JP2014014337A - Treating method of cassava pulp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a treating method of cassava pulp capable of easily and efficiently producing ethanol from cassava pulp.SOLUTION: A method for treating cassava pulp comprises: a blending step S1 of adding α-amylase, glucoamylase and an alcohol fermentation yeast to cassava pulp that has a water content of 30 mass% or greater and in-tube mixing the resultant mixture; a blending step S2 of feeding the mixture thus mixed from a feeding port formed in the upper part of a reaction tank and retaining the same therein for 4 hours or longer to perform alcohol fermentation; a step of discharging the reaction product from a discharge port formed in the bottom of the reaction tank; and a step of subjecting the same to solid-liquid separation, and then purifying ethanol in a post-step. According to this method, ethanol can be produced from the cassava pulp in a single reaction tank without conducting agitation or temperature control, and without requiring execution of saccharification and fermentation treatment in another reaction vessel after liquefaction is performed. Thus, the cassava pulp can be effectively utilized in an efficient and energy-saving way.

Description

  The present invention relates to a method for treating cassava lees that produces ethanol from cassava lees using enzymes and yeast.

In recent years, from the viewpoint of environmental protection and the like, methods for producing ethanol and other chemical products using starch contained in wheat, corn, cassava straw, etc. as a raw material are known (for example, Patent Document 1 and Non-Patent Documents). Reference 1).
By the way, cassava mash, which is the casserole mash used for starch production, is partly used as feed, but most of it is dumped and discarded. Methane gas, which is a greenhouse gas, is discharged from the cassava bowl (see Non-Patent Document 2), and environmental degradation is regarded as a problem. In addition, wheat, corn, cassava strawberries, and sweet potatoes also have a problem with food competition. For this reason, for example, a method for producing ethanol from waste such as garbage and waste materials, cassava pulp (cassava lees), or biomass has also been studied (see, for example, Patent Document 2 and Non-Patent Document 3).

Japanese Patent Application Laid-Open No. Sho 61-166397 JP 2009-112200 A

The Japan Institute of Energy "Biomass Handbook" published on September 20, 2002, pages 157-161 2008 Ministry of the Environment Consignment Project 2008 CDM / JI Project Survey Thailand Thai Cassava Utilization Ethanol Production Program CDM Project Survey Maekawa Seisakusho Co., Ltd. February 2009 Page 2-10, 2-11 Page 2-29, page 2-30 New Energy and Industrial Development Organization, Incorporated Administrative Agency FY 2010 Results Report “Technology Demonstration Project for International Technology Consumption Efficiency Improvement Technology FS Bioethanol Production Technology Demonstration Project from Cassava Pulp (Thailand)” February 2011 No. 1 8 pages, 9 pages, 84 pages

However, in the conventional method of producing ethanol from waste such as garbage and cassava pulp (cassava lees) or biomass, the waste was stirred as it was when stirring to efficiently saccharify the starch in the waste. Then, since the viscosity is high, there is a disadvantage that the energy consumed for stirring increases and the cost for producing ethanol increases. In particular, cassava cake has a high viscosity and is difficult to stir. On the other hand, it is also possible to add water to make it easier to stir, but since the starch content in the waste is low, the content of ethanol produced is also reduced and finally distilled when recovering ethanol etc. There is an inconvenience that energy is required.
Moreover, in the method for producing ethanol from the starch as described above, it is first hydrolyzed with α-amylase at about 90 ° C. and then liquefied, then cooled to about 60 ° C. and then saccharified with glucoamylase, and further from 30 ° C. to After cooling to about 35 ° C., it is necessary to ferment with yeast to produce ethanol while continuing cooling so that this temperature range is maintained. During alcoholic fermentation, the use of heat-resistant yeast is also being considered to reduce cooling energy, but heating and cooling will be carried out until ethanol is produced from starch, requiring large operating energy. Become. As described above, in the conventional method, a large amount of energy is required to use waste as a renewable energy, and even if the raw material can be easily obtained at a low cost, the operation cost is large and the operation cost is low. Reduction is desired.

