阅读说明：本技术 有机物质的制造方法 (Method for producing organic substance ) 是由 清水谕 滨地心 于 2019-08-27 设计创作，主要内容包括：本发明提供：能够从通过微生物发酵而得到的有机物质含有液中,高效地分离仅微生物等的成分的方法。本发明提供一种有机物质的制造方法,其具备：通过微生物发酵而得到有机物质含有液的微生物发酵工序；和加热所述有机物质含有液,分离为包含微生物的液体或固体成分与包含有机物质的气体成分的分离工序。(The present invention provides: a method capable of efficiently separating only components such as microorganisms from an organic substance-containing liquid obtained by microbial fermentation. The present invention provides a method for producing an organic substance, comprising: a microbial fermentation step of obtaining an organic substance-containing liquid by microbial fermentation; and a separation step of heating the organic substance-containing liquid to separate the organic substance-containing liquid into a liquid or solid component containing microorganisms and a gas component containing organic substances.)

1. A method for producing an organic substance, comprising:

a microbial fermentation step of obtaining an organic substance-containing liquid by microbial fermentation; and

and a separation step of heating the organic substance-containing liquid to separate the organic substance-containing liquid into a liquid or solid component containing microorganisms and a gas component containing organic substances.

2. A method for producing an organic substance, comprising:

a microbial fermentation step of obtaining an organic substance-containing liquid containing an organic substance having a boiling point of 115 ℃ or lower and an organic substance having a boiling point exceeding 115 ℃ by microbial fermentation; and

a separation step of heating the organic substance-containing liquid to separate the organic substance-containing liquid into a liquid or solid component containing the organic substance having a boiling point of more than 115 ℃ and the microorganism and a gas component containing the organic substance having a boiling point of 115 ℃ or less,

the heating temperature is not less than 115 ℃ and not more than 130 ℃ of the boiling point of the organic substance.

3. The manufacturing method according to claim 1 or 2, further comprising:

a liquefaction step of condensing and liquefying the gas component obtained in the separation step, wherein,

the heat of condensation generated in the liquefaction process is used as a heat source.

4. The method of manufacturing of claim 3, further comprising:

a purification step of purifying the organic substance by thermal distillation, wherein,

the heat of condensation is used as a heat source for the heating distillation in the purification step.

5. The production method according to any one of claims 1 to 4,

the microbial fermentation is fed by synthesis gas comprising carbon monoxide.

6. The manufacturing method according to claim 5,

the synthesis gas is a waste-derived gas.

7. The production method according to any one of claims 1 to 6,

the organic substance contains an alcohol having 1-6 carbon atoms.

Technical Field

The present invention relates to a method for producing an organic substance, and more particularly to a method for producing an organic substance using an organic substance-containing liquid obtained by microbial fermentation.

Background

In recent years, from the viewpoint of concerns about depletion of fossil fuel resources due to large consumption of oils, alcohols, and the like produced from petroleum as a raw material and global environmental problems such as increase of carbon dioxide in the air, attention has been paid to a method for producing various organic substances from a raw material other than petroleum, for example, a method for producing bioethanol from edible raw materials such as corn by a sugar fermentation method. However, such sugar fermentation methods using edible raw materials have the following problems: limited farm areas are used in production other than food, thus resulting in an increase in food prices.

In order to solve such problems, various methods for producing various organic substances conventionally produced from petroleum using conventionally discarded non-edible raw materials have been studied. For example, a method of producing ethanol from synthetic gas obtained by gasifying steel waste gas or waste by microbial fermentation is known.

In a method for producing ethanol from synthesis gas by microbial fermentation, ethanol produced by microbial fermentation is contained in a microbial fermentation tank, and therefore, it is necessary to extract ethanol therefrom. As a method for extracting such ethanol, for example, a method using a distillation apparatus is known.

In addition, as a method for producing an organic substance using a microorganism, a method for separating and purifying a desired organic substance is known. For example, patent document 1 proposes: the protein is coagulated by heat denaturation and the coagulated product is removed by solid-liquid separation, and the protein remaining in the lactic acid fermentation broth is removed. Further, patent document 2 describes: a method for purifying an organic substance from an organic substance-containing liquid obtained by fermentation of a microorganism by using a membrane evaporator.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2011-177159

Patent document 2: japanese patent laid-open No. 2008-545403

Disclosure of Invention

Technical problem to be solved by the invention

The organic substance-containing liquid obtained by microbial fermentation contains, in addition to a desired organic substance, a large amount of: microorganisms, dead bodies thereof, proteins derived from microorganisms, and the like. Therefore, when the organic substance-containing liquid is introduced as it is into a distillation apparatus or the like and the organic substance is separated, the organic substance is distilled off, and therefore, the concentration of a liquid or solid component such as a microorganism increases, and as a result, the viscosity of the organic substance-containing liquid in the distillation apparatus increases, and foaming occurs in the distillation apparatus, which may hinder continuous operation.

In view of the above problem, it is conceivable to remove components such as microorganisms from the organic substance-containing liquid. Conventionally, membrane separation apparatuses and centrifugal separation apparatuses have been known as means for removing microorganisms and the like, but in the case of membrane separation apparatuses, since clogging of a filter occurs, it is necessary to periodically clean and exchange the filter, and continuous removal is difficult. Further, in the case of a centrifugal separator, there is a problem that components such as microorganisms contained in the organic substance-containing liquid are very small and cannot be sufficiently separated.

The object of the invention is therefore: provided is a method by which components such as microorganisms contained in an organic substance-containing liquid obtained by fermentation of microorganisms can be removed without using a separation means such as a membrane separation device or a centrifugal separation device.

Means for solving the problems

The present inventors have found that the above problems can be solved by heating an organic substance-containing liquid obtained by microbial fermentation under certain conditions to convert components such as microorganisms into liquid or solid components, convert desired organic substances into gas components, and separate them. That is, the gist of the present invention is as follows.

[1] A method for producing an organic substance, comprising:

a microbial fermentation step of obtaining an organic substance-containing liquid by microbial fermentation; and

and a separation step of heating the organic substance-containing liquid to separate the organic substance-containing liquid into a liquid or solid component containing microorganisms and a gas component containing organic substances.

