Fermentation efficiency improver for bioethanol fermentation process and method for producing bioethanol

Abstract

To provide a fermentation efficiency improver for a bioethanol fermentation process as an additive that can improve production efficiency with a smaller amount of use. 【Solution means】The fermentation efficiency improver for a bioethanol fermentation process is characterized by containing a polyoxyalkylene compound (A1) represented by formula (1) and / or a polyoxyalkylene compound (A2) represented by formula (2). R 1 {-(AO 1 )s / (EO)m-(AO 2 )n-OR 2}p (1) R 1 {-(AO 3 )t-(AO 1 )s / (EO)m-(AO 2 )n-OR 2}p (2) R 1 is a reaction residue of a polyol having 3 to 12 carbon atoms, AO 1 , AO 2 is an oxyalkylene group having 3 to 4 carbon atoms, AO 3 is an oxyalkylene group having 2 to 4 carbon atoms, EO is an oxyethylene group, R 2 is a hydrogen atom, a methyl group, an acetyl group, s is an integer of 2 to 25, m is an integer of 2 to 40, n is an integer of 1 to 25, t is an integer of 1 to 15, p is an integer of 3 to 8, / represents a random state, and - represents a block state.

Description

[Technical Field]

[0001] This invention relates to a fermentation efficiency enhancer for the bioethanol fermentation process and a method for producing bioethanol. [Background technology]

[0002] As an additive for improving production efficiency in the bioethanol fermentation process, "an additive for the bioethanol fermentation process characterized by containing a polyoxyalkylene compound (A) having a Griffin HLB value in the range of 0 to 6 and a polyoxyalkylene polyol (B)" is known (Patent Document 1). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] WO2015 / 025538 Brochure [Overview of the project] [Problems that the invention aims to solve]

[0004] Conventional additives used in the bioethanol fermentation process have a problem in that the amount of these additives used tends to increase as production efficiency improves. The present invention aims to provide a fermentation efficiency enhancer for the bioethanol fermentation process, which can improve production efficiency with an even smaller amount of use. [Means for solving the problem]

[0005] The key feature of the fermentation efficiency enhancer for the bioethanol fermentation process of the present invention is that it comprises a polyoxyalkylene compound (A1) represented by formula (1) and / or a polyoxyalkylene compound (A2) represented by formula (2).

[0006] R 1 {-(AO 1 )s / (EO)m-(AO 2 )n-OR2}p (1) R 1 {-(AO 3 )t-(AO 1 )s / (EO)m-(AO 2 )n-OR 2}p (2)

[0007] R 1 is the reaction residue of a polyol having 3 to 12 carbon atoms, AO 1 and AO 2 are oxyalkylene groups having 3 or 4 carbon atoms, AO 3 is an oxyalkylene group having 2 to 4 carbon atoms, EO is an oxyethylene group, R 2 is a hydrogen atom, a methyl group or an acetyl group, s is an integer of 2 to 25, m is an integer of 2 to 40, n is an integer of 1 to 25, t is an integer of 1 to 15, p is an integer of 3 to 8, / represents a random form, and - represents a block form.

[0008] The feature of the method for producing bioethanol according to the present invention is that in a charge liquid obtained by mixing a sugar solution prepared using at least one selected from the group consisting of a saccharide raw material, a starch raw material, and a lignocellulose (cellulose) raw material as a raw material with a fermentation microorganism, it includes a fermentation step of adding the above fermentation efficiency improver for the bioethanol production process and performing ethanol fermentation.

Effect of the Invention

[0012] Reaction residues of polyols with 3 to 12 carbon atoms (R 1 In addition to the above, other C2-C18 monools (ethanol, 1-propanol, isopropanol, 1-hexanol, 2-ethylhexanol, 1-decanol, 5-decanol, 1-dodecanol, 1-octadecanol, and cyclohexanol, etc.), C2-C18 diols (ethanediol, propanediol, 1,2-propanediol, 1,2-butanediol, 1,2-hexanediol, 1,6-hexanediol, 1,2-dodecanediol, 1,18-octadecandiol, and 1,2-cyclohexanediol, etc.), or C2-C18 amines (dimethylamine, ethylamine, monoethanolamine, diethanolamine, triethanolamine, aniline, octylamine, laurylamine, myristylamine, oleylamine, stearylamine, ethylenediamine, diethylenetriamine, and triethylenetetramine, etc.) may also be reaction residues.

