Alcohol fermentation method and alcohol fermentation promoter

Abstract

To enhance the efficiency of alcohol fermentation by microorganisms when using fermentation raw materials containing sugars in various concentration ranges.SOLUTION: A fermentation-accelerating material containing at least one component selected from curcumin, piperine, dipotassium glycyrrhizinate, and allicin, or a derivative of the component, is added to a fermentation raw material containing sugars, and the fermentative microorganisms are utilized to induce alcoholic fermentation.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for alcohol fermentation by a microorganism and an alcohol fermentation promoter. [Background technology]

[0002] Traditionally, alcoholic fermentation has been used to produce alcoholic beverages such as wine and beer. Alcoholic fermentation is a metabolic process in which microorganisms break down sugar to produce ethanol and carbon dioxide (C6H 12 O6 → 2CH3CH2OH + 2CO2). In recent years, bioethanol has also been produced from cellulosic biomass such as wood through alcohol fermentation.

[0003] Increasing the efficiency of fermentation by microorganisms is important from the viewpoint of improving ethanol productivity. For example, Patent Document 1 describes a method for increasing the efficiency of alcoholic fermentation by adding crushed or extracted materials of any of yuzu seeds, loquat seeds, grape seeds, sesame seeds, and garlic tubers to the fermentation raw material. In the method of Patent Document 1, a fermentation raw material is a YPD medium containing 13% glucose to which yeast has been added, and the crushed or extracted materials are added thereto to carry out alcoholic fermentation. According to the method of Patent Document 1, when the crushed or extracted materials are added, the fermentation rate is increased compared to when the crushed or extracted materials are not added, and therefore the time required for sugar to be decomposed and ethanol to be produced is shortened. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2011-125229 A Summary of the Invention [Problem to be solved by the invention]

[0005] In alcoholic fermentation, sugar is taken up by yeast (microorganisms) and broken down into ethanol. It is therefore believed that the fermentation efficiency will increase if the amount of sugar taken up by yeast increases. One method for increasing the amount of sugar taken up by yeast is to increase the sugar concentration contained in the fermentation raw material. However, since the range of sugar concentrations suitable for alcoholic fermentation differs depending on the type of yeast, for example, in the method of Patent Document 1, increasing the sugar concentration contained in the YPD medium may actually decrease the fermentation efficiency.

[0006] The problem to be solved by the present invention is to make it possible to increase the efficiency of alcoholic fermentation by microorganisms when using fermentation raw materials containing sugars in various concentration ranges. [Means for solving the problem]

[0007] The alcoholic fermentation method according to the present invention, which has been achieved to solve the above problems, is as follows: A fermentation-promoting material containing at least one component selected from curcumin, piperine, dipotassium glycyrrhizinate, and allicin or a derivative of said component is added to a fermentation raw material containing sugar, and alcoholic fermentation is carried out by a fermenting microorganism.

[0008] In addition, the alcohol fermentation promoter according to the present invention, which has been made to solve the above problems, is It contains at least one component selected from curcumin, piperine, dipotassium glycyrrhizinate, and allicin, or a derivative of said component.

[0009] The inventors of the present application investigated the effects of various components contained in spices on alcoholic fermentation by microorganisms and found that four components, namely curcumin, piperine, dipotassium glycyrrhizinate, and allicin, promote alcoholic fermentation by microorganisms, and that this promoting effect is exerted over a wide range of sugar concentration conditions.

[0010] By carrying out alcoholic fermentation using the above-mentioned alcoholic fermentation method or the above-mentioned alcoholic fermentation promoter, alcoholic fermentation by microorganisms can be promoted under a wide range of sugar concentration conditions, thereby increasing fermentation efficiency.

[0011] In the above alcoholic fermentation method, The fermentation-promoting material preferably contains curcumin or a curcumin derivative.

[0012] In the alcohol fermentation promoter, It preferably contains curcumin or a curcumin derivative.

[0013] According to the alcoholic fermentation method and the alcoholic fermentation promoter having the above-mentioned configuration, alcoholic fermentation can be promoted more effectively.

