Method for producing a lignocellulose hydrolysate and use thereof
By combining a cyclic process with an elastic container and surfactants, the problems of low conversion rate and high cost in high-solids enzymatic hydrolysis are solved, achieving efficient and low-cost preparation of high-concentration fermentable sugars, which are suitable for enzymatic hydrolysis and fermentation of lignocellulose and product extraction.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- INSTITUTE OF PROCESS ENGINEERING CHINESE ACADEMY OF SCIENCES
- Filing Date
- 2022-05-30
- Publication Date
- 2026-07-21
AI Technical Summary
Existing technologies suffer from low conversion rates and high costs in high-solids enzymatic hydrolysis, and are also complex and difficult to control.
The periodic action process, developed using biomimetic principles, combines an elastic container and spheres with a surfactant. Through periodic action, it enhances the fluidity of porous media, promotes mass and heat transfer, shortens the enzymatic hydrolysis cycle, and improves enzymatic hydrolysis efficiency.
It enables the preparation of high-concentration fermentable sugars, simplifies the process, reduces costs, is suitable for high-solids enzymatic hydrolysis processes, and is easy to industrialize.
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Figure BDA0003669269640000091 
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of lignocellulose treatment technology, and relates to a method for preparing lignocellulose enzymatic hydrolysis products and their applications. Background Technology
[0002] Forest biomass energy, as an important renewable energy source, is characterized by its large reserves and clean, renewable nature, making it a crucial renewable resource. The development of a "sugar platform" for forest biomass refers to the decomposition of raw materials into monosaccharide components, with the goal of obtaining inexpensive sugars for the development of biofuels, chemicals, and other materials. The preparation of high-concentration fermentable sugars and their fermentation are important links and key steps in the biorefining of forest biomass. High-solids enzymatic hydrolysis fermentation of forest biomass has the following advantages in the preparation of high-concentration fermentable sugars: First, it increases product concentration by increasing the solids content, saving subsequent processing costs; second, it saves water consumption, as the high-solids system has a lower water content, reducing water consumption costs and significantly lowering wastewater treatment steps and expenses; third, it increases the loading coefficient, fully utilizing equipment volume, reducing the scale-up of the reactor, and directly reducing equipment investment and depreciation costs. Although the high-solids system has significant conversion advantages, the "high-solids effect"—the decrease in conversion rate as the solids content increases—cannot be ignored.
[0003] CN111118081A discloses a method for improving the saccharification efficiency of lignocellulose by glucose-assisted ball milling and its application, including raw material crushing, organic solvent extraction and defatting, mixing and reaction with sodium hydroxide solution, ball milling and enzymatic hydrolysis, etc. However, organic solvent extraction and defatting and ball milling greatly increase the cost and energy consumption of reagents in the pretreatment and enzymatic hydrolysis process, which is not conducive to industrial scale-up and promotion.
[0004] CN107177645A discloses a method for promoting the enzymatic hydrolysis of lignocellulose and recovering cellulase by cooling using amphoteric surfactants. This method utilizes the critical dissolution temperature and pH characteristics of amphoteric surfactants to effectively improve the enzymatic hydrolysis efficiency of lignocellulose and recover a certain amount of cellulase. However, the surfactants used are limited to amphoteric surfactants, and the recovery of surfactants and cellulase requires freezing conditions or pH adjustment, which increases the cost of unit operation and equipment energy consumption. Furthermore, this method is applicable to enzymatic hydrolysis systems with a solid content of less than 15% and is not suitable for high-solids enzymatic hydrolysis processes.
[0005] CN106884027A discloses a method for enhancing the enzymatic hydrolysis and saccharification of lignocellulose. By adding hair protein and coupling it with irradiation treatment, the enzymatic hydrolysis and saccharification of lignocellulose can be enhanced. However, since the hair needs to be processed before being added and the irradiation requires a specific environment and equipment, the energy consumption and cost of the lignocellulose refining process are greatly increased, which greatly limits the industrial scale-up and promotion.
