JPS5828288A - Production of alcohol from low concentration sugar liquid - Google Patents

Abstract

PURPOSE:To produce alcohol from a low concentration sugar liquid, in high yield, by contacting the sugar liquid with activated charcoal to effect the adsorption of the sugar to the charcoal, and then mixing and contacting the activated charcoal with microorganisms having alcoholic fermentation capability. CONSTITUTION:A low concentration sugar liquid (sugar concentration of 3- 6wt%) e.g. obtained by the saccharification of a cellulosic material, is supplied as a raw material 1 to the contact tank 6. The raw material 1 is transferred upward in the contact tank 6 filled with activated charcoal, and made to contact with the activated charcoal to effect the adsorption of the sugar to the charcoal. The sugar-adsorbed activated charcoal is separated from the raw material 1, sent to another contact tank 27 through the discharge valve 7 and the discharge selector valve 11, and brought into contact with a suspension of yeasts or bacteria having alcoholic fermentation capability and sent from the mixing tank 34. The mixture is sent to the other contact tank 17, and subjected to the alcoholic fermentation under anaerobic conditions. The liquid on the activated charcoal layer is transferred to the centrifugal separator 22 to separate the alcoholic fermentation liquid.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing alcohol from a low concentration sugar solution, which efficiently converts sugar into alcohol by the action of microorganisms such as yeast in a solution containing a shield such as glucose at a low concentration. be.

Ethyl alcohol is attracting attention as a fuel for internal combustion engines. Production from biomass, a resource that is regenerated every year, is particularly promising. This uses sugar contained in biomass. Examples include sugar cane juice or a sugar solution obtained by hydrolyzing polysaccharides such as starch and cellulose. Alcohol production has been technically established in the production of alcoholic beverages and fermented alcohol production using highly concentrated sugar solutions as raw materials. However, if a low-concentration sugar solution is used as a raw material, such as a saccharified solution (sugar concentration 3-6% by weight) using cellulose cellulase (cellulose hydrolase), it must be concentrated to about 10-20% by weight by evaporation or other methods. Must be. Since this concentration operation requires a large amount of energy, the energy efficiency is extremely low when producing ethanol using a low-concentration sugar solution as a raw material. by the way,
The amount of low-concentration sugar solution generated is on the rise. for example,
Alcoholic fermentation waste liquid made from highly concentrated sugar solution, mata,
Examples include cellulose saccharification liquid made from cellulose-based materials. In particular, the latter is likely to be affected by food problems in the future.
It is predicted that demand will increase as it becomes difficult to produce alcohol using raw materials. Therefore, a technology for efficiently producing alcohol from low-concentration sugar solutions is essential.

An object of the present invention is to provide an efficient method for producing alcohol from low-concentration sugar liquid.

An overview of the present invention is as follows.

The present invention is based on the fact that when activated carbon adsorbed glucose was brought into contact with yeast anaerobically, ethanol production was observed, and after the reaction, when activated carbon and yeast were brought into contact aerobically, activated carbon This proposal is based on two points: that it has been almost completely regenerated.

This method efficiently produces ethanol from a low concentration sugar solution by organically combining the following operations.

The features of the present invention include the process of contacting a low-concentration sugar solution (10% or less) with activated carbon and adsorbing the sugar onto the activated carbon, and mixing the activated carbon adsorbed with sugar with yeast or bacteria capable of fermenting alcohol under anaerobic conditions. A method for producing alcohol from low-concentration sugar liquid, which comprises a contacting step.

Hereinafter, details of the present invention will be explained with reference to the drawings.

FIG. 1 is a flowchart of an example in which granular activated carbon is used. Note that activated carbon has different methods depending on whether it is granular or powdered, but they are basically the same. The flow is that three contact tanks alternately repeat adsorption, fermentation, and regeneration, but this diagram shows
This figure shows a state in which the contact tank 6 is performing adsorption, the contact tank 17 is performing fermentation, and the contact tank 27 is performing regeneration.

The particle size of the activated carbon filled in the contact tank 6, 17.27 is preferably about 0.1 to 5 g, and in particular, 0.5 to 2 g is preferable since it has a large amount per unit volume and is suitable for yeast. Alternatively, if it is suspended with bacteria, the two can be separated in a stationary state, which is good. However, since specific gravity etc. differ depending on the material of the activated carbon, the particle size is not particularly limited. In addition, a draft tube is installed in each type of tank to facilitate fluidization.
There is no particular limitation as long as the structure has a high contact efficiency.

