JP4038577B2 - Alcohol production system and alcohol production method - Google Patents

Description

The present invention relates to an alcohol production system and an alcohol production method capable of obtaining alcohol for fuel from waste such as garbage, particularly when using yeast belonging to Saccharomyces cerevisiae used in liquor production for alcohol fermentation. about the valid alcohol production system and alcohol production how.

  In recent years, the use of biomass has attracted attention from the viewpoint of global environmental problems. In particular, research and development on technology for producing alcohol such as ethanol, which is expected as a next-generation automobile fuel, from biomass has been actively conducted. This alcohol production is performed by decomposing biomass raw material into saccharides by a saccharification process such as hydrolysis, and then converting it to ethanol by alcohol fermentation using yeast (microorganism).

  As general biomass materials, those containing sugars such as sugar cane or starches such as corn are often used. In addition, plant-based materials such as bagasse and rice straw, wood-based materials such as wood chips, and cellulose-based materials such as biomass are also used as materials. However, these saccharides and starchy raw materials are originally edible resources, and it is not preferable to use these edible resources as industrial resources for a long period of time because they antagonize the future population growth problem.

  Therefore, recently, biomass using industrial waste and the like has been studied, and for example, a method for generating alcohol from waste building materials and the like that can be used as cellulosic resources has been proposed.

  However, when using processed wood such as plywood among waste building materials, there is a problem that the yield of alcohol or organic acid in the fermentation process is lower than when using raw wood such as wood chips. there were. The reason is that processed wood uses adhesives containing acetic acid or formic acid, etc., and if these are contained in a sugar solution, it acts as a fermentation inhibitor that inhibits fermentation by microorganisms. It is. As a method for removing the fermentation inhibitor, ion exchange separation can be employed, but it is problematic in that the cost is increased. Then, the method (1st method) etc. which improve a fermentation yield by providing the pre-processing process etc. which evaporate and remove fermentation inhibitory substance saccharide | sugar from a saccharide | sugar solution are proposed (for example, refer patent document 1). ).

  For alcohol fermentation, a method that has been practiced for a long time in the field of brewing foods is used. For example, a method using Saccharomyces cerevisiae is most commonly used. However, when producing industrial or fuel ethanol that places importance on alcohol productivity, it is generally used near pH 5. For this reason, sterilization and temperature control of a culture solution and a fermentation apparatus cannot be avoided.

  Thus, yeasts having acid resistance and salt resistance have been developed. By such a method using acid-resistant yeast (second method), for example, alcohol fermentation is possible even when a sugar solution having a pH of 3 or less obtained by hydrolyzing (saccharifying) biomass raw material with an acid such as sulfuric acid is used. Become. Furthermore, since the yeast has a combination of acid resistance and salt resistance, as well as sugar resistance and alcohol resistance, sterilization of the culture medium and fermentation apparatus is unnecessary (for example, see Patent Document 2).

JP 2004-187650 A JP 2004-344084 A

  Conventionally, two methods have been proposed as described above, but each has the following problems. That is, in the first method, as described above, the sterilization and temperature control of the culture solution and the fermentation apparatus are unavoidable, and a process for removing acetic acid and the like is necessary before the fermentation process, so that a process load is imposed. There are problems such as becoming larger. On the other hand, in the second method, it is necessary to screen for a new yeast having acid resistance and the like, and it is necessary to add a nutrient source to the yeast in an alcohol fermentation process or the like, so there is an economical and process load. There were problems such as becoming larger.

  The present invention has been made in view of such problems, and the first object thereof is to effectively use raw garbage such as industrial waste as a biomass raw material, and to sterilize even when using a general-purpose Saccharomyces cerevisiae for alcohol fermentation, An object of the present invention is to provide an alcohol production system and an alcohol production method that do not require temperature control and pH adjustment and that can efficiently produce alcohol.

The alcohol production system of the present invention reacts garbage with an enzyme in an anaerobic state to produce a saccharified solution, and also mainly produces lactic acid by microorganisms living in the garbage, and the hydrogen ion concentration (pH) of the saccharified solution ) In the range of 2.5 to 5.5, and to the saccharified solution produced in the saccharification part, adding as a yeast aggregating yeast belonging to Saccharomyces cerevisiae that grows and ferments in the above pH range And a first fermentation part for alcohol fermentation. In the present specification, “garbage” refers to garbage including foods before and after heating (such as leftover food) discarded from households, hotels, convenience stores, etc., and as its components, neutral components (sugars), It contains fat-soluble components (lipids, etc.) or ionic components (proteins, amino acids, organic acids, inorganic salts) and the like . Garbage may be mixed with what is normally disposed of as “burning garbage” such as paper and wood chips.

In addition, the alcohol production method of the present invention reacts garbage with an enzyme in an anaerobic state to produce a saccharified solution, and mainly produces lactic acid by microorganisms living in the garbage, and the hydrogen ion concentration of the saccharified solution Add saccharifying yeast belonging to Saccharomyces cerevisiae that grows and ferments in the above pH range to the saccharified solution in which the (pH) is in the range of 2.5 to 5.5 and the saccharified solution produced in the saccharifying step And a fermentation process for alcohol fermentation .

  In the alcohol production system and the alcohol production method of the present invention, the alcohol is produced as follows by having each part (step) as described above.

First, in the saccharification part (process), garbage and enzymes are reacted in anaerobic conditions to produce a saccharified solution, and lactic acid is mainly produced by microorganisms that live in the garbage, and the hydrogen ion concentration ( pH) is lowered to a range of 2.5 or more and 5.5 or less. Thereby, the growth of miscellaneous bacteria is suppressed, the sterilization of the saccharified solution is unnecessary, and the environment in which the yeast added in the first fermentation part (fermentation process) grows and ferments is prepared. In the first fermentation part (fermentation step), the saccharified solution is added with a coagulable yeast belonging to Saccharomyces cerevisiae that grows and ferments as a yeast in the above pH range, and undergoes alcohol fermentation. In addition, when a rotating blade is used as the saccharification part, it is possible to separate the saccharification solution and the saccharification residue. After completion of the saccharification reaction, mesh filtration is performed, and then the filtrate is squeezed or centrifuged to obtain a saccharified clarified liquid. As a specific saccharification method, garbage, water and an enzyme are mixed and then saccharified at a temperature of 30 ° C or higher, preferably 50 ° C or higher. At that time, the amount of water is preferably ¼ or more, more preferably ½ or more of the wet weight of the garbage, and the amount of the enzyme is 100 mg or more with respect to 1 kg of the wet garbage. Is preferably 300 mg or more. Here, an anaerobic state means the state sealed so that garbage hardly touches external air. In addition, in the said garbage processing, it is good also as a minced garbage by crushing the garbage to which the lactic acid culture solution was added. Next, in the saccharification part (process), after processing waste, water, and an enzyme, for example, it saccharifies at the temperature of 30 degreeC or more, Preferably it is 50 degreeC or more, and the microorganisms which inhabit in a treatment waste process waste. Saccharification is preferred. At this time, if a rotating blade is used, it is possible to separate the saccharified solution and the saccharification residue. The amount of water is preferably ¼ or more, more preferably ½ or more with respect to the wet weight of the treated waste, and the amount of enzyme added is 50 mg or more with respect to 1 kg of the wet treated waste. Is preferably 100 mg or more. Here, acid-resistant glucoamylase or acid-resistant and heat-resistant glucoamylase may be used as the enzyme, and a cellulase enzyme may be further used after the addition of such an enzyme. As a result, the amount of enzyme added can be reduced, and sugar can be recovered more efficiently. In the saccharification part, it is preferable to add the lactic acid bacteria culture solution to the garbage so that it is 10% or less, preferably 1% or less. Further, the enzyme is added to the lactic acid bacteria culture solution, It is preferable that the composition is added after being stored in an anaerobic state and the pH is within the above range.

