KR20210006222A - Method for producing of bio-alcohol - Google Patents

Abstract

The present invention relates to a method for producing a bio-alcohol. Particularly, the present invention relates to a method for producing a bio-alcohol at a lower cost than the prior art by culturing microorganisms using a plant extract as a medium nitrogen source, wherein the plant extract is less expensive than a yeast extract, has the growth rate of a strain and the production yield of ethanol and acetic acid being similar to those of the yeast extract, and has one or more plants selected from the group consisting of malt, soybean, pea and cottonseed.

Description

Method for producing bio-alcohol {Method for producing of bio-alcohol}

The present invention relates to a method for producing bioalcohol, and according to the present invention, it is possible to manufacture bioalcohol at a lower cost.

Bioenergy is an energy that has the potential to replace fossil fuels, and is recently most widely developed and utilized.

The first-generation bioenergy production technology uses starch or sugar from cereals, and has limitations due to competition with food (Buckeridge et al., 2012; Rass-Hansen et al., 2007). The second generation bioenergy production technology to overcome this is a technology that uses lignocellulosic biomass, not food resources, as a raw material, and saccharification-fermentation processes are generally used. Among them, the saccharification process generally requires a pretreatment process, and the process is complex and the efficiency is low, which hinders production efficiency (Kootstra et al., 2009). Accordingly, the gasification-fermentation process is emerging as a new alternative. In the gasification-fermentation process, lignocellulosic biomass is converted into syngas (syntheses gas, or syngas, CO, CO ₂ , H ₂ as the main components) through a gasification process, and then bioethanol through the syngas fermentation process. And other bioalcohols or useful chemicals (Balat, 2011; Liua et al., 2014; Wilkins and Atiyeh, 2011). In addition, the gasification-fermentation process can expand raw materials to urban organic waste, agricultural by-products, and waste in addition to biomass, and has the advantage of directly utilizing waste gas from steel mills (Arafat and Jijakli, 2013; Nipattummakul et al., 2012).

Acetogenic bacteria, which are microorganisms used in the fermentation process, can produce useful products such as acetic acid and bioalcohol by using syngas as a carbon source and energy source (Michael Kopke et al., 2010; Jamal Abrini et al. al., 1994; Yanwen Shen 2017; AM Henstra et al., 2007; Kundiyana DK 2011; Chang et al., 2001). Specifically, acetogen bacteria can convert CO, CO ₂ and the like into acetic acid and ethanol by the acetyl-CoA pathway (Wood-Ljungdahl pathway). The overall reaction process for the production of acetic acid and ethanol from syngas is as follows (Ukpong et al., 2012; Vega et al., 1989):

Despite the many advantages of syngas fermentation, weaknesses that hinder commercialization include restrictions on the transfer of materials to liquid media of syngas, expensive media, and low production rates (Sun et al., 2018). However, various attempts have been made to increase the mass transfer rate of syngas, but relatively little effort has been made to optimize the composition of the medium. Attempts to optimize the composition of the medium include attempts to increase process efficiency by using trypticase or biochar, or attempts to replace expensive buffer solutions (Gao et al., 2013; Maddipati et al., 2011; Kundiyana et al., 2010; Cotter et al., 2009; Sun et al., 2018).

On the other hand, among the medium components for fermentation of syngas, yeast extract occupies the largest proportion in the production cost of the medium except for the buffer solution.

Therefore, securing a raw material that can replace expensive yeast extract generally used for syngas fermentation is a very important situation for improving economic efficiency.

KR 2010-0095012 A

An object of the present invention in a method for producing bioalcohol by fermenting syngas, an expensive yeast extract generally included in a medium for fermentation of syngas, 1 selected from the group consisting of malt, soybeans, peas, and cotton seeds. It is to provide a method for producing bioalcohol more economically by replacing it with an extract of more than one species.

In order to achieve the above object, the present invention is a method for producing bioalcohol by fermenting synthetic gas, wherein the liquid medium for fermentation is a nitrogen source of at least one plant selected from the group consisting of malt, soybeans, peas, and cotton seeds. It provides a method for producing a bioalcohol, characterized in that it comprises 0.1 to 10 g / L extract.