[0006] In summary, these methods have all improved the enzymatic hydrolysis efficiency of lignocellulose to some extent. However, the operation procedures are complex and difficult to control, and the processing cost is high. They are also not suitable for high-solids enzymatic hydrolysis processes. Therefore, considering the economic benefits and application scope in practical applications, it is very meaningful to develop a method that is easy to operate, low in cost, and suitable for high-solids enzymatic hydrolysis systems of forest biomass. Summary of the Invention
[0007] In view of the shortcomings of the prior art, the purpose of this invention is to provide a method for preparing lignocellulose enzymatic hydrolysis products and its application. The method has the advantages of simple process, energy saving and low consumption, green environmental protection and low cost. It is suitable for enzymatic hydrolysis and fermentation of lignocellulose and product extraction, and is easy to industrial production.
[0008] To achieve this objective, the present invention adopts the following technical solution:
[0009] In a first aspect, the present invention provides a method for preparing lignocellulose enzymatic hydrolysate, the method comprising: placing pretreated forest biomass raw materials in an elastic container, adding spheres and surfactants, then adding buffer solution and enzyme preparation, placing the elastic container in a periodic reactor, and obtaining the product after enzymatic hydrolysis.
[0010] The periodic action process developed based on biomimetic principles is a highly efficient method for enhancing the enzymatic hydrolysis of high-solids forest biomass. Based on the effect of periodic normal forces, it not only induces periodic deformation of the matrix and enhances the periodic fluidity of porous media, increasing and accelerating the accessibility of enzymatic reactions, improving the hydrolysis rate and conversion rate, but also enhances energy utilization. From a biomimetic perspective, this invention, based on the principle of periodic stimulation, couples spherical forces and surfactants to effectively alleviate the "solid matrix effect" in the high-solids enzymatic hydrolysis of forest biomass, promotes mass and heat transfer, accelerates the liquefaction process, shortens the hydrolysis cycle, and improves hydrolysis efficiency, thereby achieving the goal of preparing high-concentration fermentable sugars.
[0011] Preferably, the forest biomass raw materials include any one or a combination of at least two of the following: wood, bamboo, or rattan.
[0012] Preferably, the wood includes any one or a combination of at least two of eucalyptus, poplar, pine, fir, or locust.
[0013] Preferably, the pretreatment method includes any one or a combination of at least two of the following: mechanical crushing, ball milling, steam explosion, hydrothermal treatment, acid / alkali hydrolysis, and white rot fungal biodegradation.
[0014] Preferably, the material of the elastic container includes any one or a combination of at least two of the following: silicone rubber, latex, gel, ionic thin-film polymer, conductive polymer, and electronically stretchable polymer.
[0015] The elastic container selected in this invention is recyclable and reusable, and the materials used are common and inexpensive, which can effectively reduce process costs.
[0016] Preferably, the substance controlling the expansion and contraction of the elastic container includes any one or a combination of at least two of the following: gas, liquid, rigid object, or electrical conductor.
[0017] Preferably, the volume ratio of the elastic container before expansion to after expansion is 1:(50-500), for example, it can be 1:60, 1:100, 1:150, 1:200, 1:250, 1:300, 1:350, 1:400, 1:450, etc.
[0018] In this invention, the volume ratio of the elastic container before expansion to after expansion is set to 1:(50-500). Within this range, the raw material experiences a larger force range during the periodic peristalsis process, resulting in more uniform mass and heat transfer and effectively improving the enzymatic hydrolysis effect.
[0019] Preferably, the material of the sphere includes any one or a combination of at least two of stainless steel, silicone, rubber, latex or quartz.
[0020] Preferably, the volume ratio of the sphere to the elastic container before expansion is 1:(5-50), for example, it can be 1:10, 1:15, 1:20, 1:25, 1:30, 1:35, 1:40, 1:45, etc.
[0021] Preferably, the surfactant comprises any one or a combination of at least two of polysorbate (Tween), stearic acid, fatty acid glycerides, sodium dodecylbenzenesulfonate, and lecithin.