[2] A method for producing an organic substance, comprising:

a microbial fermentation step of obtaining an organic substance-containing liquid containing an organic substance having a boiling point of 115 ℃ or lower and an organic substance having a boiling point exceeding 115 ℃ by microbial fermentation; and

a separation step of heating the organic substance-containing liquid to separate the organic substance-containing liquid into a liquid or solid component containing the organic substance having a boiling point of more than 115 ℃ and the microorganism and a gas component containing the organic substance having a boiling point of 115 ℃ or less,

the heating temperature is not less than 115 ℃ and not more than 130 ℃ of the boiling point of the organic substance.

[3] The production method according to [1] or [2], further comprising:

a liquefaction step of condensing and liquefying the gas component obtained in the separation step, wherein,

the heat of condensation generated in the liquefaction process is used as a heat source.

[4] The manufacturing method according to [3], further comprising:

a purification step of purifying the organic substance by thermal distillation, wherein,

the heat of condensation is used as a heat source for the heating distillation in the purification step.

[5] The production method according to any one of [1] to [4], wherein,

the microbial fermentation is fed by synthesis gas comprising carbon monoxide.

[6] The production method according to [5], wherein,

the synthesis gas is a waste-derived gas.

[7] The production method according to any one of [1] to [6],

the organic substance contains an alcohol having 1-6 carbon atoms.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, components such as microorganisms contained in the organic substance-containing liquid obtained by fermentation of microorganisms can be removed without using a separation means such as a membrane separation device or a centrifugal separation device. Thereby, the organic substance can be continuously produced.

Drawings

FIG. 1 is a process flow chart showing an example of the method for producing an organic substance according to the present invention.

FIG. 2 is a diagram showing a pathway for producing ethanol by a fermentation action of a microorganism.

Detailed description of the invention

An example of a preferred embodiment for carrying out the present invention will be described below. However, the following embodiments are examples for illustrating the present invention, and the present invention is not limited to the following embodiments. In this specification, unless otherwise specified, the presence ratio of each component in the gas is set to a ratio based on a volume rather than a ratio based on a weight. Therefore, unless otherwise specified,% represents volume% and ppm represents ppm by volume.

The method for producing an organic substance according to the present invention includes: a microbial fermentation step of obtaining an organic substance-containing liquid by microbial fermentation; and a separation step of heating the organic substance-containing liquid to separate the organic substance-containing liquid into a liquid or solid component containing microorganisms and a gas component containing organic substances. In this case, the apparatus may further include: a raw material gas generation step, a raw material gas purification step, a liquefaction step, a purification step, a wastewater treatment step, and the like. FIG. 1 is a process flow diagram showing one example of the present invention. The process flow diagram of fig. 1 comprises: a raw material gas generation step; a raw material gas purification step; a microbial fermentation process; a separation step; a liquefaction process; a purification step; and (5) a wastewater treatment process. Hereinafter, each step will be described.

< raw Material gas production step >

The raw material gas generation step is a step of generating a raw material gas by gasifying a carbon source (see fig. 1). For example, carbon dioxide may be reduced by a reverse shift reaction to produce carbon dioxide.

The raw material gas is not particularly limited, and preferably contains carbon monoxide. In addition, the method may further include: hydrogen, carbon dioxide, oxygen, nitrogen, soot, tar, nitrogen compounds, sulfur compounds, phosphorus compounds, aromatic compounds, and the like.

When the raw material gas contains carbon monoxide, the content of carbon monoxide in the raw material gas is not particularly limited, but is preferably 0.1 vol% or more, more preferably 10 vol% or more, further preferably 20 vol% or more, particularly preferably 20 vol% or more and 80 vol% or less, and most preferably 20 vol% or more and 60 vol% or less, based on the entire volume of the raw material gas.

The raw material gas containing carbon monoxide can be generally produced by performing a heat treatment (generally called gasification) for combusting a carbon source (incomplete combustion), that is, by partially oxidizing the carbon source.

The carbon source is not particularly limited, and examples thereof include: coke ovens in steel plants, blast furnaces (blast furnace gas), converters, coal-fired power plants; waste (general waste and industrial waste) introduced into an incinerator (particularly, a gasification furnace); biomass such as wood; and various carbonaceous materials for the purpose of recovering and utilizing carbon dioxide and the like produced as by-products in various industries. Among these, the carbon source is preferably waste. In other words, the raw material gas is preferably a gas derived from waste.

More specifically, the carbon source includes: plastic waste, wet waste, municipal waste (MSW), waste tires, biomass waste, cloth waste, household waste such as paper, waste of building parts and the like, coal, petroleum-derived compounds, natural gas, shale gas and the like are particularly preferred, and unsorted municipal waste is more preferred from the viewpoint of sorting cost.

The raw material gas is preferably generated using a gasification furnace.

In the case of generating a raw material gas containing carbon monoxide, a gasification furnace that burns (incompletely burns) a carbon source can be used. Specifically, there may be mentioned: shaft furnaces, kilns, fluidized bed furnaces, gasification reformers, and the like. The gasification furnace is preferably a fluidized bed furnace type because it can achieve a high hearth load and excellent operation operability by partially combusting the waste. The waste is gasified in a fluidized bed furnace at a low temperature (about 450 to 600 ℃) and in a low oxygen atmosphere, and decomposed into a gas (carbon monoxide, carbon dioxide, hydrogen, methane, etc.) and coke containing a large amount of carbon. Further, since incombustibles contained in the waste are separated from the hearth in a sanitary state and in a low oxidation degree state, valuable substances such as iron and aluminum in the incombustibles can be selectively recovered. Therefore, resources can be efficiently recovered and utilized in the gasification of such wastes.

The temperature of the gasification in the raw material gas generation step is usually 100 ℃ to 1500 ℃, and preferably 200 ℃ to 1200 ℃.

The reaction time for the gasification in the raw material gas generation step is usually 2 seconds or more, preferably 5 seconds or more.

< Process for purifying raw Material gas >

Although the raw material gas may be supplied directly to the microbial fermentation tank as a synthesis gas, the purification of the raw material gas may be performed in a manner suitable for microbial fermentation.

