KR20190024433A - Total usage of lignocellulosic biomass through organic solvent pretreatment process - Google Patents

Abstract

The present invention relates to a method for simultaneous production of lignocellulosic biomass-derived bio-sugar, furfural and lignin through a combined treatment process of an organic solvent. According to a combined pretreatment process of the organic solvent of the present invention, it is possible to improve a sugar yield and an enzymatic saccharification rate of the biomass and to produce organic solvent lignin having solubility in the organic solvent, and it is also advantageous in that furfural can be produced with a high yield.

Description

[0001] The present invention relates to an organic solvent pretreatment process for lignocellulosic biomass,

The present invention relates to a method for simultaneous production of woody biomass-derived biosherge, furfural and lignin through an organic solvent composite treatment process.

Lignocellulosic biomass, mainly composed of cellulose and hemicellulose, which are carbohydrate polymer materials, can be converted into lignocellulosic sugar, which is an industrial fermented sugar, and can be used as a substitute for fossil fuels such as petroleum and coal. It is the most important resource in the biobased economy of manufacturing materials. Already in the United States and several other countries, bioethanol made from fermentation sugars made from woody biomass has been used as transportation fuel. Currently, biomass, which is mainly used for the production of bioethanol and woody fermentation sugars, is a herbaceous plant such as corn stalks and straw. This is because biomass contains a relatively small amount of lignin and a large amount of hemicellulose which can be easily hydrolyzed . On the other hand, acacia, eucalyptus and other tree-based biomass are characterized not only by their high lignin content but also by their dense structure.

Due to the structural characteristics of woody biomass, which is the raw material in the production of biosugars using woody biomass, the cellulose that is usable as a raw material is surrounded by hemicellulose and lignin, and the microbes are restricted in accessibility. A pretreatment process is necessarily required. To this end, various studies are being conducted to develop an effective pretreatment process.

Pretreatment of such biomass is carried out by acid-catalyzed pretreatment which absorbs various aqueous acid solutions such as water or sulfuric acid, hydrochloric acid, nitric acid and phosphoric acid and then hydrolyzes hemicellulose mainly by heating at a high temperature, sodium hydroxide, calcium hydroxide, (Alkali-catalyzed pretreatment) in which lignin is mainly hydrolyzed and dissolved by heating at a high temperature with an aqueous alkali solution such as ammonia or the like. In addition, the biomass is mechanically pulverized (mechanically pretreated) , And biological pretreatment of inoculating white rot fungi to remove lignin. In the pretreatment process, cellulose or hydrolyzed cellulose is partially hydrolyzed or hydrolyzed with an enzyme to convert the cellulose, which has become more easily hydrolyzed by dissolving or dissolving some or all of hemicellulose or lignin surrounding the cellulose, Can be manufactured.

Meanwhile, one of the methods for producing useful biochemical substances from biomass, the treatment process using an organic solvent has been mainly used in the production of biodiesel or volatile fatty acid using algae or microalgae, -1372298 and Korean Patent No. 10-1244480. Korean Patent No. 10-1155306 and Korean Patent No. 10-1155307 are known as pretreatment methods for woody biomass as an organic solvent.

Korean Patent No. 10-1372298 Korean Patent No. 10-1244480 Korean Patent No. 10-1155306 Korean Patent No. 10-1155307

The present invention relates to a method for efficiently utilizing the woody biomass through the efficient production and recovery / separation of lignin and furfural, which are various by-products, which are produced by the enzymatic digestion process using the woody biomass, .