[0014] Furthermore, the inventors of the present application have found that the above four components promote alcoholic fermentation even under high sugar concentration conditions where the alcoholic fermentation ability of yeast is thought to decrease. Therefore, in the above-mentioned alcoholic fermentation method, The concentration of the sugar contained in the fermentation raw material may be 15% by mass or more and 30% by mass or less.

[0015] According to the alcoholic fermentation method of the above configuration, a fermentation raw material containing a relatively high sugar concentration range of 15% by mass or more and 30% by mass or less is used, so that the amount of sugar taken up by the microorganism can be increased while promoting alcoholic fermentation, thereby further improving the fermentation efficiency. Effect of the Invention

[0016] According to the alcoholic fermentation method and the alcoholic fermentation promoter of the present invention, the efficiency of alcoholic fermentation by a microorganism can be increased under a wide range of sugar concentration conditions, and ethanol productivity is improved. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1(A) is a graph showing the relationship between the amount of carbon dioxide generated and the number of days for fermentation in Example 1, and FIG. 1(B) is a graph showing the relationship between the rate of carbon dioxide generation and the number of days for fermentation. [Diagram 2] FIG. 2(A) is a graph showing the relationship between the amount of carbon dioxide generated and the number of days for fermentation in Example 2, and FIG. 2(B) is a graph showing the relationship between the rate of carbon dioxide generation and the number of days for fermentation in Example 2. [Diagram 3] FIG. 3(A) is a graph showing the relationship between the amount of carbon dioxide generated and the number of days for fermentation, and FIG. 3(B) is a graph showing the relationship between the rate of carbon dioxide generation and the number of days for fermentation in Example 3. [Figure 4] FIG. 4(A) is a graph showing the relationship between the amount of carbon dioxide generated and the number of days for fermentation, and FIG. 4(B) is a graph showing the relationship between the rate of carbon dioxide generation and the number of days for fermentation in Example 4. [Diagram 5] Graph showing the relationship between the amount of carbon dioxide generated and the number of days of fermentation in Comparative Example 1 (FIG. 5(A)), Comparative Example 2 (FIG. 5(B)), and Comparative Example 3 (FIG. 5(C)). [Figure 6] Graph showing the relationship between the amount of carbon dioxide generated and the number of days of fermentation in Comparative Example 4 (FIG. 6(A)), Comparative Example 5 (FIG. 6(B)), Comparative Example 6 (FIG. 6(C)), and Comparative Example 7 (FIG. 6(D)). [Figure 7] 7(A) is a graph showing the relationship between the amount of carbon dioxide produced and the number of days for fermentation in Example 5, and FIG. 7(B) is a graph showing the relationship between the rate of carbon dioxide production and the number of days for fermentation in Example 5. [Figure 8] 8(A) is a graph showing the relationship between the amount of carbon dioxide produced and the number of days for fermentation in Example 6, and FIG. 8(B) is a graph showing the relationship between the rate of carbon dioxide production and the number of days for fermentation in Example 6. [Figure 9] 9(A) is a graph showing the relationship between the amount of carbon dioxide produced and the number of days for fermentation in Example 7, and FIG. 9(B) is a graph showing the relationship between the rate of carbon dioxide production and the number of days for fermentation in Example 7. [Figure 10] 10(A) is a graph showing the relationship between the amount of carbon dioxide produced and the fermentation time, and FIG. 10(B) is a graph showing the relationship between the rate of carbon dioxide production and the fermentation time in Example 8. [Figure 11] 11(A) is a graph showing the relationship between the amount of carbon dioxide produced and the fermentation time, and FIG. 11(B) is a graph showing the relationship between the rate of carbon dioxide production and the fermentation time in Example 9. [Figure 12] 12(A) is a graph showing the relationship between the amount of carbon dioxide produced and the fermentation time, and FIG. 12(B) is a graph showing the relationship between the rate of carbon dioxide production and the fermentation time in Example 10. [Figure 13] Graph showing the relationship between the carbon dioxide production rate and the number of days for fermentation in a reference example. [Figure 14] FIG. 14(A) is a graph showing the ethanol concentration two days after the start of fermentation, and FIG. 14(B) is a graph showing the ethanol concentration five days after the start of fermentation in Example 11. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] In the alcoholic fermentation method according to the present invention, a fermentation-promoting material containing at least one component selected from curcumin, piperine, dipotassium glycyrrhizinate, and allicin or a derivative of said component is added to a fermentation raw material containing sugar, and alcoholic fermentation is carried out using a fermenting microorganism. The alcoholic fermentation method according to the present invention is intended for a method of producing ethanol and carbon dioxide using a microorganism, regardless of whether it is for beverage, food, industrial, or other use.