[0022] Preferably, the mass ratio of the surfactant to the forest biomass raw material is 1:(10-100), for example, it can be 1:20, 1:30, 1:40, 1:50, 1:60, 1:70, 1:80, 1:90, etc.
[0023] As a preferred technical solution of the present invention, when the mass ratio of raw materials to surfactant is within the range specifically selected in the present invention, the surfactant can effectively reduce the damage to the enzyme structure caused by external forces during enzymatic hydrolysis and can effectively avoid the ineffective adsorption of lignin on the enzyme. When the amount of surfactant is too small, the external forces will severely damage the enzyme, thereby affecting the final enzymatic hydrolysis efficiency. When the amount of surfactant is too large, the above-mentioned beneficial effects will not increase significantly and the process cost will increase.
[0024] Preferably, the force applied by the periodic reactor includes any one or a combination of at least two of the following: grinding, shaking, squeezing, or kneading.
[0025] Preferably, the periodic reactor is a water bath periodic reactor or an air periodic reactor.
[0026] Preferably, the periodic reactor is a water bath periodic reactor.
[0027] As a preferred technical solution of the present invention, the method uses a water bath periodic reactor, which can better carry out mass and heat transfer. At the same time, the water also buffers the periodic force applied to the elastic container, reducing the wear of the elastic container by the robotic arm.
[0028] Preferably, the ratio of the maximum expansion volume of the elastic container to the volume of the periodic reactor is 1:(2-200), for example, it can be 1:5, 1:10, 1:30, 1:50, 1:80, 1:20, 1:150, 1:180, etc.
[0029] Preferably, the periodic frequency of the periodic reactor is 50-150 rpm, for example, it can be 60 rpm, 70 rpm, 90 rpm, 100 rpm, 120 rpm, 140 rpm, etc.
[0030] In this invention, when the operating frequency of the periodic reactor is 50-150 rpm, it can not only cause periodic deformation of the matrix and enhance the periodic flow of the porous medium fluid, but also increase and accelerate the accessibility of the enzymatic reaction and improve the enzymatic hydrolysis rate and conversion rate.
[0031] Preferably, the solid content in the system during enzymatic hydrolysis is 15-60%, for example, it can be 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, etc.
[0032] Preferably, the amount of enzyme used in the enzymatic hydrolysis process is 5-20 FPU / g DM, for example, it can be 6 FPU / g DM, 8 FPU / g DM, 10 FPU / g DM, 12 FPU / g DM, 15 FPU / g DM, 17 FPU / g DM, 19 FPU / g DM, etc.
[0033] Preferably, the temperature of the enzymatic hydrolysis process is 45-55℃ (e.g., 46℃, 47℃, 48℃, 49℃, 50℃, 51℃, 52℃, 53℃, 54℃, etc.), and the time is 24-96h (e.g., 30h, 36h, 42h, 48h, 54h, 60h, 72h, 84h, 90h, etc.).
[0034] Other specific point values within the range of the above values can be selected, and will not be elaborated on here.
[0035] Secondly, the present invention provides a fermentable sugar, which is prepared by the method for preparing the lignocellulose enzymatic hydrolysis product provided in the first aspect.
[0036] Preferably, the fermentable sugar includes any one of glucose, xylose, fructose, or arabinose.
[0037] Thirdly, the present invention provides the use of the fermentable sugar as described in the second aspect in the preparation of ethanol, butanol, lactic acid, acetoin, amino acids or enzyme preparations.
[0038] Compared with the prior art, the present invention has the following beneficial effects:
[0039] 1. An elastic material container and sphere are used as the periodic action medium. The medium used is inexpensive and recyclable.
[0040] 2. Surfactants can effectively reduce the damage to enzyme structure caused by external mechanical action and can effectively prevent the ineffective adsorption of lignin on enzymes.
[0041] 3. The use of a periodic process can effectively increase the solid content of the enzymatic hydrolysis system, promote mass and heat transfer, accelerate the liquefaction process, shorten the enzymatic hydrolysis cycle, and improve the enzymatic hydrolysis efficiency.