  Next, the saccharified solution may be subjected to normal pressure concentration or reduced pressure concentration in the concentration unit (step). At this time, it is necessary for alcoholic fermentation by concentrating the saccharified solution until the total saccharide concentration of the concentrated saccharified solution becomes 100 g / l or more and 300 g / l or less (concentration ratio of saccharified solution is 1.5 times or more and 5 times or less). As the nutrient source is concentrated, the concentration of monosaccharides in the saccharified liquid increases, and the concentration of alcohol produced by alcohol fermentation increases. Thereby, the density | concentration of the alcohol in a concentrated saccharified liquid will be 50 g / l or more and 150 g / l or less. Moreover, the pH of the saccharified solution is further reduced by concentration under reduced pressure until the concentration of lactic acid is 2 times or more of that before concentration, more specifically, 10000 mg / l or more, and further 30000 mg / l or more. Growth is suppressed. Moreover, in the concentration part, it becomes a pH value at which the yeast to be used can be suitably grown by increasing the concentration of lactic acid, and no special pH adjustment of the saccharified solution is required.

  Since the growth of miscellaneous bacteria is suppressed during the concentration process as described above, in the first fermentation part, either a sterilized or non-sterilized one can be used as the concentrated saccharified solution, and the pH adjusted or pH adjusted Anything that has not been adjusted will be available.

As alcohol fermentation in the 1st fermentation part, it can utilize with a palindromic fermentation system, a repeated batch fermentation system, or a continuous fermentation system. As the yeast, it can be utilized that agglutination of yeast belonging to Saccharomyces cerevisiae to grow and fermentation in the range of pH2.5 or pH5.5 or less. More specifically, the batch fermentation method including the fed-batch fermentation method is a method that uses an apparatus that performs automation based on the amount of gas generated or a method that repeats batch fermentation once a day. Are available. In addition, when using a continuous fermentation system, a fermentation tank having functions such as mechanical stirring and gas circulation as a fermentation apparatus and having a sedimentation separation unit in the subsequent stage, a tower reactor having a sedimentation separation unit in the upper or subsequent stage, Alternatively, a tower reactor having a draft tube in the fluidized part can be used. In addition, while applying a continuous fermentation method, alcohol fermentation pH 4.5 or less, alcohol concentration is 50 g / l or more and 150 g / less, alcohol fermentation temperature is 25 ° C. or more, and dilution rate D is 0.05 h ⁻¹ or more. Preferably it is done.

  By setting it as suitable conditions in the said concentration part and said 1st fermentation part, it becomes possible to prevent that a miscellaneous microbe grows during alcohol fermentation.

  Here, in this system and this production method, in addition to the first fermentation section, a second fermentation section is provided as a waste liquid treatment / utilization section, and the distilled waste liquid discharged from the distillation section is fermented in a methane fermentation tank. It is preferable that the biogas is generated.

  With such a configuration, after collecting biogas, it can be used as an energy source for the concentrating section or the distillation section. At that time, it is preferable to reduce the concentration of hydrogen sulfide in the mixed gas by introducing air of 5% to 10% of the generated amount of biogas into the methane fermentation tank and mixing it with the biogas, Further, it is preferable to circulate the mixed gas between the water tank and the methane fermentation tank to oxidize hydrogen sulfide to air to make it sulfur, so that the concentration of hydrogen sulfide in the mixed gas is 10 ppm or less.

  In addition, it is preferable to provide a circulatory biological denitrification tank after the methane fermentation tank and a nitrification tank after the circulatory biological denitrification tank. With such a configuration, after ammonium ions generated by methane fermentation are oxidized to nitrate ions in the nitrification tank, a part of the liquid containing the nitrate ions is circulated to the denitrification tank, so that it remains after methane fermentation. Organic matter and nitrate ions are removed simultaneously.

According to the alcohol production system or the alcohol production method of the present invention, lactic acid is mainly produced in the saccharification part (saccharification step), and the hydrogen ion concentration (pH) of the saccharified solution is within a specific range (2.5 or more and 5.5 or less). ), The growth of miscellaneous bacteria is suppressed and sterilization of the saccharified solution becomes unnecessary, and an environment in which yeast added in the first fermentation part (fermentation process) grows and ferments is formed, and then the first fermentation Part (fermentation process), because specific flocculating yeast is added to this saccharified solution, sterilization, pH adjustment and addition of nutrients to the yeast are unnecessary, and the alcohol production concentration is high. The effect of becoming. These effects are achieved by bringing the total sugar concentration of the concentrated saccharified solution to a range of 100 g / l or more and 300 g / l or less in the concentrating part (concentration step), and further concentrating lactic acid so that the pH value naturally becomes a suitable value. Become more prominent.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[First Embodiment]
FIG. 1 shows a configuration example of an alcohol production system 1 according to the present embodiment. Note that the alcohol production method of the present invention is embodied in the operation of the alcohol production system 1, and therefore will be described together, and redundant description will be omitted.

  The alcohol production system 1 according to the present embodiment includes an alcohol production unit 10 and a waste liquid treatment / use unit 20. The alcohol production unit 10 includes a saccharification unit 11, a concentration unit 12, a first fermentation unit 13, a distillation unit 14, and a dehydration unit 15. From the biomass raw material (garbage.waste) W1, alcohol (for fuel and industrial alcohol) ) L1 is generated. The biomass raw material W1 is, for example, garbage that is discharged as industrial waste. Therefore, the alcohol production system 1 is also a solution to the problem of waste disposal.

  The waste liquid treatment / utilization unit 20 includes a second fermentation unit 21 following the distillation unit 14, a cogeneration unit 22 and a circulation biological denitrification / nitrification 23 following the second fermentation unit 21, and a circulation biological desorption. And a decoloring section 24 following the nitrification / nitrification 23. The steam obtained in the cogeneration unit 22 can be used in the concentration unit 12 and the distillation unit 14.

  The saccharification part 11 is a process which reacts the garbage W1 and an enzyme, and saccharifies starch substance, a part of cellulose, etc. which are contained in garbage, and produces | generates saccharified liquid L2. During the saccharification period, lactic acid fermentation occurs mainly by microorganisms that live in the garbage W1, and the organic acid A mainly composed of the produced lactic acid A1 is contained. Thereby, the hydrogen ion index (pH) of the saccharified liquid L2 However, it is maintained at, for example, pH 2.5 or more and 5.5 or less. The apparatus used for the saccharification unit 11 may be a reaction tank in which the contact between the garbage and the enzyme is good. For example, a rotating drum or a rotating blade is preferable. In particular, the rotating blade is preferable because after the saccharification is completed, the saccharified solution can be recovered and then the saccharification residue can be recovered while being roughly pulverized. As a specific saccharification method, garbage, water and an enzyme are mixed and then saccharified at a temperature of 30 ° C or higher, preferably 50 ° C or higher. At that time, the amount of water is preferably ¼ or more, more preferably ½ or more of the wet weight of the garbage, and the amount of the enzyme is 100 mg or more with respect to 1 kg of the wet garbage. Is preferably 300 mg or more.

  The concentration part 12 concentrates the saccharified clarified liquid obtained by mesh-filtering the saccharified liquid L2, and squeezing and filtering, and produces | generates the concentrated saccharified liquid L3. The total sugar concentration of the concentrated saccharified solution L3 is preferably 100 g / l or more and 300 g / l or less (the concentration ratio of the saccharified solution is 1.5 times or more and 5 times or less). This is because the concentration of the alcohol L1 produced in the first fermentation part (alcohol fermentation part) 13 is increased by increasing the concentration of monosaccharides in the saccharified liquid L2 while the nutrient sources necessary for alcohol fermentation are concentrated. Because it can. The concentration of the alcohol in the concentrated saccharified solution is 50 g / l or more and 150 g / l or less. As the concentration method, atmospheric concentration or vacuum concentration is used.

  In addition, the concentration unit 12 concentrates the saccharified solution L2 until the concentration of lactic acid A1 produced by saccharification is at least twice that before the concentration, more specifically 10000 mg / l or more, further 30000 mg / l or more. It also has a function of reducing the growth of bacteria, and therefore, the growth of miscellaneous bacteria is suppressed. That is, the sterilization of the concentrated saccharified liquid L3 (saccharified liquid L2) becomes unnecessary. Here, the saccharified solution L2 is concentrated until the concentration of lactic acid A1 becomes twice or more that before concentration, whereby the pH of the concentrated saccharified solution L3 becomes natural within a range of, for example, 2.5 or more and 5.5 or less. Since the yeast used in the first fermentation unit 13 grows in this pH region, it is not necessary to specifically adjust the pH of the concentrated saccharified solution L3.