In the case where the raw material gas is derived from waste, generally, the raw material gas tends to contain carbon monoxide in a range of 0.1 vol% to 80 vol%, carbon dioxide in a range of 0.1 vol% to 40 vol%, hydrogen in a range of 0.1 vol% to 80 vol%, nitrogen compounds in a range of 1ppm or more, sulfur compounds in a range of 1ppm or more, phosphorus compounds in a range of 0.1ppm or more, and/or aromatic compounds in a range of 10ppm or more. In addition, other substances such as environmental pollutants, dust particles, and impurities may be contained. Therefore, when the synthesis gas is supplied to the microbial fermentation tank, it is preferable to reduce or remove substances unsuitable for stable cultivation of the microorganisms, compounds in an unfavorable amount, and the like from the raw material gas so that the content of each component contained in the raw material gas is in a range suitable for stable cultivation of the microorganisms.

That is, the raw material gas purification step is a step of removing or reducing specific substances such as various contaminants, dust particles, impurities, and undesirable amounts of compounds from the raw material gas (see fig. 1). In the pretreatment step, synthesis gas can be obtained from the raw material gas. The pretreatment step may be carried out using 1 or 2 or more of the following separation devices: a gas cooler (water separation device), a low-temperature separation type (cryogenic separation type) separation device, a cyclone, a fine particle (soot) separation device such as a bag filter, a scrubber (water-soluble impurity separation device), a desulfurization device (sulfide separation device), a membrane separation type separation device, a deoxidation device, a pressure swing adsorption type separation device (PSA), a temperature swing adsorption type separation device (TSA), a pressure swing and temperature swing adsorption type separation device (PTSA), a separation device using activated carbon, a separation device using a copper catalyst or a palladium catalyst, and the like.

The raw material gas used in the method for producing an organic substance according to the present invention (hereinafter, the gas obtained by purifying the raw material gas may be referred to as "synthesis gas") preferably contains carbon monoxide. Further, it may further comprise: hydrogen, carbon dioxide, nitrogen.

As the synthesis gas used in the present invention, a gas obtained by the following steps can be used: the carbon source is gasified to generate a raw material gas (raw material gas generation step), and then the concentration of each component of carbon monoxide, carbon dioxide, hydrogen and nitrogen in the raw material gas is adjusted to reduce or remove the substances and compounds.

The carbon monoxide concentration in the synthesis gas is usually 20 vol% to 80 vol%, preferably 25 vol% to 50 vol%, and more preferably 35 vol% to 45 vol% with respect to the total concentration of carbon monoxide, carbon dioxide, hydrogen, and nitrogen in the synthesis gas.

The hydrogen concentration in the synthesis gas is usually 10 vol% or more and 80 vol% or less, preferably 30 vol% or more and 55 vol% or less, and more preferably 40 vol% or more and 50 vol% or less, based on the total concentration of carbon monoxide, carbon dioxide, hydrogen, and nitrogen in the synthesis gas.

The carbon dioxide concentration in the synthesis gas is usually 0.1 vol% to 40 vol%, preferably 0.3 vol% to 30 vol%, more preferably 0.5 vol% to 10 vol%, and particularly preferably 1 vol% to 6 vol% with respect to the total concentration of carbon monoxide, carbon dioxide, hydrogen, and nitrogen in the synthesis gas.

The nitrogen concentration in the synthesis gas is usually 40 vol% or less, preferably 1 vol% or more and 20 vol% or less, and more preferably 5 vol% or more and 15 vol% or less, based on the total concentration of carbon monoxide, carbon dioxide, hydrogen, and nitrogen in the synthesis gas.

The concentrations of carbon monoxide, carbon dioxide, hydrogen and nitrogen can be set within predetermined ranges by changing the composition of the C — H — N element of the carbon source in the raw material gas generation step and appropriately changing the combustion conditions such as the combustion temperature and the oxygen concentration of the supplied gas during combustion. For example, the following methods exist: changing to a carbon source with a high C-H ratio such as waste plastics without changing the concentrations of carbon monoxide and hydrogen; in the raw material gas generation step, a gas having a high oxygen concentration is supplied without decreasing the nitrogen concentration.

The synthesis gas used in the present invention is not particularly limited except for the above components, and may further include: sulfur compounds, phosphorus compounds, nitrogen compounds, and the like. The content of each of these compounds is preferably 0.05ppm or more, more preferably 0.1ppm or more, and still more preferably 0.5ppm or more. The content of each of the compounds is preferably 2000ppm or less, more preferably 1000ppm or less, further preferably 80ppm or less, further preferably 60ppm or less, and particularly preferably 40ppm or less. By setting the content of the sulfur compound, the phosphorus compound, the nitrogen compound, and the like to the lower limit or more, there is an advantage that the microorganism can be cultured appropriately, and by setting the content to the upper limit or less, there is an advantage that the medium is not contaminated by various nutrient sources not consumed by the microorganism.

Examples of the sulfur compound include: sulfur dioxide, CS₂、COS、H₂S, wherein H₂S and sulfur dioxide are preferred because they are easily consumed as a nutrient source for microorganisms. Therefore, it is more preferable that H is contained in the synthesis gas in the range₂Sum of S and sulfur dioxide.

Phosphoric acid is preferred as the phosphorus compound because it is easily consumed as a nutrient source for microorganisms. Therefore, it is more preferable that phosphoric acid is contained in the synthesis gas in the range.

Examples of the nitrogen compound include: nitrogen monoxide, nitrogen dioxide, acrylonitrile, acetonitrile, HCN, and the like are preferred because HCN is easily consumed as a nutrient source for microorganisms. Therefore, it is more preferable that HCN is contained in the synthesis gas in the range.

In the synthesis gas, the aromatic compound is preferably 0.01ppm or more, more preferably 0.03ppm or more, still more preferably 0.05ppm or more, and particularly preferably 0.1ppm or more. The aromatic compound is preferably 90ppm or less, more preferably 70ppm or less, still more preferably 50ppm or less, and particularly preferably 30ppm or less. When the content of the aromatic compound is not less than the lower limit, the microorganism tends to be cultured favorably. On the other hand, when the content of the aromatic compound is not more than the upper limit, the culture medium tends to be less likely to be contaminated by various nutrient sources not consumed by the microorganisms.

As described above, the synthesis gas is obtained by purifying a raw material gas, and the raw material gas is preferably a waste-derived gas. Thus, the synthesis gas is preferably a gas derived from waste.