  An object of this invention is to provide the processing method of the cassava lees which can produce | generate ethanol efficiently easily from a cassava lees.

  The cassava lees treatment method of the present invention is a cassava lees treatment method for producing ethanol from cassava lees, wherein α-amylase, glucoamylase and alcohol-fermenting yeast are added to cassava lees having a water content of 30% by mass or more. A mixing step and a reaction step in which the cassava lees added with the α-amylase, the glucoamylase and the alcohol-fermenting yeast in the mixing step are retained in a reaction tank and subjected to alcohol fermentation. To do.

And in this invention, the said mixing | blending process shall be set as the structure which throws into the said reaction tank the mixture obtained by mixing (alpha) -amylase, glucoamylase, and alcohol fermented yeast with the said cassava lees, makes it retain, and carries out alcohol fermentation. Is preferred.
Furthermore, in this invention, it is preferable that the said mixing | blending process sets it as the structure which obtains the said mixture by carrying out line mixing of the said cassava lees, the said alpha-amylase, the said glucoamylase, and the said alcohol fermentation yeast.
Further, in the present invention, the blending step is performed so that the cassava cake put into the reaction tank, the α-amylase, the glucoamylase, and the alcohol-fermenting yeast are multi-layered in the reaction tank. The α-amylase, the glucoamylase, and the alcohol-fermenting yeast are preferably added to the cassava cake.
In the present invention, it is preferable that the mixing step further includes adding at least one of cellulase, pectinase and protease to the cassava cake.
Furthermore, in the present invention, it is preferable that the reaction step uses a reaction tank having a charging port at the top and a discharging port for discharging the reaction product after alcohol fermentation at the bottom.
Moreover, in this invention, it is preferable to set it as the structure which the said reaction process retains for 4 hours or more in the said reaction tank.
In the present invention, in the blending step, the α-amylase is added at 9 × 10 ⁻⁵ U or more and 600 U or less per 1 g of the cassava cake, and the glucoamylase is added at 3 × 10 ⁻⁴ U or more per 1 g of the cassava cake. It is preferable that the composition be added at 200 U or less.
In the present invention, the alcohol-fermenting yeast is preferably Saccharomyces cerevisiae or Kluyveromyce marxianus.

  According to the present invention, the cassava cake having a water content of 30% by mass or more in which α-amylase, glucoamylase and alcohol-fermenting yeast are blended is retained in the reaction tank for alcohol fermentation, so that the conventional liquefaction treatment was performed. Later, it is not necessary to carry out saccharification / fermentation treatment in a separate container, and ethanol can be produced from cassava cake in a single reaction tank without the need for agitation and temperature adjustment. Efficient and effective use of firewood.

The basic flow which shows the processing operation of the cassava bowl of one Embodiment of this invention. The flow for increasing the amount of ethanol production which shows processing operation of cassava lees of other embodiments of the present invention. The flow which shows processing operation (comparative example 1) of the conventional cassava cake for explaining the present invention. The graph which shows the experimental result regarding the relationship between stirring mixing and ethanol production. The graph which shows the experimental result regarding the relationship between the presence or absence of heating and ethanol production. The graph which shows the experimental result regarding the relationship between heating temperature and ethanol production.

Hereinafter, a processing method for cassava cake according to an embodiment of the present invention will be described with reference to FIG.
As shown in FIG. 1, the processing method of cassava lees according to the present embodiment includes a compounding step S1 in which an enzyme and yeast are added to the cassava lees to obtain a mixture, and a reaction tank (not shown) showing the mixture obtained in the compounding step S1. And a reaction step S2 in which alcohol fermentation is performed.

