JP2005065695A - Production method and production system for ethanol - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new method and a new system for producing alcohol by solid fermentation, and to provide a method and a system for producing ethanol without discharging waste liquid in alcohol producing process. <P>SOLUTION: The method for producing ethanol by using raw materials containing starch by fermentation comprises following processes; a pellet forming process forming pellets from the raw material, a saccharification process seeding Koji mold to the pellets to obtain saccharified pellets, a solid fermenting process adjusting water content of the fermented mash which comprises the saccharificated pellets, yeast and water, to 30-60 wt.% at the start of fermentation and then performing the solid fermentation. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for producing ethanol by fermentation using a raw material containing starch, and more particularly to an ethanol production method and an ethanol production system that do not generate waste liquid during the ethanol production process.

  The amount of waste discharged in Japan (1996) is 405 million tons for industrial waste and 50.69 million tons for general waste. Among these wastes, food waste accounts for 19.4 million tons, of which general waste is 16 million tons (6 million tons from business and 10 million tons from households) and is discharged from the food manufacturing industry Business industrial waste is 3.4 million tons. Of the total 19.4 million tons, 91% is incinerated and only 9% is converted to recycled products.

  Under this situation, a law (commonly known as the Food Recycling Law) concerning the promotion of recycling of food recycling resources was enforced in 2001 (May 1, 2001). As a result, food-related businesses such as food manufacturing, processing wholesale, retailing, and the restaurant industry have had to work on reducing and recycling food waste discharged from the workplace.

  Suppression, recycling, and weight reduction are priorities as food waste emission reduction measures, but in particular, technologies for recycling (conversion to compost, feed, fuel, etc.) are desired. .

In particular, the alcohol fermentation method for converting food waste to alcohol is being actively developed for practical use in Japan. For example, in Japanese Patent Application Laid-Open No. 2002-159954, a sugar containing sugar produced in this saccharification step is produced by causing an enzyme solution to act on cellulosic waste in a primary treatment facility provided at a primary treatment point. A method of acquiring alcohol by transporting a contained liquid to a central facility provided at a secondary treatment point and performing fermentation using a sugar-containing liquid at the central facility is disclosed (Patent Document 1).
JP 2002-159954 A

  However, the conventional ethanol fermentation method employs a so-called liquid fermentation method in which alcohol fermentation is performed using liquid fermentation mash. For this reason, distillation waste having a high COD concentration and distillation residue remaining after alcohol recovery are generated, and therefore, these treatment / disposal measures are difficult.

  Therefore, in the present invention, the conventional alcohol fermentation method has been fundamentally reviewed, and an attempt has been made to apply a solid fermentation method different from liquid fermentation with distillation drainage. That is, an object of the present invention is to develop a novel alcohol production method and system by a solid fermentation method, and to construct an ethanol production method and an ethanol production system that do not discharge waste liquid in the alcohol production process.

  The present invention has been made to solve the above problems, and in a method for producing ethanol using a raw material containing starch and obtaining ethanol by fermentation, a pellet forming step for forming pellets from the raw materials, and the pellets A saccharification step for inoculating koji molds to obtain saccharified pellets, and a solid for solid fermentation by adjusting the water content at the start of fermentation of the fermentation mash composed of the saccharified pellets, yeast and water to 30 to 60% by weight A method for producing ethanol comprising a fermentation process.

  Here, solid fermentation refers to a fermentation method that is performed in a solid state from the start to the end of fermentation using fermentation mash that maintains the minimum amount of water that allows yeast growth and ethanol fermentation.

  In the conventional liquid fermentation method, yeast is added to an aqueous solution containing about 5 to 10% by weight of reducing sugar and cultured. When alcohol is recovered by distillation after alcohol fermentation, waste liquid and fermentation residue are generated. In the solid fermentation method, since only the fermentation residue is produced after ethanol is recovered by distillation, there is no generation of waste liquid, and work and costs for waste liquid treatment become unnecessary. Moreover, since the water content is lower than that of the liquid fermentation method, the generation of malodor is small and the ethanol can be easily recovered.

  Moreover, the handling of a fermentation raw material can be made easy by pelletizing the raw material containing starch. Moreover, since transportation becomes easy, transportation costs can be suppressed. Furthermore, in the saccharification process, koji molds are likely to grow, so that saccharification efficiency can be improved. In addition, it is more preferable to form the said pellet in the magnitude | size of a rice grain.