The 1st fermentation part 13 carries out the alcohol fermentation of the concentrated saccharified liquid L3, and produces | generates the straw L4. As yeast used for alcoholic fermentation, at least one of non-aggregating yeast and aggregating yeast growing at a pH of 2.5 or more and 5.5 or less can be used. Specifically, examples of the non-aggregating yeast include Saccharomyces cereviciae EP1 strain, and examples of the aggregating yeast include Saccharomyces cereviciae KF-7 strain. Moreover, batch fermentation, repeated batch fermentation, or continuous fermentation can be used as a method for alcoholic fermentation. As the batch fermentation, a fed-batch fermentation method may be used, and as the repeated batch fermentation, a method using an apparatus that performs automation based on the amount of gas generated or a method of repeating batch fermentation once a day is preferable. A chemostat system is preferred.

As a fermentation apparatus used for the first fermentation unit 13, a fermenter having functions such as mechanical stirring and gas circulation and having a sedimentation separation unit in the subsequent stage, a tower reactor having a sedimentation separation unit in the upper or subsequent stage, or a flow A tower type reactor having a draft tube in the part can be used. In particular, when the continuous fermentation method is used as the alcohol fermentation and the flocculating yeast is used as the yeast, it is preferable to use the fermenter. In addition, while applying the continuous fermentation method, the alcohol fermentation temperature is 25 ° C. or higher, preferably 30 ° C. or higher, and the dilution rate D is 0.05 h ⁻¹ or higher, preferably 0.2 h ⁻¹ or higher, more preferably 0.3 h. It is preferable to carry out alcoholic fermentation at ⁻¹ or higher. Here, the dilution rate D (h ⁻¹ ) is a value obtained by dividing the concentrated saccharified solution supply rate F (m ³ / h) by the actual volume V (m ³ ) of the fermenter, as shown in Equation 1.
(Equation 1)
D = F / V

  As described above, the concentrated saccharified solution L3 suppresses the growth of miscellaneous bacteria by the lactic acid concentration and pH, and does not particularly require sterilization treatment or pH adjustment. When the concentrated saccharified solution L3 is subjected to alcoholic fermentation in a pH state, sterilization treatment or pH adjustment may be performed.

Here, by setting the conditions suitable for the concentration part (concentrated saccharified solution pH around 4 and lactic acid concentration) and the first fermentation part (fermentation pH around 4 and D is 0.2 h ⁻¹ or more), during alcoholic fermentation It is possible to completely prevent the growth of various bacteria.

  The distillation part 14 distills the straw L4 and separates it into a crude alcohol L5 and a distillation waste liquid L6.

  The dehydrating unit 15 dehydrates the crude alcohol L5 to generate the anhydrous alcohol L1. This anhydrous alcohol L1 is used by being added to gasoline. In Japan, it is already approved to add 3% to gasoline. In the future, the proportion of addition is expected to increase as in Brazil and the United States.

The 2nd fermentation part 21 produces | generates biogas G1 by carrying out methane fermentation of the distillation waste liquid L6 in the methane fermentation tank 21A. This biogas G1 contains, for example, methane (CH4) useful as an energy source and unnecessary carbon dioxide gas or hydrogen sulfide. Since hydrogen sulfide corrodes gas engines and boilers, dry desulfurization, wet desulfurization, and biological desulfurization are generally performed, but there are problems of secondary contamination and processing costs. Therefore, in the second fermentation unit 21, the mixture containing the biogas G1 and the air is introduced by introducing 5% or more and 10% or less of the generated amount of the biogas G1 into the methane fermentation tank and mixing it with the biogas G1. It is preferable to reduce the concentration of hydrogen sulfide in the gas G2 to 10 ppm or less, for example. If the hydrogen sulfide concentration is still high, as shown in FIG. 2, in addition to the methane fermentation tank 21A, a water tank 21B is provided in the latter stage, and the mixed gas G2 is circulated between the methane fermentation tank 21A and the water tank 21B. By doing so, the concentration of hydrogen sulfide in the mixed gas G2 may be reduced. The biogas G1 thus easily desulfurized can be used as an energy source for the concentration unit 12 or the distillation unit 14.

  The cogeneration unit 22 converts the energy into steam G3 and plant power E1 by using the biogas G1 (mixed gas G2) as an energy source. This steam G3 serves as a heat source for the concentration unit 12 and the distillation unit 14. That is, the biogas G1 can be used as an energy source for the concentration unit 12 or the distillation unit 14.

  Moreover, in the 2nd fermentation part 21, protein is hydrolyzed, becomes an amino acid, is deaminated, and an ammonium ion is produced | generated. Moreover, the organic substance containing the organic acid which was not methane-fermented remains. Therefore, it is preferable to provide a denitrification tank 23A downstream of the methane fermentation tank 21A and the water tank 21B, and further a nitrification tank 23B (circulation biological denitrification / nitrification section 23) downstream of the denitrification tank 23A. As a result, after ammonium ions are oxidized to nitrate ions in the nitrification tank 23B, a part of the liquid containing the nitrate ions is circulated to the denitrification tank 23A and processed, thereby simultaneously treating organic substances including the organic acid and nitrate ions. Can be removed. The treated water thus highly treated can be discharged as it is or after being decolorized, or can be reused as water added to the saccharification unit 11. In addition, the process liquid discharged | emitted from 21 A of methane fermenters can also be effectively utilized as liquid fertilizer L7, without processing as mentioned above.

  The decoloring unit 24 decolorizes the treated water that has been highly treated to produce treated water L8 and discharges it into the river. The treated water L8 can be reused as an alternative to water added to the garbage at the saccharification unit 11.

  Next, the operation of the alcohol production system 1 having such a configuration will be described.

  First, in the saccharification part 11 of the alcohol production part 10, the saccharified liquid L2 is produced | generated by saccharifying the garbage W1 with an enzyme, for example, being grind | pulverized with a rotary blade. At this time, lactic acid is mainly produced by microorganisms that inhabit the garbage, and the hydrogen ion index (pH) of the saccharified solution L2 is lowered.

  The saccharified liquid L2 having a lowered pH is separated from the saccharification residue and then concentrated by, for example, vacuum concentration in the concentration unit 12. At this time, the saccharified solution L2 is concentrated until the total saccharide concentration of the concentrated saccharified solution L3 becomes 100 g / l or more and 300 g / l or less, and in order to lower the pH of the concentrated saccharified solution L3, the concentration of lactic acid is twice that before the concentration. Try to be above.

  The concentrated saccharified solution L3 produced in the concentration unit 12 is subjected to alcohol fermentation in the first fermentation unit 13 by, for example, aggregating yeast belonging to Saccharomyces. The yeast may be other flocculating yeast or non-aggregating yeast as long as it grows in the range of pH 2.5 or more and pH 5.5 or less. As the fermentation method, a batch fermentation method, a repeated batch fermentation method or a continuous fermentation method is used. The soot L4 produced here is distilled in the distillation section 14 to be separated into the crude alcohol L5 and the distillation waste liquid L6. The crude alcohol L5 is dehydrated in the dehydrating unit 15 to become alcohol L1.

  On the other hand, the distillation waste liquid L6 generated in the alcohol production section 10 is sent to the waste liquid treatment / use section 20 for processing or use as follows.

That is, this distillation waste liquid L6 is sent to the 2nd fermentation part 21, and becomes biogas G1 by carrying out methane fermentation in the methane fermentation tank 21A. This biogas G1 contains unnecessary carbon dioxide and hydrogen sulfide together with methane (CH4) useful as an energy source. Hydrogen sulfide not only harms the human body but also corrodes boilers and generators. Then, in the 2nd fermentation part 21, 5 to 10% of the generation amount of biogas G1 is introduce | transduced in the methane fermentation tank 21A, this is mixed with biogas G1, and in the mixed gas G2 The concentration of hydrogen sulfide is reduced to 10 ppm or less. If the concentration of hydrogen sulfide is still high, the concentration of hydrogen sulfide in the mixed gas G2 is reduced by circulating the mixed gas G2 between the methane fermentation tank 21A and the water tank 21B.