According to the present invention, the advantage of reducing the production cost of bioalcohol by using extracts of one or more plants selected from the group consisting of malt, soybeans, peas, and cotton seeds instead of expensive yeast extracts generally used for syngas fermentation. There is this.

1 is a graph showing changes in cell mass, ethanol production concentration, and acetic acid production concentration in a culture process using a liquid medium containing a yeast extract of Comparative Example 1 of the present invention.
2 is a graph showing changes in cell mass, ethanol production concentration, and acetic acid production concentration in a culture process using a liquid medium containing the malt extract of Example 1 of the present invention.
3 is a graph showing changes in cell mass, ethanol production concentration, and acetic acid production concentration in a culture process using a liquid medium containing the pea extract of Example 3 of the present invention.

Hereinafter, the present invention will be described in detail.

According to an embodiment of the present invention, in the method for producing bioalcohol by fermenting syngas, the liquid medium for fermentation is a nitrogen source, at least one selected from the group consisting of malt, soybeans, peas, and cotton seeds. It provides a method for producing bioalcohol, comprising 0.1 to 10 g/L of plant extract.

The plant extract may be included in the liquid medium in an amount of 0.1 to 10 g/L, preferably 0.2 to 5.0 g/L, more preferably 0.2 to 2.0 g/L, as a substitute for the yeast extract.

When the content of the plant extract in the liquid medium is less than the lower limit, not only the growth of microorganisms is slowed, but also the production amount of bioethanol is significantly reduced, and when it exceeds the upper limit, the growth of microorganisms or the production amount of bioethanol It does not have a significant effect and only increases the cost of manufacturing the medium.

The extract of at least one plant selected from the group consisting of malt, soybeans, peas and cotton seeds may preferably be an enzyme hydrolyzed extract or an acid hydrolyzed extract of the plant.

The plant extract may be prepared by a conventional method, for example, extracting one or more plants selected from the group consisting of malt, soybeans, peas and cotton seeds with water or 30 to 99.9% by weight of alcohol; Mixing 0.1 to 2.0 parts by weight of a proteolytic enzyme, preferably pectinase, based on 100 parts by weight of the extract, and enzymatic treatment at 40 to 60° C. for 1 to 5 hours; Filtering and concentrating the enzyme-treated extract; can be prepared by a method comprising.

Alternatively, extracting at least one plant selected from the group consisting of malt, soybeans, peas and cotton seeds with water or 30 to 99.9% by weight of alcohol; Mixing hydrochloric acid, nitric acid, or sulfuric acid to the extract at a concentration of 0.1 to 5% by weight, and acid hydrolysis at 100 to 150°C, preferably 110 to 130°C for 30 to 80 minutes, preferably 40 to 70 minutes; Filtering and concentrating the acid hydrolyzed extract; can be prepared by a method comprising.

The extract of at least one plant selected from the group consisting of malt, soybeans, peas and cotton seeds has a remarkably excellent effect in terms of increasing the production of bioethanol compared to extracts of other plants.

In addition, the liquid medium for fermentation may further contain tryptone 0.1 to 10 g/L, preferably 0.2 to 5.0 g/L, and more preferably 0.2 to 2.0 g/L.

When the content of tryptone is less than the lower limit, the desired effect cannot be achieved, and when the content of the tryptone exceeds the upper limit, the increase in the effect is negligible even when the tryptone content is increased, resulting in poor economy.

In particular, when the content of tryptone in the liquid medium for fermentation is within the range of 0.2 to 2.0 g/L, not only the productivity of bioalcohol is greatly increased, but the ethanol/acetic acid production cost is also increased.

On the other hand, when the tryptone is used in combination with the plant extract of the present invention in a liquid medium for bioalcohol production, it was confirmed through a specific experiment that it greatly contributes to the increase in bioalcohol production.

In the present invention, as a specific example of a preferred liquid medium composition for the fermentation, 0.5 to 2.0 g of NH ₄ Cl, 0.1 to 0.5 g of K ₂ HPO ₄ , 0.1 to 2.0 g of MgCl ₂ , CaCl ₂ per 1 L of liquid medium 2H ₂ O 0.05 to 0.2 g, KCl 0.1 to 0.5 g, NaCl 0.5 to 2.0 g, NaHCO ₃ 0.5 to 2.0 g, 0.25 to 7.5 g of extracts of one or more plants selected from the group consisting of malt, soybeans, peas and cotton seeds, Tryptone 0.1 to 10 g/L, resazurin 0.0005 to 0.002 g, L-cysteine HCl 0.1 to 2.0 g, Na ₂ SO9H ₂ O 0.1 to 2.0 g, 1 M phosphate buffer solution 5 to 15 mL, trace metal solution 5 To 15 mL and 0.5 to 2.0 mL of vitamin solution.