  Moreover, according to the preferable aspect of this invention, when the moisture content of the said raw material is 70% or more, it is preferable to provide the pre-processing process which adjusts the moisture content of the said raw material.

  The pellets preferably have a moisture content of 30% by weight or less. By reducing the water content of the pellets to 30% by weight or less, the water activity is reduced. As a result, the fermentation raw material is not oxidized and spoiled, and the storage stability can be improved. Reduction can be achieved. Furthermore, since the weight is reduced, the transportation cost can be reduced.

  Further, according to a preferred embodiment of the present invention, the koji mold is preferably selected from Aspergillus kawachii, Aspergillus oryzae, Aspergillus sojae, or Aspergillus saitoi.

  Further, the present invention is a method for producing ethanol by fermentation using a raw material containing starch, and comprises a saccharification step of inoculating koji mold on the raw material to obtain a saccharified raw material, the saccharified raw material, yeast and water There is provided a method for producing ethanol comprising: a solid fermentation step in which solid fermentation is performed by adjusting the water content at the start of fermentation of fermentation moromi to 30 to 60% by weight.

  If the moisture content of the fermentation raw material is less than 70%, there is no need for moisture adjustment, and the fermentation raw material can be directly subjected to the saccharification step without performing pelletization. Therefore, when a raw material having a water content of less than 70% is used, it can be more easily used as a fermentation raw material for solid fermentation, and the pretreatment step and the pellet forming step can be omitted, so that the cost of ethanol production can be reduced.

  Furthermore, the present invention provides a pellet forming apparatus for forming pellets from a starch-containing raw material, a koji making apparatus for producing saccharified pellets by culturing the pellets inoculated with koji mold, the saccharified pellets, yeast and water. An ethanol production system comprising a solid fermenter for fermenting a fermented mash having a water content of 30 to 60% under anaerobic conditions, and a distillation apparatus for distilling the fermented mash after the fermentation to recover ethanol Is to provide.

  By adopting such a configuration, there is no generation of waste liquid when distillation is performed after the end of alcohol fermentation, and work and cost for waste liquid treatment become unnecessary. Moreover, since the water content is lower than that of the liquid fermentation method, the generation of malodor is small and the ethanol can be easily recovered.

  According to the present invention, since alcohol fermentation is performed by a solid fermentation method having a relatively low water content, there is no generation of waste liquid that has become a problem during alcohol recovery, and work and costs for waste liquid treatment are unnecessary. Become. Moreover, since the residue after distillation contains abundant proteins derived from yeast and koji mold, it can be used as livestock feed.

  Next, the present invention will be described in more detail with reference to the drawings. FIG. 1 shows an outline of an ethanol production system 1 of the present embodiment.

  As shown in the figure, the ethanol production system 1 of the present embodiment includes a compression device 10, a steam drying device 20, a pellet forming device 30, a koji making device 40, a solid fermenter 70, a distillation device 80, and a rectifying device 84. Composed. Hereinafter, these configurations will be described.

  The compression apparatus 10 is a raw material containing starch, and a water content of 70% by weight or more is introduced from the hopper 12 to remove water in the raw material by the compression roller 14 and to contain impurities contained in the raw material. It is for removing things.

  The steam drying device 20 sprays high-temperature and high-pressure superheated steam S on the raw material supplied from the compression device 10 and stirs with the stirring blade 21 until the water content in the raw material becomes 10 to 60% by weight. It is for drying.

  The pellet forming apparatus 30 is for forming granular pellets from the raw material dried to a water content of 10 to 30% by weight with the steam drying apparatus 20. It is preferable that the pellets to be formed have a rice grain size.

  The koji-making apparatus 40 is for obtaining saccharified pellets by inoculating koji molds on the pellets produced by the pellet forming apparatus 30 and saccharifying the starch contained in the pellets with koji mold enzymes.