[0042] 4. The process is simple, requires little equipment, and is easy to scale up. Detailed Implementation
[0043] To further illustrate the technical means and effects of the present invention, the following describes the technical solution of the present invention in conjunction with preferred embodiments of the present invention. However, the present invention is not limited to the scope of the embodiments.
[0044] Example 1
[0045] This embodiment provides a method for preparing lignocellulose enzymatic hydrolysis products, the method being as follows:
[0046] 1) Poplar wood chips are coarsely crushed to form relatively uniform wood chips of 0.1cm×1cm. Then, they are pretreated by steam explosion at 1.0MPa for 20min. The pretreated material is then dried for later use.
[0047] 2) Take 10g of the pretreated material from step 1) and place it in a container with a diameter of 50cm. 3 The silicone bag, after expansion, has a maximum volume of 5000 cm³. 3 ;
[0048] 3) Add 5 stainless steel balls, 5 silicone balls and 5 quartz balls with a diameter of 1cm to the silicone bag, and then add Tween 80. In step 2), the mass ratio of Tween 80 to the material is 1:30.
[0049] 4) Add 15 FPU / g DM cellulase and citrate-sodium citrate buffer solution with pH 4.8 to the material in step 3) to achieve a solid content of 40%.
[0050] 5) Place the silicone bag at 10dm 3 The lignocellulose enzymatic hydrolysis products were collected in a water bath cyclic reactor with a cyclic frequency of 100 rpm and a reaction time of 72 hours at 50°C.
[0051] Example 2
[0052] This embodiment provides a method for preparing lignocellulose enzymatic hydrolysis products, the method being as follows:
[0053] 1) Eucalyptus wood chips are coarsely crushed to form relatively uniform wood chips of 0.1cm×2cm. Then, they are subjected to hydrothermal pretreatment at 170℃ for 60 minutes with 1% glacial acetic acid as a catalyst. The pretreated material is then dried for later use.
[0054] 2) Take 10g of the pretreated material from step 1) and place it in a container with a diameter of 50cm. 3 The silicone bag, after expansion, has a maximum volume of 2500 cm³. 3 ;
[0055] 3) Add 10 stainless steel balls with a diameter of 1cm to the silicone bag, and then add sodium dodecylbenzenesulfonate, wherein the mass ratio of sodium dodecylbenzenesulfonate to the material in step 2) is 1:100;
[0056] 4) Add 5 FPU / g DM cellulase to the material from step 3) and add citrate-sodium citrate buffer solution with a pH of 4.8, so that the solid content is 15%;
[0057] 5) Place the silicone bag at 25dm 3 The lignocellulose enzymatic hydrolysis product was collected in a water bath cyclic reactor with a cyclic frequency of 50 rpm and a reaction time of 96 hours at 45°C.
[0058] Example 3
[0059] This embodiment provides a method for preparing lignocellulose enzymatic hydrolysis products, the method being as follows:
[0060] 1) The bamboo strips are coarsely crushed to form relatively uniform bamboo chips of 0.1cm×2cm. Then, they are mechanically crushed and pre-treated and passed through a 40-mesh standard sieve. The pre-treated material is then dried for later use.
[0061] 2) Take 10g of the pretreated material from step 1) and place it in a container with a diameter of 50cm. 3 The silicone bag, after expansion, has a maximum volume of 25 dm³. 3 ;
[0062] 3) Add 5 stainless steel balls and 5 silicone balls, each with a diameter of 1cm, to the silicone bag, and then add lecithin. The mass ratio of lecithin to the material in step 2) is 1:10.
[0063] 4) Add 20 FPU / g DM cellulase to the material from step 3) and add citrate-sodium citrate buffer solution with a pH of 4.8, so that the solid content is 60%.
[0064] 5) Place the silicone bag in a 5m... 3 The lignocellulose enzymatic hydrolysis product was collected in a water bath cyclic reactor with a cyclic frequency of 150 rpm and a reaction time of 36 hours at 55°C.
[0065] Example 4
[0066] This embodiment provides a method for preparing lignocellulose enzymatic hydrolysis products. The only difference between this method and Embodiment 1 is that in step 3), the amount of surfactant added is: the mass ratio of Tween 80 to the material is 0.1:100, and the mass of the material remains unchanged; other steps and parameters are the same as in Embodiment 1.