[0019] Curcumin, piperine, dipotassium glycyrrhizinate, and allicin are components contained in turmeric, pepper, licorice, and garlic, respectively. Turmeric, pepper, licorice, and garlic are all plant materials used as spices. Many spices have long been known to have antiseptic and bactericidal effects. The present inventors conducted experiments to investigate the antiseptic and bactericidal effects of various components contained in spices, and found that some components contained in spices (spice components) have the effect of promoting alcoholic fermentation by yeast. The alcoholic fermentation method and the alcoholic fermentation promoter according to the present invention were obtained based on such findings.

[0020] The present inventor has developed a novel method for investigating the antiseptic and bactericidal effects of spice ingredients. In this method, yeast is inoculated into a medium containing sugar, and cultured under conditions in which alcoholic fermentation by the yeast occurs, and the presence or absence of the antiseptic and bactericidal effects of the spice ingredients is evaluated based on the amount of carbon dioxide generated. This evaluation method utilizes the phenomenon that if yeast grows and proliferates normally during culture, the amount of carbon dioxide generated increases due to alcoholic fermentation, but if the growth of the yeast is inhibited (antibacterial) or killed (bactericidal), and the number of yeast decreases, the amount of carbon dioxide generated decreases. Therefore, this evaluation method is a method for evaluating the antibacterial and bactericidal effects of spice ingredients on yeast using the amount of carbon dioxide as an index, and is also a method for evaluating the promoting effect of spice ingredients on alcoholic fermentation by yeast. In addition, this evaluation method can be used to evaluate alcoholic fermentation by microorganisms including yeast, to evaluate the antibacterial and bactericidal effects of various ingredients on microorganisms that perform alcoholic fermentation, or to evaluate the promoting effect of alcoholic fermentation.

[0021] <Microorganisms> The microorganism may be any microorganism capable of decomposing sugars to produce ethanol and carbon dioxide through alcoholic fermentation, and examples of such microorganisms include yeast, Zymomonas bacteria, and Zymobacter bacteria. Among these, yeast is a representative microorganism that performs alcoholic fermentation, and yeasts of the Saccharomyces, Schizosaccharomyces, and Zygosaccharomyces genera can be used. Specifically, one or more types of yeasts selected from Saccharomyces cerevisiae, Saccharomyces pasteurianus, Saccharomyces bayanus, Schizosaccharomyces pombe, and Zygosaccharomyces rouxii can be used. Saccharomyces cerevisiae is mainly used to produce alcoholic beverages such as beer, wine, and sake, and to make bread. Saccharomyces pastorianus, Saccharomyces bayenus, and Schizosaccharomyces pombe are mainly used to produce alcoholic beverages such as beer, wine, and whiskey, and Zygosaccharomyces rusexi is mainly used to produce soy sauce, miso, and balsamic vinegar.

[0022] <Fermentation ingredients> The fermentation feedstock contains sugar. The sugar contained in the fermentation feedstock is typically glucose, but can also be C6H 12 Monosaccharides other than glucose, represented by O6 (such as fructose), can also be used, and as long as they produce ethanol and carbon dioxide through alcoholic fermentation by microorganisms, they can be used as C6H 12 Monosaccharides represented by a chemical formula other than O6 may also be used. Disaccharides other than monosaccharides (e.g., sucrose (cane sugar) and maltose (malt sugar)) and polysaccharides may also be used. Sugars may also be those contained in fruit juice, molasses from sugarcane or sugar beet, or those obtained by saccharifying cellulosic biomass raw materials such as wood or herbs. Saccharification can be carried out by a method using a saccharifying enzyme or a method using an acid or alkali.