Raw material 1 with a low concentration sugar solution (approximately 10% or less) is supplied to a contact tank 6, rises in the contact tank 6, and comes into contact with activated carbon. Examples of low-concentration sugar solutions include cellulose enzymatic saccharification solutions, alcoholic fermentation waste solutions, and dilute shield solutions, but those with a sugar concentration of 10% or less are targeted. At this time, the raw material valve 2, the discharge valve 7, the exhaust valve 9, and the discharge switching valve 11 are open, and the circulation valve 3, the ventilation valve 5, the return valve 8, and the prosthetic valve 10 are closed. Further, the circulation pump 4 is stopped. Therefore, the raw material that has come into contact with the activated carbon and has had sugar adsorbed by the activated carbon is allowed to flow into the contact tank 27 through a conduit provided with the discharge valve 7 and the discharge switching valve 11, and the raw material 1 and the activated carbon are separated. Fixed amount of raw material 1
After passing the liquid through, the raw material valve 1 and the discharge switching valve 11
is closed, the return valve 8 is opened, and a suspension of yeast or bacteria is supplied from the mixing tank 34 by the return pump 35.

It is preferable that the volume of the suspension is at most twice the filled volume of the activated carbon because fermentation will be faster. The yeast Alui used is Saccharomyces cerevisiae as a bacterium.
e, Saccharomyces carisb
erge.

n5is, BaciJlus sterotherm
There is no particular limitation as long as it is an ethanol-producing bacterium such as S. ophillus. In addition, the bacterial cell concentration is 50 to 100 g
/ is in good condition. The mixing tank 34 is for mixing yeast or bacteria separated by the centrifuge 22 with a medium 36 that does not contain a carbon source. The medium 36 used varies depending on the bacteria used. For example, Saccharomycescer
The case of E. evisiae is as follows; however, there are various reagents such as a nitrogen source, so there is no particular limitation.

Medium composition: yeast extract 6g/l, urea 4g/tz
Potassium phosphate 1.0 g / lz Disodium phosphate 1.0 g / As magnesium sulfate 0.5 g
/ t% Cal'7ium chloride 0.16 g/l, I)
When the supply of the H4,0 yeast or bacteria suspension is completed, the return pulp 8 is closed, the circulation pulp 3 is opened, and the circulation pump 4 is started. This state is the contact tank 17. Raw materials: pulp 12, ventilation pulp 15, discharge valve 18
, the return pulp 19 is closed, the circulation pulp 13 and the exhaust pulp 20 are opened, and the circulation pump 14' is in operation. The #i ring pump 14 presses the upper liquid of the contact tank 17 into the lower part of the contact tank to fluidize and mix the activated carbon. The inside of the contact tank 17 has a pH of 1 and a temperature suitable for fermentation, for example, 5accha rom.
If yces ogrevis i ae, then p
The temperature is controlled at H4.0 and 30C. After a certain period of time has passed, the circulation pump 14 is stopped and the circulation pulp 13
Close and let stand. After standing still, the discharge valve 18 is opened, and the liquid above the activated carbon layer is drawn out and sent to the centrifuge 22. The centrifugal separator 22 separates the yeast or bacteria slurry into a fermentation liquid containing ethanol, and the slurry liquid is transferred to a mixing tank 34 by driving a pump j3, and the fermentation liquid containing ethanol is extracted from a tube 37. After the liquid has been drained, the discharge pulp 18 is closed, the ventilation pulp 15 is opened, and air is forced in from the compressor 16.

This state is the contact tank 27. The raw material pulp 23, circulation valve 24, discharge valve 28, return pulp 29, prospulp 31, and discharge switching pulp 32 are closed, and the ventilation pulp 26 is opened. While controlling the pH and temperature in the tank to values suitable for growth, air is aerated for a certain period of time, and the residual yeast or bacteria and activated carbon are mixed. Then, the ventilation pulp 26 is closed, the discharge valve 28 is opened, and the discharge switching pulp 3 is closed.
2. Open the raw material pulp 23 and pass the raw material 1 through it. This state is the contact tank 6.

As described above, each contact tank performs ethanol fermentation of a low concentration sugar solution by repeating adsorption, fermentation, and regeneration. In addition, 21 is discharge switching pulp, 2
5 is a circulation pump, and 30 is an exhaust pulp.

Example 1 Using granular activated carbon, adsorption of glucose, fermentation by contacting activated carbon and yeast under anaerobic conditions, and regeneration by contacting activated carbon and yeast under aerobic conditions were performed.

