JPS58129989A - Continuous preparation of alcohol by fermentation - Google Patents

Abstract

PURPOSE:To improve the yield of an alcohol from a raw material saccharide, by setting a fermenting device having a means of separate a carrier from a fermented solution in the front part and a fermenting device of the fluidized bed type in the rear part, cultivating a bacterium capable of ferementing an alcohol attached to a carrier in the front part and an immobilized yest in the rear part. CONSTITUTION:For example, a solution of waste molasses diluted by five times is fed through the pump 71 to the fermenting device 51, sent from the branched part 53b with a small diameter of the solid-liquid separating part 51 of the device through the pump 72 to the fermenting device 61 of the fluidized bed type, and circulated through the pump 73. A bacterium capable of fermenting an alccohol attached to a carrier is cultivated in the fermenting device 51, and an immobilized yeast in the fermenting device 61 under fluidizing conditions. The solution of waste molasses is fermented in high yield by the two kinds of microorganisms. The fermented solution having finished fermentation is taken out of the top 62 of the fermenting device 61. The bacterium in the fermenting device 51 is separated by the solid-liquid separating member 53 and reused.

Description

[Detailed description of the invention] The present invention relates to a method for continuous production of alcohol by fermentation.

In recent years, fermented alcohol, which can be obtained without using petrochemicals, has been in the spotlight as an energy alternative to petroleum. This includes sugar cane, molasses, sweet potatoes, potatoes, corn, etc.

The raw material is cellulose or starch, and it is produced by fermenting it through the action of bacterial cells. In this method, alcohol productivity is considered to depend on bacterial cell concentration.
ing. Therefore, in order to increase the bacterial cell concentration, a method of circulating the bacterial cells and a so-called immobilized cell growth method in which yeast is encapsulated in a polysaccharide-based substance are being developed. However, in the former case, the centrifugal separator used to concentrate and separate the bacterial cells is
Solid matter present in the culture solution causes clogging or nozzle clogging, making it increasingly difficult to circulate the microbial cells.

Therefore, it is necessary to periodically clean the centrifuge, which makes the work extremely troublesome. In the latter case, there are many technical problems that are difficult to solve in mass production on an industrial scale.

In view of these circumstances, the inventors of the present invention have conducted extensive research to increase the concentration of bacterial cells in the fermenter, and as a result, have completed the present invention.

The method for producing alcohol according to the present invention is a fermentation device Q equipped with a separation means for separating a carrier from a reaction solution. This is a continuous alcohol production method.

An example of a fermentation device equipped with a separation means is Haggi's. In other words, the fermentation apparatus (1) shown in Figure 1 (a)
A fermentation tank (3) equipped with stirring*t21 is provided with a carrier sedimentation section (4) on the side, and the carrier is sedimented and separated in the circulation section (4) to prevent it from flowing out of the tank. It is. Furthermore, the fermentation apparatus Cl11 shown in FIG.
The carrier flowing out from the fermentation tank αJ is separated by sedimentation in a sedimentation tank (141), and the sedimented carrier is returned to the fermentation tank 031.Furthermore, the fermentation apparatus 21+ shown in FIG.
In this method, a stirring blade ■ is placed at the bottom of the fermentation tank @, and a cylindrical liquid circulation member (two pieces) is placed vertically above the blade to allow the reaction liquid to flow down inside the circulation member ■ and circulate within the premises. and liquid circulation member-
The carrier is separated from the reaction solution above the reactor. Furthermore, the fermentation apparatus (31) shown in Fig. 1) has a solid-liquid separation member (property) in the shape of an approximately Y-shaped tube for separating the carrier from the reaction liquid placed inside the fermentation tank equipped with an agitator (2). Carbon dioxide gas is discharged from the large-diameter branch, and the reaction liquid is taken out from the small-diameter branch. And these fermentation devices fi+ 01121) C311 are all p
The structure is such that H and temperature can be controlled to optimum values.

As shown in FIG. 2, the fluidized bed fermentation apparatus is mainly composed of a glass fermentation tank (41) and is configured to be able to control temperature and pH. And the fermentation raw materials are pumped (
The reaction solution is supplied to the bottom of the four tanks (41) by the pump (43), and is returned from the top to the bottom of the four tanks by the pump (43), and flows out from the carrier sedimentation section (circle) at the top of the tank. A conventional packed fermentation device is used.