In order to solve the above-described problems, the present invention provides a method for producing a fiber-reinforced fibrous carbohydrate having a reduced average particle size and increased surface area through rapid hydration and friction milling of woody biomass; An organic solvent pre-treatment step of delignifying the pretreated product with a mixture of an organic solvent and a catalyst; A solid-liquid separation step of separating the biomass having undergone the organic solvent complex pretreatment step into a solid phase and a liquid phase; A lignin production step of obtaining lignin in a solid state from the liquid hydrolyzate separated through the solid-liquid separation step; A furfural producing step of producing the furals from the liquefied hydrolyzate of lignin by secondary acid pre-treatment; An enzymatic hydrolysis step of hydrolyzing the solid phase biomass separated through the solid-liquid separation step by adding a saccharifying enzyme; And a sugar solution recovery step of recovering the sugar solution prepared through the enzymatic hydrolysis step. The present invention also provides a method for utilizing whole wood biomass by an organic solvent complex treatment process.

According to the organic solvent hybrid pretreatment process according to the present invention, the enzyme saccharification rate and sugar yield of the biomass can be improved.

In addition, according to the organic solvent hybrid pretreatment process according to the present invention, it is possible to produce organic solvent lignin having solubility in an organic solvent, and to produce the purulate with high yield.

FIG. 1 shows the enzyme digestibility of a solid hydrolyzate after an ethanol organic solvent pre-treatment according to an embodiment of the present invention.
FIG. 2 shows sugar yields of the solid hydrolyzate after the ethanol organic solvent hybrid pretreatment according to an embodiment of the present invention.
FIG. 3 shows the production yield of organic solvent lignin after the ethanol organic solvent pre-treatment according to an embodiment of the present invention.
FIG. 4 is a graph showing the yield of perfluoric production by two-step hydrolysis after production of organic solvent lignin according to one embodiment of the present invention.

Hereinafter, the present invention will be described in detail. The terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms and the inventor may appropriately define the concept of the term in order to best describe its invention It should be construed as meaning and concept consistent with the technical idea of the present invention. Also, unless otherwise stated, all percentages are by weight percent.

In order to achieve the above object, the present invention provides a method for producing a fiber-reinforced fibrous material, the method comprising the steps of: preparing a fiber-reinforced fibrous material having a reduced average particle size and increased surface area through rapid hydration and friction milling of woody biomass; An organic solvent pre-treatment step of delignifying the pretreated product with a mixture of an organic solvent and a catalyst; A solid-liquid separation step of separating the biomass having undergone the organic solvent complex pretreatment step into a solid phase and a liquid phase; A lignin production step of obtaining lignin in a solid state from the liquid hydrolyzate separated through the solid-liquid separation step; A furfural producing step of producing the furals from the liquefied hydrolyzate of lignin by secondary acid pre-treatment; An enzymatic hydrolysis step of hydrolyzing the solid phase biomass separated through the solid-liquid separation step by adding a saccharifying enzyme; And a sugar solution recovery step of recovering the sugar solution prepared through the enzymatic hydrolysis step. The present invention also provides a method for utilizing whole wood biomass by an organic solvent complex treatment process.

The pretreatment product preparation step according to an embodiment of the present invention may be performed by adding water to the raw material biomass together and performing friction grinding using a twin screw mill.

More specifically, the average particle size of the pretreated material may be somewhat different depending on the kind of the woody biomass used, but it is preferably 1 to 5 mm or so. Suitable equipment for this pretreatment is to simultaneously hydrate the biomass and friction grinding It is preferable to use a twin screw-mill. It is preferable to dispose the kneading block and the forward screw at not less than one set and not more than six sets so that the bi-mass screw is crushed at the same time as hydration of the biomass. In order to enlarge the surface area, It is more preferable to arrange it. In the present invention, it is preferable that the biomass is sufficiently hydrated in order to facilitate rapid hydration and crushing of the biomass in the pretreatment of the woody biomass. For this purpose, it is preferable to add water above the dry biomass weight, It is more preferable to add 2 to 10 times of water.

In the organic solvent pre-treatment step according to an embodiment of the present invention, the organic solvent may be an alcohol, and the catalyst may be an inorganic acid or an organic acid. More preferably, the catalyst may be sulfuric acid.