  An example of the iron making apparatus 40 is shown in FIG. Furthermore, a part of the iron making apparatus 40 is shown in detail in FIG. As shown in FIGS. 2 and 3, the iron making apparatus 40 includes a thermostatic chamber 42 that houses a film container 41 to be described later, a blower pump 43 for blowing air, and a flow rate of air in the blower pump 43. A flow meter 44, a humidifier 45 filled with water to give an appropriate humidity to the air, a soot cylinder 46 for diffusing the air sent from the blower pump to the humidifier 45, and removing germs in the air And a heater 48 and a cooler 49 for adjusting the temperature of the thermostatic chamber 41. A check valve 50 is connected to the connection tube 90 between the humidifier 45 and the precision filter 47 to prevent backflow of air.

  The film container 41 is made of a flexible material, and has an air supply port 51 to which an air supply tube 91 is connected, an exhaust port 52 to which an exhaust tube 92 is connected, and a funnel 53 for introducing bacilli (not shown). A temperature sensor installation port 56 for installing the connected inoculation port 54 and temperature sensor 55 inside the film container 41 is formed.

  The temperature in the film container 41 is measured by the temperature sensor 55 and displayed on a thermometer 57 connected to the temperature sensor 50. A pressure adjustment cock 54 for adjusting the pressure in the film container 41 is mounted downstream of the exhaust tube 92, and a temperature / humidity sensor for measuring the temperature and humidity of the exhaust discharged from the exhaust tube 92. 60. A carbon dioxide sensor 61 for measuring the concentration of carbon dioxide in the exhaust gas constantly monitors the environment inside the film container 41.

  The film container 41 is supported in the thermostat 42 by a support 62 installed in the thermostat 42.

  As shown in FIG. 2, the pellet P and Aspergillus oryzae Asp are put into a film container 41 and cultured at a constant temperature while aeration is performed, whereby the starchy material in the pellet P is saccharified and becomes a saccharified pellet. .

  The solid fermenter 70 is for performing yeast fermentation by adding yeast Y to the saccharified pellets and setting the water content of the fermentation mash to 30 to 60% by weight. The solid fermenter 70 includes a heater 71 for maintaining the temperature at the optimum temperature of the yeast Y, and a stirring blade 72 for supplying oxygen necessary for the homogenization of the added yeast Y and the growth of the added yeast Y. ing. During the fermentation, the stirring blade 72 is stopped, and solid fermentation proceeds under anaerobic conditions.

  The distillation apparatus 80 is for distilling ethanol from the fermentation mash after the fermentation to obtain high-concentration ethanol. As the distillation apparatus, a single distillation machine, a continuous distillation machine, a vacuum distillation machine, or the like can be used. By performing distillation, about 60% by weight of ethanol can be obtained from the fermentation mash after the solid fermentation.

  The rectifying device 84 is used for the purpose of obtaining higher quality and higher concentration alcohol. By performing rectification, 90% by weight or more of ethanol can be finally obtained.

  Next, a method for producing ethanol from a raw material containing starch using the above-described apparatus will be described.

<Preparation of raw materials>
The fermentation raw material is not particularly limited as long as it contains starch, and food, agricultural products, agricultural waste, cooking residues discharged from restaurants, lunch centers, and the like can be used. Since food waste such as cooking residues often contains a large amount of contaminants and moisture, when using a raw material having a moisture content of 70% or more, the contaminants are removed using the compression apparatus 10 shown in FIG. After that, rough dehydration is performed, and further drying is performed using the steam dryer 20 to reduce the water content to 30% by weight or less.

  Further, the raw material is pelletized by the pellet forming apparatus 30. Although the size of the pellets formed can be set as appropriate, it is preferably formed in a size of rice grains from the viewpoint of efficiently breeding koji molds in the saccharification step described later.

  Thus, by drying and pelletizing a raw material, the quality as a fermentation raw material can be stabilized, handling becomes easy, and saccharification in the saccharification process mentioned later can be performed efficiently.

  In addition, when the water content of the raw material is less than 70% by weight, pelletization may be performed without particularly adjusting the water content. In addition, when it is possible to easily granulate by means such as crushing, means other than the pellet forming apparatus 30 may be used.

<Saccharification process>
The pelletized raw material is saccharified using the iron making apparatus 40. After putting pellets into the film container 41 shown in FIG. 3 and further adjusting the water content to 30 to 60% by weight with distilled water, the air in the film container is evacuated with a vacuum pump or the like, Sterilize with an autoclave.