[0023] The sugar concentration in the fermentation raw material is preferably 10% by mass or more and 30% by mass or less, more preferably 15% by mass or more and 30% by mass or less, and even more preferably 20% by mass or more and 30% by mass or less. When the sugar concentration is 10% by mass or more, a sufficient amount of ethanol can be produced by alcoholic fermentation. When the sugar concentration is 30% by mass or less, a decrease in the alcoholic fermentation ability of the microorganism can be prevented.

[0024] In addition to sugar, the fermentation raw material may contain components necessary for alcoholic fermentation by microorganisms. For example, the fermentation raw material may contain nutrients such as peptone or growth promoters such as yeast extract.

[0025] <Fermentation promoting materials> The fermentation-promoting material contains at least one component selected from curcumin, piperine, dipotassium glycyrrhizinate, and allicin, or a derivative of the component. As described above, curcumin, piperine, dipotassium glycyrrhizinate, and allicin are components contained in the spices turmeric, pepper, licorice, and garlic, respectively. Therefore, the fermentation-promoting material may be a ground product or extract of these spices, or a mixture thereof. For example, the fermentation-promoting material may be curry powder. In order to promote alcoholic fermentation more effectively, it is preferable that the fermentation-promoting material contains at least curcumin or a curcumin derivative. Examples of curcumin derivatives include demethoxycurcumin and bisdemethoxycurcumin. In the present invention, "promoting alcoholic fermentation" means that the amounts of ethanol and carbon dioxide produced by microorganisms are increased. In particular, it means that the amounts of ethanol and carbon dioxide are increased in the early stage of alcoholic fermentation (within 48 hours from the start of alcoholic fermentation).

[0026] The concentration of at least one component selected from curcumin, piperine, dipotassium glycyrrhizinate, and allicin or a derivative of said component contained in the fermentation raw material after the addition of the fermentation-promoting material is appropriately set depending on the type of component selected, but from the viewpoint of more effectively promoting alcoholic fermentation, it is preferably 0.01 mg / mL or more and 10 mg / mL or less, more preferably 0.1 mg / mL or more and 10 mg / mL or less, and even more preferably 0.1 mg / mL or more and 1 mg / mL or less.

[0027] <Alcoholic fermentation> Alcoholic fermentation is carried out by adding a fermentation promoter and a microorganism to the fermentation raw material and culturing the microorganism at a temperature suitable for the microorganism (usually 25°C to 35°C). Ethanol obtained by alcoholic fermentation can be used as fuel or beverages. When ethanol is used as a beverage, the flavor and physiological activity of the added components (i.e., curcumin, piperine, dipotassium glycyrrhizinate, and allicin) can be imparted to the beverage.

[0028] The alcoholic fermentation method according to the present invention will be described below with reference to several examples, but these are merely illustrative and the present invention is not limited thereto. In the examples (and comparative examples) described below, the stimulating effect of spice components on alcoholic fermentation by yeast was evaluated using the evaluation method described in paragraph

[0020] . In the following examples, the cultivation of yeast to evaluate the stimulating effect of spice components using the above evaluation method will be referred to as a "fermentation test." EXAMPLES

[0029] <Fermentation test> The X2180 strain (ATCC (American Type Culture Collection) 26109, NCYC (National Collection of Yeast Cultures) 826), a diploid laboratory strain of yeast (Saccharomyces cerevisiae), was used and cultured overnight at 30°C with shaking in YPD medium (1% yeast extract, 2% peptone, 2% glucose). The initial yeast density was OD 600 The above yeast was inoculated into a test tube containing 5 mL of high-concentration glucose-containing YPD medium (1% yeast extract, 2% peptone, 20% glucose) so that the OD = 0.1, and curcumin was added to the test tube at concentrations of 0.01 mg / mL, 0.1 mg / mL, and 1 mg / mL, respectively, to prepare various curcumin-added samples. 600 The yeast was inoculated into a test tube containing 5 mL of the high-concentration glucose-containing YPD medium so that the β-glucose ratio was 0.1, and a control sample was prepared without adding curcumin. Various curcumin-added samples and control samples were statically cultured at 30°C and subjected to alcoholic fermentation. The weights of each curcumin-added sample and control sample were measured using an electronic balance every 24 hours from the start of fermentation, and the amount of carbon dioxide generated in each sample was calculated by subtracting the weight after a certain time from the weight at the start of fermentation. The fermentation test was performed three times independently for each sample.