In the liquid medium composition, the trace metal solution is 1.0 to 2.0 g of nitrilotriacetic acid, 1 to 5 g of MgSO ₄ ㅇ7H ₂ O, MnSO ₄ ㅇH ₂ per 1 L of the transition metal solution. O 1.0 to 2.0 g, NaCl 0.5 to 2.0 g, FeSO ₄ o7H ₂ O 0.05 to 0.2 g, CoSO ₄ o7H ₂ O 0.1 to 0.5 g, CaCl ₂ o2H ₂ O 0.05 to 0.2 g, ZnSO ₄ o7H ₂ O 0.1 to 0.5 g, CuSO ₄ ㅇ5H ₂ O 0.005 to 0.02 g, KAl(SO ₄ ) ₂ ㅇ12H ₂ O 0.01 to 0.05 g, H ₃ BO ₃ 0.005 to 0.02 g, Na ₂ MoO ₄ ㅇ2H ₂ O 0.005 To 0.02 g, NiCl ₂ ㅇ6H ₂ O 0.01 to 0.05 g, Na ₂ SeO ₃ ㅇ5H ₂ O 0.0001 to 0.0005 g, Na ₂ WO ₄ ㅇ2H ₂ O 0.0001 to 0.001 g.

In addition, in the liquid medium composition, the vitamin solution is biotin 10 to 30 mL, folic acid 10 to 30 mg, pyridoxine HCl 50 to 200 mg, thiamine HCl 10 to 100 mg, riboflavin 10 per 1 L of vitamin solution. To 100 mg, nicotinic acid 10 to 100 mg, D-Ca-pantothenate 10 to 100 mg, p- aminobenzoic acid 10 to 100 mg, vitamine B ₁₂ 5 to 20 mg, lipoic acid 10 to 100 mg. .

In the present invention, the synthesis gas may be any one gas selected from hydrogen, carbon monoxide, carbon dioxide, and nitrogen, or a mixture of two or more. The synthesis gas may be waste gas or exhaust gas, and may be produced by gasifying coal or biomass, or by treating the waste gas or exhaust gas with at least one of irradiation, ultrasonic decomposition, and pyrolysis.

As a specific example of the syngas of the present invention, it may have a composition of 10 to 60 vol% CO, 10 to 30 vol% CO ₂ , 5 to 30% H ₂ , and 10 to 60 vol% N ₂ .

Anaerobic bacteria are used as the microorganisms for producing the bioalcohol , and Crosstridium ljungdahlii , Clostridium autoethanogenum , Clostridium thermoaceticum , and cross Tridium aceticum , Acetobacterium woodii , Thermoanaerobacterium kivui , Butyribacterium methylotrophicum , Crosstridium acetobutyricum ( Clostridium acetobutylicum ), Clostridium formicacetricum , Clostridium kluyveri , Clostridium thermocellum , Clostridium thermosaccharolyticum , Eubacterium limosum and Peptostreptococcus productus are representative biocatalysts that produce ethanol and acetic acid using carbon monoxide and carbon dioxide as carbon sources and hydrogen as electron sources.

In the bioalcohol production method described in the present invention, a specific fermentation process is not particularly limited as long as the fermentation conditions are satisfied. In other words, the fermentation process is any commonly used in the art such as batch fermentation, batch-ped fermentation, continuous fermentation, in-situ extraction fermentation, or in-situ gas extraction fermentation, etc. It may be a fermentation process. The specific working steps of each process are known to the person skilled in the art and will not be described further here.

Hereinafter, a preferred embodiment is presented to aid the understanding of the present invention, but the following examples are only illustrative of the present invention, and it is obvious to those skilled in the art that various changes and modifications are possible within the scope and spirit of the present invention, It is natural that such modifications and modifications fall within the appended claims.

