JPS58129988A - Continuous preparation of alcohol by fermentation - Google Patents

Abstract

PURPOSE:To improve the yield of an alcohol from a raw material saccharide, by arranging two fermenting devices having a means to separate a carrier from a fermented solution in series, cultivating a bacterium capable of fermenting an alcohol attached to a carrier by the former fermenting device and a flocculating yeast by the latter. CONSTITUTION:For example, a solution of waste molasses diluted by five times is fed through the pump 47 to the fermenting device 41, and sent from the branched part 45b with a small diameter of the solid-liquid separating member 45 of the device through the pump 48 to the fermenting device 42. A bacterium capable of fermenting an alcohol, attached to a carrier, is cultivated in the fermenting device 41, and a flocculating yeast in the fermenting device 42. The solution of waste molasses is subjected to alcohol fermentation by the two in high yield. The fermented solution having finished fermentation is taken out from the branched part 46b with a small diameter of the solid-liquid separating member 46 of the fermenting device 42. The bacterium in the fermenting device 41 and the yeast in the fermenting device 42 are separated from the solid-liquid separating members 45 and 46 respectively, 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. It is made from sugar cane, molasses harvested from it, cellulose or starch from sweet potatoes, potatoes, corn, etc., and is fermented by the action of bacterial cells!
do. In this method, alcohol productivity is thought to depend on the bacterial cell concentration. 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 microbial cells becomes clogged or nozzles clogged by solid matter present in the culture solution, 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 addition, in the case of subsequent production, 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 involves arranging two fermentation apparatuses i'j in series, each equipped with a separation means for separating the carrier from the reaction solution, and culturing bacteria with alcohol fermentation ability attached to the carrier in the first stage. In addition, this is a continuous method for producing alcohol by fermentation, which is characterized by culturing flocculant yeast +11 in the latter stage.

Examples of fermentation apparatus rj equipped with separation means include those shown in the accompanying drawings. In other words, Figure 1 (a)
The fermentation apparatus shown in t# (11 is a fermentation tank (3) equipped with an agitator (2) with a carrier sedimentation part (4) on the side thereof, and the carriers are sedimented and separated in the same part (4). The fermentation apparatus tUt shown in FIG. The carriers flowing out from the tank (13) are separated by sedimentation in the sedimentation tank (141), and the sedimented carriers are returned to the fermentation tank (131).Furthermore, the fermentation device (21) shown in FIG. In this method, a stirring blade @ is placed at the bottom of the fermentation tank 23+, and a cylindrical liquid circulation member is placed perpendicularly to the side of the blade, and the reaction liquid is transferred to the fermentation tank 24+.
The liquid circulating member is arranged to separate the carrier from the reaction liquid at the L side.

Furthermore, the fermentation apparatus 01) shown in Fig. 1) has a stirrer (2
) is equipped with a solid-liquid separation member (341) in the shape of an approximately Y-shaped tube that separates the carrier from the reaction liquid, and discharges carbon dioxide gas from the large diameter branch and removes the reaction liquid from the small diameter branch. These fermentation apparatuses (1) CIll f211 and F311 are all constructed so that the pH and temperature can be controlled to optimum values.

In the first stage, crushed vermiculite, activated carbon, zeolite, etc. are preferably used as the carrier for bacterial cell attachment from the viewpoint of fluidity of the carrier. Bacteria with alcohol fermentation ability include Zymomonas mobilis.
mobilis) is preferably used because it has excellent natural adhesion to the carrier. This bacterium is called Cane (ca.
nθ) Among the fermentable sugars contained in juice and blackstrap molasses, sucrose, glucose, and fructose f [fermented to produce alcohol. Bacteria having alcohol fermentation ability may be any bacteria that have good natural adhesion, and are not limited to -F bacteria. By culturing the microbial cells attached to the carrier in the first stage, the concentration of microbial cells in the tank can be increased and the productivity of alcohol from the f-2 fermentable sugar can be improved.