  At this time, in the second fermentation unit 21, the protein is hydrolyzed to become an amino acid and deaminated to produce ammonium ions. Further, although organic matter containing organic acid that has not been subjected to methane fermentation remains, ammonium ions are oxidized to nitrate ions in the circulating biological nitrification tank 23B, and a part of the liquid containing the nitrate ions is circulated to the denitrification tank 23A. As a result, the organic substance A and nitrate ions are simultaneously removed.

  The biogas G1 (mixed gas G2) from which hydrogen sulfide has been removed is sent to the cogeneration unit 22 where it is converted into steam G3 and plant power E1. Among them, the steam G3 is used as a heat source for the concentration unit 12 or the distillation unit 14 of the alcohol production unit 10. In addition, the methane fermentation treated water is not only effectively used as liquid fertilizer, but also discharged into a river after advanced treatment → decolorization by the second fermentation section or after advanced treatment. Highly treated water or advanced treatment → decolorized treated water is reused as raw garbage. Alternatively, aeration is performed in the denitrification tank 23A of the circulating biological denitrification / nitrification unit 23, and further, aeration is performed in the nitrification tank 23B to oxidatively decompose BOD components, and ammonium ions are oxidized to nitrate ions. Can be used as a liquid fertilizer containing nitrate ions. An immersion flat membrane or the like may be placed in the nitrification tank 23B.

  In the above alcohol production system 1, alcohol L <b> 1 is generated by performing the above processing, and the following specific effects are exhibited.

  In this alcohol production system 1, first, in the saccharification part 11, an enzyme is added to the garbage W to be saccharified. At this time, lactic acid is mainly produced by microorganisms living in the garbage, and pH is shifted to the acidic side. , Growth of miscellaneous bacteria is suppressed.

  Next, the saccharified solution L2 is concentrated in the concentrating unit 12 so that the concentrated saccharified solution L3 is generated, and the total saccharide concentration of the concentrated saccharified solution L3 is in the range of 100 g / l to 300 g / l. Therefore, the concentration of monosaccharides in the saccharified liquid L3 increases, and the generated alcohol L1 concentration increases in the first fermentation part. In addition, since the concentration of lactic acid A1 is concentrated until it is twice or more that before concentration, the pH of the saccharified solution L2 is lowered. Therefore, not only the growth of miscellaneous bacteria is suppressed during this concentration process, but also the proliferation of miscellaneous bacteria can be almost completely suppressed by the pH, lactic acid concentration and alcohol concentration in the first fermentation part. In addition, in the concentrating part 11, the pH of the saccharified solution L2 is adjusted to a certain range by increasing the concentration of lactic acid A1, so that, for example, Saccharomyces cerevisiae generally used for brewing is used. Can be suitably grown.

  As described above, according to the alcohol production system (method) of the present embodiment, in the saccharification unit 11, lactic acid is generated by microorganisms that live in the garbage W, and the pH of the saccharified solution L2 is lowered. 12, the concentrated saccharified liquid L3 is concentrated in the range of 100 g / l to 300 g / l and the concentrated saccharified liquid L3 has a pH of about 4 due to the concentration of lactic acid. Addition of nutrients to yeast is unnecessary. Furthermore, the concentration of alcohol produced in the first fermentation section is increased, and washing out before germs grow by increasing D (increasing the supply of concentrated saccharified solution) in continuous fermentation. Therefore, the concentrated saccharified solution can be supplied without sterilization, and long-term continuous fermentation becomes possible.

  Moreover, since the 2nd fermentation part 21 was provided as the waste liquid process and utilization part 20, and it was made to produce | generate biogas G1 by carrying out the methane fermentation of the distillation waste liquid L6 discharged | emitted from the distillation part 14 in the methane fermentation tank 21A, The biogas G1 can be used as an energy source for the concentration unit 12 or the distillation unit 14 in the alcohol production unit 10. At that time, 5% or more and 10% or less of the generated amount of biogas G1 is introduced into the methane fermentation tank 21A and mixed with the biogas G1, thereby reducing the concentration of hydrogen sulfide in the mixed gas G2. Furthermore, the concentration of hydrogen sulfide in the mixed gas G2 is reduced to 10 ppm or less by circulating the mixed gas G2 between the water tank 21B and the methane fermentation tank 21A to oxidize hydrogen sulfide to sulfur. It becomes possible to make it lower.

  In addition, the circulation biological denitrification tank 23A is provided at the rear stage of the methane fermentation tank 21A and the water tank 21B, and the nitrification tank 23B is provided at the rear stage of the circulation biological denitrification tank 23A. Nitrate ions can be removed simultaneously.

  The alcohol production system (method) has been described above. Next, a sugar production method (second embodiment) useful for such a system (method) will be described with reference to FIG.

[Second Embodiment]
This sugar production method includes a garbage processing step 31, a saccharification step 32, and a concentration step 33, and generates sugar as a concentrated saccharified liquid L3 from a biomass raw material (garbage W1).

  In the garbage disposal step 31, 10% or less, preferably 1% or less of the lactic acid bacteria culture solution L0 is added to the garbage W1, and then it is kept in an anaerobic state to produce the treated waste W2. Specifically, as shown in FIG. 6A, for example, after adding the lactic acid bacteria culture solution L0 to the garbage W1 filled in the container 41, a plastic bag containing water on the garbage W1. An anaerobic state is established by placing 42 and sealing. By holding this anaerobic state, the waste is treated as W2. At this time, as shown in FIG. 6 (B), it is also possible to add garbage (W12, W13) for treatment, and further, after adding the lactic acid bacteria culture solution L0 to the garbage, it is crushed. Thus, it may be processed in the form of a mince. Further, the amount of the lactic acid bacteria culture solution L0 to be added may be 1% or less with respect to the wet weight of the garbage W1.

  In the saccharification step 32, the treated waste W2 and the enzyme F are reacted to saccharify starch and some cellulose contained in the treated waste W2 to generate a saccharified solution L2. Specifically, after the treated waste W2, water, and enzyme F are mixed, saccharification is performed at a temperature of 30 ° C or higher, preferably 50 ° C or higher. At this time, the amount of water is preferably ¼ or more, more preferably ½ or more with respect to the wet weight of the treated waste W2.

  The enzyme F may be an acid-resistant enzyme that works even at a pH of about 3, such as acid-resistant glucoamylase. Alternatively, glucoamylase having acid resistance and heat resistance may be used. Further, after the addition of such an enzyme, a cellulase enzyme may be further added. This makes it possible to recover sugar more efficiently. The amount of enzyme F is preferably 50 mg or more, more preferably 100 mg or more, with respect to 21 kg of wet waste.

  The apparatus used for the saccharification process 32 as described above may be a reaction tank in which the treated waste W2 and the enzyme F are in good contact with each other. For example, a rotating drum or a rotating blade is preferable. In particular, the rotating blade is preferable because after the saccharification is completed, the saccharified solution L2 is recovered, and then the saccharification residue S can be recovered while being roughly pulverized.

  In the concentration step 33, the saccharified clarified liquid obtained by mesh filtration and squeezing and filtering the saccharified liquid L2 is concentrated to produce a concentrated saccharified liquid L3. The total sugar concentration of the concentrated saccharified solution L3 is preferably 100 g / l or more and 300 g / l or less (the concentration ratio of the saccharified solution is 1.5 times or more and 5 times or less). This is because, when the concentrated saccharified liquid L3 is used for alcohol production, the nutrient source necessary for alcohol fermentation is concentrated and the concentration of monosaccharides in the saccharified liquid L2 is increased to produce high concentration alcohol. Because it can. In addition, the alcohol concentration in the concentrated saccharified liquid L3 is 50 g / l or more and 150 g / l or less. As the concentration method, atmospheric concentration or vacuum concentration is used.