<Example>

Example 1: Preparation of bioethanol using malt extract

1-1. Microbial strain and liquid medium

Clostridium autoethanogenum (DSM 10061) was purchased and used from Deutsche Sammlung von Mikroorganismen end Zellkulturen (DSMZ) GmbH (Braunschweig, Germany), and a basic liquid medium containing malt extract was used as a nitrogen source. And maintained. The malt extract was purchased from Sigma-Aldrich Co. (MO, USA) (product no. 105391). Other compounds were used by purchasing reagent grade products.

Components contained in 1L of the liquid medium are as follows.

NH ₄ Cl 1.0 g, K ₂ HPO ₄ 0.33 g, MgCl ₂ 0.52 g, CaCl ₂ ㅇ2H ₂ O 0.1 g, KCl 0.33 g, NaCl 1.0 g, NaHCO ₃ 1.0 g, malt extract 0.5 g or 5 g, rezazurin (resazurin) 0.001 g, L-cysteine HCl 0.5 g, Na ₂ SO9H ₂ O 0.5 g, 1 M phosphate buffer solution 10 mL, transition metal solution 10 mL, vitamin solution 1 mL.

The transition metal solution was prepared to contain the following components in 1 L.

Nitrilotriacetic acid 1.5 g, MgSO ₄ o7H ₂ O 3.0 g, MnSO ₄ oH ₂ O 0.5 g, NaCl 1.0 g, FeSO ₄ o7H ₂ O 0.1 g, CoSO ₄ o7H ₂ O 0.18 g, CaCl ₂ o2H ₂ O 0.10 g, ZnSO ₄ ㅇ7H ₂ O 0.18 g, CuSO ₄ ㅇ5H ₂ O 0.01 g, KAl(SO ₄ ) ₂ ㅇ12H ₂ O 0.02 g, H ₃ BO ₃ 0.01 g, Na ₂ MoO ₄ ㅇ2H ₂ O 0.01 g, NiCl ₂ o6H ₂ O 0.03 g, Na ₂ SeO ₃ o5H ₂ O 0.0003 g, Na ₂ WO ₄ o2H ₂ O 0.0004 g.

In addition, the vitamin solution was prepared to contain the following components in 1 L.

Biotin 20 mL, folic acid 20 mg, pyridoxine HCl 100 mg, thiamine HCl 50 mg, riboflavin 50 mg, nicotinic acid 50 mg, D-Ca-pantothenate 50 mg, p- aminobenzoic acid 50 mg, vitamine B ₁₂ 10 mg, lipoic acid 50 mg.

The method for preparing the liquid medium followed the method for preparing an absolute anaerobic medium recommended by ATCC.

Synthesis gas is similar to the actual composition _{CO 20 vol%, CO 2 20} vol%, it was used to manufacture the artificially with H ₂ 10%, N ₂ composition of 50 vol%.

1-2. Culture experiment

Clostridium autoethanogenum is an absolute anaerobic bacterium, and culture experiments were conducted under anaerobic conditions.

Incubation was carried out by filling a 150 mL serum bottle with 25 mL liquid medium, sealing it with a butyl rubber sopper, and putting an aluminum cap on it. After inoculating the subcultured culture equivalent to 10% by volume in the liquid medium, syngas was injected so that the pressure of the headspace of the serum bottle was about 240 kPa. Cultivation was performed at a temperature of 37° C. and a stirring speed of 200 rpm using a shaking incubator. Syngas was purged with syngas every 24 hours for 5 minutes, and then incubated for 14 days by additionally injecting syngas into the headspace of the serum bottle. Sample collection was performed every 2 days.

Example 2: Preparation of bioethanol using malt extract and tryptone

In the same manner as in Example 1, the liquid medium was prepared by adding 0.5 g of tryptone, and bioethanol was prepared using this.

Example 3: Preparation of bioethanol using pea extract

It was carried out in the same manner as in Example 1, but bioethanol was prepared using pea extract instead of the malt extract as a nitrogen source. The pea extract was purchased from Sigma-Aldrich Co. (MO, USA) (product no. 04316).

Example 4: Preparation of bioethanol using pea extract and tryptone

It was carried out in the same manner as in Example 3, but the liquid medium was prepared by adding 0.5 g of tryptone, and bioethanol was prepared using this.