[0030] Fig. 1(A) is a graph showing the relationship between the amount of carbon dioxide generated and the number of days of fermentation in Example 1, and Fig. 1(B) is a graph showing the relationship between the rate of carbon dioxide generation and the number of days of fermentation. In Fig. 1(A), the vertical axis shows the average amount of carbon dioxide generated (g), and in Fig. 1(B), the vertical axis shows the average rate of carbon dioxide generation (g / 24h). Error bars show standard deviation.

[0031] As shown in Figures 1(A) and 1(B), in all curcumin-added samples, the amount of carbon dioxide generated (carbon dioxide fermentation rate) 24 hours after the start of fermentation was increased compared to the control sample without added curcumin. In particular, in the curcumin-added sample with a curcumin concentration of 1 mg / mL, the amount of carbon dioxide generated (carbon dioxide generation rate) 24 hours after the start of cultivation was increased by approximately 120% compared to the control sample. These results demonstrate that the addition of curcumin promotes alcoholic fermentation. EXAMPLES

[0032] Except for using piperine instead of curcumin, the fermentation test was carried out in the same manner as in Example 1. Figure 2(A) is a graph showing the relationship between the amount of carbon dioxide generated and the number of days for fermentation in Example 2, and Figure 2(B) is a graph showing the relationship between the rate of carbon dioxide generation and the number of days for fermentation.

[0033] As shown in Figure 2(A) and Figure 2(B), in the piperine-added samples with piperine concentrations of 0.01 mg / mL and 0.1 mg / mL, the amount of carbon dioxide generated (carbon dioxide generation rate) 24 hours after the start of fermentation was similar to that of the control sample, but the amount of carbon dioxide generated after 48 hours was higher than that of the control sample. In addition, in the piperine-added sample with piperine concentration of 1 mg / mL, the amount of carbon dioxide generated (carbon dioxide generation rate) 24 hours after the start of fermentation was higher than that of the control sample, and the increase rate was about 60%. These results show that the addition of piperine promotes alcoholic fermentation. EXAMPLES

[0034] Except for using dipotassium glycyrrhizinate instead of curcumin, the fermentation test was carried out in the same manner as in Example 1. Figure 3(A) is a graph showing the relationship between the amount of carbon dioxide generated and the number of days for fermentation in Example 3, and Figure 3(B) is a graph showing the relationship between the rate of carbon dioxide generation and the number of days for fermentation.

[0035] As shown in Figures 3(A) and 3(B), in all dipotassium glycyrrhizinate-added samples, the amount of carbon dioxide generated (carbon dioxide generation rate) 24 hours after the start of fermentation was increased compared to the control sample. In particular, in the dipotassium glycyrrhizinate-added sample with a dipotassium glycyrrhizinate concentration of 1 mg / mL, the amount of carbon dioxide generated (carbon dioxide generation rate) 24 hours after the start of fermentation was increased by approximately 60% compared to the control sample. These results demonstrate that the addition of dipotassium glycyrrhizinate promotes alcoholic fermentation. EXAMPLES

[0036] Except for using allicin instead of curcumin, the fermentation test was carried out in the same manner as in Example 1. Figure 4(A) is a graph showing the relationship between the amount of carbon dioxide generated and the number of days for fermentation in Example 4, and Figure 4(B) is a graph showing the relationship between the rate of carbon dioxide generation and the number of days for fermentation.

[0037] As shown in Figure 4(A) and Figure 4(B), the amount of carbon dioxide generated (carbon dioxide generation rate) after 24 hours from the start of fermentation was higher in the allicin-added sample with an allicin concentration of 0.01 mg / mL than in the control sample. In the allicin-added sample with an allicin concentration of 0.1 mg / mL, the amount of carbon dioxide generated (carbon dioxide generation rate) after 24 hours from the start of fermentation was slightly lower than in the control sample, but the amount of carbon dioxide generated after 48 hours was higher than in the control sample. On the other hand, in the allicin-added sample with an allicin concentration of 1 mg / mL, only a small amount of carbon dioxide was generated even 5 days after the start of fermentation. From these results, it was found that the addition of allicin promotes alcoholic fermentation, but when the allicin concentration increases, the yeast is inactivated due to the antibacterial properties of allicin, and alcoholic fermentation is suppressed.