< microbial fermentation step >

The microbial fermentation step is a step of obtaining an organic substance-containing liquid by microbial fermentation (see fig. 1). In this case, the microorganism may be fermented by: a raw material gas obtained by the raw material gas generation step; or a raw material gas (synthesis gas) obtained by the raw material gas purification step. Among them, the synthesis gas is preferably used from the viewpoint of suitably carrying out microbial fermentation. Further, it is also possible to use: a synthesis gas obtained by adding a predetermined gas to the raw material gas obtained in the raw material gas generation step and the gas (synthesis gas) obtained in the raw material gas purification step. Examples of other given gases include: at least 1 compound selected from sulfur compounds, phosphorus compounds and nitrogen compounds of sulfur dioxide, etc. In one embodiment, the microbial fermentation is preferably performed using a raw material gas containing carbon monoxide or a synthesis gas containing carbon monoxide as a raw material, and more preferably using a synthesis gas containing carbon monoxide as a raw material. In this case, the raw material gas or the synthesis gas is preferably a waste gas. Hereinafter, the raw material gas or the synthesis gas used for the microbial fermentation may be collectively referred to as "synthesis gas or the like".

The microbial fermentation is generally carried out by a microbial fermentation tank. The microorganism fermenter used is preferably a continuous fermentation apparatus. In general, any shape of the microbial fermentation tank can be used, and examples thereof include: stirring type, air lift type, bubble type, ring type, open bond type, photo-biological type. Among them, a known loop reactor having a main tank and a reflux unit can be suitably used. When the loop reactor is used, it preferably further comprises: a circulation step of circulating the liquid culture medium between the main tank and the reflux unit.

The synthesis gas and the like and the microbial culture solution may be continuously supplied to the microbial fermentation tank, but the synthesis gas and the like and the microbial culture solution need not be supplied at the same time, and the synthesis gas and the like may be supplied to the microbial fermentation tank to which the microbial culture solution is supplied in advance. It is known that certain anaerobic microorganisms produce organic substances, which are valuable substances such as ethanol, from a substrate gas such as a synthesis gas by fermentation, and such gas-utilizing microorganisms are cultured in a liquid medium. For example, a liquid medium and gas-utilizing bacteria may be supplied and contained, and the liquid medium may be stirred in this state, and synthetic gas or the like may be supplied into the microbial fermentation tank. Thus, the gas-utilizing bacteria can be cultured in a liquid medium, and organic substances can be produced from synthetic gas or the like by the fermentation action thereof.

In the microbial fermentation tank, the temperature of the medium or the like (culture temperature) may be any temperature, and is preferably about 30 to 45 ℃, more preferably about 33 to 42 ℃, and still more preferably about 36.5 to 37.5 ℃.

The culture time is preferably 12 hours or more, more preferably 7 days or more, particularly preferably 30 days or more, and most preferably 60 days or more. The upper limit of the incubation time is not particularly limited, but is preferably 720 days or less, and more preferably 365 days or less, from the viewpoint of maintenance of the apparatus and the like. The culture time is a time from the addition of the inoculum to the culture vessel until the entire culture medium in the culture vessel is discharged.

The microorganism (species) contained in the microorganism culture solution is preferably a microorganism capable of producing a desired organic substance by microbial fermentation of a synthesis gas mainly composed of carbon monoxide (see fig. 2). For example, the microorganism (species) is preferably a microorganism that produces organic substances from synthetic gas or the like by the fermentation action of gas-utilizing bacteria, and particularly a microorganism having a metabolic pathway of acetyl CoA. Among the gas-utilizing bacteria, the genus Clostridium (Clostridium) is more preferable, and Clostridium autoethanogenum is particularly preferable, but not limited thereto. Further examples are given further below.

The gas-utilizing bacteria include both eubacteria and archaea. Examples of the eubacteria include: bacteria of the genus Clostridium (Clostridium), bacteria of the genus Moorella (Moorella), bacteria of the genus acetobacter (acetobacter), bacteria of the genus Carboxydocella, bacteria of the genus Rhodopseudomonas (Rhodopseudomonas), bacteria of the genus Eubacterium, bacteria of the genus butyrobacterium (butyrobacterium), bacteria of the genus Oligotropha, bacteria of the genus Bradyrhizobium (Bradyrhizobium), bacteria of the genus ralstonia as aerobic type hydrogen oxidizing bacteria, and the like.

On the other hand, examples of archaea include: bacteria of the genus Methanobacterium (Methanobacterium), Methanobrevibacterium (Methanococcus), Methanococcus (Methanococcus), Methanosarcina (Methanosarcina), Methanococcum (Methanosphaera), Methanopyrus (Methanothermobacter), Methanothrix (Methanothrix), Methanocystis (Methanocystus), Methanovesiculothrix (Methanoylis), Methanopyrus (Methanologlus), Methanopyrus (Methanopyrum), Methanopyrus (Methanopyrus), Thermomyces (Methanopyrus), Thermoascus (Thermoascus), and Arcalobacter. Among them, preferred archaebacteria are bacteria of the genus Methanosarcina, Methanococcus, Methanopyrus, Methanomyces, Pyrococcus, Thermus, and Archaeoglobus.

In addition, from the viewpoint of excellent utilization of carbon monoxide and carbon dioxide, the archaebacteria are preferably bacteria of the genus Methanosarcina, Methanopyrus, or Methanococcus, and particularly preferably bacteria of the genus Methanosarcina or Methanococcus. Specific examples of bacteria of the genus Methanosarcina include: methanosarcina pasteurii, Methanosarcina mazei, Methanosarcina acetosa, etc.

From among the gas-utilizing bacteria as described above, bacteria having a high ability to produce a target organic substance can be selected and used. For example, the gas-utilizing bacteria having a high ethanol production ability include: clostridium autoethanogenum, Clostridium immortal, Clostridium acetobacter, Clostridium carboxidigorans, Moorella thermoacetica, Acetobacter woododii, etc. Among them, Clostridium autoethanogenum is particularly preferred.

The medium used during the cultivation of the microorganism (species) is not particularly limited if it has an appropriate composition corresponding to the bacteria, but is a liquid containing water as a main component and nutrients (e.g., vitamins, phosphoric acid, etc.) dissolved or dispersed in the water. Such a medium is prepared so that the gas-utilizing bacteria can be proliferated well. For example, when Clostridium is used as a culture medium for microorganisms, reference is made to "0097" to "0099" of the specification of U.S. patent application publication No. 2017/260552.

The organic substance-containing liquid obtained by the microbial fermentation step contains an organic substance and other components.