Comparative Example 1: Preparation of bioethanol using yeast extract

In the same manner as in Example 1, but using yeast extract instead of the malt extract as a nitrogen source to prepare bioethanol. The yeast extract was purchased from Becton, Dickinson and Co. (NJ, USA) (product no. 212750).

<Experimental Example>

Analysis method

Cell mass concentration

The cell mass concentration was expressed by measuring the optical density (OD) at 600 nm using a UV-visible spectrophotometer (Optizen POP, Mecasys Co, Seoul, Korea). The dry cell mass was calculated and expressed from the optical density using a calibration curve equation.

Concentration of ethanol and acetic acid

The concentrations of ethanol and acetic acid were analyzed using gas chromatography (7890B, Agilent Technologies, Inc., Santa Clara, CA, USA) attached to a flame ionization detector (FID) with an analyzer. A capillary column (HP-5 column, 30m ㅧ 0.32mm, Agilent, USA) was used as the column, and the inlet temperature was operated at 225 ℃, split ratio 50:1, and FID temperature 250 ℃. As a carrier gas, hydrogen was used to maintain an initial flow rate of 2 mL/min and a holding time of 1.5 minutes, and the flow rate was increased to 4 mL/min at a ramping rate of 0.5 mL/min. The initial temperature of the oven was 90 °C and the temperature was increased to 250 °C at a rate of 40 °C/min.

Ingredient analysis

The following analysis was performed for component analysis of the extracts described in Examples and Comparative Examples. The mineral component was analyzed using an inductively coupled plasma-optical emission spectrometer (ICP-OES, Optima 5300 DV, PerkinElmer Inc., USA). Amino acid component analysis was performed using high-performance liquid chromatography (HPLC, Dionex Ultimate 3000, Thermo Scientific, Waltham, MA, USA), and carbohydrates were phenolic sulfuric acid color development method.

Experimental Example 1: Component Analysis

First, component analysis of the malt extract, pea extract, and yeast extract used in Examples or Comparative Examples is performed, and is shown in Table 1 below.

ingredient Malt extract Pea extract Yeast extract Dry mass(wt%) 98 97 98 Carbohydrate(wt%) 76 11 15 Amino acids (wt%) 3.6 17.6 35.2 Total minerals(wt%) <0.3 <5.6 <6.4 Ca 0.01 <0.05 0.087 Co <0.05 <0.05 <0.05 Cu <0.05 <0.05 <0.05 Fe <0.05 <0.05 <0.05 K 0.295 1.360 4.094 Mg 0.027 <0.05 0.075 Mn <0.05 <0.05 <0.05 Na 0.238 3.084 0.479 Sn <0.05 <0.05 <0.05 Zn <0.05 <0.05 <0.05 P 0.057 0.772 1.384

As shown in Table 1, when the component analysis results of the malt extract show a significant difference from 35.2% by weight and 6.4% by weight of the yeast extract, with an amino acid of 3.6% by weight or less and a mineral of 0.9% by weight or less. On the other hand, the content of carbohydrates is 76% by weight, much higher than 15% by weight of yeast extract.

In addition, when looking at the results of the component analysis of the pea extract, the amino acid content is 17.6% by weight, which shows a large difference from 35.2% by weight of the yeast extract, but it is judged that this does not have a decisive effect on the growth of the strain and the production of the product.

Experimental Example 2: Effect on strain growth and product production

In order to verify the usefulness of malt extract as a low-cost substitute for yeast extract, the effects of each component on the growth of microorganisms and production of ethanol and acetic acid in the Clostridium autoethanogenum culture process were analyzed.

1 is a graph showing changes in cell mass, ethanol production concentration, and acetic acid production concentration in a culture process using a liquid medium containing a yeast extract of Comparative Example 1 of the present invention.

As shown in FIG. 1, the optical density after 14 days culture was 1.48 when 0.5 g/L of yeast extract was used, and 1.64 when 5 g/L of yeast extract was used. The ethanol production concentration was 2.16 g/L when 0.5 g/L of yeast extract was used, and decreased to 1.69 g/L when 5 g/L of yeast extract was used. The production concentration of acetic acid was 1.64 g/L when 0.5 g/L yeast extract was used and increased to 2.85 g/L when 5 g/L yeast extract was used.