  Next, separately from the funnel 53, bran meal cultured at 30 ° C. for 3 days is used as an inoculum. Then, the temperature of the thermostatic chamber 42 is set to an optimum temperature for the koji mold, and iron making is performed while aeration is performed. By culturing the koji mold in this manner, a saccharified pellet in which the raw starch is saccharified is obtained.

  Aspergillus oryzae KBN606 (for soy sauce), Aspergillus oryzae KBN615 (for soy sauce), Aspergillus sojae KBN650 (for soy sauce), Aspergillus oryzae KBN930 (for miso), Aspergillus oryzae KBN943 (for wheat miso), Aspergillus oryzae KB10 ), Aspergillus kawachii KBN2001 (for shochu), Aspergillus kawachii P10-1 (for shochu), Aspergillus awamori KBN2012 (for shochu), Aspergillus saitoi KBN2024 (for awamori), etc., especially Aspergillus kawachii KBN2001 (for shochu) ), Aspergillus kawachii P10-1, Aspergillus oryzae KBN1015, Aspergillus oryzae KBN943, Aspergillus sojae KBN650, Aspergillus saitoi KBN2024, and Aspergillus awamori KBN2012 are preferably used.

  In addition, the manufactured saccharification pellet can be utilized as an inoculum (starter) of the next saccharification process.

<Fermentation process>
The saccharified pellets are put into the fermenter 70 together with water and yeast, and supply oxygen necessary for the homogenization of the added yeast Y and the growth of the added yeast Y. After stirring for 1-2 days intermittently, fermentation is performed under anaerobic conditions. The moisture content of the fermented moromi is adjusted to 30 to 60% by weight. By adjusting the water content in this manner, alcoholic fermentation can be performed without generating waste liquid from the start to the end of the fermentation.

  Almost no alcohol is produced when the water content is less than 30% by weight. On the other hand, when the water content exceeds 60% by weight, particularly when the water content is 70% by weight or more, waste liquid is generated after alcohol recovery, which is not preferable.

  The temperature can be appropriately set depending on the optimum temperature of the yeast, but it is preferable to set the temperature to 20 to 25 ° C. because it is economical from the viewpoint of cost.

  Yeast of the genus Saccharomyces serevisiae generally used for alcohol fermentation can be used. A part of the moromi after the fermentation can be used as an inoculum (starter) for the next fermentation. The alcohol concentration at the end of fermentation is about 5% by weight.

<Distillation and rectification process>
After completion of the fermentation, the solid mash is distilled by the distillation apparatus 80, and the alcohol concentration is concentrated to about 60% by weight. Further, by rectifying with the rectifying device 84, the alcohol concentration can be finally set to 90% by weight or more.

  The obtained alcohol can be used in various fields as an industrial alcohol. In addition, since the distillation residue contains abundant proteins derived from yeast and koji mold and is nutritionally excellent, it can be effectively used as livestock feed.

  An example in which ethanol is produced by solid-state fermentation using a food residue as a raw material will be described. As fermentation raw materials, food residues discharged from lunch centers and student cafeterias were used. The food residue was preliminarily removed of impurities other than the food residue and excess water using a garbage compression device (manufactured by Nishihara Environmental Health Laboratory Co., Ltd.).

  Thereafter, the food residue was steam dried by a steam dryer (manufactured by Nishihara Environmental Health Laboratory Co., Ltd.) so that the water content was 20% or less.

  Next, dry pellets (hereinafter referred to as “food residue pellets”) in which food residues were granulated into rice grains were manufactured using a forming machine (manufactured by Nishihara Environmental Health Laboratory Co., Ltd.). The composition of the food residue pellet was 20% by weight of water, 20% by weight of total sugar, 7% by weight of reducing sugar, and 18% by weight of protein.

  Next, 700 g of distilled water was added to and mixed with 1000 g of this food residue pellet, and a bag-like laminate film (about 300 mm long, about 400 mm wide, about 400 mm high, with a constricted supply port, exhaust port, and inoculation port) About 40 mm), and the bag was heat-sealed to form a sealed film container (see FIG. 3).