[Mixing process]
In blending step S1, α-amylase, glucoamylase and alcohol-fermenting yeast are added to cassava cake having a water content of 30% by mass or more to obtain a mixture.
The cassava straw used as a raw material is waste discharged when the cassava starch is produced from the cassava straw, and is not limited to any production method of cassava starch.
As the cassava cake used as a raw material, a water content of 30% by mass or more, preferably 70% by mass or more and 90% by mass or less is used. This is because if the water content is less than 30% by mass, it takes a very long time to decompose all the undegraded cassava cake after adding the enzymes and yeast described later. Furthermore, if the water content is less than 30% by mass, the rate of temperature rise of the koji is increased due to the heat generated during ethanol production, and the yeast activity is reduced. Moreover, since substances other than cassava starch are concentrated due to the low water content, ethanol production may be hindered by the influence of the concentrated substances. On the other hand, if it exceeds 90% by mass, the concentration of ethanol in the reaction product obtained after the reaction step described later becomes low, and the amount of energy required for the purification of ethanol in the subsequent step may increase.
Here, the raw cassava cake having a water content of 30% by mass, that is, the cassava cake discarded after the starch is extracted from the cassava cake is not limited. For example, water is added to a dried cassava cake so that the water content is 30% by mass or more, preferably 70% by mass or more and 90% by mass or less, or a raw cassava cake and a dried cassava cake are mixed. What added water as needed may be used.

α-Amylase is added at 9 × 10 ⁻⁵ U to 600 U, preferably 8 × 10 ⁻³ U to 0.6 U, per 1 g of cassava koji.
Here, if it is less than 9 × 10 ⁻⁵ U, it takes time to decompose the starch of cassava lees, and even if it is added in excess of 600 U, the cassava lees are not decomposed and do not remain and are decomposed into ethanol. This is because it is not effective in terms of cost-effectiveness.
Glucoamylase is added at 3 × 10 ⁻⁴ U or more and 200 U or less, preferably 3 × 10 ⁻² U or more and 0.2 U or less per 1 g of cassava koji.
Here, if it is less than 3 × 10 ⁻⁴ U, it takes time to decompose the starch of cassava lees. Even if it is added more than 200 U, cassava lees are not decomposed and do not remain and are decomposed into ethanol. This is because it is not effective in terms of cost-effectiveness.

Furthermore, it is preferable to further add at least one of cellulase, pectinase and protease in addition to α-amylase and glucoamylase as the enzyme. By further adding these enzymes, it is possible to shorten the time until the cassava cake is decomposed to produce ethanol.
Cellulase is preferably added at 1 × 10 ⁻⁴ U or more and 100 U or less, particularly 1 × 10 ⁻² U or more and 0.1 U or less per 1 g of cassava koji.
Pectinase is preferably added at 1 × 10 ⁻³ U to 1000 U, particularly 1 × 10 ⁻¹ U to ¹ U, per 1 g of cassava koji.
Protease is preferably added at 1 × 10 ⁻⁴ U to 100 U, particularly 1 × 10 ⁻² U to 0.1 U, per 1 g of cassava koji.

As the alcohol-fermenting yeast, what is generally called yeast can be used. For example, Saccharomyces cerevisiae or Kluyveromyce marxianus which is a heat-resistant yeast is preferably used. In particular, as will be described in detail later, in the reaction step, when the temperature rises to a certain level (at 45 ° C. or higher) during alcohol fermentation, Kluyveromyce marxianus, which is a heat-resistant yeast, is particularly suitable.
The alcohol-fermenting yeast is preferably added at an initial yeast concentration of 0.05 to 10 in terms of optical density. That is, by adding within this range, the treatment time for producing ethanol from the sugar produced by the enzyme by the alcohol-fermenting yeast does not require a long time even if it is not stirred, and the required amount of the alcohol-fermenting yeast An increase in cost can also be prevented. In addition, if the alcohol-fermenting yeast to be added returns and uses a part of the alcohol-fermenting yeast grown in the subsequent reaction step, it is not necessary to newly add alcohol-fermenting yeast, and ethanol can be produced at a lower cost. be able to.