From these experimental results, it can be confirmed that increasing the concentration of yeast extract in the medium increases the growth of the strain and the production of acetic acid, but decreases the production of ethanol.

2 is a graph showing changes in cell mass, ethanol production concentration, and acetic acid production concentration in a culture process using a liquid medium containing the malt extract of Example 1 as a substitute for the yeast extract. Overall, it is not significantly different from FIG. 1.

As shown in FIG. 2, the optical density after 14 days culture was 1.37 when 0.5 g/L of malt extract was used, and 1.61 when 5 g/L of malt extract was used. The ethanol production concentration was 3.37 g/L when 0.5 g/L of malt extract was used, which was significantly improved compared to 2.16 g/L when the same concentration of yeast extract was used, and 2.93 when 5 g/L of malt extract was used. It decreased slightly to g/L. The production concentration of acetic acid was 3.11 g/L when 0.5 g/L malt extract was used, and it increased to 4.17 g/L when 5 g/L malt extract was used.

3 is a graph showing changes in cell mass, ethanol production concentration, and acetic acid production concentration in a culture process using a liquid medium containing the pea extract of Example 3 as a substitute for the yeast extract.

As shown in FIG. 3, the optical density after 14 days culture was 1.71 when 0.5 g/L pea extract was used, and 1.65 when 5 g/L pea extract was used. The ethanol production concentration was 3.76 g/L when 0.5 g/L pea extract was used, which was 74% higher than 2.16 g/L when the same concentration of yeast extract was used, and when 5 g/L pea extract was used. It decreased slightly to 2.04 g/L. The production concentration of acetic acid was 2.58 g/L when 0.5 g/L pea extract was used, and increased to 2.99 g/L when 5 g/L pea extract was used.

Overall, the strain growth characteristics were not significantly different from the case of using the yeast extract, but showed improved quantitative results.

Experimental Example 3: Improvement of ethanol productivity by tryptone

In the case of including tryptone in the fermentation liquid for fermentation of synthetic gas, it was attempted to determine how it affects ethanol productivity. To this end, an experiment was conducted by adding tryptone to the liquid medium of Comparative Example 1 containing a yeast extract generally used for fermentation of synthetic gas. Thereafter, Clostridium autoethanogenum acetonegen was used for syngas fermentation by the method of Comparative Example 1, and the effects on strain growth and ethanol and acetic acid production were analyzed and shown in Table 2 below. The tryptone input concentration was varied at 0.5, 2.5, and 5.0 g/L, and compared with the control group without the tryptone.

Trypton (g/L) 0 0.5 2.5 5 OD 1.48 1.43 1.56 1.51 Dry cell mass(g/L) 0.575 0.557 0.605 0.585 Ethanol concentration(g/L) 2.16 6.01 1.25 1.79 Acetic acid concentration(g/L) 1.64 1.38 5.47 4.78 Ethanol volumetric productivity (g/Lㅇd) 0.154 0.429 0.089 0.128 Acetic acid volumetric productivity(g/Lㅇd) 0.117 0.099 0.391 0.341 Ethanol specific productivity(g/gㅇd) 0.268 0.772 0.147 0.218 Acetic acid specific productivity(g/gㅇd) 0.054 0.016 0.313 0.191 Ethanol/acitic acid ratio 1.32 4.35 0.23 0.37

As shown in Table 2, for strain growth, there was no significant difference in the control group without tryptone or the experimental group using 0.5, 2.5, 5.0 g/L.

However, when looking at the production characteristics of ethanol and acetic acid, when 0.5 g/L of tryptone is added, the production of acetic acid decreases and ethanol production is increased, whereas when 2.5 and 5.0 g/L of tryptone are added, acetic acid It can be seen that the production of ethanol more than doubles and the ethanol production decreases.

In particular, when 0.5 g/L of tryptone was added, not only the volume productivity of ethanol was increased, but also the ethanol/acetic acid production ratio was significantly increased from 1.32 to 4.35 in the control group.

Experimental Example 4: Comparison of productivity and economy of ethanol and acetic acid

The volume productivity of ethanol and acetic acid according to Examples and Comparative Examples were measured and shown in Table 3 below.