[0013] Oxyalkylene group (AO) having 3 or 4 carbon atoms 1 and AO 2 Examples of these include oxypropylene, oxybutylene, oxyisobutylene, and oxytetramethylene. Of these, oxypropylene, oxybutylene, and oxytetramethylene are preferred from the viewpoint of production efficiency.

[0014] Oxyalkylene group (AO) with 2-4 carbon atoms 3 Examples of these include oxyethylene, oxypropylene, oxybutylene, oxyisobutylene, and oxytetramethylene. Of these, oxyethylene, oxypropylene, oxybutylene, and oxytetramethylene are preferred from the viewpoint of production efficiency.

[0015] In equations (1) and (2), "(AO 1 )s", (AO 2 )n", (AO 3 The )t may contain multiple types of oxyalkylene groups, and if it contains multiple types of oxyalkylene groups, each is preferably in a block shape.

[0016] s is preferably an integer between 2 and 25, more preferably between 2 and 20, and particularly preferably between 3 and 15. Production efficiency is further improved within this range.

[0017] m is preferably an integer between 2 and 40, more preferably between 3 and 35, and particularly preferably between 3 and 30. Production efficiency is further improved within this range.

[0018] n is preferably an integer between 1 and 25, more preferably between 2 and 20, and particularly preferably between 3 and 15. Production efficiency is further improved within this range.

[0019] t is preferably an integer between 1 and 15, more preferably between 2 and 10, and particularly preferably between 3 and 5. Production efficiency is further improved within this range.

[0020] p is preferably an integer between 3 and 8, and more preferably between 3 and 6. Production efficiency is further improved within this range.

[0021] The polyoxyalkylene compound (A1) represented by formula (1) and / or the polyoxyalkylene compound (A2) represented by formula (2) may each consist only of the same type of polyoxyalkylene compound, or multiple types of polyoxyalkylene compounds (for example, R 1 , AO 1 , AO 2 , AO 3 s, m, n, t, R 2 It may also consist of a collection of compounds in which p differs. Furthermore, in the polyoxyalkylene compound (A1) represented by formula (1), p {-(AO 1 )s / (EO)m-(AO 2 )n-OR 2 The} group is AO 1 , AO 2 s, m, n and / or R 2 Some or all of the combinations may be different for p elements. Also, in the polyoxyalkylene compound (A2) represented by formula (2), p elements {-(AO 3 )t-(AO 1 )s / (EO)m-(AO 2 )n-OR 2 The} group is AO 1 , AO 2 , AO 3 s, m, n, t and / or R 2 The combination may consist of p distinct elements, some or all of them.

[0022] The cloud point (°C) of the polyoxyalkylene compound (A1) represented by formula (1) and / or the polyoxyalkylene compound (A2) represented by formula (2) is preferably 30 to 60, more preferably 35 to 55, and particularly preferably 40 to 50. Production efficiency is further improved within this range.

[0023] When both polyoxyalkylene compound (A1) and polyoxyalkylene compound (A2) are included, from the viewpoint of production efficiency, it is preferable that the cloud point (°C) of either polyoxyalkylene compound (A1) or polyoxyalkylene compound (A2) is within the above range, and more preferably that both the cloud point of polyoxyalkylene compound (A1) and the cloud point of polyoxyalkylene compound (A2) are within the above range.

[0024] The cloud point is one of the physical properties that measures hydrophilicity; a higher cloud point indicates greater hydrophilicity, and it is measured as follows.

[0025] Prepare the measurement solution by uniformly dissolving 99g of deionized water and 1g of the sample to be measured (if it does not dissolve, cool it until it dissolves). Take about 5cc of this measurement solution into a glass test tube, place a thermometer in the measurement solution and heat it while stirring until the measurement solution becomes cloudy, then slowly cool it while stirring until the measurement solution becomes completely clear, and read the temperature at which it becomes completely clear. This is defined as the cloud point.

[0026] The fermentation efficiency enhancer for the bioethanol fermentation process of the present invention may contain other components in addition to polyoxyalkylene compound (A1) and polyoxyalkylene compound (A2), as long as they do not inhibit the effects of the present invention. Examples of other components include defoaming agents, thickeners, dispersants, preservatives, antifreeze agents, and diluent solvents (water, mineral oil, organic solvents, etc.).