[0067] Example 5
[0068] This embodiment provides a method for preparing lignocellulose enzymatic hydrolysis products. The method differs from that in Embodiment 1 only in that the amount of surfactant added in step 3) is: the mass ratio of Tween 80 to the material is 15:100, and the mass of the material remains unchanged; other steps and parameters are the same as in Embodiment 1.
[0069] Example 6
[0070] This embodiment provides a method for preparing lignocellulose enzymatic hydrolysis products. The method differs from that in Embodiment 1 only in that the cycle frequency in step 5) is 30 rpm, while the other steps and parameters are the same as in Embodiment 1.
[0071] Example 7
[0072] This embodiment provides a method for preparing lignocellulose enzymatic hydrolysis products. The only difference between this method and that of Embodiment 1 is that the cycle frequency in step 5) is 180 rpm, while the other steps and parameters are the same as those in Embodiment 1.
[0073] Example 8
[0074] This embodiment provides a method for preparing lignocellulose enzymatic hydrolysis products. The only difference between this method and Embodiment 1 is that the periodic reactor in step 5) is an air periodic reactor. The other steps and parameters are the same as in Embodiment 1.
[0075] Example 9
[0076] This embodiment provides a method for preparing lignocellulose enzymatic hydrolysis products. The only difference between this method and Embodiment 1 is that the maximum volume of the expanded silicone bag in step 2) is 100 cm³. 3 The other steps and parameters are the same as in Example 1.
[0077] Comparative Example 1
[0078] This comparative example provides a method for preparing lignocellulose enzymatic hydrolysis products. The difference between this method and Example 1 is that a water bath shaker is used instead of a water bath periodic reactor in step 5). The remaining steps and parameters are the same as in Example 1.
[0079] Comparative Example 2
[0080] This comparative example provides a method for preparing lignocellulose enzymatic hydrolysate. The difference between this method and Example 1 is that step 3) is: only Tween 80 is added to the silicone bag, without adding the spheres, wherein the solid-liquid ratio of the material to Tween 80 is 5% (w / v).
[0081] The remaining steps and parameters are the same as in Example 1.
[0082] Comparative Example 3
[0083] This comparative example provides a method for preparing lignocellulose enzymatic hydrolysis products. The difference between this method and Example 1 is that step 3) is: only 5 stainless steel balls, 5 silicone balls and 5 quartz balls with a diameter of 1 cm are added to the silicone bag, without adding surfactant. The remaining steps and parameters are the same as in Example 1.
[0084] The enzymatic hydrolysis rates of Examples 1-9 and Comparative Examples 1-3 are shown in Table 1. The enzymatic hydrolysis rate was calculated as follows:
[0085] Enzymatic hydrolysis rate (glucose yield) = Glucose production in enzymatic hydrolysis products (g) × 0.9 × 100% ÷ Mass of cellulose in raw materials (g)
[0086] Table 1: Lignocellulose enzymatic hydrolysis rate
[0087]
[0088]
[0089] The effect data from Examples 1-3 show that after enzymatic hydrolysis of forest biomass using the method of the present invention, the glucose yield is as high as 89.5%, indicating that the method has the advantage of high enzymatic hydrolysis efficiency.
[0090] Examples 4 and 5 show that when the amount of surfactant added is too high or too low, the glucose yield after enzymatic hydrolysis of lignocellulose is 84.8% or 83.3%, which is a decrease. Examples 6 and 7 show that when the operating frequency of the periodic reactor is too low, the enzymatic hydrolysis rate of the raw material decreases, while when the operating frequency is too high, although the enzymatic hydrolysis rate is improved, the improvement effect is not significant, and the required energy is higher. Example 8 shows that compared with the air-water-soluble periodic reactor, the water bath periodic reactor has a better final enzymatic hydrolysis efficiency of lignocellulose. As shown in Example 9, when the maximum expansion volume of the elastic container is too small, the glucose yield after enzymatic hydrolysis of lignocellulose is 83.8%, which is also a decrease. This is because when the expansion volume is too small, it affects the periodic peristalsis effect of the raw material, thus affecting the enzymatic hydrolysis efficiency. As shown in Comparative Example 1, when a regular water bath shaker is used to replace the periodic reactor, the glucose yield after enzymatic hydrolysis of lignocellulose is 75.4%, which is a significant decrease. As shown in Comparative Examples 2 and 3, the addition of spheres and surfactants in the method also has a significant impact on improving the enzymatic hydrolysis efficiency of lignocellulose.