Examples of the organic substance include: an alcohol having 1 to 6 carbon atoms, a diol having 1 to 6 carbon atoms, a carboxylic acid having 1 to 6 carbon atoms, a hydroxycarboxylic acid having 1 to 6 carbon atoms, a ketone having 3 to 6 carbon atoms, an olefin having 2 to 6 carbon atoms, and an alkadiene having 2 to 6 carbon atoms.

Examples of the alcohol having 1 to 6 carbon atoms include: methanol, ethanol, propanol, isopropanol, and the like.

Examples of the diol having 1 to 6 carbon atoms include: 2, 3-butanediol, and the like.

Examples of the carboxylic acid having 1 to 6 carbon atoms include: acetic acid, and the like.

Examples of the hydroxycarboxylic acid having 1 to 6 carbon atoms include: lactic acid, and the like.

Examples of the ketone having 3 to 6 carbon atoms include: acetone.

Examples of the olefin having 2 to 6 carbon atoms include: isoprene, and the like.

Examples of the alkanediene having 2 to 6 carbon atoms include: butadiene, and the like.

Of these, the organic substance preferably contains: the alcohol having 1 to 6 carbon atoms and the diol having 1 to 6 carbon atoms preferably include: ethanol, propanol, isopropanol, and 2, 3-butanediol, and further preferably ethanol. The organic substances may be contained singly or in combination of 2 or more.

In one embodiment, the organic substance is preferably an organic substance having a boiling point of 115 ℃ or lower, preferably ethanol, propanol, isopropanol, acetone, isoprene, or butadiene, more preferably ethanol, propanol, isopropanol, or acetone, still more preferably ethanol or acetone, and particularly preferably ethanol.

The other components are not particularly limited, and include: microorganisms, dead bodies thereof, proteins derived from microorganisms, components derived from a medium, water, and the like.

Generally, the organic substance-containing liquid is obtained as a suspension. In this case, the protein concentration in the suspension varies depending on the type of microorganism, but is usually 30 to 1000 mg/L. The protein concentration in the organic substance-containing solution can be measured by the Kjeldahl method.

The organic-substance-containing liquid may be used to separate a part of a desired organic substance in advance by solid-liquid separation using a press, a centrifuge, a filter, or the like. This makes it possible to separate a purified liquid containing a desired organic substance from an organic substance-containing liquid containing microorganisms and the like. As a result, the total amount of the organic substance-containing liquid to be separated in the separation step described later can be reduced, and the separation step can be performed efficiently. In this case, the purified solution containing the desired organic substance may be directly introduced into a purification step described later.

< separation step >

The separation step is a step of heating the organic substance-containing liquid to separate the organic substance-containing liquid into a liquid or solid component containing microorganisms and a gas component containing organic substances (see fig. 1).

In the conventional method, when the organic substance is purified by a purification step such as distillation of an organic substance-containing liquid obtained in the microbial fermentation step as described above, foaming may occur in the distillation apparatus due to microorganisms, proteins derived from microorganisms, or the like, and continuous operation may be hindered.

Further, even if microorganisms or proteins derived from microorganisms in the organic substance-containing liquid are removed in advance by a membrane separation apparatus or a centrifugal separation apparatus, there is a problem that the filter must be periodically cleaned and exchanged due to clogging when the membrane separation apparatus is used, and the separation cannot be sufficiently performed when the centrifugal separation apparatus is used.

In contrast, in the present invention, a state change based on heating is utilized. That is, by heating the organic substance-containing liquid, only a desired organic substance can be separated by using the organic substance as a gas and using the microorganisms, proteins derived from the microorganisms, and the like as a liquid or a solid. This separation step by heating can eliminate operations such as cleaning and exchange of the filter unlike the case of using a conventional membrane separation apparatus, and can perform sufficient separation unlike the case of using a centrifugal separation apparatus. Further, by removing microorganisms, proteins derived from microorganisms, and the like in the organic substance-containing liquid in advance, it is possible to avoid the problem that the operation of the continuous body is hindered by bubbling in the subsequent distillation apparatus as in the conventional case. Thereby, the organic substance can be continuously produced.

The liquid or solid component is a component that is brought into a liquid or solid state by heating the organic substance-containing liquid. Specifically, there may be mentioned: microorganisms, residues of microorganisms, proteins derived from microorganisms, components derived from a medium, water, and the like.

The gas component includes an organic substance. Further, the organic substance-containing liquid may further contain a component that becomes a gas state after heating the organic substance-containing liquid. Specifically, water and the like may be mentioned in addition to the organic substance.

The heating temperature of the organic substance-containing solution varies depending on the kind of the organic substance, but is preferably 30 to 500 ℃, more preferably 50 to 200 ℃, still more preferably 80 to 180 ℃, and particularly preferably 100 to 150 ℃.

The pressure during heating is preferably 0.00001 to 1MPa, more preferably 0.01 to 0.2MPa, and still more preferably 0.5 to 0.15 MPa. In the case of heating the organic substance-containing liquid with steam, the pressure during heating can be controlled from the viewpoint of adjusting the heating temperature.

Among them, the organic substance-containing solution is heated at normal pressure (101.3k Pa), preferably at 50 to 200 ℃, more preferably at 80 to 180 ℃, still more preferably at 90 to 150 ℃, and particularly preferably at 95 to 120 ℃ from the viewpoint of economy.

The heating time in the separation step varies depending on the heating conditions, but is not particularly limited as long as a gas component can be obtained. The heating time in the separation step is usually 5 seconds to 2 hours, preferably 5 seconds to 1 hour, and more preferably 5 seconds to 30 minutes, from the viewpoint of efficiency and economy.

Here, in the case where a plurality of organic substances are produced by microbial fermentation, it is preferable to separate only desired organic substances.

In this case, the desired organic substance is preferably an organic substance having a boiling point of 115 ℃ or lower, preferably ethanol, propanol, isopropanol, acetone, isoprene, or butadiene, more preferably ethanol, propanol, isopropanol, or acetone, still more preferably ethanol or acetone, and particularly preferably ethanol.

The undesirable organic substance is preferably an organic substance having a boiling point of more than 115 ℃, preferably 2, 3-butanediol, acetic acid, lactic acid, and more preferably 2, 3-butanediol, acetic acid.

In this case, the liquid or solid component contains: undesirable organic matter, microorganisms, residues of microorganisms, proteins derived from microorganisms, components derived from culture medium, water. In this case, a desired organic substance may be contained as the case may be.