And, as a method of adding these enzymes and alcohol-fermenting yeast, various conventionally known methods such as mixing in a tube by a screw conveyor or a line mixer that conveys cassava lees to the reaction tank of the reaction step, mixing in a kneader, etc. You can use the method.
In addition, by setting it as the structure which mixes in a pipe | tube in the conveyance path conveyed to the reaction tank of said reaction process, the tank only for stirring and mixing becomes unnecessary, and while the whole processing apparatus can be reduced in size and simplified, Enzymes can be mixed using the energy transferred to the reaction tank, and the energy consumption of ethanol production can be reduced.
By such in-tube mixing, a mixture in which the enzyme and alcohol-fermenting yeast are added to the cassava cake is obtained.

[Reaction process]
In the reaction step S2, the mixture obtained in the blending step S1 is put into one reaction tank, and liquefaction, saccharification, and alcohol fermentation are performed.
Although there are no particular restrictions on the configuration of the reaction tank, the liquid phase increases as liquefaction, saccharification, and alcohol fermentation progress. For example, the mixture is introduced from above, and the reaction product is discharged from the bottom to the outside of the tank. It is preferable that a discharge port is provided at the top and a discharge port at the bottom so that the discharge can be performed. In particular, heat is recovered from the mixture during the reaction, for example, the mixture is cooled by heat exchange with the medium, and the recovered heat is provided with a heat exchange device that uses the water as heat for heating or heating, thereby making energy more effective. Can be recovered.
The reaction in the reaction vessel may be either a batch type or a continuous type.

In the reaction step, the reaction time from the introduction of the mixture into the reaction tank to the discharge from the tank is preferably 24 hours or longer and 120 hours or shorter. That is, the mixture is charged at a temperature of 25 ° C. or more and 35 ° C. or less where the temperature rises somewhat due to room temperature or friction during transportation. This is because in the case of a mixture at such a temperature, alcohol fermentation is sufficiently advanced in 24 hours or more and 120 hours or less.
That is, when it is shorter than 24 hours, starch decomposition and alcohol fermentation are not sufficiently completed, and sugar remains. In addition, when the reaction is not sufficiently completed even after 120 hours, it is in a state where a long time is required for the ethanol generation treatment, and ethanol cannot be efficiently generated.
In the reaction tank, stirring and heating are not performed, and the processing proceeds while the charged mixture is left as it is. That is, starch is decomposed into dextrin by α-amylase, the produced dextrin is decomposed into glucose by glucoamylase, and ethanol is produced from glucose by alcohol-fermenting yeast.

The reaction product thus obtained in the reaction step is transferred to a subsequent ethanol separation step after solid-liquid separation, and ethanol is recovered with higher purity.
As the solid-liquid separation method, various conventionally known methods such as filter press and centrifugation can be applied.
As a method for recovering ethanol in the ethanol separation step, various conventionally known methods such as distillation can be applied. Note that ethanol may be directly recovered by heating the reaction product without performing solid-liquid separation.

[Effects of Embodiment]
In the said embodiment, the starch in cassava lees is made into an enzyme by putting the mixture which added alpha-amylase, glucoamylase, and alcohol-fermenting yeast to the cassava lees with a moisture content of 30 mass% or more in a reaction tank, and making it stay. Since it is gradually decomposed and the water content is high with respect to the starch content, the temperature during fermentation can be suppressed, and inactivation of the yeast due to temperature rise can be prevented. Furthermore, since the water content is high, the viscosity of the mixture does not increase so much even if heated, and even if the liquefaction and the alcoholic fermentation are not performed in a multistage process with stirring after the conventional liquefaction treatment, Just by putting it in the reaction vessel and leaving it to stand, the same degree of ethanol can be produced in the same treatment time.
Therefore, since it is not necessary to carry out stirring even with a high-viscosity cassava bowl, an apparatus for stirring the high-viscosity material and a large energy for stirring are not required, and the cassava bowl can be easily and low-energy with a simple configuration. The ethanol can be produced from the cassava, and the cassava can be efficiently and easily used as a renewable energy.