In the organic solvent pre-treatment step according to an embodiment of the present invention, a mixture of ethanol and sulfuric acid is preferably used.

The organic solvent that can be used in the organic solvent hybrid pretreatment step according to an embodiment of the present invention may include alcohols (methanol, ethanol, propanol, etc.), polyhydric alcohols (glycerol, ethylene glycol and the like), alkylene carbonate, . Among them, pretreatment using alcohols is the most widely used solvent when biomass is used as a raw material, and it is characterized in that hemicellulose and lignin are simultaneously dissolved in a liquid phase to improve saccharification enzyme accessibility to cellulose. Among the above-mentioned alcohols, ethanol is a solvent which is easy to recover the solvent, and is advantageous in that the cost is low and the boiling point is low, thereby effectively disintegrating the biomass at a relatively low temperature. The ethanol is less toxic and less combustible than methanol having similar characteristics . More specifically, an aqueous solution containing 50% ethanol is preferable.

In the organic solvent hybrid pretreatment step according to an embodiment of the present invention, inorganic acid (sulfuric acid, hydrochloric acid, nitric acid, etc.), alkali (calcium hydroxide, sodium hydroxide, etc.), organic acid (acetic acid, formic acid, maleic acid, etc.) . Among them, inorganic acid can decompose hemicellulose more easily than alkaline, which is difficult to decompose hemicellulose, and has higher acidity than organic acid, so that hydrolysis reaction can be induced under relatively mild conditions. Therefore, in order to utilize whole biomass of woody biomass, inorganic acid which can degrade hemicellulose and lignin simultaneously under more mild condition was used as a catalyst, and sulfuric acid, which is known to be most effective for harmonizing biomass dislocation, was used. More specifically, a sulfuric acid aqueous solution having a concentration of 1% (w / v) is preferred.

The organic solvent complex pretreatment step according to an embodiment of the present invention may include an organic solvent lignin recovery step in which lignin dissolved in an organic solvent is separately separated and recovered. More preferably, the lignin recovery step may be to precipitate lignin from the liquid hydrolyzate using water.

It is preferable that the organic solvent hybrid pretreatment step according to an embodiment of the present invention is performed at a temperature of 140 ° C or higher and the purifier production step is a step of recovering the purulant after the secondary acid pretreatment at 170 ° C or higher desirable.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG. In particular, the technical idea of the present invention and its core structure and action are not limited by this. In addition, the content of the present invention can be implemented by various other types of equipment, and is not limited to the embodiments and examples described herein.

1. Grinding of biomass

Eucalyptus species ( Eucalyptus pellita ), which is a degradation- resistant species, was used as the woody biomass used in the present invention. The lignocellulosic biomass was obtained by putting eucalyptus chips into a twin-screw grinder and pulverizing while water was added. The supplied samples had a powder content of 2 mm or less and had a moisture content of about 60%. The samples were stored in a zipper bag before use in the pretreatment process.

2. Organic solvent pre-treatment

The pretreatment process of the organic solvent complex was carried out to increase the accessibility of the saccharification enzyme to the cellulose as a process for inducing delignification. In the organic solvent hybrid pretreatment, 50 g of a sample containing about 60% of water was immersed in a heat-resistant glass container (1: 8, w / v) together with a 50% ethanol solvent containing 400 ml of a 1% sulfuric acid catalyst, (SUS 316), and the reaction temperature was changed to 140, 150, 160, 170 ℃ for 10 minutes. The temperature rise time was fixed to 50 minutes until the target reaction temperature was reached. On the other hand, in order to confirm the effect of the acid catalyst, a control without sulfuric acid catalyst was set and treated at the most severe reaction temperature of 170 ° C. for 10 minutes. After reaching the target reaction time of 10 min after pretreatment of the organic solvent complex, the reactor was cooled using an ice chamber so that the reactor temperature reached 60 ° C. After cooling, the hydrolyzate and liquid hydrolyzate were separated from each other by using filter paper (Hyundai NO.52).