[0038] (Comparative Example 1), (Comparative Example 2), (Comparative Example 3) Fermentation tests were carried out in the same manner as in Example 1, except that menthol (Comparative Example 1), capsaicin (Comparative Example 2), or gingerol (Comparative Example 3) was used instead of curcumin. Figures 5(A), 5(B), and 5(C) are graphs showing the relationship between the amount of carbon dioxide generated and the number of days of fermentation in Comparative Examples 1, 2, and 3, respectively. Menthol, capsaicin, and gingerol are components contained in mint, chili pepper, and ginger, respectively.

[0039] As shown in Figure 5(A), Figure 5(B), and Figure 5(C), in the samples with any of the added ingredients, the amount of carbon dioxide generated after 24 hours was almost the same as or smaller than that of the control sample. This tendency did not change even if the number of fermentation days increased. From these results, it was found that menthol, capsaicin, and gingerol do not promote alcoholic fermentation.

[0040] (Comparative Example 4), (Comparative Example 5), (Comparative Example 6), (Comparative Example 7) Fermentation tests were carried out in the same manner as in Example 1, except that limonene (Comparative Example 4), linalool (Comparative Example 5), cuminaldehyde (Comparative Example 6), or allyl isothiocyanate (Comparative Example 7) was used instead of curcumin. Figures 6(A), 6(B), 6(C), and 6(D) are graphs showing the relationship between the amount of carbon dioxide generated and the number of days of fermentation in Comparative Examples 4, 5, 6, and 7, respectively. Limonene, linalool, cuminaldehyde, and allyl isothiocyanate are components contained in citrus peels, coriander seeds, cumin seeds, and wasabi, respectively.

[0041] As shown in Figures 6(A), 6(B), 6(C), and 6(D), almost no carbon dioxide was generated after 24 hours in any of the samples with added ingredients. None of the samples with added ingredients generated more carbon dioxide than the control sample even after fermentation for an extended period of time. These results indicate that limonene, linalool, cuminaldehyde, and allyl isothiocyanate inhibit alcoholic fermentation. EXAMPLES

[0042] Fermentation tests were performed in the same manner as in Example 1, except that YPD media with different sugar concentrations (high-concentration glucose-containing YPD(10) medium (yeast extract 1%, peptone 2%, glucose 10%), high-concentration glucose-containing YPD(20) medium (yeast extract 1%, peptone 2%, glucose 20%), and high-concentration glucose-containing YPD(30) medium (yeast extract 1%, peptone 2%, glucose 30%)) were used, and curcumin was added to a concentration of 1 mg / mL.

[0043] FIG. 7(A) is a graph showing the relationship between the amount of carbon dioxide generated and the number of days of fermentation in Example 5, and FIG. 7(B) is a graph showing the relationship between the rate of carbon dioxide generation and the number of days of fermentation. As shown in FIG. 7(A) and FIG. 7(B), in all of the curcumin-added samples using YPD media with glucose concentrations of 10%, 20%, and 30%, the amount of carbon dioxide generated (carbon dioxide generation rate) 24 hours after the start of fermentation was increased compared to the control samples corresponding to each glucose concentration. From the above results, it was found that the addition of curcumin promotes alcoholic fermentation even at high sugar concentrations (20% to 30%) that are thought to reduce the sugar metabolic ability of yeast. EXAMPLES

[0044] A fermentation test was carried out in the same manner as in Example 1, except that demethoxycurcumin was used in addition to curcumin and added to a concentration of 1 mg / mL. EXAMPLES

[0045] Fermentation tests were carried out in the same manner as in Example 1, except that in addition to curcumin, bisdemethoxycurcumin was used and added to a concentration of 1 mg / mL.