Further, the gas component contains a desired organic substance. In addition, water may be included. In addition, undesirable organic substances may be contained according to circumstances.

In one embodiment, the desired organic substance is an organic substance having a boiling point of 115 ℃ or lower, and the undesired organic substance is an organic substance having a boiling point of more than 115 ℃. In this case, the separation step is a step of: an organic substance-containing liquid containing an organic substance having a boiling point of 115 ℃ or lower and an organic substance having a boiling point exceeding 115 ℃ is heated and separated into a liquid or solid component containing microorganisms and the organic substance having a boiling point exceeding 115 ℃ and a gas component containing the organic substance having a boiling point of 115 ℃ or lower.

In this case, the heating temperature of the organic substance-containing liquid is preferably not less than 115 ℃ and not more than 130 ℃, more preferably not less than 10 ℃ and not more than 120 ℃ higher than the boiling point of the organic substance having a boiling point of not more than 115 ℃, still more preferably not less than 20 ℃ and not more than 110 ℃ higher than the boiling point of the organic substance having a boiling point of not more than 115 ℃, and particularly preferably not less than 20 ℃ and not more than 103 ℃ higher than the boiling point of the organic substance having a boiling point of not more than 115 ℃. In the above temperature range, it is preferable to use an organic substance having a boiling point of 115 ℃ or lower as a gas component as a desired organic substance, and use an organic substance having a boiling point of more than 115 ℃ as an undesired organic substance as a solid or liquid component.

That is, according to an embodiment of the present invention, there is provided a method for producing an organic substance, including: a microbial fermentation step of obtaining an organic substance-containing liquid containing an organic substance having a boiling point of 115 ℃ or lower and an organic substance having a boiling point exceeding 115 ℃ by microbial fermentation; and a separation step of heating the organic substance-containing liquid to separate a liquid or solid component containing the organic substance having a boiling point of more than 115 ℃ and the microorganism from a gas component containing the organic substance having a boiling point of 115 ℃ or less, wherein the heating is performed at a temperature of 130 ℃ or higher than the boiling point of the organic substance having a boiling point of 115 ℃ or less.

In one embodiment of the present invention, the desired organic substance includes ethanol, and the undesired organic substance includes at least one of 2, 3-butanediol and acetic acid. In this case, the separation step is a step of: heating an organic matter-containing liquid containing ethanol and at least one of 2, 3-butanediol and acetic acid, and separating into a liquid or solid component containing microorganisms and at least one of 2, 3-butanediol and acetic acid and a gaseous component containing ethanol.

In this case, the heating temperature of the organic substance-containing solution is preferably 78 to 130 ℃, more preferably 88 to 120 ℃, still more preferably 98 to 110 ℃, and particularly preferably 98 to 103 ℃.

That is, according to an embodiment of the present invention, there is provided a method for producing an organic substance, including: a microbial fermentation step of obtaining an organic substance-containing liquid containing ethanol and at least one of 2, 3-butanediol and acetic acid by microbial fermentation; and a separation step of heating the organic substance-containing liquid to separate the organic substance-containing liquid into a liquid or solid component containing at least one of 2, 3-butanediol and acetic acid and microorganisms and a gas component containing ethanol, wherein the heating is performed at 78 to 130 ℃.

The manufacturing method preferably includes: a microbial fermentation step of obtaining an organic substance-containing liquid containing ethanol, 2, 3-butanediol, and acetic acid by microbial fermentation; and a separation step of heating the organic substance-containing liquid to separate the organic substance-containing liquid into a liquid or solid component containing 2, 3-butanediol, acetic acid, and microorganisms and a gas component containing ethanol.

The apparatus used in the separation step is not particularly limited as long as it can efficiently separate the organic substance-containing liquid into a liquid or a solid component (microorganisms, dead bodies thereof, proteins derived from microorganisms, etc.) and a gaseous component (organic substance) by thermal energy. Specific examples of the apparatus include: a rotary dryer, a fluidized bed dryer, a vacuum dryer, a conduction heating dryer, and the like. Among these, in particular, from the viewpoint of efficiency in separating the organic substance-containing liquid having a low solid content concentration into a liquid or a solid content and a gas content, it is preferable to use a conductive heating type dryer. Examples of the conductive heating type dryer include a drum type dryer and a disc type dryer.

< liquefaction Process >

The liquefaction step is a step of condensing the gas component containing the organic substance obtained in the separation step to liquefy the gas component (see fig. 1). The apparatus used in the liquefaction step is not particularly limited, and a heat exchanger, particularly a condenser, is preferably used. Examples of the condenser include a water-cooled type, an air-cooled type, and an evaporative type. Among them, water cooling is particularly preferable. The condenser may comprise one or more stages.

The liquefied material obtained by the liquefaction step preferably contains no components contained in the organic material-containing liquid, such as microorganisms, dead bodies thereof, and proteins derived from microorganisms. Even when the liquefied product contains a protein, the concentration is preferably 40mg/L or less, more preferably 20mg/L or less, and still more preferably 15mg/L or less.

In the liquefaction step, heat of condensation of the gas component is generated. The condensation heat generated in the liquefaction step can be used as a heat source as described below.

< purification step >

The purification step is a step of purifying the organic substance (see fig. 1). In this case, the purification means separating the organic substance-containing liquid into: a distillate in which the concentration of the objective organic substance is increased, and a pot-out in which the concentration of the objective organic substance is decreased. The organic substance to be purified may be a purified liquid containing the organic substance separated after the microbial fermentation step, a substance obtained by condensing and liquefying the gas component obtained after the separation step, or a mixture of these substances.

Examples of the apparatus used in the purification step include: a distillation apparatus, a treatment apparatus including a pervaporation membrane, a treatment apparatus including a zeolite dehydration membrane, a treatment apparatus for removing a low boiling point substance having a boiling point lower than that of an organic substance, a treatment apparatus for removing a high boiling point substance having a boiling point higher than that of an organic substance, a treatment apparatus including an ion exchange membrane, and the like. These devices may be used alone or in combination of 2 or more. As the unit operation, distillation by heating and membrane separation are preferably used.

Among them, the purification step preferably includes thermal distillation. That is, in one embodiment, the method preferably includes a purification step of purifying the organic substance by thermal distillation.