In the concentration step 33, the saccharified solution L2 is concentrated until the concentration of lactic acid A1 produced by saccharification is 2 times or more of that before concentration, more specifically 10000 mg / l or more, further 30000 mg / l or more. It also has a function of reducing the growth of bacteria, and therefore, the growth of miscellaneous bacteria is suppressed. That is, the sterilization of the concentrated saccharified liquid L3 (saccharified liquid L2) becomes unnecessary. Here, by concentrating the saccharified liquid L2 until the concentration of lactic acid A1 becomes twice or more that before concentration, the pH of the concentrated saccharified liquid L3 is naturally adjusted to a range of, for example, 2.5 or more and 5.5 or less. The In addition, since yeast used for alcoholic fermentation grows in this pH range, pH adjustment and sterilization treatment for concentrated saccharified liquid L3 are not particularly required, but the remaining germs are further reduced or a suitable pH. When the concentrated saccharified solution L3 is subjected to alcoholic fermentation in the state described above, sterilization treatment or pH adjustment may be performed. As suitable conditions for the concentration step 33, for example, by setting the dilution rate D to 0.2 h ⁻¹ or more at around fermentation pH 4, it is possible to completely prevent the growth of miscellaneous bacteria during alcohol fermentation.

  Next, the action and effect of this sugar production method will be described.

  First, in the food waste treatment step 31, by adding 10% or less, preferably 1% or less of the lactic acid bacteria culture solution L0 to the food waste W1, the food waste W1 undergoes lactic acid fermentation and the pH is lowered. Therefore, the freshness of the garbage W1 is maintained. Therefore, a reduction in the recovery rate of the saccharified liquid L2 and generation of an organic acid that inhibits alcohol fermentation such as acetic acid in the saccharified liquid L2 are suppressed. Thus, the processing waste W2 is obtained by processing the garbage W1.

  Subsequently, in the saccharification step 32, the saccharified liquid L2 is generated by saccharifying the treated waste W2 by the enzyme F while being pulverized by, for example, a rotating blade. At the same time, lactic acid fermentation occurs mainly by microorganisms that live in the treated waste W2, and the treated waste W2 is saccharified. As a result, the organic acid A containing lactic acid A1 as a main component is generated, and the hydrogen ion index (pH) of the saccharified liquid L2 is kept acidic at about pH 3-4. This suppresses the growth of miscellaneous bacteria and makes it unnecessary to sterilize the saccharified solution.

  The saccharified liquid L2 having a lowered pH is separated from the saccharified residue S and further purified to the saccharified clarified liquid L3 by the filtration described above, and then the saccharide is recovered as the concentrated saccharified liquid L3 in the concentration step 33.

  As described above, according to the sugar production method of the present embodiment, in the garbage processing step 31, after 10% or less, preferably 1% or less of the lactic acid bacteria culture solution L0 is added to the garbage W1, the anaerobic state is maintained. Therefore, the freshness of the garbage W1 is maintained. Therefore, since it is possible to suppress the reduction in the recovery rate of the saccharified liquid L2 and the generation of organic acids that inhibit alcohol fermentation such as acetic acid in the saccharified liquid L2, it is possible to efficiently generate sugar. The sugar (glucose) thus produced can be used not only as alcohol but also as a raw material for fuel cells such as glucose cells.

Hereinafter, specific examples of the first embodiment will be described.
(Examples 1-1 and 1-2)
In Examples 1-1 and 1-2, a batch fermentation test was performed using the garbage W1 discharged from the hotel.

  First, 20 kg of food waste (raw food) such as rice cake and leftovers, 10 l of water (tap water), and 12 g of glucoteam of Nagase ChemteX Corporation as glucoamylase are put into a saccharification tank, and the temperature is 50 ° C. Stir for 6 hours under. After that, a large solid content was removed by mesh filtration, and further a fine solid content was removed with a filter press to obtain about 20 kg of saccharified liquid (saccharified clarified liquid) L2. Here, the wet weight means the weight (mass) including liquid waste mixed in food waste. In addition, since glucosteam contains half of the food additive, the substantial enzyme input is 6 g.

The initial state of the obtained saccharified liquid L2 was analyzed. As a result, initial glucose concentration 82g / l, pH4.10, total nitrogen concentration 4.65g / l, NH ₄ ⁺ nitrogen concentration: 4.35g / l, NO ₃ ^- Nitrogen concentration: 0.1 g / l) in there were. In addition, for the organic acid, it was found that lactic acid fermentation was proceeding considerably since the lactic acid concentration was 15700 mg / l and acetic acid was 1500 mg / l. In general fermentation, 1% ammonium sulfate is often added to the total sugar concentration, but in this example, the total nitrogen concentration of the saccharified liquid L2 is 5.7% with respect to the initial glucose concentration as described above. Since it was high, no ammonium sulfate was added.

(Medium preparation)
Subsequently, in Example 1-1, 90 ml of the initial saccharified liquid L2 is collected and charged into an empty sterilized 300 ml Erlenmeyer flask. In Example 1-2, the saccharified liquid L2 in the initial state is a nutrient source. 90 ml of a yeast extract (YE; Yeast Extract) added to a concentration of 10 g / l was sampled and placed in a 300 ml Erlenmeyer flask that had been sterilized in the air. Furthermore, by adding 10 ml of the preculture solution prepared in advance to each Erlenmeyer flask, an additive-free medium of Example 1-1 and a YE-added medium of Example 1-2 were prepared. That is, in Examples 1-1 and 1-2, each medium was prepared without concentrating, adjusting the pH, and sterilizing the saccharified solution. The inoculation amount of the preculture solution is generally 5 to 10% in volume ratio, but here, the preculture solution was inoculated so as to be 10% in the saccharified solution that has not been sterilized as described above. The same applies to the non-sterilized examples thereafter. The pre-culture solution is stored in a 5% YPD medium (glucose 5 g / l, yeast extract (YE) 1 g / l, polypeptone 1 g / l) in a slant (slope medium; a method of storing yeast in an agar medium). The inoculated yeast was inoculated with 1 platinum ear and then cultured by shaking at 30 ° C. and 160 rpm for 16 hours.

(Batch fermentation test)
The Erlenmeyer flask containing each medium of Examples 1-1 and 1-2 was immersed in a constant temperature water bath at 30 ° C., and a batch fermentation test was performed under the condition of 400 rpm. 24 hours and 48 hours after the start of the batch fermentation test The alcohol (ethanol) concentration in was measured.

Table 1 shows the ethanol concentrations produced in Examples 1-1 and 1-2 after 24 hours and 48 hours after fermentation. From this result, 24 hours after the start of fermentation, the ethanol concentration of Example 1-1 (non-added medium) was about 10 g / l lower than that of Example 1-2 (YE-added medium). However, after 48 hours from the start of fermentation, there was almost no difference in ethanol concentration in each Example. The fermentation yield 48 hours after the start of fermentation was about 95% in the YE-added medium. From this result, it was found that the fermentation rate was improved by adding yeast extract. Here, the fermentation yield (W) is the actual yield (Y) with respect to the theoretical yield (X) of ethanol, as shown in Equation 2, assuming that the reaction formula of Formula 1 is the formation reaction of all alcohols. Means the percentage of The theoretical yield (X) of alcohol is determined by the reaction (mass) ratio (glucose: alcohol = 180: 92) and the amount of glucose (Z) in the concentrated saccharified liquid L3, as shown in Equation 3.
(Formula 1)
C6H12O6 → 2C2H5OH + 2CO2
(Equation 2)
(Fermentation yield W) = (actual yield Y) / (theoretical yield X) × 100
(Equation 3)
(Theoretical yield X) = {(glucose amount Z in concentrated saccharified liquid L3) × 92} / 180

(Examples 2-1 to 2-4)
In Examples 2-1 to 2-4, after preparing the saccharified liquid L2 from the garbage W1 discharged from the convenience store, using the concentrated saccharified liquid L3 obtained by further concentrating the saccharified liquid L2, an additive-free medium and YE added While preparing the culture media, batch fermentation tests were performed on those media that were sterilized and those that were not sterilized.