In the latter stage, the flocculating yeast may be any yeast having flocculating ability and alcohol fermentation ability.

In particular, ssccharomyces
Those of the genus s) are preferably used. By culturing flocculating yeast in the latter stage, unreacted fermentable sugars that were not fermented in the earlier stage are fermented to produce alcohol, thereby improving the alcohol fermentation yield from sugar. can.

Since the alcohol production method according to the present invention is configured as described above, the following effects are achieved.

(1) In the first stage, since a carrier is used to attach the bacterial cells, the solid surface area to which the bacterial cells can attach is increased, and the concentration of bacterial cells in the tank can be increased.As a result, alcohol production is improved. performance can be significantly improved.

(2) Since flocculating yeast is cultured in the latter stage, the unreacted fermentable axis that was not fermented in the first stage can be fermented by fermentation t:J, and as a result, the fermentation yield can be greatly improved. I can do it.

131 Bacteria with good adhesion to microorganisms and flocculating enzymes 1; Since the above is used, the average terminal velocity of microorganisms increases, and therefore the microorganisms can be separated from the reaction solution by simple separation means, and the equipment is Significant cost advantages can be obtained.

Comparative example 1 Quiet i? Using a fermenter for culturing, Sacca U was used as a microorganism.
Myces hormocensis (Saccharo+nyc
θSformosensis) Engineering FO Deposit No. 0216
(hereinafter referred to as microorganism A), a 5-fold diluted Cane's molasses medium (yeast extract: 3 g) in a sterile stream was used as the fermentation raw material.
//, (NH4)2so+:ig/l! , Kr(2po
4:19/l and MgO/266H2o: 0.5g/
Batch fermentation was carried out at a wetness of 3 Ω° 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 mobilisae FO
Deposit No. 13756 (hereinafter referred to as Microorganism C) and Zymomonas mobilis A T OO Deposit No. 1098
No. 8 (hereinafter referred to as Microorganism Ri), each L
The above operation was repeated.

Figure 2 shows the relationship between static culture time and ethanol concentration for each microorganism. As shown in the figure, microorganism A has the best alcohol fermentation ability (approximately 5% on the second day).
51//1. , is microorganism B, and for microorganisms C and D, the alcohol concentration is about 40 f even on the 4th day.
It was only /l.

Comparative Example 2 Flocculating baker's yeast produced by Kyowa Hakko Co., Ltd. was cultured in a fermentation apparatus (31) with an actual volume of 1.2 e as shown in Figure 1), and the same sterilized flow as used in Comparative Example 1 was used as a fermentation raw material. A 5-fold diluted Cane's molasses medium was continuously supplied at a flow rate of 06e/h, and continuous fermentation was carried out under the fermentation conditions of a temperature of 30° C. and a pH of 5. The reaction solution was continuously drawn out using a microtube pump. The ethanol concentration in the effluent reaction solution was approximately the same as in the case of batch fermentation (Comparative Example 1), approximately 579/l.
Met.

Example A fermentation apparatus shown in FIG. 3 was used. This is the actual volume shown in Figure 1) of 1.21! Equipment 2 of the same type as the fermentation equipment (31)
The fermenters are arranged in series, with the front and rear fermenters f41) (4'l)
J each has a stirrer F431 +441, temperature control and.

It is configured to be able to control the water and pH. In addition, these fermenters +411 (4'lr are each equipped with a solid-liquid separation member +451 (4G) in a substantially Y-shaped tubular shape that separates the carrier from the reaction solution, and the large-diameter branch part (45
a) Exhaust carbon dioxide gas from (46m) and connect to small diameter branch (
45b) (461)) to discharge the reaction solution. Then, the fermentation raw materials are pumped (4η) to the front stage tank (
41), and then the reaction liquid is sent from the former tank (41) to the latter tank f4Z by the pump (481), and the reaction liquid is sent to the latter tank f4Z by the pump (481).
It is designed to be taken out from the latter stage tank (421).