In the heating distillation, a desired organic substance is distilled out using a distillation apparatus, and can be obtained with high purity. The temperature in the distiller at the time of distilling the organic substance (particularly ethanol) is not particularly limited, but is preferably 110 ℃ or lower, more preferably 100 ℃ or lower, and still more preferably about 70 to 95 ℃. By setting the temperature in the distiller to the above range, the necessary separation of the organic substance from other components, that is, the distillation of the organic substance can be reliably performed.

The pressure in the distillation apparatus for distilling the organic substance may be normal pressure, preferably lower than normal pressure, and more preferably about 60 to 95kPa (absolute pressure). By setting the pressure in the distillation apparatus to the above range, the separation efficiency of the organic substance can be improved, and the yield of the organic substance can be improved. Although depending on the kind of the desired organic substance, for example, the yield (concentration of ethanol contained in the distillate after distillation) in the case where the obtained organic substance is ethanol is preferably 90% by weight or more, and more preferably 95% by weight or more.

For the membrane separation, a known separation membrane can be suitably used, and for example, a zeolite membrane can be suitably used.

The concentration of the organic substance contained in the distillate separated in the purification step is preferably 20 to 99.99 mass%, more preferably 60 to 99.9 mass%.

On the other hand, the concentration of the organic substances contained in the pot liquid is preferably 0.001 to 10 mass%, more preferably 0.01 to 5 mass%.

The pot-out liquid separated in the purification step contains substantially no nitrogen compound. In the present invention, "not substantially contained" does not mean that the concentration of the nitrogen compound is 0ppm, but means that the tank effluent obtained in the purification step has a nitrogen compound concentration to such an extent that the wastewater treatment step is not required. In the separation step, the organic substance-containing liquid obtained in the microbial fermentation step is not purified of a desired organic substance, but is separated into a liquid or solid component containing the microorganisms and a gas component containing the organic substance as described above. At this time, the nitrogen compounds remain on the liquid or solid component side containing the microorganisms, and therefore the nitrogen compounds are not contained in large amounts in the gas component containing the organic substances. Therefore, it is considered that when the organic substance is purified from the liquefied product obtained by liquefying the gas component, the obtained pot-discharged liquid contains substantially no nitrogen compound. Even if the tank effluent contains nitrogen compounds, the concentration of the nitrogen compounds is 0.1 to 200ppm, preferably 0.1 to 100ppm, more preferably 0.1 to 50 ppm.

Further, the pot-out liquid separated in the purification step does not substantially contain a phosphorus compound for the same reason as described above. The phrase "substantially not contained" does not mean that the concentration of the phosphorus compound is 0ppm, but means that the pot effluent obtained in the purification step has a phosphorus compound concentration to such an extent that the wastewater treatment step is unnecessary. Even when the pot-out liquid contains a phosphorus compound, the concentration of the phosphorus compound is 0.1 to 100ppm, preferably 0.1 to 50ppm, and more preferably 0.1 to 25 ppm. As described above, according to the method of the present invention, it is considered that the tank effluent discharged in the organic substance purification step does not substantially contain nitrogen compounds or phosphorus compounds, and hardly contains other organic substances, and therefore, the conventionally required wastewater treatment step can be simplified.

< Process for treating waste Water >

The pot effluent separated in the purification step may be subjected to a wastewater treatment step (see fig. 1). In the wastewater treatment step, organic substances such as nitrogen compounds and phosphorus compounds can be further removed from the tank effluent. In this step, the organic matter can be removed by subjecting the tank effluent to anaerobic treatment or aerobic treatment. The removed organic matter can be used as a fuel (heat source) in the purification process.

The treatment temperature in the wastewater treatment process is usually 0 to 90 ℃, preferably 20 to 40 ℃, and more preferably 30 to 40 ℃.

Since the liquid or solid components including microorganisms are removed from the tank liquid obtained through the separation step, the load of wastewater treatment and the like is reduced as compared with the tank liquid directly supplied to the purification step from the microbial fermentation step.

In the wastewater treatment step, the concentration of nitrogen compounds in the treatment liquid obtained by treating the pot effluent is preferably 0.1 to 30ppm, more preferably 0.1 to 20ppm, even more preferably 0.1 to 10ppm, and particularly preferably no nitrogen compounds are contained. The concentration of the phosphorus compound in the treatment liquid is preferably 0.1 to 10ppm, more preferably 0.1 to 5ppm, further preferably 0.1 to 1ppm, and particularly preferably the tank effluent does not contain a phosphorus compound.

< utilization of condensation Heat generated in liquefaction Process >

As described above, the condensation heat generated in the liquefaction process can be used as a heat source. By utilizing the heat of condensation, organic substances can be produced efficiently and economically.

The region utilizing the heat of condensation is not particularly limited, and may be: a raw material gas generation step, a raw material gas purification step, a microbial fermentation step, a separation step, a purification step, and a wastewater treatment step.

In the case where the condensation heat is used as a heat source in the raw material gas generation step, for example, the condensation heat can be used as a heat source of heat required for gasification of a carbon source.

When the condensation heat is used as a heat source in the raw material gas purification step, the condensation heat may be used as a heat source for a temperature swing adsorption Type Separation Apparatus (TSA) or a pressure temperature swing adsorption type separation apparatus (PTSA), for example.

In the case where the condensation heat is used as a heat source in the microbial fermentation step, the condensation heat may be used as a heat source for maintaining the culture temperature, for example.

In the case where the condensation heat is used as a heat source in the separation step, for example, the condensation heat can be used as a heat source for heating the organic substance-containing liquid.

In the case where the heat of condensation is used as a heat source in the purification step, for example, it can be used as a heat source for heating distillation.

In the case where the condensation heat is used as a heat source in the wastewater treatment process, for example, the condensation heat may be used as a heat source for the wastewater treatment temperature.

Of these, the heat of condensation is preferably used as a heat source for heating and distillation in the purification step. That is, in one embodiment of the present invention, a method for producing an organic substance preferably includes: a liquefaction step of condensing and liquefying the gas component obtained in the separation step; and a purification step of purifying the organic substance from the liquefied product obtained in the liquefaction step by heating distillation, wherein the heat of condensation generated in the liquefaction step is used as a heat source for the heating distillation in the purification step.