The contact tank has an inner diameter of 10 crn and a height of 100 crn, and an inner circular pipe with an inner diameter of 4 m and a height of 40 crn is connected from the bottom of the tank by 3 m.
It was installed at the position of Crn so that the center coincided with the tank. The tank was filled with activated carbon having a particle size of 1 to 21 WI at 4K.

A 1% glucose aqueous solution was passed through the tank bottom at 5 t/h. As a result, the relationship between the amount of liquid passed and the glucose concentration in the discharged liquid as shown in FIG. 2 was obtained, and the amount of liquid passed exceeded 15.

Then, Saccharomyces cereVis
iae and a mixed solution of the medium having the above-mentioned composition were added. At this time, the bacterial cell concentration was 60 g/l. Then, the liquid is extracted from the top of the platform and pumped into the tank from the bottom.
Activated carbon was allowed to flow slowly. In addition, the temperature inside the tank and I
)H was controlled at 30C, 4, and 0, respectively.

The results of fermentation are shown in Figure 3. The ethanol concentration in the liquid reached 10 g/l in 3 hours.

Next, after standing still for 30 minutes, the fermentation prosthesis was pulled out from the outlet, and while maintaining the pH and temperature inside the tank, ventilation was performed from the bottom of the tank for 3 hours. After aeration, a 1% glucose solution was passed through the chamber, and almost the same results as in FIG. 2 were obtained.

Example 2 The same experiment was carried out using the apparatus of Example 1 for aqueous glucose solutions of 0.2, 0.5, 1, 5, 20, 30, and 40 g/l. However, in the adsorption step, the flow rate of each aqueous solution was 10 t/h for 5 g/ or less, and 1 t/h for 20 g/ or more.

As a result, an ethanol solution of approximately 10 g/l was obtained through the fermentation operation in each case. Note that the amount processed decreased as the glucose concentration increased.

From the above, it can be seen that the present invention can be applied to a wide range of low concentration sugar solutions.

Example 3 The concentration of ethanol produced in Example 1 was investigated when the filling amount was changed to F3 K9.

Glucose concentration was 10 g/l. In addition, to circulate the liquid during the fermentation operation, a net was installed at the extraction port to circulate only the liquid.

As a result, the concentration of the produced ethanol was H12 tg/l, which was approximately twice that of Example 1.

Example 4 As shown in FIG. 1, a continuous operation was performed by switching the three layers.

Each type had the seed shape used in Example 1, and was filled with 4 to 9 pieces of activated carbon having a particle size of 1 to 2 mm. The operation of the valves and pump centrifuge was controlled by a program timer. The switching time on each side was 3.5 hours, and the conditions for adsorption, fermentation, and regeneration were the same as in Example 1.

As a result, an average of 1 Pros with an ethanol concentration of 6 to 1 og/l was obtained per hour.

Next, an example in which powdered activated carbon is used will be described with reference to the flowchart of FIG. 4.

The difference from using granular activated carbon is that the activated carbon and yeast or bacteria flow through the flow in a mixed state without being separated.

The raw material 1 and a suspension of activated carbon and yeast or bacteria are supplied to a contact tank 39 and mixed and stirred. Next, activated carbon and yeast or bacteria are separated from the discharged liquid of the contact tank 39 by a centrifuge 4o, and these are stored in a buffer tank 42, and the remainder is discharged from a pipe 41 as a separated liquid. A slurry of activated carbon and yeast or bacteria is supplied to a fermenter 44 by a slurry pump 43. At this time, the medium excluding the C source is the medium 'f4J! ! ! It is supplied from tank 45. In addition,
The yeast or bacterial cells my in the fermenter 44 are 50 to 1
00g/ is in good condition. The pH 9 temperature in the fermenter 44 is a value suitable for yeast or bacteria.

- be sent. The activated carbon and yeast or bacteria that have remained for a certain period of time are discharged from the fermenter 44 together with the fermentation broth.

Then, the fermentation liquid 47, activated carbon, and yeast or bacteria are separated by centrifugation 46.

A slurry of activated carbon and yeast or bacteria is stored in a buffer tank 48 and then sent to a regeneration tank 50 by a slurry pump 49. The regeneration tank 50 is maintained at a temperature and pH suitable for the growth of yeast or bacteria, and air 51 is pressurized from the bottom of the tank for aeration and agitation. After the activated carbon and the bacteria remain for a certain period of time, they are sent to the contact tank 39 by the slurry pump 52.

As described above, a slurry of powdered activated carbon and yeast or bacteria is continuously passed through the adsorption, fermentation, and regeneration steps to perform ethanol fermentation of a low-concentration sugar solution.