[0027] Polyoxyalkylene compounds (A1) and (A2) can be prepared by known alkylene oxide addition reactions (addition reaction of a C3-C12 polyol with a C3 or C4 alkylene oxide and ethylene oxide), methylation (reaction with methyl halogen, etc., following the addition reaction), and / or acetylation (reaction with acetic anhydride, etc., following the addition reaction).

[0028] If the fermentation efficiency improver of the present invention contains polyoxyalkylene compound (A1) and polyoxyalkylene compound (A2), there are no restrictions on the method of preparing the fermentation efficiency improver for the bioethanol fermentation process of the present invention, as long as these can be uniformly mixed. Furthermore, if other components are included, there are no restrictions on the method of preparing the fermentation efficiency improver for the bioethanol fermentation process of the present invention, as long as polyoxyalkylene compound (A1) and / or polyoxyalkylene compound (A2) and the other components can be uniformly mixed.

[0029] The present invention provides a method for producing bioethanol that is subject to known methods and may include a juice extraction step, a pre-saccharification treatment step and / or a saccharification step and an ethanol fermentation step, depending on the raw materials used.

[0030] The ethanol fermentation process involves mixing a sugar solution prepared from at least one raw material selected from the group consisting of carbohydrate raw materials, starch raw materials, and woody (cellulose) raw materials with ethanol fermentation microorganisms to obtain a starter liquid, to which the above-mentioned fermentation efficiency enhancer is added and ethanol fermentation is carried out.

[0031] The sugar solution is prepared by known methods, etc. When using a carbohydrate raw material, it can be obtained by juicing the raw material (juicing step). When using a starch raw material, it can be obtained by fermenting the starch solution and / or dispersion obtained by juicing and grinding the raw material with a starch-degrading enzyme or a microorganism possessing a starch-degrading enzyme (saccharification step). Furthermore, when using a woody (cellulose) raw material, the dispersion of cellulose obtained by grinding the raw material is treated with a strong acid or strong alkali under high temperature and pressure conditions, then the high pressure is released and steam explosion or the like is performed to reduce the molecular weight of the cellulose (saccharification pretreatment step), and then it can be obtained by fermenting it with a cellulose-degrading enzyme or a microorganism possessing a cellulose-degrading enzyme (saccharification step).

[0032] Carbohydrate sources include food resources rich in carbohydrates, such as sugarcane, molasses, and sugar beets.

[0033] Starch sources include food resources rich in starch, such as corn, sorghum, potatoes, sweet potatoes, and wheat.

[0034] Woody (cellulose) raw materials include non-edible plant resources rich in cellulose, such as timber and waste building materials. Timber includes coniferous trees (pine, fir, hemlock, spruce, larch, and radiata pine, etc.) and broad-leaved trees (eucalyptus, poplar, beech, maple, and birch, etc.), as well as kenaf, mitsumata, kozo, gampi, mulberry, Manila hemp, reed, and bamboo. These woods may be thinned wood, paper waste, sawmill waste, driftwood, and pruned wood, and may also include branches, roots, and leaves. Waste building materials include discarded woody building materials, discarded woody pallets, and discarded woody packaging materials.

[0035] In the ethanol fermentation process, in which a fermentation efficiency enhancer is added to a brewing liquid obtained by mixing sugar solutions prepared from each raw material with ethanol-fermenting microorganisms, the ethanol-fermenting microorganisms that can be used include known microorganisms for bioethanol fermentation, and known yeasts (for example, the fermenting microorganisms described in paragraph 0023 of Japanese Patent Publication No. 2013-39085).

[0036] Starch-degrading enzymes or microorganisms possessing starch-degrading enzymes that can be used in a saccharification process in which a starch solution and / or dispersion is fermented by a starch-degrading enzyme or a microorganism possessing a starch-degrading enzyme include known starch-degrading enzymes or microorganisms possessing starch-degrading enzymes, and examples include starch-degrading enzymes or microorganisms possessing starch-degrading enzymes described in paragraph 0005 of Japanese Patent Publication No. 2004-520830 and paragraph 0008 of Japanese Patent Publication No. 2016-501512.

[0037] Strong acids or strong alkalis that can be used in the pre-saccharification treatment process include known acids and alkalis used for bioethanol fermentation, such as sulfuric acid and sodium hydroxide. Many methods are known for the pre-saccharification treatment process, and acids, alkalis, organic solvents, and vapors can be used individually or in appropriate combinations.