  Next, 2 g of bran meal (Aspergillus sojae KBN650) separately cultured at 30 ° C. for 3 days was inoculated from the inoculation port provided in the film container as a seed meal. After inoculation of the seed meal, the film container is placed in a thermostatic bath shown in FIG. 2, and saccharified food residue pellets are formed by performing koji making at 34 ° C. while supplying air at 5 L / min for 2 to 3 days. Obtained.

  Further, 1000 g of the food residue pellet prepared as described above is added to 1000 g of the saccharified food residue pellet, water is added so that the water content becomes 60% by weight, and the mixture is sufficiently stirred and mixed. It put into the fermenter. Then, 200 ml of shochu yeast (Saccharomyces cerevisiae) cultured at 25 ° C. for 2 days in a YM medium having the composition shown in Table 1 below was added, and solid fermentation was performed at 25 ° C. for 5 days. The fermentation mash was stirred at a rate of once per hour for 2 days from the start of fermentation.

  After completion of the fermentation, the fermentation moromi was distilled using a distiller (manufactured by Uniflows Co., Ltd.) to obtain 100 ml of ethanol having an alcohol content of 67%. The residue after distillation was used for livestock feed.

  As a fermentation raw material, waste bread (mainly the ear part of bread) discarded from a bread factory was used. Since the waste bread had a moisture content of 36% by weight, it was not pretreated for moisture adjustment. The waste bread used was crushed to about 1 cm square. The composition of the waste bread was 36% by weight of water, 40% by weight of total sugar, 22% by weight of reducing sugar, 2% by weight of lipid, 2% by weight of ash, and 20% by weight of others.

  Next, 1000 g of this waste bread is put into a bag-like laminate film (approximately 300 mm long, approximately 400 mm wide, approximately 40 mm high) having a narrow supply port, exhaust port, and inoculation port, and the bag is heat sealed. It was set as the airtight film container (refer FIG. 3).

  Next, 2 g of bran meal (Aspergillus saitoi KBN2024) separately cultured at 30 ° C. for 3 days was inoculated from the inoculation port provided in the film container as a seed meal. After inoculation with the seed pod, the film container is placed in the constant temperature water tank shown in FIG. 2 and saccharified bread mash is obtained by performing cocoon formation at 34 ° C. while supplying 5 L / min for 2 to 3 days. It was.

  Add 1000g of waste bread crushed to 1cm square to 1000g of the obtained bread cake, add water to a water content of 60% by weight, mix well with stirring, and then add to a closed solid fermenter did. To this, 200 ml of shochu yeast (Saccharomyces cerevisiae) cultured in a YM medium having the composition shown in Table 1 at 25 ° C. for 2 days was added, and solid fermentation was performed at 25 ° C. for 3 days. In addition, the fermentation mash was stirred at a rate of once per hour for 1 day from the start of fermentation.

  After completion of the fermentation, the fermented mash was distilled with a vacuum still to obtain about 100 ml of ethanol.

  Banana skin was used as a fermentation raw material. The banana peel was subjected to pre-removal of impurities other than the banana peel using a compression device (manufactured by Nishihara Environmental Health Laboratory Co., Ltd.), and the banana peel was steam-dried so that the water content was 20% by weight or less. Thereafter, dry pellets (hereinafter referred to as “banana pellets”) that were granulated into rice grains were manufactured using a forming machine (manufactured by Nishihara Environmental Health Laboratory Co., Ltd.). In addition, the composition of the banana peel before pelletization was 82% by weight of water, 12% by weight of total sugar, 6% by weight of reducing sugar, 2% by weight of lipid, 3% by weight of protein, and 1% by weight of ash.

  Next, 1000 g of banana pellets are placed in a bag-like laminate film (300 mm long, about 400 mm wide, about 40 mm high) with a constricted supply port, exhaust port, and inoculation port. (See FIG. 3).

  Next, 2 g of bran meal (Aspergillus sojae KBN650) separately cultured at 30 ° C. for 3 days was inoculated from the inoculation port provided in the film container as a seed meal. After inoculation with the seed pods, the film container is placed in the thermostatic water tank shown in FIG. 2, and saccharified banana pellets are obtained by performing koji making at 34 ° C. while supplying air at 5 L / min for 2 to 3 days. It was.