As shown in FIG. 3, these fermentation apparatuses are arranged such that a fermentation apparatus equipped with a separation means is at the front stage, and a fluidized bed type or packed type fermentation apparatus is at the rear stage.

In the first stage, the carrier for attaching the bacterial cells may be small-diameter particles with good abrasion resistance and fluidity, and an optimal example is crushed vermiculite. The carrier may be made of ceramic or plastic. Bacteria with alcohol fermentation ability include Zymomonas mobilis (Zymomonas mobilis).
onaamobilia) is preferably used because it has excellent natural adhesion to the carrier. This bacterium ferments sucrose, glucose, and fructose among the fermentable sugars contained in cane juice and blackstrap molasses to produce alcohol.

Bacteria with alcohol fermentation ability may be any bacteria that has good natural adhesion (but is not limited to the above bacteria. By culturing the bacteria adhering to the carrier in the W stage, the concentration of bacteria in the tank can be increased, and the above bacteria can be used. The productivity of alcohol from fermentable sugar can be improved.

In the latter stage, the immobilized yeast may be of any type as long as it has alcohol fermentation ability, and in particular, Saccharomyces
Those of the genus Ccharomyces are preferably used. Immobilized yeast is one in which yeast is immobilized by entrapping it in polyacrylamide gel, sodium alginate, K1 carrageenan, etc. using a conventional method. Then, in the latter stage, by culturing the immobilized yeast, unreacted fermentable sugars that were not fermented by bacteria in the previous stage are fermented to produce alcohol, and the alcohol fermentation yield from sugar is increased. can be improved.

Since the alcohol production method according to the present invention is configured as described above, effects similar to those described above are produced.

(1) In the first step, a carrier is used to attach the bacterial cells, so the solid surface area to which the bacterial cells can adhere is determined by
, the bacterial cell concentration in the S tank can be increased, and as a result, alcohol productivity can be significantly improved.

(2) Since immobilized yeast is cultured in the latter stage, unreacted fermentable sugars that were not fermented in the first stage can be fermented by the yeast, and as a result, the fermentation yield can be significantly improved.

(3) Since cells with good adhesion to the carrier are used in the first stage, the average terminal velocity of the cells is high, and therefore the cells can be separated from the reaction solution by a simple separation method, reducing equipment costs. You can get big advantages.

Comparative Example 1 Using a fermenter for static culture, microorganisms were grown.
I? Ise XS Hol%sensis (Saceharomy)
eesformosensia) IFO Deposit No. 0216
(hereinafter referred to as microorganism A), sterilized 5-fold diluted Cane's molasses medium (yeast extract: 3
9/l, (NH4)2804: 1 f/l.

KH2PO421g/l and MgCl2.6H
Batch fermentation was carried out at a fermentation temperature of 30° C. and the fermentation characteristics were examined over time.

Instead of the above microorganisms, baker's yeast manufactured by Kyowa Hakko Co., Ltd. (hereinafter referred to as
Microorganism B), Zymomonas mobilis IFO
The above operation was repeated using Deposit No. 13756 (hereinafter referred to as Microorganism C) and Zymomonas mobilis ATCC Deposit No. 10988 (hereinafter referred to as Microorganism D), respectively.

Figure 4 shows the relationship between the concentrations of the fluorophores. As you can see from the same figure,
Regarding alcohol fermentation ability, microorganisms^ are the best (2
The alcohol concentration was approximately 559//l on the fourth day, followed by microorganism B, and the alcohol concentration of microorganisms C and D was only approximately 409/l even on the fourth day.

Comparative Example 2 A fluidized bed fermentation apparatus with an actual volume of 0.7j shown in FIG. 2 was used. The immobilized yeast Saecha formocensis (Saecha
romyeea formoaensis ) I FO
Deposit No. 0216 was filled to a concentration of about 5 vol% to the culture medium, and the same sterilized 5-diluted Cane waste molasses medium used in Comparative Example 1 was used as a fermentation raw material at a flow rate of 0.03. //h Continuous fermentation was carried out for fermentation optometry.

The ethanol concentration in the effluent reaction solution after the reaction is determined by the batch fermentation (
It was about 55,971, which is almost the same as in Comparative Example 1).