3. Recovery and separation of lignin

It is known that the pretreatment of organic solvent complex is superior to that of conventional dilute acid pretreatment under the acid catalytic condition to dissolve lignin into liquid hydrolyzate, and organic solvent lignin can be obtained from liquid hydrolyzate by adding distilled water. Therefore, in order to utilize lignocellulosic biomass completely, lignin, which is a by-product of organic solvent complex pretreatment, was recovered from liquid hydrolyzate and liquid hydrolyzate obtained by pre-treatment with organic solvent and filter paper (Hyundai No. 52) To produce organic solvent lignin. Lignin was precipitated (1: 3, v / v) by adding 1200 ml of distilled water to 400 ml of the filtrate sample, and lignin was solidified using the same filter paper as that used in the solid-liquid separation of the organic solvent pre- After that, organic solvent lignin was obtained and its yield was measured.

4. Enzymatic saccharification

After the pretreatment of the organic solvent complex, the solid hydrolyzate obtained by solid-liquid separation with filter paper (Hyundai No. 52) was used for enzyme saccharification. 20 ml of sodium acetate buffer (20 mM) was added to 1 g of the solid hydrolyzate, and 15 FPU / g of enzyme was added thereto. The enzyme was Cellic CTec2 from Novozyme and glycosylation was carried out using a vertical stirring incubator of FINEPCR at 50 ° C for 72 hours. After the saccharification was completed, the saccharified liquid was separated using the same filter paper as that used in the ethanol organic solvent pre-treatment step. The obtained liquid phase was analyzed using a high performance liquid chromatograph (Dionex) to calculate the sugar yield.

5. Recovery and Separation of Furfural

After the production of organic solvent lignin, the liquid hydrolyzate obtained by solid - liquid separation with filter paper (Hyundai No.52) was used for the two - stage hydrolysis to produce the perfuller. The two-step hydrolysis was carried out by adding the above liquid hydrolyzate and 1.75% aqueous sulfuric acid solution at a ratio of 1: 1 (v / v) to adjust the sulfuric acid catalyst concentration to 1% 170, 180, and 190 ℃ for 10 min. The temperature rise time to reach the target temperature was set to 50 min. The reaction products obtained by the two-step hydrolysis were filtered using a 0.45 μm syringe filter (Adventec) and analyzed by a high-performance liquid chromatograph (Dionex).

The analysis results of the chemical composition of the solid hydrolyzate obtained after the pre-treatment with ethanol organic solvent are shown in Table 1 below.

Content (%) Raw material 170 <
0% SA * 140 <
1% SA 150 ° C,
1% SA 160 ° C,
1% SA 170 <
1% SA Reaction time (min) 10 10 10 10 10 10 Sugars 58.1
± 0.2 57.0
± 0.5 47.0
± 0.4 37.8
± 1.1 36.2
± 0.8 33.1
± 0.4 Glucose 46.3
± 0.5 46.9
± 0.5 45.2
± 0.4 37.1
± 1.1 35.9
± 0.8 32.9
± 0.4 XMG ** 11.4
± 0.2 10.1
± 0.0 1.8
± 0.0 0.7
± 0.0 0.4
± 0.0 0.2
± 0.0 Arabinose 0.4
± 0.1 0.0
± 0.0 0.0
± 0.0 0.0
± 0.0 0.0
± 0.0 0.0
± 0.0 Lignin 34.0
± 0.2 29.3
± 0.7 16.5
± 0.0 15.9
± 0.1 11.4
± 0.2 14.6
± 0.3 Klason
lignin 31.3
± 0.2 27.1
± 0.6 15.6
± 0.1 15.4
± 0.1 11.1
± 0.2 14.3
± 0.3 Acid soluble
lignin 2.6
± 0.1 2.1
± 0.1 0.9
± 0.1 0.5
± 0.1 0.3
± 0.0 0.3
± 0.0