  1000 g of saccharified banana pellets is further charged with 1000 g of banana peel granulated into a large grain of rice, water is added so that the water content becomes 60% by weight, and the mixture is sufficiently stirred and mixed, and this is a sealed solid fermenter It was thrown into. To this, 200 ml of shochu yeast (Saccharomyces cerevisiae) cultured for 2 days at 25 ° C. in a YM medium having the composition shown in Table 1 was added, and solid fermentation was performed at 25 ° C. for 5 days. In addition, the fermentation mash was stirred at a rate of once per hour for 1 day from the start of fermentation.

  After completion of the fermentation, about 50 ml of ethanol was obtained by distilling the fermented mash with a vacuum still.

  As a fermentation raw material, taro cultivated on a farm owned by Tokyo University of Agriculture was used. Since taro has a moisture content of 69% by weight, no pretreatment for moisture adjustment was performed. In addition, taro crushed to about 1 cm square was used. The composition of taro was 69% by weight of water, 23% by weight of total sugar, 6% by weight of reducing sugar, and 3% by weight of protein.

  Next, 1000 g of this taro is put into a bag-like laminate film (length 300 mm, width about 400 mm, height about 40 mm) with a narrow supply port, exhaust port, and inoculation port, and the bag is heat sealed to form a sealed film container. (See FIG. 3).

  Next, 2 g of bran rice bran (Aspergillus awamori KBN2012) separately cultured at 30 ° C. for 3 days was inoculated from the inoculation port provided in the film container as a seed meal. After inoculation with the seed pod, the film container is placed in the thermostatic water tank shown in FIG. 2, and saccharified taro potato is obtained by performing cocoon formation at 34 ° C. while supplying air at 5 L / min for 2 to 3 days. It was.

  Add 1000g of taro crushed to about 1cm square to 1000g of saccharified taro potato, add water to a water content of 60% by weight, and mix well. I put it in. 200 ml of shochu yeast (Saccharomyces cerevisiae) cultured at 25 ° C. for 2 days in a YM medium having the composition shown in Table 1 was added thereto, and solid fermentation was performed at 25 ° C. for 5 days. In addition, from the start of fermentation, fermentation mash was stirred at a rate of once per hour.

  After completion of the fermentation, the fermented mash was distilled with a vacuum still to obtain about 100 ml of ethanol.

1 shows an outline of an ethanol production system 1 of the present embodiment. It is a figure which shows an example of the iron making apparatus. It is the figure which showed a part of iron making apparatus 40 in detail.

Explanation of symbols

  1: ethanol production system, 10: compression device, 20: steam drying device, 30: pellet forming device, 40: koji making device, 41: film container, 70: solid fermenter, 80: distillation device, 84: rectification device

Claims (6)

In a method of producing ethanol by fermentation using raw materials containing starch,
A pellet forming step of forming pellets from the raw materials;
A saccharification step for obtaining saccharified pellets by inoculating koji mold on the pellets;
A solid fermentation process for solid fermentation by adjusting the water content at the start of fermentation of the fermentation mash comprising the saccharified pellets, yeast and water to 30 to 60% by weight;
A method for producing ethanol comprising:   Furthermore, the manufacturing method of the ethanol of Claim 1 provided with the pre-processing process which adjusts the moisture content of the said raw material.   The method for producing ethanol according to claim 1 or 2, wherein the moisture content of the pellets is 30% by weight or less.   The ethanol production according to any one of claims 1 to 3, wherein the koji mold is selected from Aspergillus kawachii, Aspergillus oryzae, Aspergillus sojae, or Aspergillus saitoi. Method. In a method of producing ethanol by fermentation using raw materials containing starch,
A saccharification step for obtaining a saccharified raw material by inoculating koji mold on the raw material;
A solid fermentation process in which solid fermentation is performed by adjusting the water content at the start of fermentation of the fermentation moromi composed of the saccharification raw material, yeast and water to 30 to 60% by weight;
A method for producing ethanol comprising: A pellet forming apparatus for forming pellets from a raw material containing starch,
A koji making apparatus for producing a saccharified pellet by culturing the pellet inoculated with koji mold,
A solid fermenter for fermenting the fermented mash having a water content of 30 to 60% composed of the saccharified pellets, yeast and water under anaerobic conditions;
A distillation apparatus for recovering ethanol by distilling the fermented mash after the fermentation,
Ethanol production system with

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