JPS6028271B2 - Method for producing alcohol using solid state fermentation method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to carrying out a saccharification reaction in a solid medium, culturing yeast, and carrying out alcoholic fermentation.

The feature is that air or inert gas is circulated in a closed system to control the temperature and moisture content of the solid medium, and the alcohol content in the solid medium is kept below a certain limit by removing the generated alcohol. The purpose of this method is to increase the rate of alcohol production and increase the raw material utilization rate of the culture medium. The solid-state fermentation method for alcohol production has been practiced since ancient times in China, using ``Kiyokushi,'' and there are examples of this in Japan as well, but most of these methods involve using solid natural products such as grains and sweet potatoes. This is a method in which alcohol is fermented by mold or yeast by leaving it as a culture medium, and then distilling it to obtain alcohol.

However, with these methods, since the water contained in the solid medium is limited, molds and yeasts will suffer from product interference (alcohol inhibition) even if a small amount of alcohol is produced, and the alcohol production rate and raw material utilization rate will be low. , the productivity is extremely low compared to alcohol production methods using liquid fermentation methods. In addition, as a characteristic of solid-state fermentation, there is a problem in that the culture medium and temperature rise due to fermentation heat, so measures such as installing cooling pipes and tray culture methods have been taken, but these are inconvenient for operation and are not suitable for large-scale production equipment. is not suitable. because of these reasons,
In Japan, only the liquid culture method has been used to produce alcohol, including alcoholic beverages, but the present invention is a practical alcohol production method using a solid fermentation method that solves these problems. , potatoes and other biomass resources can be directly converted into alcohol in a solid state. In addition, since the residue (clear) after fermentation can be easily dried, there is no need for equipment to treat distillation waste liquid, and the dried product can be effectively recycled as feed or fertilizer. These are major features of the present invention. The outline of the method for producing alcohol by solid-state fermentation in the present invention is as follows.

{11 Air or inert gas is circulated through a reaction vessel filled with a solid medium to control the temperature and moisture content of the medium, and the saccharification reaction, yeast growth, and alcohol fermentation are performed.

'2' By circulating air or inert gas, the alcohol produced in the solid medium is removed, and by keeping it at about 5 (W/V)% or less based on the moisture in the medium, the alcohol production rate is increased. and increase raw material utilization.

'3} An energy-saving alcohol recovery system is adopted in which the alcohol in the air or inert gas is cooled and removed using a heat pump device, and the gas is reheated, humidified, and circulated.

The alcohol concentration in the distillate at this time was approximately 20 (W/
V)%. '4} The temperature and moisture and alcohol concentrations of the solid medium are controlled by the flow rate of air or inert gas, the condensation temperature in the heat pump device, and the capacity of the humidifier.

The details will be explained below using examples.

Example 1 The solid fermentation reaction vessel 1 (inner diameter 4 sides, height 30 sides) shown in Fig. 1 was filled with 20 pieces of steamed rice, and fermented for about 40 hours at 30 o'clock while ventilation with humidified air was carried out using a humidifier. Bacteria ($per
glusor ae) was cultured.

In addition to this, yeast (Saccharomyce
0.43g/k9-IDM
(abbreviation for initial dry weight of the tower, hereinafter referred to as the same machine) was added, and the air inside the reaction vessel 1 and each device was evaporated with carbon dioxide gas to stop the growth of Koji bacteria. After being left in this state for one day while keeping the temperature at 30 qC, the blower and heat pump were driven. The gas flow rate at this time was approximately 24 so/hr. In the reaction vessel 1 shown in FIG. 1, the starch of steamed rice is converted into glucose by the enzyme of Koji mold, and the produced glucose is converted into alcohol by yeast. The alcohol generated here migrates into the ventilation gas as alcohol vapor, is removed from the reaction vessel 1, and is condensed together with water vapor in the condenser 3 in the heat pump device 2 to become a highly concentrated alcohol solution, which is stored in the tank 4. Ru. The low-temperature and high-temperature gas from which alcohol and moisture have been removed is heated by a heater 5 in the heat pump device,
The gas becomes a high-temperature, low-humidity gas, which is further humidified by the humidifier 9, and becomes a gas containing about 30% saturated water vapor, which is ventilated into the reaction vessel 1 again. Here, a vapor-liquid equilibrium is established between the concentration of alcohol produced in the soil of reaction vessel 1 and the amount of alcohol transferred into the ventilation gas, and the alcohol concentration in the medium in the reaction vessel is It can be estimated from the alcohol concentration of the alcohol solution. The results of alcohol fermentation and alcohol recovery performed for 11 days by the continuous circulation operation as described above are shown in FIGS. 2, 3, and Table 1.