Moreover, in the said embodiment, in the conveyance path which conveys cassava lees to a reaction tank, an enzyme and alcohol fermenting yeast are added beforehand, and it mixes in a pipe | tube, and puts this mixture into a reaction tank, and implements a reaction process. doing. For this reason, since the enzyme and the alcohol-fermenting yeast are uniformly mixed in the cassava cake, the reaction proceeds efficiently, the reaction time can be shortened, and the production efficiency of ethanol can be improved. In particular, it is not necessary to carry out a separate kneading process with a kneader or the like by in-pipe mixing, and since mixing can be performed in the transport path for transporting the cassava cake to the reaction tank, it is possible to mix more efficiently and to facilitate the processing operation. At the same time, energy for kneading can be reduced, and ethanol can be generated efficiently.
Further, by adding at least one of cellulase, pectinase and protease to the cassava cake, the reaction time in the reaction step can be shortened, and ethanol can be efficiently produced.
In addition, by mixing the various enzymes and alcohol-fermenting yeast in the cassava cake, the enzyme, alcohol-fermenting yeast and cassava cake are uniformly mixed, and the reaction time in the reaction process can be shortened.
Furthermore, the reaction vessel is configured such that the mixture is introduced from the top and the reaction product is discharged from the bottom, so that it is sequentially decomposed to produce ethanol, or water flows out from inside the cell. The phase fraction flows down to the bottom of the reaction vessel and is discharged. For this reason, the reaction product can be easily recovered even by simply allowing the mixture inserted without stirring the mixture in the reaction vessel, and the liquid phase is increased in the vicinity of the bottom so that the reaction can be performed in the liquid phase. Since the reaction proceeds without agitation and the reaction is accelerated, ethanol can be generated sufficiently without the reaction time becoming too long. it can.
Then, it is allowed to stay in the reaction tank for 4 hours or longer, preferably 24 hours or longer and 120 hours or shorter to generate ethanol, so that it can be sufficiently decomposed without adjusting the temperature and stirring of heating and cooling. It can produce ethanol efficiently.

[Modification]
It should be noted that the present invention is not limited to the above-described embodiment, but includes modifications and improvements as long as the object of the present invention can be achieved.
For example, the cassava cake was mixed with enzyme and alcohol-fermenting yeast in the blending process. For example, the cassava cake was mixed by dropping impact when the cassava cake was put into the reaction vessel, or the cassava cake, enzyme and alcohol were added to the reaction vessel. Fermentation yeast may be added little by little so as to form a thin layer. In addition, in these structures, alcohol can be generated without special stirring and mixing. In particular, if the structure is supplied in a layered form, alcohol can be generated in the same processing time as in the case of mixing in advance.
And in the said embodiment, although the structure which introduce | transduces a mixture from the upper part of a reaction tank and discharged | emits a reaction product from the bottom part was illustrated, for example, when the volume of a reaction tank becomes large, pressure resistance, equipment cost, etc. A configuration may be adopted in which the mixture is introduced from the top at a point and discharged from the top by pumping or the like.

In addition, when the mixture is charged into the reaction vessel, the mixture is simply charged. However, as shown in FIG. 2, for example, the cassava cake may be heated before the enzyme or alcohol-fermenting yeast is added.
Specifically, after carrying out heating process S11 which heats cassava lees at 60 ° C or more and 120 ° C or less with water vapor, for example, starch is gelatinized, each enzyme and alcohol fermentation yeast are added, and it mixes in a pipe (mixing process) S1), the reaction step S2 is performed by charging the reaction vessel.
As shown in FIG. 2, the processing efficiency can be improved by heating to a temperature at which starch is gelatinized. In addition, even if it heats below the temperature which gelatinizes starch, the activity of each enzyme and alcohol fermentation yeast increases, and the processing time which produces | generates ethanol can be shortened.
Moreover, processing efficiency can be improved by heating the cassava cake before adding yeast and alcohol fermentation yeast compared with the case where it heats after mixing previously.
In the embodiment shown in FIG. 2, water vapor is used as a method for heating the cassava cake. However, when the water content of the cassava cake is sufficient, heating may be performed by applying various conventional heating methods. . When the water content of the cassava cake is less than 50% by mass, water can be supplied by heating with steam instead of adding water, and thus heating with steam is particularly effective.