Remark Example 1 Example 2 Example 3 Example 4 Comparative Example 1 0.5
(g/L) 5
(g/L) 0.5
(g/L) 0.5
(g/L) 5
(g/L) 0.5
(g/L) 0.5
(g/L) 5
(g/L) OD 1.37 1.61 1.44 1.71 1.65 1.68 1.48 1.64 Dry cell mass(g/L) 0.532 0.623 0.559 0.662 0.640 0.652 0.575 0.635 Ethanol concentration(g/L) 3.37 2.93 6.56 3.76 2.04 6.61 2.16 1.69 Acetic acid concentration(g/L) 3.11 4.17 1.98 2.58 2.99 2.23 1.64 2.85 Volumetric productivity(g/L·d) Ethanol 0.241 0.209 0.469 0.269 0.146 0.472 0.154 0.121 Acetic acid 0.222 0.298 0.141 0.184 0.214 0.159 0.117 0.204 Specific productivity(g/g·d) Ethanol 0.453 0.336 0.839 0.406 0.228 0.725 0.268 0.190 Acetic acid 0.066 0.102 0.022 0.049 0.105 0.024 0.054 0.120

As shown in Table 3, in the case of Example 1, a liquid medium containing 0.5 g/L of malt extract was found to be more preferable than a liquid medium containing 5 g/L of malt extract, and in Example 2, malt Only an experiment was performed on 0.5 g/L of the extract. In addition, even in the case of Example 3, the liquid medium containing 0.5 g/L of pea extract appeared to be more preferable than the liquid medium containing 5 g/L of pea extract, and in Example 4, 0.5 g/L of pea extract Only the experiment was performed.

From Examples 2 and 4 in Table 3, it can be seen that when the plant extract of the present invention and tryptone are used in combination in a liquid medium for bioalcohol production, the production amount of bioalcohol is significantly increased.

On the other hand, the proportion of the medium price to the cost of the entire culture process is very large. Yeast extract accounts for 32% of the cost of the medium in the general medium used for syngas fermentation (Gao et al., 2013). The purchase price of malt extract, pea extract and yeast extract used in this experiment is $52.40, $101.10 and $141 per 500 g, respectively. That is, malt extract is 62.8% cheaper than yeast extract, and it is possible to reduce the cost of manufacturing the entire medium by about 20%. In addition, pea extract is 28.3% cheaper than yeast extract, and it is possible to reduce the total cost of manufacturing the medium by about 10%.

In the case of the pea extract, the reduction in the cost of manufacturing the medium is less than that of the malt extract, but it is considered that it can greatly contribute to the economic improvement of the fermentation process when the productivity increase rate is considered.

Although the present invention has been described as the above-mentioned preferred embodiment, it is possible to make various modifications or variations without departing from the gist and scope of the invention. In addition, the appended claims include such modifications or variations that fall within the gist of the present invention.

Claims (7)

In the method for producing bioalcohol by fermenting synthetic gas,
The liquid medium for fermentation comprises 0.1 to 10 g/L of extracts of one or more plants selected from the group consisting of malt, soybeans, peas and cotton seeds as a nitrogen source. The method of claim 1,
The method for producing bioalcohol, characterized in that the liquid medium further comprises 0.1 to 10 g/L of tryptone. The method of claim 1,
The synthesis gas is a method of producing bioalcohol, characterized in that any one gas selected from hydrogen, carbon monoxide, and carbon dioxide, or a mixture of two or more. The method of claim 1,
The synthesis gas is a method for producing bioalcohol, characterized in that produced by gasifying coal or biomass. The method of claim 1,
The synthesis gas is produced by treating waste gas or exhaust gas by a method selected from radiation irradiation, ultrasonic decomposition, and pyrolysis. The method of claim 1,
The liquid medium is Crostridium ljungdahlii , Clostridium autoethanogenum , Clostridium thermoaceticum , Clostridium aceticum , Acetobacterium woodii , Thermoanaerobacterium kivui , Butyribacterium methylotrophicum , Clostridium acetobutylicum , and Crosstridium formica Clostridium formicacetricum , Clostridium kluyveri , Clostridium thermocellum , Clostridium thermosaccharolyticum , Eubacterium limosum And Peptostreptococcus productus ( Peptostreptococcus productus ) a method for producing a bioalcohol , characterized in that it contains at least one selected from the. The method of claim 1,
The method for producing bioalcohol, characterized in that the bioalcohol is ethanol.

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