  First, the weight ratio of food waste (food waste) and water (tap water), such as lunch boxes that have expired, is food waste: water = 2: 1 (wet weight of food waste 12.8 kg, about tap water) 6 kg), 7.7 g of the same glucoamylase as in Examples 1-1 and 1-2 was added, and the mixture was stirred at a temperature of 50 ° C. for 6 hours. Thereafter, a large solid content was removed by performing mesh filtration, and a fine solid content was further removed by a filter press to obtain about 12.5 kg of saccharified liquid (saccharified clarified liquid) L2. In addition, since the food additive is contained in half in glucosteam, the input amount of substantial enzyme is 3.85 g.

  Subsequently, 5 kg of the obtained saccharified solution L2 is put into a 10-liter eggplant flask, and the glucose concentration is about 17% at 60 ° C. or 80 ° C. under reduced pressure of 10 mmHg using an evaporator (EYELA ROTARY VACUUM EVAPORATORN-11). Concentrated saccharified liquid L3 was obtained by concentrating under reduced pressure until it became. The initial state of the concentrated saccharified solution L3 was a glucose concentration of 174 g / l, a lactic acid concentration of 9900 mg / l, and an acetic acid concentration of 640 mg / l.

  Subsequently, in Examples 2-1 and 2-2, 90 ml of the non-sterilized concentrated saccharified solution L3, that is, the concentrated saccharified solution L3 as it was was put into a 300 ml Erlenmeyer flask that had been sterilized empty, and then Example 2-1 Was prepared in the same manner as in Example 1-1, and a non-added medium was prepared in the same manner as in Example 1-2. In Examples 2-3 and 2-4, 90 ml of concentrated saccharified liquid L3 was collected and placed in a 300 ml Erlenmeyer flask, and then sterilized with a sterilizer at 120 ° C. for 15 minutes. For Example 2-3, a non-added medium was prepared in the same manner as in Example 1-1, and for Example 2-4, a YE-added medium was prepared in the same manner as in Example 1-2. That is, in Examples 2-1 to 2-4, each medium was prepared without adjusting the pH.

  For Examples 2-1 to 2-4, a batch fermentation test was performed in the same manner as in Examples 1-1 and 1-2, and the ethanol concentration was measured.

  Table 2 shows the ethanol concentrations produced in Examples 2-1 to 2-4 after 24 and 48 hours of fermentation. From this result, it was found that after 24 hours from the start of the test, the fermentation rate was improved by concentration in any of the examples regardless of the presence or absence of sterilization. Further, after 48 hours from the start of the test, the non-sterilized Examples 2-1 and 2-2 had a slightly higher ethanol concentration than the Examples 2-2 and 2-3 in which the sterilization treatment was performed. The fermentation yield of Example 2-1 was as high as about 97%. In addition, the calculation method of fermentation yield is the same as that of Examples 1-1 and 1-2.

  In addition, Examples 2-1 to 2-4 using the concentrated saccharified liquid L3 have a fermentation yield of 5 to 5 hours after the fermentation test 48 hours more than Example 1-1 (non-added medium) using the saccharified liquid L2. It was also found that the fermentation yield can be improved by concentrating the saccharified solution by 7%.

  From the above, it has been found that ethanol can be generated with high efficiency regardless of the sterilization of the concentrated saccharified solution, the addition of nutrient sources such as YE, and the presence or absence of pH adjustment.

(Examples 3-1 and 3-2)
In Examples 3-1 and 3-2, in the same manner as in Examples 1-1 and 1-2, saccharified liquid L2 was separately prepared from garbage W1 discharged from the hotel, and then Examples 2-1 and 2-2 were prepared. Of lactic acid concentration by concentrating saccharified liquid L2 and preparing a non-additive medium and a YE-added medium using concentrated saccharified liquid L3 (non-sterilized) having a high lactic acid concentration and performing batch fermentation tests in the same manner as -2 I investigated. Regarding the initial state of the concentrated saccharified liquid L3, the glucose concentration was 152.5 g / l, the lactic acid concentration was 31100 mg / l, the acetic acid concentration was 1200 mg / l, and the pH was 4.3.

  Table 3 shows the ethanol concentrations produced after 24 hours and 48 hours of fermentation in Examples 3-1 and 3-2. From these results, the same ethanol concentration was obtained in all Examples regardless of the presence or absence of YE addition 24 hours and 48 hours after the start of the test. Here, compared with Examples 2-1 and 2-2, the ethanol concentration was slightly lower after 24 hours and 48 hours from the start of the test, and the fermentation yield after 48 hours of Examples 3-1 and 3-2. 90% and 97% of Example 2-1 were slightly lower, but a high fermentation yield of over 90% could be obtained. Therefore, it was found that the lactic acid concentration was preferably 10,000 mg / l or more, and even if it was 30000 mg / l or more, no fermentation was observed and ethanol fermentation was possible. In addition, it is the same as that of Examples 1-1 and 1-2 also about the calculation method of the fermentation yield of a present Example.

Example 4
In Example 4, a continuous fermentation test was performed using the concentrated saccharified solution L3 obtained by separately preparing the saccharified solution L2 from the garbage W1 discharged from the hotel and concentrating it.

  The saccharified liquid L2 was produced in the same manner as in Examples 1-1 and 1-2, and the saccharified liquid L2 was concentrated in the same manner as in Examples 2-1 and 2-2 to obtain a concentrated saccharified liquid L3. Regarding the initial state of the concentrated saccharified liquid L3, the glucose concentration was 153 g / l, the lactic acid concentration was 34900 mg / l, the acetic acid concentration was 1400 mg / l, and the pH was 4.0. In addition, since the produced concentrated saccharified liquid L3 is non-sterilized, it was stored in the refrigerator until the continuous fermentation test was started.

  Subsequently, after adding 0.45 l of the preculture solution to the continuous fermenter, the concentrated saccharified solution (non-sterilized / non-added medium) is supplied from the bottom of the tower reactor using a tube pump. Started. The preculture solution used was prepared in the same manner as that used in Example 1-1.

  As the continuous fermenter, an acrylic tower reactor having an actual volume of 0.45 l and a solid-gas-liquid three-phase separation unit at the top was used. A pH electrode was inserted at the top so that the pH could be controlled. An external jacket was provided in the fluidized part, and constant temperature water was allowed to flow so that the fermentation temperature could be maintained at a predetermined temperature. A ball filter was installed at the bottom so that a small amount of air sterilized through the ball filter could be vented into the tower reactor. In addition, branch pipes were attached to the top and the bottom so that the concentrated saccharified liquid (liquid in the tank) during fermentation could be circulated from the top to the bottom.

(Continuous fermentation test)
From the start of the test to the third day of the start of the test, the pH of the concentrated saccharified liquid L3 before the start of the test was 4.0, so the pH of the solution in the tank was controlled to be 4.3, the fermentation temperature was 30 ° C, The air was supplied at a dilution rate of 0.1 h ⁻¹ under the condition of air flow rate of 0.025 vvm. Start of the test day 3 until the test after 20 day, D = 0.2 h ^-1, went stepwise increasing the dilution rate D such that D = 0.3h ^-1. Furthermore, from the 25th day of the test to the 40th day of the test, the continuous fermentation test was continuously performed under the condition of D = 0.3 h ⁻¹ without controlling the pH of the solution in the tank.

FIG. 3 shows changes over time in the ethanol concentration produced when the dilution rate was increased stepwise in the continuous fermentation test of Example 4. FIG. 4 shows the productivity of ethanol with respect to the dilution rate D and the fermentation yield with respect to the dilution rate D using stable data at each dilution rate D in FIG. From these results, the ethanol concentration reached 70 g / l on the third day from the start of the test. From the 3rd day to the last day (40th day) of the test, even if the dilution rate D is increased stepwise as described above, the ethanol concentration is 70 g / l to 72 g / l with almost no change. It was found that stable continuous fermentation was possible. Further, from the 25th day to the 40th day of the test, the test was continued under the condition of D = 0.3h ^-1 without controlling the pH in the fermenter. Although it was lowered to about 4.0, the ethanol concentration was not changed, and a productivity of 21 g / l / h to 22 g / l / h and a fermentation yield of 90% to 92% could be achieved. Here, the productivity is obtained by the product of the generated ethanol concentration P and the dilution rate D (productivity = P × D). In addition, it is the same as that of Examples 1-1 and 1-2 also about the calculation method of the fermentation yield of a present Example.