And in a reaction process, in order to improve the activity of alcohol fermentation yeast, you may add nutrient sources, such as phosphorus and nitrogen.
As phosphorus, it is preferable to add 3 × 10 ⁻⁴ % by mass or more and 0.03% by mass or less in terms of phosphorus. As a nitrogen source, it is preferable to add 1 × 10 ⁻³ mass% or more and 0.1 mass% or less in terms of nitrogen.

  In addition, the specific configuration and form in the implementation of the present invention may be other structures as long as the object of the present invention can be achieved.

Next, an experiment conducted on the processing method of the embodiment shown in FIG. 1 will be described.
The present invention is not limited by the following examples and comparative examples.

[Experiment 1]
Hereinafter, Experiment 1 relating to the effect of the mixing conditions of cassava meal, enzyme, and alcohol-fermenting yeast on ethanol production will be described.
{material}
The raw material was 2000 g of cassava koji with a water content of 85%, cellulase, pectinase, α-amylase and glucoamylase were used as enzymes, and Saccharomyces cerevisiae was used as yeast.

{Experimental conditions}
Ethanol production conditions were carried out under the following four conditions.
(Comparative Example 1)
As shown in FIG. 3 , in Comparative Example 1, α-amylase was mixed in a 10 L jar fermenter in a cassava bowl to which 2000 ml of water had been added in advance (step S21) , and then stirred at 90 ° C. for 1 hour. Liquefaction treatment was performed (step S22) . Thereafter, glucoamylase and cellulase were added to the product obtained by the liquefaction treatment (step S23) , and saccharification treatment was performed at 50 ° C. for 24 hours with stirring (step S24) . Furthermore, yeast and yeast extract (nitrogen source and phosphorus source) were added (step S25) , and fermentation treatment was performed at 30 ° C. for 24 hours with stirring (step S26) .
(Comparative Example 2)
In Comparative Example 2, α-amylase, glucoamylase, cellulase, yeast, and yeast extract (nitrogen source and phosphorus source) were sprinkled in a cassava cake to which 2000 ml of water had been added in advance in a 10 L jar fermenter. And allowed to react for 48 hours.
Example 1
Example 1 uses a biaxial kneader in which α-amylase, glucoamylase, cellulase, yeast, and yeast extract (nitrogen source and phosphorus source) are added to cassava lees added with 2000 ml of water in advance. The mixture mixed at 55 rpm for 10 minutes was allowed to react for 48 hours in a 10 L jar fermenter.
(Example 2)
Example 2 was allowed to react with stirring for 48 hours instead of standing for 48 hours in Example 1.

{result}
After the reaction, the solid content was removed by centrifugation and filtration, and then the amount of ethanol was measured using gas chromatography. The result is shown in FIG.
From the results shown in FIG. 4, almost no ethanol was obtained in Comparative Example 2 in which the enzyme and yeast were not sufficiently mixed with cassava cake. In addition, it was recognized that the reaction proceeded without stirring as long as the liquid phase component was generated and the enzyme and yeast were in contact with each other.
Moreover, in Example 1 which mixes an enzyme and yeast beforehand, it was recognized that ethanol equivalent to the comparative example 1 which implements a saccharification process and a fermentation process in multiple steps, stirring conventionally is produced | generated. Moreover, in Example 2 which implements stirring at the time of reaction, ethanol equivalent to Example 1 was produced, and the effect of stirring was not recognized.

[Experiment 2]
Next, Experiment 2 relating to the effect of heating before reaction on ethanol production will be described.
{Experimental conditions}
(Example 3)
Example 3 shows that 50 g of cassava cake having a water content of 85%, α-amylase, glucoamylase, cellulase, yeast (Kluyveromyce marxianus), yeast extract (nitrogen source and phosphorus source), Was mixed for 10 minutes at 55 rpm using a twin-screw kneader, and the resulting mixture was allowed to react for 72 hours using a 300 ml beaker.
Example 4
In Example 4, 50 g of cassava cake having a water content of 85% was heated at 80 ° C. for 15 minutes using an autoclave, and then a mixture was obtained in the same manner as in Example 3 and allowed to stand for 72 hours for reaction.
{result}
After the reaction, the solid content was removed by centrifugation and filtration, and then the amount of ethanol was measured using gas chromatography. The result is shown in FIG.
From the results shown in FIG. 5, in Example 4 in which starch was gelatinized by heating in advance, about twice as much ethanol was produced as in Example 3 in which the starch was not heated. From this, it is understood that the processing efficiency can be improved by preliminarily heating and gelatinizing.