Glucose 10051/V yeast extract 39/lKH2PO41f/1 (NH4)2SO41fil MgO/2sfiH20o, 511/1 antifoaming agent (manufactured by Next Summer Silicon Co., Ltd.) Add a medium consisting of 0.39/1 to +'+fJ Al at 400mf in the second stage tank. (42) to 6
00 ml each, and 5 pieces of heat-treated crushed vermiculite (60 to 80 mesh) were added to the pre-stage tank (41).
wt'/vol! %, and the medium was heat sterilized. Then, using the medium described in "7f"
Zymomonas mobilis deposited at ATOC No. 1
100 mj of culture solution No. 0988? was added to the pre-stage tank (41), and 100 y of culture solution of Saccharomyces brewer's yeast No. 2018 was cultured in the same manner as above.
Add r+, / to the latter tank (421. Both tanks (4I) [4
2) The microorganisms were grown by controlling the temperature at 4.5°C and 30'C for about 8 hours.

Next, sterilized 5-fold diluted Cane's molasses medium (yeast extract: 39//% (NH4)2SO4:I
f/J, KH2PO4:1f/l and Mg0I! 2*
5H20: 0.5f/l), flow rate 0.071
! Continuous fermentation was carried out under the above-mentioned fermentation conditions by continuously supplying the mixture to the pre-stage tank (41) at a rate of 1/h. The ethanol concentrations in the reaction liquid at each outlet of the front and rear tanks +411 and +421 were 45 f//l and 64 f/l, respectively.

Next, increase the raw material supply flow rate from 0.07//h to 0.141
/ h % 0.211 / h O, J: Hi 0.2
The ethanol concentration was measured at each flow rate by increasing the flow rate to 81/h. FIG. 4 shows the relationship between the raw material dilution rate (-raw material supply flow @ /fermentation tank metallic odor volume) and alcohol productivity. As you can see from the same figure, alcoholic beverages 1
Productivity improves in proportion to the dilution rate, and the productivity increases at a dilution rate of 0.2h-1 (
At a flow rate of 0.28 f/h), alcohol productivity is approximately 139
The result was a high i+f4 of /l・h. Also, the latter tank f4
There was almost no change in the ethanol concentration of the reaction solution flowing out from a.

As described above, by using two post-ITQ fermentation devices rt equipped with separation means, by culturing bacteria with alcohol fermentation ability attached to the carrier in the first stage and culturing flocculating yeast in the second stage, a high A high fermentation yield and high alcohol productivity could be obtained. On the other hand, it has been reported that the ethanol productivity is 2 to 3 f/l@h in the conventional continuous culture method that does not use a carrier for bacterial attachment.

As described above, according to the present invention, it is possible to maintain a high alcohol fermentation yield and significantly improve productivity.

[Brief explanation of the drawing]

Figure 1 (a), (b), and (c) are all schematic diagrams of fermentation equipment equipped with separation means, and Figure 2 is a graph showing the relationship between culture time and ethanol concentration for various microorganisms in batch fermentation. FIG. 3 is a schematic diagram of the fermentation apparatus used in the examples, and FIG. 4 is a graph showing the relationship between raw material dilution rate and alcohol productivity in the examples. (41) @@Fist first stage fermentation tank, +42) @@11 second stage fermentation tank, +45) +461...Solid-liquid separation member. Patent applicants: 4 people other than Hitachi Zosen Corporation Figure 2 Between Shizuka 14 and efiJ (day) 4 station rate (■・1-gas)

Claims (1)

[Claims] Two fermentation devices equipped with separation means for separating the carrier from the reaction solution are arranged in series, and bacteria with alcohol fermentation ability attached to the carrier are cultured in the 11th stage, and flocculating yeast is cultured in the latter stage. A method for continuous production of alcohol by fermentation.