[0091] The applicant declares that this invention illustrates a method for preparing lignocellulose enzymatic hydrolysis products and its application through the above embodiments, but this invention is not limited to the above embodiments, that is, it does not mean that this invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of the raw materials for the product, addition of auxiliary components, and selection of specific methods, etc., all fall within the protection and disclosure scope of this invention.
[0092] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.
[0093] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.
Claims
1. A method for preparing lignocellulose enzymatic hydrolysis products, characterized in that, The method for preparing the lignocellulose enzymatic hydrolysis product includes: placing pretreated forest biomass raw materials in an elastic container, adding spheres and surfactants, then adding buffer solution and enzyme preparation, placing the elastic container in a periodic reactor, and obtaining the product after enzymatic hydrolysis; The mass ratio of the surfactant to the forest biomass raw material is 1:(10-100). The ratio of the volume of the elastic container before expansion to the volume of the periodic reactor is 1:(2-200). The periodic reactor is a water bath periodic reactor or an air periodic reactor; The operating speed of the periodic reactor is 50-150 rpm; The volume ratio of the elastic container before expansion to after expansion is 1:(50-500). The volume ratio of the sphere to the elastic container before expansion is 1:(5-50). The surfactant includes any one or a combination of at least two of polysorbate, fatty acid glycerides, sodium dodecylbenzenesulfonate, and lecithin; The solids mass fraction in the system during enzymatic hydrolysis is 15%-60%.
2. The method for preparing the lignocellulose enzymatic hydrolysis product according to claim 1, characterized in that, The forest biomass raw materials include any one or a combination of at least two of the following: wood, bamboo, or vine.
3. The method for preparing the lignocellulose enzymatic hydrolysis product according to claim 2, characterized in that, The timber includes any one or a combination of at least two of eucalyptus, poplar, pine, fir, or locust.
4. The method for preparing the lignocellulose enzymatic hydrolysis product according to claim 1, characterized in that, The pretreatment method includes any one or a combination of at least two of the following: mechanical crushing, steam explosion, hydrothermal treatment, acid / alkali hydrolysis, and white rot fungal biodegradation.
5. The method for preparing the lignocellulose enzymatic hydrolysis product according to claim 1, characterized in that, The material of the elastic container includes any one or a combination of at least two of the following: silicone rubber, latex, gel, ionic thin-film polymer, conductive polymer, and electrostretching polymer.
6. The method for preparing the lignocellulose enzymatic hydrolysis product according to claim 1, characterized in that, The substance that controls the expansion and contraction of an elastic container includes any one or a combination of at least two of the following: gas, liquid, rigid object, or electrical conductor.
7. The method for preparing the lignocellulose enzymatic hydrolysis product according to claim 1, characterized in that, The sphere is made of any one or a combination of at least two of the following materials: stainless steel, silicone, rubber, latex, or quartz.
8. The method for preparing the lignocellulose enzymatic hydrolysis product according to claim 1, characterized in that, The force source of the periodic action reactor includes any one or a combination of at least two of the following: grinding, shaking, squeezing, or kneading.
9. The method for preparing the lignocellulose enzymatic hydrolysis product according to claim 1, characterized in that, The amount of enzyme preparation used in the enzymatic hydrolysis process is 5-20 FPU / g of raw material dry matter.
10. The method for preparing the lignocellulose enzymatic hydrolysis product according to claim 1, characterized in that, The enzymatic hydrolysis is performed at a temperature of 45-55℃ for 24-96 hours.