* sulfuric acid

** xylose, mannose, galactose

As shown in Table 1, in the case of glucose content, most of the glucose remained in the non-catalytic condition without the catalyst, whereas in the case of the 1% sulfuric acid catalyst, the hydrolysis of the cellulose occurred due to the pH, As the temperature increased, the amount of glucose remained at 32.9% at 170 ℃, which is the highest temperature condition. In the case of XMG content of hemicellulose, almost no decomposition was observed under the non-catalytic condition, whereas in the condition of sulfuric acid catalyst, most of hemicellulose was decomposed at a mild condition of 140 ° C and its amount was increased with increasing reaction temperature . In the case of the content of lignin, the content was decreased even under the non-catalytic condition. This is because the lignin molecule having a bond such as aryl ether which is relatively easily dissociated is dissociated by the oxonium ion generated at high temperature, It seems to be dissolved in the liquid hydrolyzate. On the other hand, as the reaction temperature increased, the content of lignin decreased gradually up to 160 ℃ due to decomposition with sulfuric acid catalyst. However, the content of lignin increased again at 170 ℃. This suggests that lignin is decomposed by the pretreatment to be liberated as a hydrolyzate of the liquid, and as the severity of the reaction is increased, it is disassociated into a lignin molecule which is difficult to bind to ethanol and then recondensed to increase the content of lignin.

The results of the enzyme digestion of the solid hydrolyzate obtained after the pre-treatment with ethanol organic solvent are shown in FIG. Enzyme digestibility test results showed that the enzyme digestion was not observed in the raw samples that were not pretreated, and the enzyme digestibility was 8.1% in the experimental conditions without the catalyst. On the other hand, the enzyme digestibility tended to increase as the temperature was increased under the condition of sulfuric acid catalyst, and it was confirmed that most of the sugars in solid hydrolyzate except lignin were all converted to glucose when the temperature was 160 ° C or higher. This is probably due to decomposition of hemicellulose and lignin bound to cellulose by the pretreatment of 50% ethanol organic solvent with sulfuric acid catalyst to improve the accessibility to the cellulose.

The sugar yield of the solid hydrolyzate obtained after the pre-treatment with ethanol organic solvent was shown in Fig. As a result of calculation of the yield of glucose showing the amount of glucose obtained after saccharification of the raw material with respect to glucose, the yield of sugar was very low at 2.1% of the raw sample. In the non-catalytic condition, the yield of glucose was also 19.4% It is considered that the complex pretreatment has little effect on the dislocation harmonization for the improvement of sugar yield. On the other hand, in the case of the experimental sphere injected with sulfuric acid catalyst, the yield of sugar increased gradually with increasing temperature, and showed a maximum yield of 83.3% at 160 ° C, but tended to decrease with increasing reaction temperature. This suggests that the degradation of hemicellulose and lignin gradually occurs as the severity of the reaction increases, but the loss of glucose in the solid hydrolyzate occurs. Therefore, in order to utilize lignocellulosic biomass completely using 50% ethanol pretreatment, hemicellulose and lignin can be effectively used as liquid hydrolyzate at the same time, and it is preferable to perform pretreatment at 160 ° C at which high yield of glucose can be produced.

The production yield of organic solvent lignin using the liquid hydrolyzate obtained after the pre-treatment with ethanol organic solvent is shown in Fig. The results of organic solvent lignin production using liquid hydrolyzate after pre-treatment with ethanol organic solvent showed the highest yield of organic solvent lignin production of 35.3% compared to the raw lignin content at 160 ° C under sulfuric acid catalyst conditions. This is in agreement with the chemical composition analysis result of the ethanol organic solvent pre-treatment mentioned above, which is the result of decomposition of lignin at 160 ° C under sulfuric acid catalyst and liberated as liquid hydrolyzate. On the other hand, the sum of the content of the organic solvent lignin obtained from the liquid hydrolyzate and the content of the lignin remaining in the solid hydrolyzate does not satisfy the content of the lignin of the raw sample. This means that the lignin It is considered that this is due to the fact that it remains in the liquid hydrolyzate in the form of monomer or oligomer.