[0046] Figures 8(A) and 9(A) are graphs showing the relationship between the amount of carbon dioxide generated and the number of days of fermentation in Examples 6 and 7, respectively, and Figures 8(B) and 9(B) are graphs showing the relationship between the rate of carbon dioxide generation and the number of days of fermentation in Examples 6 and 7, respectively. As shown in Figures 8(A), 8(B) and 9(A) and 9(B), the amount of carbon dioxide generated (carbon dioxide generation rate) 24 hours after the start of fermentation was increased in the samples to which demethoxycurcumin or bisdemethoxycurcumin was added, compared to the control sample. These results demonstrate that alcoholic fermentation can be promoted even when a curcumin derivative is used. EXAMPLES

[0047] <Fermentation test> The diploid laboratory strain of yeast (Saccharomyces cerevisiae), X2180, was used and cultured overnight at 30°C with shaking in YPD medium (1% yeast extract, 2% peptone, 2% glucose). The initial yeast density was OD 600 The yeast was inoculated into a culture vessel containing 50 mL of high-concentration glucose-containing YPD medium (1% yeast extract, 2% peptone, 20% glucose) so that the OD = 0.1, and curcumin was added to the culture vessel at concentrations of 0.01 mg / mL, 0.1 mg / mL, 1 mg / mL, and 10 mg / mL to prepare various curcumin-added samples. 600 A control sample was prepared by inoculating the yeast into a culture vessel containing 50 mL of the high-concentration glucose-containing YPD medium so that the β-glucose content was 0.1. The various curcumin-added samples and the control sample were statically cultured at 30°C and subjected to alcoholic fermentation. The amount of carbon dioxide generated was measured using an automatic gas generation measuring device (Fermograph II-W, manufactured by ATTO Corporation). The fermentation test was performed three times independently for each sample.

[0048] FIG. 10(A) is a graph showing the relationship between the amount of carbon dioxide generated and the fermentation time in Example 8, and FIG. 10(B) is a graph showing the relationship between the rate of carbon dioxide generation and the fermentation time in Example 8. As shown in FIG. 10(A) and FIG. 10(B), the amount of carbon dioxide generated and the rate of carbon dioxide generation increased 24 hours after the start of fermentation in the curcumin-added samples containing any concentration of curcumin, compared to the control sample. The carbon dioxide generation rates were similar in the various curcumin-added samples with curcumin concentrations of 0.1 mg / mL, 1 mg / mL, and 10 mg / mL. From the above results, it was found that alcoholic fermentation was promoted at curcumin concentrations of 0.01 mg / mL to 10 mg / mL, and that alcoholic fermentation was promoted more effectively at curcumin concentrations of 0.1 mg / mL to 10 mg / mL in particular. EXAMPLES

[0049] The fermentation test was carried out in the same manner as in Example 8, except that in addition to curcumin, ground turmeric was used and added to a concentration of 1 mg / mL to prepare a curcumin-added sample and a turmeric-added sample.

[0050] FIG. 11(A) is a graph showing the relationship between the amount of carbon dioxide generated and the fermentation time in Example 9, and FIG. 11(B) is a graph showing the relationship between the rate of carbon dioxide generation and the fermentation time in Example 9. As shown in FIG. 11(A) and FIG. 11(B), the amount of carbon dioxide generated and the rate of carbon dioxide generation 24 hours after the start of fermentation were slightly smaller in the turmeric-added sample than in the curcumin-added sample, but the amount of carbon dioxide generated and the rate of carbon dioxide generation 24 hours after the start of fermentation were greater in both the curcumin-added sample and the turmeric-added sample than in the control sample. From the above results, it was found that alcoholic fermentation was promoted even when ground turmeric, a spice containing curcumin, was used instead of curcumin. EXAMPLES

[0051] The fermentation test was carried out in the same manner as in Example 8, except that curry powder (product name: S&B Curry Powder, manufactured by S&B Foods Co., Ltd.) was used in addition to curcumin and added to a concentration of 1 mg / mL to prepare a curcumin-added sample and a curry powder-added sample. The curry powder used in Example 10 contains turmeric and pepper.