[0038] In a saccharification process in which cellulose is fermented with a cellulose-degrading enzyme or a microorganism possessing a cellulose-degrading enzyme, usable cellulose-degrading enzymes or microorganisms possessing cellulose-degrading enzymes include known cellulose-degrading enzymes or microorganisms possessing cellulose-degrading enzymes, and examples include the cellulose-degrading enzyme or microorganisms possessing cellulose-degrading enzymes described in paragraph 0036 of Japanese Patent Application Publication No. 2019-048828.

[0039] In the fermentation process, in which the above-mentioned fermentation efficiency enhancer is added to a liquid obtained by mixing sugar solutions prepared from each raw material with ethanol-fermenting microorganisms, there are no particular restrictions on the amount of the above-mentioned fermentation efficiency enhancer to be added, but based on the weight of the ethanol-fermenting microorganisms, 3 × 10 -4 Approximately 30% by weight is preferable.

[0040] In the fermentation process, where the above-mentioned fermentation efficiency enhancer is added to a mash liquid obtained by mixing sugar solution and fermentation microorganisms, the resulting fermented liquid can be recovered and purified into bioethanol by distillation or other means.

[0041] In addition to the method of adding the above-mentioned fermentation efficiency enhancer for the bioethanol production process to ethanol fermentation, other methods include adding the fermentation efficiency enhancer to the brewing liquid and then fermenting it, or adding the fermentation efficiency enhancer to the sugar solution, mixing it with ethanol-fermenting microorganisms to make a brewing liquid, and then fermenting it with ethanol, or adding the fermentation efficiency enhancer to the ethanol-fermenting microorganisms, mixing it with the sugar solution to make a brewing liquid, and then fermenting it with ethanol. [Examples]

[0042] The present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto.

[0043] <Examples 1-17> The following polyoxyalkylene compounds (a11-a19: corresponding to formula (1), a21-a28: corresponding to formula (2)) were synthesized by known methods (alkylene oxide addition reaction, acetylation reaction, methyl etherification reaction, etc.), and were respectively designated as the fermentation efficiency improvers (1)-(17) for the bioethanol fermentation process of the present invention (Examples 1-17). Hereinafter, po represents propylene oxide, eo represents ethylene oxide, THF represents tetrahydrofuran, bo represents butylene oxide, / represents random addition, and - represents block addition, with the content corresponding to formula (1) or formula (2) described in < >.

[0044] (a11) PO(24 mol) / EO(18 mol)-PO(18 mol) adduct of sorbitol <R 1 : Reaction residue of sorbitol, AO 1 : Oxypropylene, AO 2 :Oxypropylene, s:4, m:3, n:3, p:6, R 2 : Hydrogen atom >, cloud point 42°C

[0045] (a12) (tri)methyl ether of glycerin po(63 mol) / eo(90 mol)-po(9 mol) adduct. <R 1 : Reaction residue of glycerol, AO 1 : Oxypropylene, AO 2 :Oxypropylene, s:21, m:30, n:3, p:3, R 2 :methyl>, cloud point 50℃

[0046] (a13) (tri)acetate of glycerin THF(15 mol) / eo(18 mol)-po(24 mol) adduct <R 1 : Reaction residue of glycerol, AO 1 :Oxytetramethylene, AO 2 :Oxypropylene, s:5, m:6, n:8, p:3, R 2 :Acetyl>, cloud point 40℃

[0047] (a14) ditrimethylolpropane po(16 mol) / eo(60 mol)-po(60 mol) adduct <R 1: Reaction residue of ditrimethylolpropane, AO 1 : Oxypropylene, AO 2 :Oxypropylene, s:4, m:15, n:15, p:4, R 2 : Hydrogen atom >, cloud point 44℃

[0048] (a15) Pentaerythritol po(60 mol) / eo(76 mol)-bo(16 mol) adduct <R 1 : Reaction residue of pentaerythritol, AO 1 : Oxypropylene, AO 2 :Oxybutylene, s:15, m:19, n:4, p:4, R 2 : Hydrogen atom>, cloud point 47°C

[0049] (a16) PO(21 mol) / EO(30 mol)-PO(15 mol) adduct of glycerin <R 1 : Reaction residue of glycerol, AO 1 : Oxypropylene, AO 2 :Oxypropylene, s:7, m:10, n:5, p:3, R 2 : Hydrogen atom>, cloud point 50℃

