JPS58165792A - Continuous process for alcohol fermentation - Google Patents

Abstract

PURPOSE:Formed porous pieces are dispersed in the liquid in the fermentation tank and the liquid is stirred with blades to which sheets of porous materials are adhered to effect fermentation, thus permitting efficient alcohol fermentation in a short time. CONSTITUTION:As formed porous pieces 6 dispersed in the fermentation tank, are used a variety of foamed products with a pore diameter more than 5mu, equal to the average yeast diameter. The amount of the pieces is about 2-50% based on the total volume of the fermentation liquid containing the pieces. The stirring blades 5 in the tank 3 are made in multistages and made to rotate at 10-200rpm. The stirring blades are covered with porous sheets of 1-5mm. thickness so that they are imparted shock-absorbing properties. Before the yeast is added to the fermentation tank 3 from the yeast culture, the stirring blades are treated with an acid to propagate the yeast till 1X10<8>/ml in the tank 3. Then, the porous pieces washed with an acid 6 are added thereto and the saccharide solution is poured from the tank 1 into the fermentation tank 3.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for continuously carrying out alcoholic fermentation using yeast or bacteria using carbohydrates as raw materials.

To produce alcohol from carbohydrates, microorganisms such as yeast or bacteria are used, or enzymes isolated from these microorganisms are used to carry out alcohol fermentation, but most conventional alcohol fermentation methods are batch-based. It is a semi-batch type using recycled yeast.

In conventional batch-type alcohol fermentation, it takes 2 tons to 0 hours to complete fermentation in a fermenter, and in order to increase the amount of alcohol produced, it is necessary to install a large-capacity fermenter. be.

In addition, in semi-batch alcohol fermentation using yeast recirculation, the number of yeast in the tank can be maintained at 8 cells/ml, usually ~3X/θ, so the amount of alcohol produced per unit volume is lower than in the batch method. Approximately 5 times more J2 alcohol/1. /
It becomes h r. However, this method requires steps such as centrifuging the used yeast and acid washing, which increases the cost, and has the disadvantage that there are many opportunities for contamination with various bacteria and that management is complicated.

In recent years, in order to increase the amount of alcohol produced per unit volume, a process has been developed in which yeast is immobilized in a fermenter to continuously produce alcohol.

In this immobilized yeast method, yeast is immobilized on a photocurable resin and then inserted into a sheet in the form of a sheet. In this method, the photocurable resin and yeast are mixed, and the yeast is molded into a notebook or the like in a state as close to sterile as possible. A molding process is required, and the process of aseptically inserting the finished sheet into a tank with a large capacity (usually about /θorr?) also requires a high degree of skill. In addition, in the method of immobilizing yeast using a colloid solution such as alginate or carrageenan, when an immobilized yeast carrier is used as a packed bed, troubles such as clogging due to leaked yeast and inorganic substances are likely to occur. Furthermore, when used as a fluidized bed, the strength of the immobilization carrier becomes a problem and the expensive immobilized yeast needs to be replaced every few months.

The present invention has been proposed in view of the above circumstances, and provides a method for allowing continuous alcoholic fermentation to occur efficiently and in a short period of time by allowing a large amount of yeast to exist in a fermenter. In alcoholic fermentation using yeast or bacteria, molded porous strips are present in the fermenter liquid, and fermentation is carried out while stirring the strips with a stirring blade to which a porous material note is attached. This continuous alcohol fermentation method is characterized by the fact that it requires almost no complicated operation and maintenance.

The molded porous strips and porous material sheet used in the present invention may be any porous material having a pore diameter of jμ or more, which is the average size of yeast, since yeast ingrowth occurs in the porous strips. things can be used,
Preferably, it has a large number of pores with diameters of about 1l-i and 20-00μ. As such a porous material, various kinds of Subonoji bodies having continuous voids can be used. That is, synthetic resins such as polyvinyl acetate, polyurethane, polyvinyl chloride, polyethylene, etc.
D 5 @ a K l"14'; h b・12,
The size of the molded porous strips is such that the thickness is such that the yeast within the porous strips can be dispersed and suspended in the fermentation liquor and come into sufficient contact with the fermentation liquor.
/~10cm, diameter O/~30m symmetrical, asymmetrical circular or thickness 07~10mm, length and width θ/~30
It is preferable to use a symmetrical or asymmetrical rectangular shape of tmn. The larger the amount of porous particles added to the fermentation liquid, the greater the amount of yeast retained in the fermentation liquid, and therefore the fermentation rate can be increased with a short residence time. It is necessary to be able to stir the dispersed, suspended yeast attached to the porous tubes so that they can sufficiently come into contact with the fermentation liquid, that is, to have a good fluidity state. Therefore, it is preferable that the amount of porous pieces is about 20 to 100 cm based on the total volume of the fermentation liquid to which the pieces are added. Stirring may be carried out only by mechanical stirring using a stirring blade, or may be carried out in combination with stirring by blowing air or other gas or by vibration. Stirring is usually done at a rotation speed of 70 to 20 rpm to obtain a good fluidity without causing detachment of the yeast attached to the porous pipe or sedimentation of small pieces, but if the fermenter is made thicker or a better fluidity is obtained. It is better to install multiple stages of stirring blades to obtain the desired amount. Also, due to the centrifugal force applied to the porous strips during stirring, the density of the strips near the stirring shaft of S- becomes slightly smaller, which reduces the number of yeasts near the stirring shaft and prevents contact between the stirring blades and the porous strips. In this case, if the stirring blade does not have a buffering property, there is a risk of peeling off the adhered and flocculated yeast, so attach a porous material sheet to the stirring blade to compensate for the missing yeast near the stirring shaft and protect the yeast particles that flocculate. do.