[Experiment 3]
Next, Experiment 3 related to the effect of the heating temperature on ethanol production in Experiment 2 will be described.
{Experimental conditions}
(Example 5)
Example 5 was performed in the same manner as Example 4 except that the heating temperature in Example 4 of Experiment 2 was 30 ° C.
(Examples 6 to 10)
Examples 6 to 10 were performed in the same manner as Example 4 except that the heating temperatures in Example 4 of Experiment 2 were 60 ° C., 70 ° C., 80 ° C., 100 ° C., and 120 ° C., respectively.
{result}
After the reaction, the solid content was removed by centrifugation and filtration, and then the amount of ethanol was measured using gas chromatography. The result is shown in FIG.
From the results shown in FIG. 6, from 60 ° C. (Example 6) at which starch gelatinization begins, when ethanol is heated at 30 ° C. (Example 5), the amount of ethanol produced is more than doubled to 100 ° C. In (Example 9), the generation amount is nearly three times. In addition, in the case of heating to 120 ° C. (Example 10), since the temperature is too high and the activities of the enzyme and yeast are starting to decrease, it is considered that the amount of ethanol produced has decreased. It can be seen that it is preferable that the temperature be 60 ° C. or higher and 120 ° C. or lower.

S1 compounding process S2 reaction process S11 heating process

Claims (9)

A method for treating cassava lees producing ethanol from cassava lees,
A blending step of adding α-amylase, glucoamylase and alcohol-fermenting yeast to cassava cake having a water content of 30% by mass or more;
A cassava lees added with the α-amylase, the glucoamylase and the alcohol-fermenting yeast in the blending step are retained in a reaction tank and subjected to alcohol fermentation, and the cassava lees are characterized in that Processing method. The said compounding process throws into the reaction tank the mixture obtained by mixing (alpha) -amylase, glucoamylase, and alcohol fermenting yeast with the said cassava lees, makes it retain, and carries out alcoholic fermentation. How to treat cassava coffee. The said cassava lees, the said alpha-amylase, the said glucoamylase, and the said alcohol-fermenting yeast are line-mixed and the said mixing process obtains the said mixture. The processing method of the cassava lees of Claim 2 characterized by the above-mentioned. In the blending step, the cassava lees charged into the reaction vessel and the α-amylase, the glucoamylase, and the alcohol-fermenting yeast are multilayered in the reaction vessel. The method for treating cassava lees according to claim 1, wherein the α-amylase, the glucoamylase, and the alcohol-fermenting yeast are added. 5. The cassava meal according to claim 1, wherein at least one of cellulase, pectinase, and protease is further added to the cassava meal in the mixing step. Processing method. The reaction step uses, as the reaction tank, one having an inlet at the top and an outlet for discharging a reaction product after alcohol fermentation at the bottom. A method for treating cassava lees according to claim 1. The method for treating cassava lees according to any one of claims 1 to 6, wherein the reaction step is allowed to stay in the reaction tank for 4 hours or more. The blending step is
The α-amylase is added at 9 × 10 ⁻⁵ U or more and 600 U or less per 1 g of the cassava cake,
The said glucoamylase is added at 3 * 10 < ^-4 > U or more and 200 U or less per 1g of said cassava straws. The processing method of cassava straw according to any one of Claims 1-7 characterized by the above-mentioned. The method for treating cassava lees according to any one of claims 1 to 8, wherein the alcohol-fermenting yeast is Saccharomyces cerevisiae or Kluyveromyce marxianus.

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