[0052] FIG. 12(A) is a graph showing the relationship between the amount of carbon dioxide generated and the fermentation time in Example 10, and FIG. 12(B) is a graph showing the relationship between the carbon dioxide generation rate (mL / 12h) and the fermentation time in Example 10. As shown in FIG. 12(A) and FIG. 12(B), the amount of carbon dioxide generated and the carbon dioxide generation rate 24 hours after the start of fermentation were slightly smaller in the curry powder-added sample than in the curcumin-added sample, but the amount of carbon dioxide generated 24 hours after the start of fermentation was greater in both the curcumin-added sample and the curry powder-added sample than in the control sample. From these results, it was found that alcoholic fermentation was promoted even when curry powder was used instead of curcumin.

[0053] Although it is unclear how much curcumin is contained in the ground turmeric and curry powder used in Examples 9 and 10, the ground turmeric and curry powder samples showed almost the same alcohol fermentation ability as the curcumin-added sample in Examples 9 and 10, so it is considered that the ground turmeric and curry powder contained a sufficient amount of curcumin to show alcohol fermentation ability. In addition, since the curry powder used in Example 10 contains pepper in addition to turmeric, it is also considered that the alcohol fermentation was promoted by the action of curcumin, a component contained in turmeric, and piperine, a component contained in pepper.

[0054] (Reference example) A control sample was prepared in the same manner as in Example 8 using sake yeast (K701 strain), known to have a high alcohol fermentation ability, and laboratory yeast (X2180 strain), and a fermentation test was carried out.

[0055] FIG. 13 is a graph showing the relationship between the carbon dioxide generation rate and the number of days of fermentation in the reference example. When comparing the carbon dioxide generation rates of sake yeast and laboratory yeast, they were almost the same after 24 hours from the start of fermentation, and after 48 hours, the carbon dioxide generation rate of sake yeast was about 47% higher than that of laboratory yeast. On the other hand, in Example 10, in the curcumin-added sample, the carbon dioxide generation rate after 24 hours from the start of fermentation increased by about 240% compared to the control sample, and in the curry powder-added sample, the carbon dioxide generation rate increased by about 190% compared to the control sample. The control sample using laboratory yeast in the reference example corresponds to the control sample in Example 10. From the above, it was found that the carbon dioxide generation rate within 24 hours from the start of culture was higher in the sample to which curcumin or curry powder was added than in the control sample using sake yeast with high alcohol fermentation ability. EXAMPLES

[0056] The curcumin-added sample, curry powder-added sample, and control sample were subjected to alcoholic fermentation in the same manner as in Example 10. The ethanol concentration (Vol%) contained in each sample was measured using F-kit Ethanol (manufactured by JK International Co., Ltd.) according to the kit's protocol.

[0057] Figure 14(A) is a graph showing the ethanol concentration two days after the start of fermentation in Example 11, and Figure 14(B) is a graph showing the ethanol concentration five days after the start of fermentation. As shown in Figures 14(A) and 14(B), the ethanol concentrations were higher in the curcumin-added sample and the curry powder-added sample than in the control sample. Furthermore, the amount of ethanol produced in the control sample over five days from the start of fermentation was produced in the curcumin-added sample over two days. These results demonstrate that the addition of curcumin or curry powder promotes alcoholic fermentation and improves ethanol productivity.

Claims

1. A method for alcoholic fermentation comprising adding a fermentation-promoting material containing at least one component selected from curcumin, piperine, dipotassium glycyrrhizinate, and allicin or a derivative of said component to a fermentation raw material containing sugar, and carrying out alcoholic fermentation using a fermenting microorganism.

2. The method for alcohol fermentation according to claim 1 , wherein the fermentation-promoting material comprises curcumin or a curcumin derivative.

3. The alcohol fermentation method according to claim 1 or 2, wherein the concentration of the sugar contained in the fermentation raw material is 15% by mass or more and 30% by mass or less.

4. An alcohol fermentation promoter comprising at least one component selected from curcumin, piperine, dipotassium glycyrrhizinate, and allicin, or a derivative of said component.

5. The alcohol fermentation promoter according to claim 4 , comprising curcumin or a curcumin derivative.

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