The results of the production of the two-step hydrolyzed furfural using the liquid hydrolyzate after the production of the organic solvent lignin are shown in FIG. Liquid hydrolyzate obtained after the production of organic solvent lignin was used to produce furfural by two - step hydrolysis. Furfural is generally converted to pentoses such as xylose and arabinose, which constitute hemicellulose in biomass, and is known to be easily produced by acid hydrolysis. Experimental results show that a very small amount of furfural was detected in the non-catalytic condition because it was liberated as a small amount of xylose hydrogel hydrolyzate by ethanol organic solvent pre-treatment (Table 1). On the other hand, the conversion of perfluorinated hydrocarbons in the first step pretreatment liquid was accelerated as the reaction temperature increased, and the yield increased to 6.3% at 170 ℃. On the other hand, as a result of the two - step hydrolysis, the fermentation yield of the experimental hydrolyzate obtained by hydrolysis of organic solvent at 160 ℃ was 180 ℃. Phosphorus is converted from pentose by acid pretreatment, and at the same time, conversion to condensation reaction or other conversion occurs. Therefore, as the temperature of the two-stage hydrolysis increases, the conversion of xylose present in the liquid hydrolyzate after the first-step pretreatment is promoted to increase the yield of the purulent. However, at 180 ° C or higher, And the yield was decreased. In addition, in the test zone at 170 ° C where a large amount of the ferulic was already produced by the first stage pretreatment, the amount of condensation or other conversion products existing in the liquid hydrolyzate existing in the existing liquid hydrolyzate, And the yield was lower than that at 160 ℃.

Claims (10)

A pretreatment step of producing fibrous hydrate having a reduced average particle size and increased surface area through rapid hydration and friction grinding of woody biomass;
An organic solvent pre-treatment step of delignifying the pretreated product with a mixture of an organic solvent and a catalyst;
A solid-liquid separation step of separating the biomass having undergone the organic solvent complex pretreatment step into a solid phase and a liquid phase;
A lignin production step of obtaining lignin in a solid state from the liquid hydrolyzate separated through the solid-liquid separation step;
A furfural producing step of producing the furals from the liquefied hydrolyzate of lignin by secondary acid pre-treatment;
An enzymatic hydrolysis step of hydrolyzing the solid phase biomass separated through the solid-liquid separation step by adding a saccharifying enzyme; And
And a sugar solution recovery step of recovering the sugar solution prepared through the enzymatic hydrolysis step. The method according to claim 1,
Wherein the pretreated water is prepared by adding water to the raw material biomass and performing a friction milling process using a twin screw mill. How to use. The method according to claim 1,
Wherein the organic solvent is an alcohol in the organic solvent complex pretreatment step. The method according to claim 1,
Wherein the catalyst is a mineral acid or an organic acid in the organic solvent complex pretreatment step. The method according to claim 1,
Wherein the catalyst is sulfuric acid in the organic solvent complex pretreatment step. The method according to claim 1,
Wherein the organic solvent composite pretreatment step uses a mixture of ethanol and sulfuric acid. The method according to claim 1,
Wherein the lignin production step further comprises an organic solvent lignin recovery step of separately separating and recovering lignin dissolved in the organic solvent. The method of claim 7,
Wherein the lignin-recovering step comprises precipitating lignin from the hydrolyzate using water, wherein the lignin is precipitated from the hydrolyzate. The method according to claim 1,
Wherein the organic solvent hybrid pretreatment step is performed at a temperature of 140 ° C or higher. The method according to claim 1,
Wherein the purge production step is a step of pre-treating the second acid at a temperature of 170 ° C or higher, and then collecting the purine. The method for utilizing the total amount of the woody biomass through the organic solvent composite treatment process.

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