Figure 2 shows the distillation rate and alcohol concentration of the condenser-distilled alcohol solution and the alcohol concentration in the medium estimated from the vapor-liquid equilibrium data, and the alcohol concentration in the medium was 5 (W/V)%. The following shows that fermentation took place.

Figure 3 shows the sum of crab exudate and ethanol in the humidifier for 11 days. Table 1 shows the mass balance and ethanol yield after the completion of fermentation. 76% of the starch in the medium before alcohol fermentation was consumed, and the sugar alcohol yield was 0.38 (k9 - alcohol/k9 -IDM
), which was 76% of the theoretical yield.

This value is comparable to that obtained during liquid culture.
The final alcohol yield was 270 (g/k 91 mM). In addition, the amount of yeast cells after fermentation is 25.
The result was 5 g/k9-mM, indicating that the bacterial cells proliferated during fermentation. Table 1 Solid fermentation test results using steamed rice packed layer Example 2 Instead of the solid medium of Example 1, glucose concentration was 18 (W'V)% in pulp particles with high water retention.
Alcohol fermentation was carried out by the ventilation gas circulation method in the same manner as in Example 1 using a culture medium in which Wickerham's synthetic liquid beach soil was absorbed, and the produced alcohol was recovered.

The diameter of the pulp particles used was 5 pieces or less, and 200 square meters of synthetic liquid was absorbed into 4 pieces of pulp particles. Add 0.3 oni/kg of yeast to this pulp, 3 pi○, gas flow rate 1
Alcoholic fermentation was carried out for 7 days at 2 hours/hr. The results are shown in FIG. 4, FIG. 5, and Table 2. Table 2 Fermentation test results using pulp particle packed layer

[Brief explanation of drawings]

FIG. 1 is a flowchart of a method for producing ethanol using a solid-state fermentation method. 1...Reaction container, 2...Heat pump device, 3... ...Condenser, 4...Storage tank, 5...Heater, 6...
Compressor, 7... Blower, 8... Gas flow meter, 9... Humidifier, A... Carbon dioxide gas. Figure 2 shows the progress of the crab extraction rate and alcohol concentration of the crab exudate and the estimated alcohol concentration of the culture medium in Example 1, and the symbols --- in the figure indicate the alcohol concentration of the distillate;
01 indicates the alcohol concentration of the medium, and -→person←- indicates the speed of crab release.
The figure shows the progress of alcohol recovery in Example 1. FIG. 4 shows the progress of the crab extrusion rate and alcohol concentration of the crab extrusion liquid and the estimated alcohol concentration of the culture medium in Example 2, and the symbols -・- in the figure indicate the alcohol concentration of the extrusion liquid, 1○ 1 indicates the alcohol concentration in the medium,
-→ to "-" indicates the expulsion speed. Fig. 5 shows the progress of alcohol recovery in Example 2. Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5

Claims (1)

[Scope of Claims] 1 Alcohol fermentation is carried out in a reaction vessel filled with a solid medium, and the temperature and moisture of the solid medium are controlled by circulating air or inert gas, and the solid medium is A method for producing alcohol, which comprises removing alcohol from. 2. The method for producing alcohol according to claim 1, wherein the reaction vessel is filled with a liquid culture medium impregnated into a water-retentive filler.