[0050] (a17) Penta(methyl ether) of xylitol bo(15 mol) / eo(50 mol)-po(35 mol) adduct <R 1 : Reaction residue of xylitol, AO 1 : Oxybutylene, AO 2 :Oxypropylene, s:3, m:10, n:7, p:5, R 2 :methyl>, cloud point 41℃

[0051] (a18) xylitol po(30 mol) / eo(35 mol)-po(20 mol) adduct <R 1 : Reaction residue of xylitol, AO 1 : Oxypropylene, AO 2 :Oxypropylene, s:6, m:7, n:4, p:5, R 2 : Hydrogen atom >, cloud point 46°C

[0052] (a19) The bo(48 mol) / eo(60 mol)-THF(18 mol) adduct of sorbitol <R 1 : The reaction residue of sorbitol, AO 1 : Oxibutylene, AO 2 : Oxytrimethylene, s:8, m:10, n:3, p:6, R 2 : Hydrogen atom>, cloud point 46 °C

[0053] (a21) The po(20 mol)-THF(16 mol) / eo(40 mol)-bo(32 mol) adduct of diglycerin <R 1 : The reaction residue of diglycerin, AO 3 : Oxipropylene, AO 1 : Oxytrimethylene, AO 2 : Oxibutylene, t:5, s:4, m:10, n:8, p:4, R 2 : Hydrogen atom>, cloud point 40 °C

[0054] (a22) The (tetra)acetate of the eo(20 mol)-bo(12 mol) / eo(16 mol)-THF(20 mol) adduct of pentaerythritol <R 1 : The reaction residue of pentaerythritol, AO 3 : Oxyethylene, AO 1 : Oxibutylene, AO 2 : Oxytrimethylene, t:5, s:4, m:3, n:5, p:4, R 2 : Acetyl>, cloud point 49 °C

[0055] (a23) The tri(methyl ether) of the po(12 mol)-po(15 mol) / eo(45 mol)-po(12 mol) adduct of glycerin <R 1 : The reaction residue of glycerin, AO 3 : Oxipropylene, AO 1 : Oxipropylene, AO 2 : Oxipropylene, t:4, s:5, m:15, n:4, p:3, R 2 : Methyl>, cloud point 50 °C

[0056] (a24) The po(9 mol)-bo(36 mol) / eo(90 mol)-THF(45 mol) adduct of glycerin <R1 : Reaction residue of glycerin, AO 3 : Oxypropylene, AO 1 : Oxibutylene, AO 2 : Oxytrimethylene, t: 3, s: 12, m: 30, n: 15, p: 3, R 2 : Hydrogen atom >, cloud point 45 °C

[0057] (a25) Pentaerythritol's bo(12 mol)-THF(12 mol) / eo(32 mol)-bo(24 mol) adduct <R 1 : Reaction residue of pentaerythritol, AO 3 : Oxibutylene, AO 1 : Oxytrimethylene, AO 2 : Oxibutylene, t: 3, s: 3, m: 8, n: 6, p: 4, R 2 : Hydrogen atom >, cloud point 49 °C

[0058] (a26) Sorbitol's THF(18 mol)-bo(36 mol) / eo(60 mol)-THF(42 mol) adduct <R 1 : Reaction residue of sorbitol, AO 3 : Oxytrimethylene, AO 1 : Oxibutylene, AO 2 : Oxytrimethylene, t: 3, s: 6, m: 10, n: 7, p: 6, R 2 : Hydrogen atom >, cloud point 41 °C

[0059] (a27) (Hexa)acetate of sorbitol's eo(24 mol)-po(90 mol) / eo(54 mol)-po(18 mol) adduct <R 1 : Reaction residue of sorbitol, AO 3 : Oxyethylene, AO 1 : Oxypropylene, AO 2 : Oxypropylene, t: 4, s: 15, m: 9, n: 3, p: 6, R 2 : Acetyl >, cloud point 43 °C

[0060] (a28) Sorbitol's po(18 mol)-po(30 mol) / eo(42 mol)-po(36 mol) adduct <R 1: Reaction residue of sorbitol, AO 3 : Oxypropylene, AO 1 : Oxypropylene, AO 2 :Oxypropylene, t:3, s:5, m:7, n:6, p:6, R 2 : Hydrogen atom >, cloud point 41°C

[0061] <Example 18> Ten parts by weight of polyoxyalkylene compound (a16) and 90 parts by weight of polyoxyalkylene compound (a21) were uniformly mixed to obtain the fermentation efficiency improver (18) for the bioethanol fermentation process according to the present invention (Example 18).