Example $3 A fermentation apparatus shown in Figure 3 was used. This consists of a fermenter with an actual volume of 1 and 21 as shown in Figure 1) and a fermenter with an actual volume of 0 as shown in Figure 2.
．． 77 fluidized bed fermentation devices are arranged in front and behind. The pre-stage tank 511 has a stirring rack, is configured to be able to control temperature and pH, and is equipped with a substantially Y-shaped solid-liquid separation member [Co., Ltd.] for separating the carrier from the reaction liquid. ] Carbon dioxide gas is discharged from the large diameter branch (53m), and the reaction liquid is discharged from the small diameter branch 115 (53b). On the other hand, the latter stage tank (61) is also configured to be able to control temperature and pH, and has a carrier sedimentation section (62) at the top of the n1 tank. Then, the fermentation raw material is supplied to the first stage tank 1511 by the pump (71), and then the reaction liquid is transferred from the first stage tank 151) to the second stage tank (61) by the pump (72).
The water is sent to the tank and circulated in the latter tank (61) by a pump (73).

Glucose 100g/j Yeast Extract 3 f/l KH2PO419/1 (NH4)2804 1ri71MgC1
2.6H200,5f/1 Antifoaming agent (manufactured by Next Summer Silicon Co., Ltd.) 0.397
400 ml of culture medium consisting of 1 was filled in all of the former tanks and 600 ml of the latter tank (61), and heat-treated crushed vermiculite (60 to 80
Mesh) was added at a concentration of 5 wt/vol%, and the medium was heat sterilized. Next, 100 m of the culture solution of Zymomonas mobilis ATCC Deposit No. 10988, which was cultured using the above medium, was transferred to the former tank r51.
Added to 1. In addition, the immobilized yeast Satucharomyces hormocensis (Saochar
I F O
(θ Deposit No. 0216 was added to the rear tank at a concentration of approximately 5%. Both the front and rear tanks (51+(61) were used to grow organisms.

Next, sterilized 5-fold diluted Cane's molasses medium (yeast extract: aIi/js (Na3)2so
4:xfI7'1XKa2po4:19/l and M
Continuous fermentation was carried out under the above-mentioned fermentation conditions by continuously supplying Cl2.6H20 (containing 0.5 g/I) to the pre-stage tank 51) at a flow rate of 0.11/h. Both front and rear tanks 1511 (
The ethanol concentrations in the reaction solution in 61#A Dehi were 459/l and 64 g/j, respectively.

Next, change the raw material supply flow rate from 0.1//h to 0.191/b
−,0,2911b and 0.38? /h, and the ethanol concentration at each flow rate was measured. The relationship between the raw material dilution rate (=raw material supply flow rate/fermentation tank golden odor volume) and alcohol productivity is shown in FIG. As can be seen from the figure, alcohol productivity increases in proportion to the dilution rate, with a dilution rate of 0.2
1171 (flow rate 0.3817 h), the alcohol productivity was as high as about 135'//llb. Moreover, the ethanol concentration of the reaction liquid flowing out from the latter stage tank (61) hardly changed.

As described above, using a fermentation device equipped with a separation means in the first stage and a fluidized bed fermentation tank in the second stage, bacteria with alcohol fermentation ability attached to the carrier are cultured in the first stage tank, and bacteria with alcohol fermentation ability are cultured in the second stage tank. By culturing the immobilized yeast in this way, we were able to obtain high fermentation yields and high alcohol productivity. On the other hand, it has been reported that in the basic continuous squeeze culture method that does not use carriers for attachment of bacterial cells, the ethanol productivity is 2 to 3 g/l @h. Thus, according to the present invention,
It is possible to maintain a high alcohol fermentation yield and significantly improve productivity.

[Brief explanation of drawings]

Figure 1 (a), (b), and G9) are all schematic diagrams of a fermentation device equipped with separation means, Figure 2 is a schematic diagram of a fluidized bed fermentation device, and Figure 3 is a fermentation device used in the examples. FIG. 4 is a graph showing the relationship between culture time and ethanol concentration for various microorganisms in batch fermentation, and FIG. 5 is a graph showing the relationship between raw material dilution rate and alcohol productivity that can be used in Examples. G11...Pre-stage tank equipped with separation means, (61)...
Fluidized bed type rear stage tank. Patent applicants: 4 people other than Hitachi Zosen Corporation Figure 2 Figure 3

Claims (1)

[Claims] A fermentation device equipped with a separation means for separating the carrier from the reaction solution is placed in the first stage, a fluidized bed type or packed fermentation device is placed in the second stage, and bacteria with alcohol fermentation ability attached to the carrier are cultured in the first stage. A method for continuous production of alcohol by fermentation, characterized by culturing immobilized yeast in the latter stage.