The organic substance obtained by the liquefaction step is subjected to a purification step of purifying the organic substance by heating and distillation as described above. In this case, condensation heat is generated in the vicinity of the heating distillation. Therefore, the condensation heat can be efficiently used by using the condensation heat as it is as a heat source for heating distillation existing in the vicinity. Further, by bringing the condensation heat generation unit and the heating distillation unit close to each other, piping for transporting a heat source can be shortened, and the cost can be reduced. The piping generally has a heat retaining function and durability, and this affects the cost of the apparatus.

In addition, by using the condensation heat generated in the liquefaction step as a heat source for the heating distillation, instead of using the gas component obtained in the separation step as it is as a heat source for the heating distillation, the organic substance can be separated from the heat source, and as a result, the heat source can be efficiently used. For example, in the case of thermal distillation, the organic substance is usually introduced from the bottom of a distillation column. Therefore, when the gas component obtained in the separation step is introduced into the column bottom, the efficiency is not high from the viewpoint of heating. On the other hand, the organic substance and the heat source (e.g., steam) are separated in the liquefaction step, and the organic substance is introduced from the bottom of the column, and the heat source (e.g., steam) is introduced from, for example, the lower portion, the middle portion, and the upper portion of the side wall of the distillation column, whereby the organic substance can be efficiently heated.

< organic Material and use thereof >

The use of the organic substance obtained by the production method of the present invention is not particularly limited. The organic substance obtained by the production can be used as a raw material for plastics, resins, etc., or can be used as various solvents, sterilizing agents, or fuels. Ethanol having a high concentration is useful as fuel ethanol to be mixed with gasoline or the like, and is also useful as a raw material for cosmetics, beverages, chemicals, fuel (injection fuel) or the like, or an additive for foods or the like, for example, and has extremely high versatility.

Examples

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples as long as the gist of the present invention is not exceeded.

[ example 1]

An inoculum of clostridium autoethanogenum (microorganism) and a liquid medium (containing an appropriate amount of phosphorus compounds, nitrogen compounds, various minerals, and the like) for culturing bacteria are charged into a continuous fermentation apparatus (fermentation tank) provided with a main reactor, a synthetic gas supply hole, a medium supply hole, and a discharge hole.

Next, a synthesis gas containing 30 vol% of carbon monoxide, 10 vol% of carbon dioxide, 35 vol% of hydrogen, and 25 vol% of nitrogen was prepared, supplied to the continuous fermentation apparatus, and cultured at 37 ℃ (microbial fermentation).

After the culture, the organic substance-containing solution discharged from the microbial fermentation tank is collected. The obtained organic substance-containing solution was a suspension containing ethanol, 2, 3-butanediol (2,3-BDO), acetic acid, microorganisms and dead microorganisms, water and the like, and the protein concentration in the organic substance-containing solution was 170 mg/L. The protein concentration was measured by the kjeldahl method.

A hollow Disc (Disc) provided in a conduction heating type drying apparatus (SCD-500, a CD dryer manufactured by Semura iron works, Ltd.) was heated at 120 to 125 ℃ under normal pressure (0.1MPa) (Disc surface temperature: 100 ℃) to bring the organic substance-containing liquid obtained by the cultivation into contact with the heated Disc, and the liquid or solid component was separated from the gas component. The separated gas component is condensed and liquefied by a condenser to obtain a liquefied product. The protein concentration of the resulting liquefied product was measured to be 13 mg/L.

When ethanol was used as the desired organic substance and 2,3-BDO and acetic acid were used as the organic substances of the undesired organic substances, the contents of ethanol (boiling point: 78 ℃), 2,3-BDO (boiling point: 177 ℃), acetic acid (118 ℃) and water in the liquefied product of the 1 st organic substance-containing liquid were measured, and the recovery rate was calculated. As a result, the recovery rate of ethanol was 93 vol%, the recovery rate of 2,3-BDO was 56 vol%, the recovery rate of acetic acid was 58 vol%, and the recovery rate of water was 100 vol%. The results obtained are shown in table 1 below.

It is assumed that foaming was hardly observed as a result of a foaming test based on bubbling the obtained liquefied product in a heated state in the distillation step in the distillation column.

[ example 2]

A liquefied product was obtained in the same manner as in example 1, except that the pressure during heating in the conductive heating type drying apparatus was set to 0.15MPa, and the surface temperature of the hollow disk (plate) was changed to 115 ℃.

The recovery rates of ethanol, 2,3-BDO, acetic acid and water were measured in the same manner as in example 1 and were 95 vol%, 78 vol%, 74 vol% and 100 vol%, respectively. The results obtained are shown in table 1 below.

[ example 3]

A liquefied product was obtained in the same manner as in example 1, except that the pressure during heating in the conductive heating type drying apparatus was set to 0.12MPa, and the surface temperature of the hollow disk (plate) was changed to 105 ℃.

The recovery rates of ethanol, 2,3-BDO, acetic acid and water were measured in the same manner as in example 1 and were 95 vol%, 65 vol%, 67 vol% and 100 vol%, respectively. The results obtained are shown in table 1 below.

[ example 4]

A liquefied product was obtained in the same manner as in example 1, except that the pressure during heating in the conduction heating type drying apparatus was set to 0.08MPa, and the surface temperature of the hollow disk (plate) was changed to 95 ℃.

The recovery rates of ethanol, 2,3-BDO, acetic acid and water were measured in the same manner as in example 1 and were 72 vol%, 55 vol%, 51 vol% and 95 vol%, respectively. The results obtained are shown in table 1 below.

[ example 5]

A liquefied product was obtained in the same manner as in example 1, except that the pressure during heating in the conductive heating type drying apparatus was changed to 0.05MPa and the surface temperature of the hollow disk (plate) was changed to 85 ℃.

The recovery rates of ethanol, 2,3-BDO, acetic acid and water were measured in the same manner as in example 1 and were 65 vol%, 50 vol%, 41 vol% and 82 vol%, respectively. The results obtained are shown in table 1 below.

[ Table 1]

Comparative example 1

The foaming test by bubbling was also performed on the organic substance-containing liquid used in example 1, and as a result, vigorous foaming was confirmed.

From the above results, it can be seen that: the organic substance-containing liquid containing microorganisms is heated to separate the liquid or solid component containing microorganisms and the like from the gas component containing organic substances, and the gas component is condensed to obtain a liquefied product, thereby suppressing foaming in the subsequent purification step.