Next, specific examples and comparative examples of the second embodiment will be described. As garbage W1, what contained 118g of saccharides as a total saccharide per 1kg of wet weight (containing about 80% of water) was used. The total sugar was quantified by taking 10 ml of a sample from 0.5 kg of water and mixing well with 1 kg of garbage, and adding 90 ml of distilled water and 10 ml of a 25% hydrochloric acid solution to the sample. After hydrolyzing, the solubilized Nelson method was used with the hydrolyzed solution neutralized in pH.
(Examples 5-1 to 5-5)
In Examples 5-1 to 5-5, the waste W1 was put into the container 41, and then treated waste W2 sprayed with the lactic acid bacteria culture solution L0 and held for 3 days. Saccharification was carried out at the reaction temperature. As the enzyme F, Glucozyme 20000 in Example 5-1, Nagase Enzyme N-40 in Example 5-2, Sumiteam in Example 5-3, Sumiteam AL in Example 5-4, and Example 5-5. Then, Sumiteam shochu was used. Furthermore, other saccharification conditions in each example were adjusted to the conditions shown in Table 4.

  Under the above conditions, the organic acid (lactic acid and acetic acid) concentration and pH after 1 hour and 6 hours of reaction time were measured. The lactic acid concentrations for each reaction time were 6200 mg / l and 6250 mg / l, and the acetic acid concentration was 1300 mg / l. 1 and 1310 mg / l, pH was 3.8, and the measured values were almost constant. From this result, it was found that the germs hardly grew and the freshness of the garbage was kept constant.

7 to 11 show the relationship of the glucose concentration (g / l) to the saccharification time (reaction time (h)) in each Example, and Table 5 shows the glucose concentration and sugar of the saccharified solution. The recovery was summarized. From these results, the highest glucose concentration and sugar recovery rate were obtained in Example 5-2 (Nagase Enzyme N-40), and Nagase Enzyme N-40 exhibited particularly excellent acid resistance compared to other enzymes. I found it. The glucose concentration was quantified using an F-kit glucose (Boehringer Mannheim Co., Ltd., import / seller JK International) reagent. In addition, the sugar recovery rate was obtained by Equation 2 (the same applies to the following examples).
(Formula 2)
(Sugar recovery rate) = (Glucose concentration produced by enzyme reaction / total sugar concentration in garbage and water mixture) × 100

(Examples 6-1 to 6-4)
In Examples 6-1 to 6-4, the waste W1 was put into the container 41, and then treated waste W2 sprayed with the lactic acid bacteria culture solution L0 and held for 3 days. Saccharification was carried out at the reaction temperature. As enzyme F, 212 mg of Nagase enzyme agent N-40 was used in Example 6-1, 170 mg of Nagase enzyme agent N-40 was used in Example 6-2, and 127 mg of Nagase enzyme agent N-40 was used in Example 6-3. In Example 6-4, 600 mg of glucosteam 20000 (containing 50% food additive) was used. Furthermore, other saccharification conditions in each example were adjusted to the conditions shown in Table 6.

  12 to 15 show the relationship of the glucose concentration (g / l) to the reaction time (h) in each example, and Table 7 shows the glucose concentration and sugar recovery rate of the saccharified liquid in each example. Summarized. As a result, the highest glucose concentration was obtained in Example 6-1, the sugar recovery rate reached 85.5%, which was nearly 9% higher than Example 5-2 in which the reaction temperature was 50 ° C. In Examples 6-2 and 6-3, high sugar recovery rates of 81.9% and 81.7% were also obtained when the amount of Nagase enzyme N-40 added was reduced. On the other hand, about the glucosteam 20000 of Example 6-4, the saccharide | sugar collection | recovery rate became 24.4%, and fell significantly rather than Example 5-1 which made reaction temperature 50 degreeC. From this, it turned out that Nagase enzyme agent N-40 is an enzyme excellent in heat resistance in addition to acid resistance.

  From the results of Examples 5-1 to 5-5 and Examples 6-1 to 6-4, it is effective to use an enzyme having acid resistance or acid resistance and heat resistance for the enzyme used in the saccharification step. I understood it.

(Comparative Examples 1 and 2)
In Comparative Examples 1 and 2 with respect to Examples 5-1 to 5-5, the waste W1 was put into a container and left for 3 days at room temperature (25 ° C. to 33 ° C.) without spraying the lactic acid bacteria culture solution L0. Saccharification was performed using Molds propagated on the surface of the treated waste W3 and had a rotting odor peculiar to garbage.

  Next, an enzyme was added to the treated waste W3 and saccharification was performed at a reaction temperature of 50 ° C. As the enzyme, Glucozyme 20000 was used in Comparative Example 1, and Nagase Enzyme N-40 was used in Comparative Example 2.

  Under the above conditions, the organic acid (lactic acid and acetic acid) concentration and pH after 1 hour and 6 hours of reaction time were measured. The lactic acid concentration was 7950 mg / l and 8520 mg / l, and the acetic acid concentration was 1440 mg / l and 1910 mg / l. The values of l and pH were slightly shifted to the acidic side at about 3.6. That is, the organic acid concentration showed a higher value than that of Examples 5-1 to 5-5, and tended to increase with time. Since this is considered to be mainly due to contamination of garbage in garbage, it was also found from this result that when the lactic acid bacteria culture solution was not used, spoilage progressed due to propagation of the bacteria.

  FIG. 16 and FIG. 17 show the relationship of glucose concentration (g / l) to the saccharification time (reaction time (h)) in each comparative example, and Table 8 shows the glucose concentration and saccharide of the saccharified solution. The recovery was summarized. From these results, although Comparative Example 2 (Nagase Enzyme N-40) has a higher sugar recovery rate than Comparative Example 1 (Glucoteam 20000), Example 5-1 using lactic acid bacteria culture solution L0 was used. It was found that the sugar recovery rate was lower than that of 5-2.

  From the results of Examples 5-1 to 5-5 and Comparative Examples 1 and 2, it was found that the sugar recovery rate from the garbage was improved by spraying the lactic acid bacteria culture solution to maintain the freshness of the garbage. .

It is a block diagram showing the structure of the alcohol production system which concerns on the 1st Embodiment of this invention. It is a block diagram showing the structure of a 2nd fermentation part and the subsequent circulation type biological denitrification and nitrification part. It is a characteristic view showing the daily change of the production | generation ethanol concentration when the dilution rate of Example 4 is changed in steps. It is a characteristic view showing the productivity of ethanol with respect to the dilution rate of Example 4, and the fermentation yield with respect to the dilution rate. It is a block diagram showing the structure of the sugar production method which concerns on the 2nd Embodiment of this invention. It is a figure for demonstrating a garbage disposal process. It is a characteristic view showing the relationship of the glucose concentration with respect to the reaction time of Example 5-1. It is a characteristic view showing the relationship of the glucose concentration with respect to the reaction time of Example 5-2. It is a characteristic view showing the relationship of the glucose concentration with respect to the reaction time of Example 5-3. It is a characteristic view showing the relationship of the glucose concentration with respect to the reaction time of Example 5-4. It is a characteristic view showing the relationship of the glucose concentration with respect to the reaction time of Example 5-5. It is a characteristic view showing the relationship of the glucose concentration with respect to the reaction time of Example 6-1. It is a characteristic view showing the relationship of the glucose concentration with respect to the reaction time of Example 6-2. It is a characteristic view showing the relationship of the glucose concentration with respect to the reaction time of Example 6-3. It is a characteristic view showing the relationship of the glucose concentration with respect to the reaction time of Example 6-4. 6 is a characteristic diagram showing the relationship of glucose concentration with respect to reaction time in Comparative Example 1. FIG. 6 is a characteristic diagram showing the relationship of glucose concentration with respect to reaction time in Comparative Example 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Alcohol production system, 2 ... Alcohol production method, 10 ... Alcohol production part, 11 ... Saccharification part, 12 ... Concentration part, 13 ... First fermentation part, 14 ... Distillation part, 15 ... Dehydration part, 20 ... Waste liquid treatment Utilization part, 21 ... second fermentation part, 21A ... methane fermentation tank, 21B ... water tank, 22 ... cogeneration, 23 ... circulation biological denitrification / nitrification part, 23A ... denitrification tank, 23B ... nitrification tank, 24 ... Decolorization section, 31 ... garbage treatment process, 32 ... saccharification process, 33 ... concentration process, 41 ... container, 42 ... plastic bag, A ... organic acid, A1 ... lactic acid, E1 ... plant power, G1 ... biogas, G2 ... Mixed gas, G3 ... steam, L0 ... lactic acid bacteria culture solution, L1 ... fuel alcohol, L2 ... saccharified solution, L3 ... concentrated saccharified solution, L4 ... soot, L5 ... crude alcohol, L6 ... distillation waste solution, L7 ... liquid fertilizer, L8 ... Treated water, S ... saccharification Residue, W1 ... garbage, W2, W3 ... processing garbage

