As for the method of laminating the porous sheet 10 and the disc 9, any method such as adhesion or screwing may be used. Although any material can be used for the porous sheet, open-celled synthetic resin foams such as polyvinyl acetate, polyurethane, polyvinyl chloride, and polyolefin are generally used, and preferably a soft sponge sheet is used. In the fermenter of the present invention, bacterial cells are retained and cultured in the pores of an open-cell porous sheet laminated on a disk rotating in the fermentation solution, resulting in a high fermentation rate due to a high concentration of bacterial cells. Therefore, the larger the volume ratio of the porous sheet in the fermentation solution is, the better. However, if this volume ratio is too large, the mutual spacing between the disks arranged in parallel on the rotating shaft will become narrower, and the The flow of fermentation liquid is obstructed. Therefore, the volume ratio of the porous sheet to the fermentation liquor is usually 10 to 70%, preferably 30 to 50%. The shape of the fermenter can be arbitrary, but from the viewpoint of the volume ratio of the porous sheet mentioned above, it is desirable that the distance between the disk and the tank wall be small. It is preferable to make it into a gutter shape or a semi-cylindrical shape that follows the shape of the disk. A discharge port 12 is provided at the bottom 11 of the fermenter for use in discharging settled scum and the like. It has been found that the rotation speed of the perforated sheet should not be too rapid. The most effective rotation speed is selected depending on the size of the disk, the viscosity of the fermentation liquid, etc. The fermentor of the present invention can be used either batchwise or continuously, and can be used for both anaerobic fermentation and aerobic fermentation. When used for aerobic fermentation, in order to supply oxygen to the bacterial cells, the liquid level of the fermentation liquid should be such that the upper part of the rotating porous sheet is above the liquid level, and the air supply piping for oxygen supply should be provided. In the fermenter of the present invention, the porous sheets laminated on disks rotate slowly in the fermentation liquid, so that
There is no fear that the inside of the fermenter will be clogged with scum or suspended matter, unlike in a packed fermenter. In addition, since the fermentation liquid is stirred by the rotation of the disk, there is no risk that the porous sheet as a carrier will be covered with scale, and the pores of the porous sheet are open cells, and the bacterial cells Since the pore diameter is sufficiently large compared to the size of the pores, the movement of the fermentation liquid within the pores is easy, and material transfer such as access of raw materials to the microorganisms in the pores and separation of fermentation products is good. It will be held in In particular, when a soft sponge is used as the porous sheet, when the porous sheet rotates and comes to the surface of the liquid, the sponge deforms due to the weight of the fermentation liquid contained in it and falls within open cells due to the gravity of the fermentation liquid. As a result, forced flow of the fermentation liquor within the pores occurs, which has the effect of further improving mass transfer. It is also possible to create forced flow within the pores by passing a rotating sponge sheet through a squeeze section provided in the fermenter. Due to this forced flow, the active bacteria fixed on the pore walls do not easily peel off, but rather the less active old bacteria detach, and the pores of the porous sheet contain more active bacteria. A constant amount of proliferating bacteria is always maintained, and an excellent fermentation rate can be maintained over a long period of time. Although the above explanation is about fermentation, it goes without saying that the fermenter of the present invention can also be used as a variety of biochemical reactors by attaching a sheet on which enzymes are immobilized to a disk. Example Alcohol fermentation using raw sweet seaweed as a raw material was carried out using a device similar to the fermenter shown in FIGS. 1 and 2. Liquefaction and saccharification are performed using an enzymatic method to reduce sugar concentration
A sugar syrup slurry adjusted to 14% by weight using an oil bacterium was used as the raw material liquid. The fermenter has a practical volume of 1300ml and a thickness of 1mm.
2mm thick on both sides of the hard PVC disk,
A polyvinyl acetate sponge with a diameter of 86 mm was fixed with staples. Experiments were conducted by changing the number of sponge disks attached to the rotating shaft from 5 to 20.
The fermenter is kept in a constant temperature water tank at 32°C. Prepare amashiyo liquid and sake mother (Haken No. 1) in advance in the fermenter, and after culturing for 24 hours, amashiyo liquid slurry

[Table] Sponge volume *

Claims (1)

[Scope of Claims] 1. Fermentation characterized in that a plurality of disks each having open-cell porous sheets laminated on the plate surface are arranged perpendicularly to the horizontal axis of rotation in a tank. Tank. 2. The fermenter according to claim 1, wherein the open-cell porous sheet is soft. 3 The open-cell porous sheet has a pore diameter of 1 to 1000 μm
The fermenter according to claim 1 or 2, which is 4. Claim 1, in which the volume ratio of the open-cell porous sheet in the liquid in the tank is 10 to 70%.
The fermenter according to any one of Items 1 to 3.