Example 5 Using the apparatus shown in FIG. 4, ethanol fermentation with a low concentration sugar solution was carried out using powdered activated carbon.

The volumes of the contact tank, fermentation tank, and regeneration tank are each 4 tons,
The weight was 101.4 tons, and the charging rate was 0.6.

The operation is as follows.

A 10 g/l glucose solution and a suspension of activated carbon and yeast were continuously supplied to the contact tank at 4 t/h and 1 t7 h, respectively, and the mixed liquid was discharged at 5 t/h. The concentrations of activated carbon and yeast at the inlet are approximately IK9, respectively.
/ and 0.1 to 9/l. Note that the temperature of the contact tank was 20±3C. A slurry of activated carbon and yeast was recovered from the discharged liquid from the contact tank using a centrifugal separator, and was supplied to the fermentation tank at a rate of 0.5x7h. At this time, add 1 medium at the same time.
It was supplied at t7h. Then, the liquid in the tank was discharged at a rate of 1.5 t/h. The fermentation conditions were the same as in Example 1. Next, the activated carbon and yeast slurry and fermentation liquid were separated from the discharged liquid by centrifugation. As a result, a fermentation liquid with an ethanol grit of 18 to 22 g/l was obtained. Obtained.

In addition, when the supply amount of the medium was 0.5 t/h, the ethanol concentration of the fermentation liquid was 30 to 43 g/'t.

Next, add the activated carbon and yeast slurry to each concentration at IK.
9/ and 0. A medium was added to give a concentration of IKy/l to form a suspension. Furthermore, it was sent to a regeneration tank and aerated and stirred. Then, the activated carbon and yeast suspension were supplied to the contact tank and reused.

According to the present invention, a low concentration sugar solution can be used as a raw material for ethanol fermentation without concentrating it, which is efficient and economical. Furthermore, the present invention is highly versatile and can be applied not only to butanol fermentation using acetone-butanol bacteria, but also to organic acid and amino acid fermentations.

[Brief explanation of the drawing]

Fig. 1 is a flow diagram showing an embodiment of the present invention when granular activated carbon is used, Fig. 2 is a breakthrough curve diagram of granular activated carbon according to an embodiment of the present invention, and Fig. 3 is a flow diagram showing an embodiment of the present invention using granular activated carbon. FIG. 4 is a diagram showing the results of fermentation due to contact with yeast, and is a flow chart showing an embodiment of the present invention when powdered activated carbon is used. 1... Raw material, 4... Circulation pump, 6... Contact tank,
16...Compressor, 17...Contact tank, 22.
...Centrifugal separator, 27...Contact tank, 39...Contact tank, 40...Centrifugal separator, 44...Fermentation tank, 47...
・Fermentation tank, 50... Regeneration tank. Fig. 2) θ 5 10 ° Z through i (
Quantity r horn 3rd eye ρ /23 I season βη (h)

Claims (1)

[Claims] 1. Bringing activated carbon into contact with a low-concentration sugar solution as a raw material to cause the activated carbon to adsorb sugar, and then separating the activated carbon that has adsorbed sugar from the low-concentration sugar solution; 1. A method for producing alcohol from a low concentration sugar solution, characterized in that a microbial suspension is mixed under anaerobic conditions and this microbial suspension with activated carbon is fermented to produce alcohol. 2. In claim 1, the activated carbon is separated from the alcohol after fermentation, the separated activated carbon is brought into contact with a microbial suspension under aerobic conditions, the activated carbon is separated after the contact, and then the activated carbon is A method for producing alcohol from a low-concentration sugar solution, which is characterized in that it is reused in contact with a low-concentration sugar solution. 3. Mixing powdered activated carbon and a suspension of microorganisms with a low-concentration sugar solution as a raw material, and allowing the powdered activated carbon to adsorb sugar,
Thereafter, the slurry of activated carbon and microorganisms that has absorbed sugar is separated from the low-concentration sugar solution, and the slurry of powdered activated carbon and microorganisms is supplied with a liquid and mixed under anaerobic conditions. A method for producing alcohol from a low-concentration sugar solution, which comprises fermenting this suspension containing alcohol to produce alcohol. 4. In claim 3, after fermentation, the powdered activated carbon and the microorganism suspension are separated from the alcohol, the separated powdered activated carbon and the microorganism suspension are mixed under aerobic conditions, and then the A method for producing alcohol from a low concentration sugar solution, which is characterized in that the suspension is reused for mixing with a low concentration sugar solution.