Claims (24)

In an anaerobic state, garbage and enzymes are reacted to produce a saccharified solution, and lactic acid is mainly produced by microorganisms living in the garbage, and the hydrogen ion concentration (pH) of the saccharified solution is 2.5 or more and 5 A saccharification part in the range of 5 or less ;
And a first fermentation section for adding an aggregating yeast belonging to Saccharomyces cerevisiae that grows and ferments in the pH range to the saccharified solution produced in the saccharification section and subjecting it to alcohol fermentation. Production system. In the saccharification part, the culture solution of lactic acid bacteria is added to the garbage so that it is 10% or less.
The alcohol production system according to claim 1. The enzyme is added after the lactic acid bacteria culture solution is added and stored in an anaerobic state for a certain period of time and the pH is lowered.
The alcohol production system according to claim 2. Has a concentration part for concentrating the saccharified solution generated in the glycated part, either said first fermentation unit of claim 1 to 3, characterized in that to alcoholic fermentation the concentrated saccharified solution generated in the rectifying section alcohol production system according to any one of claims. It was distilled before Symbol mash produced by the first fermentation unit, a distillation unit for separating the crude alcohol and stillage,
The alcohol production system according to any one of claims 1 to 4, further comprising: a dehydration unit that dehydrates the crude alcohol to generate alcohol. In the saccharification part, after mixing the garbage, water having a weight of 1/4 or more with respect to the wet weight of the garbage, and 100 mg or more of the enzyme with respect to 1 kg of the wet weight, The alcohol production system according to any one of claims 1 to 5 , wherein saccharification is performed at a temperature. The alcohol according to any one of claims 1 to 6 , wherein, in the saccharification part, the garbage is saccharified in a rotating blade or a rotating drum, and the resulting saccharification residue is separated from the saccharified solution. Production system. The alcohol production system according to claim 7 , wherein after the saccharified solution obtained by the rotating blade is recovered, the saccharified residue is recovered while being roughly pulverized. Concentrating the saccharified liquid at atmospheric pressure or under reduced pressure in the concentrating section, and concentrating nutrient sources necessary for alcoholic fermentation by setting the total sugar concentration of the concentrated saccharified liquid to 100 g / l or more and 300 g / l or less. The alcohol production system according to any one of claims 4 to 8 , characterized in that The alcohol production system according to claim 9, wherein a concentration ratio of the saccharified solution is 1.5 to 5 times. In the concentrating portion, the saccharified solution is concentrated under reduced pressure or normal pressure until the concentration of lactic acid becomes twice or more that before concentration, and the pH is lowered, and the concentration of monosaccharides in the saccharified solution is increased. The alcohol production system according to any one of claims 4 to 8 , wherein growth of various bacteria is suppressed. In the concentration section, the concentrated saccharified solution is concentrated by concentrating the saccharified solution until the concentration of lactic acid is 10,000 mg / l or more, and reducing the pH of the saccharified solution to suppress contamination due to the growth of various bacteria. The alcohol production system according to any one of claims 4 to 8 , wherein sterilization is not required. The alcohol production system according to claim 4 , wherein in the concentration unit, the pH of the saccharified solution is adjusted by increasing the concentration of the lactic acid. The alcohol production system according to any one of claims 1 to 13 , wherein the enzyme is an acid-resistant glucoamylase or an acid-resistant and heat-resistant glucoamylase. In the first fermentation section, the alcohol concentration is 50 g / l or more and 150 g / l or less, the alcohol fermentation pH is 4.5 or less, the fermentation temperature is 25 ° C. or more, and the dilution rate D (h ⁻¹ ) is 0.05 h ^−. The alcohol according to any one of claims 1 to 14 , wherein the non-sterilized concentrated saccharified solution is continuously fermented while suppressing contamination due to the growth of various germs by washing before the germs grow as ¹ or more. Production system. In the first fermentation section, a continuous fermentation system and aggregating yeast are used as the alcohol fermentation, and the fermentation tank has functions such as mechanical stirring and gas circulation as a fermentation apparatus and is provided with a sedimentation separation section in the subsequent stage, in the upper or subsequent stage. The alcohol production system according to any one of claims 1 to 15 , wherein a tower reactor having a sedimentation separation section or a tower reactor having a draft tube in a fluid section is used. A second fermentation unit having a methane fermentation tank as a waste liquid treatment / utilization unit is provided, biogas is generated by fermenting the distillation waste liquid generated in the distillation unit in the methane fermentation tank, and the biogas is added to the concentration unit The alcohol production system according to claim 5 , wherein the alcohol production system is used as an energy source of at least one of the distillation unit. In the second fermentation part, by introducing 5% or more and 10% or less of the amount of biogas generated into the methane fermentation tank and mixing it with the biogas, in the mixed gas containing the biogas and air The alcohol production system according to claim 17, wherein the concentration of hydrogen sulfide is reduced. A water tank is provided after the second fermenter, and the mixed gas is circulated between the methane fermenter and the water tank to oxidize hydrogen sulfide to sulfur, and the concentration of hydrogen sulfide in the mixed gas. The alcohol production system according to claim 17 , wherein the alcohol production system is reduced to 10 ppm or less. A circulatory biological denitrification tank is provided after the methane fermentation tank, and a nitrification tank is provided after the circulatory biological denitrification tank, so that ammonium ions generated by methane fermentation can be converted into the circulatory biological nitrification. The organic matter and nitrate ions remaining after the methane fermentation are simultaneously removed by oxidizing the nitrate ions in the tank and then circulating a part of the liquid containing the nitrate ions to the denitrification tank. Item 20. The alcohol production system according to Item 19 . Claim 20, characterized in that added to the saccharification portion treated water obtained in the decolorization portion provided downstream of the treated water or the nitrification tank resulting in the nitrification tank as an alternative of water added to the garbage Alcohol production system. In an anaerobic state, garbage and enzymes are reacted to produce a saccharified solution, and lactic acid is mainly produced by microorganisms living in the garbage, and the hydrogen ion concentration (pH) of the saccharified solution is 2.5 or more and 5 A saccharification step with a range of 5 or less ;
Wherein the sugar solution produced in the saccharification step, the alcohol production method which comprises a fermentation step of adding a flocculent yeast belonging to Saccharomyces cerevisiae to grow and fermentation in the range of the pH as a yeast to alcohol fermentation. A concentration step of concentrating the saccharified solution produced in the saccharification step,
The alcohol production method according to claim 22 , wherein the concentrated saccharified solution produced in the concentration step is subjected to alcohol fermentation in the fermentation step. The alcohol production method according to claim 22 or 23 , wherein the enzyme is glucoamylase having acid resistance or glucoamylase having acid resistance and heat resistance.

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