[0062] <Example 19> Sixty parts by weight of polyoxyalkylene compound (a13) and fourty parts by weight of polyoxyalkylene compound (a28) were uniformly mixed to obtain the fermentation efficiency improver (19) for the bioethanol fermentation process according to the present invention (Example 19).

[0063] <Example 20> Thirty parts by weight of polyoxyalkylene compound (a18) and seventy parts by weight of polyoxyalkylene compound (a24) were uniformly mixed to obtain the fermentation efficiency improver (20) for the bioethanol fermentation process according to the present invention (Example 20).

[0064] <Comparative Example> In accordance with Example 1 of Patent Document 1, a homogeneous mixture of {9 parts by weight of lignoceryl ether of a butanol propylene oxide (60 mol) adduct, 1 part by weight of ethyl ether of a montanyl alcohol propylene oxide (10 mol) ethylene oxide (10 mol) block adduct, and 90 parts by weight of polyoxypropylene (60 mol) glycol} was obtained as a comparative additive for the bioethanol fermentation process.

[0065] <Fermentation efficiency test> Bioethanol fermentation liquid was prepared by uniformly mixing 200 parts by weight of commercially available sugarcane molasses (purchased from Nippon Garlic Co., Ltd.), 50 parts by weight of commercially available dry yeast (Oriental Dry Yeast purchased from Oriental Yeast Co., Ltd.), and 750 parts by weight of ion-exchanged water. 300 mL of this fermentation liquid was placed in a glass graduated cylinder with an inner diameter of 50 mm and a height of 350 mm. 30 μL (30 μL or 50 μL only for the comparative example) of the measurement sample (efficiency improver for the bioethanol fermentation process obtained in each example and comparative example) was added using a microsyringe. The graduated cylinder was placed in a constant temperature water bath heated to 40°C, and the volume of the bioethanol fermentation liquid (mL) after 30 minutes of stirring was read. The production efficiency (%) was calculated using the following formula. A larger value indicates that a smaller fermentation tank can be used in production, resulting in better production efficiency.

[0066] (Production efficiency) = 300 × 100 / (Volume of bioethanol fermented liquid after 30 minutes)

[0067] [Table 1]

[0068] The bioethanol fermentation process efficiency improvers of the present invention (Examples 1-20) were able to improve production efficiency with even smaller amounts of use compared to conventional bioethanol fermentation process additives (Comparative Example). Based on these results, the bioethanol fermentation process efficiency enhancer of the present invention is suitable as an agent for improving the production efficiency of bioethanol.

Claims

1. A fermentation efficiency enhancer for the bioethanol fermentation process, characterized by containing a polyoxyalkylene compound (A1) represented by formula (1) and / or a polyoxyalkylene compound (A2) represented by formula (2). R １ {-(AO １ ) / / (EO)m-(AO ２ ).-OR ２ }p (1) R １ {-(AO ３ )t-(AO １ )s / (EO)m-(AO ２ )n-OR ２ }p (2) R １ is a reaction residue of a polyol having 3 to 12 carbon atoms, AO １ and AO ２ is an oxyalkylene group having 3 or 4 carbon atoms, AO ３ R is an oxyalkylene group having 2 to 4 carbon atoms, EO is an oxyethylene group, R is ２ represents a hydrogen atom, a methyl group, or an acetyl group; s is an integer from 2 to 25; m is an integer from 2 to 40; n is an integer from 1 to 25; t is an integer from 1 to 15; p is an integer from 3 to 8; / represents a random pattern; and - represents a blocky pattern.

2. The fermentation efficiency enhancer for the bioethanol production process according to claim 1, wherein the cloud point of the polyoxyalkylene compound (A1) and / or polyoxyalkylene compound (A2) is 30 to 60°C.

3. A sugar solution prepared using at least one raw material selected from the group consisting of carbohydrate raw materials, starch raw materials, and woody (cellulose) raw materials is mixed with fermentation microorganisms to obtain a brewing liquid. A method for producing bioethanol, characterized by comprising a fermentation step of fermenting ethanol with the addition of a fermentation efficiency improver for the bioethanol production process described in claim 1 or 2.

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