The thickness of the porous material sheet is preferably set to /~jms in view of good adhesion of yeast and stirring resistance.

No special equipment is required to retain the yeast within the porous strips of the present invention. Before adding the yeast from the fermentation tank to the fermentation tank, the stirring blades are activated. ; - Confirm that it has been washed with a 2.0 acid solution, and add /x70' yeast to the fermenter.
Grow to mL and then add porous strips. This porous piece may also be simply washed with an acid solution of PH/, 5' to 20, and no further sterilization treatment is required.

In the continuous fermentation method of the present invention, the average residence time of the fermentation liquor in the fermenter is due to the high concentration of yeast, such as sugar If the concentration of is 73-Otsuichi~/g weight, the yeast concentration in the porous material volume is 7~.
The yield is 2 x 109 cells/ml, which is 7θ times that of normal bulk fermentation, and is approximately the same as that of recently developed immobilized yeast, so several hours is sufficient. The porous material is physically and chemically stable even after a long period of time in the fermenter, and has the characteristic that it can be taken out after 200 hours of operation, washed with acid, and used repeatedly.

The continuous alcoholic fermentation method of the present invention can also be applied to fermentation methods other than alcohol in which continuous fermentation is performed using yeast.

Hereinafter, the method of the present invention will be explained using the apparatus shown in the figures together with comparative examples.

Example/and- Store in storage tank (1).

Saccharomyces alba (Saccharomyces)
formosensi days N a k a Z a w
A paddle-shaped blade (5) with 5 layers of porous material notes pasted on which 200mt of sake mash was previously acid-treated.
into the fermenter (3), which is equipped with a stirrer (4) having a The sugar solution from the sugar solution storage tank (1) was further pumped into this 2.3 t fermenter (3) using the pump (2) until the total amount of yeast reached 11. Insert an air blowing pipe through the manhole 00 from the stirring hole 1 to blow air into it. This time is about 6 hours.

After the yeast multiplication, the air blowing pipe is taken out and the acid-washed porous strips (6) are added into the tank through the manhole αQ at a volume ratio of 1 to give fO%, and the lid of the manhole (10 is closed! rOr
After stirring continuously at pm, the raw sugar solution is injected from the sugar solution storage tank (1) into the fermentation tank (3) using the pump (2), and the fermented solution is extracted in a gas-liquid mixed phase state through the extraction pipe (7). Fermentation liquid storage tank (
9) was stored. The fermentation temperature was 3.2°C.

A sample bottle (8) was placed in the middle of the extraction tube (7) to collect the fermented liquid in several cases as needed. A known amount of hydrochloric acid is added to the sample bottle (8) in advance, and the yeast in the sample liquid is killed or ceases its activity. The ethanol concentration and residual sugar content in the sample solution were measured. By changing the sugar solution supply rate, the residence time in the fermenter was changed to 7 hours and 5 hours! The results obtained for the cases are shown in Table 1.

The porous material used was a notebook made of polyvinyl acetate sponge (PVF Subonoji manufactured by Seibu Gomu Kogyo ■).
6) is about 2 tan X! r tan X j m
I used one sliced into m squares, and pasted a note with a thickness of 2 cylinders on the stirring blade (5).

This continuous fermentation was carried out for 70 days, and the ethanol concentration in the fermentation liquid obtained during this period remained almost constant, allowing stable operation. When the residence time was set to 7 hours, the ethanol production rate per unit volume was 10.3 t/l/H, and the fermentation ratio g♂-weight ratio could be obtained using only the fermenter/tank, indicating that the fermentation was almost completed. Indicated.

Comparative Example/and Co. Operation was carried out for 70 days in exactly the same manner as in Example/and No. except that no porous particles were added and no porous material notebook was attached to the stirring blade. The results obtained are shown in Table 1. The concentration of ethanol produced is extremely low, and by shortening the residence time in the trench, the amount of ethanol produced is also reduced.

[Brief explanation of the drawing]

The figure is a flow sheet of an apparatus showing an embodiment of the continuous alcohol fermentation method of the present invention. /: Sugar solution storage tank, 2: Pump 3: Fermentation tank g: Stirrer j: Stirring blade 2: Porous strip 7: Extraction tube g: Sample bottle: Storage tank 10: Manball Applicant Mitsubishi Kakoki Co., Ltd.

Claims (4)

[Claims] (1) In alcoholic fermentation using yeast or bacteria, molded porous strips are present in the fermenter liquid, and fermentation is carried out while stirring the strips with a stirring blade to which a porous material note is attached. Characteristic continuous alcohol fermentation method. (2) The molded porous strip is circular with a thickness of 07-10 mm and a diameter of 0/-30 mm or a thickness of 0. /~10 throats,
Side length: Claim number (
Method described in section 1) (3) Claim 1, wherein the molded porous strips are present in the total amount of fermentation liquid in the fermentation premises with a volume of 2δ to SO;
or the method described in paragraph 2. (4) The method according to claim (1), (2) or (3), wherein a porous material sheet is attached to the stirring blade to a thickness of 3 ms.