CN102936606A - Method for preparing reducing monosaccharide from biomass hydrolysis - Google Patents

Abstract

The invention discloses a method for preparing reducing monosaccharide from biomass hydrolysis. The method comprises the main steps of putting lignocellulose biomass in a stirring reactor, hydrolyzing under a normal pressure or a pressure close to the normal pressure by using a dilute acid as a catalyst, wherein partial biomass raw material can be supplemented during the hydrolysis process; washing residues after the hydrolysis is finished; and performing enzyme hydrolysis in the same reactor, wherein a discharged acid solution can used for the enzyme hydrolysis of next batch of the raw materials after being neutralized; and the washing water can be used for washing the residues of acid hydrolysis of the next batch of the raw materials. With the method, pretreatment of the biomass can be carried out in a mild condition and performed with enzyme hydrolysis in the same reactor, thereby significantly reducing pretreatment cost.

Description

Translated fromChinese

一种由生物质水解制备还原性单糖的方法A method for preparing reducing monosaccharides by hydrolysis of biomass

技术领域technical field

本发明涉及一种由生物质水解制备还原性单糖的技术，具体地说是采用在同一个反应器内对含纤维素生物质原料串联进行稀酸水解和酶水解以制备还原性单糖的工艺。 The present invention relates to a technology for preparing reducing monosaccharides by hydrolyzing biomass, specifically the method of dilute acid hydrolysis and enzymatic hydrolysis of cellulose-containing biomass raw materials in the same reactor to prepare reducing monosaccharides craft. the

背景技术Background technique

能源和环境问题正受到越来越大的重视。从长远看液体燃料短缺将是困扰人类发展的大问题。在此背景下，生物质作为唯一可转化为液体燃料的可再生资源，正日益受到重视。地球上的生物质资源十分丰富，估计其年产量相当于目前所需能源的十倍，但被作为能源利用的还不到1％，故生物质制液体燃料的技术很有发展前途，这中间又以木质纤维素类生物质制燃料乙醇最易工业化。 Energy and environmental issues are receiving more and more attention. In the long run, the shortage of liquid fuel will be a big problem that plagues human development. Against this background, biomass is gaining increasing attention as the only renewable resource that can be converted into liquid fuels. Biomass resources on the earth are very rich, and its annual output is estimated to be ten times that of the current required energy, but less than 1% is used as energy. Therefore, the technology of biomass to liquid fuel has a promising future. The production of fuel ethanol from lignocellulosic biomass is the easiest to industrialize. the

木质纤维素类生物质制酒精的方法是把该原料中的纤维素水解为单糖，再把单糖发酵成乙醇。但该原料中的纤维素大分子会通过大量的氢键连接在一起，形成晶体结构的纤维束。这样的结构使得纤维素的性质很稳定，它不溶于水，也无还原性。在常温下不发生水解，在高温下水解也很慢。只有在催化剂存在下，纤维素的水解反应才能显著地进行。常用的催化剂是无机酸和纤维素酶，由此分别形成了酸水解和酶水解工艺。 The method of producing alcohol from lignocellulosic biomass is to hydrolyze the cellulose in the raw material into monosaccharides, and then ferment the monosaccharides into ethanol. However, the cellulose macromolecules in this raw material will be linked together by a large number of hydrogen bonds to form fiber bundles with a crystal structure. Such a structure makes the properties of cellulose very stable, it is insoluble in water, and has no reducibility. Hydrolysis does not occur at normal temperature, and hydrolysis is very slow at high temperature. Only in the presence of a catalyst can the hydrolysis reaction of cellulose proceed significantly. Commonly used catalysts are inorganic acids and cellulase, thus forming acid hydrolysis and enzymatic hydrolysis processes, respectively. the

酶水解有不少优点。它在常温下进行，过程能耗低。酶有很高的选择性，可生成单一产物，故得到的糖产率很高(大于95％)。由于酶水解中基本不加化学药品，且仅生成很少的副产物，所以提纯过程相对简单，也避 免了污染。 Enzymatic hydrolysis has several advantages. It is carried out at normal temperature, and the energy consumption of the process is low. The enzyme is highly selective and can form a single product, so high sugar yields (greater than 95%) are obtained. Since no chemicals are added in the enzymatic hydrolysis and only few by-products are generated, the purification process is relatively simple and pollution is avoided. the

酶水解工艺开发中的一个重要课题是原料预处理。由于构成生物质的纤维素，半纤维素和木质素间互相缠绕，且纤维素本身存在晶体结构，会阻止酶接近纤维素表面，故生物质直接酶水解时效率很低。通过预处理可除去木质素，溶解半纤维素，或破坏纤维素的晶体结构，从而增大其可接近表面，提高水解产率。好的预处理工艺应能满足以下条件：(1)可促进糖的生成或有利于后面的酶水解；(2)能避免碳水化合物的降解损失；(3)避免生成对水解和发酵有害的副产品；(4)经济上合理。 An important topic in the development of enzymatic hydrolysis process is the pretreatment of raw materials. Because the cellulose, hemicellulose, and lignin that make up the biomass are intertwined, and the crystal structure of the cellulose itself prevents enzymes from accessing the cellulose surface, the efficiency of direct enzymatic hydrolysis of biomass is very low. Pretreatment can remove lignin, dissolve hemicellulose, or destroy the crystal structure of cellulose, thereby increasing its accessible surface and improving hydrolysis yield. A good pretreatment process should be able to meet the following conditions: (1) It can promote the formation of sugar or facilitate subsequent enzymatic hydrolysis; (2) It can avoid the degradation loss of carbohydrates; (3) Avoid the generation of by-products that are harmful to hydrolysis and fermentation (4) Economically reasonable. the

已对许多预处理方法进行了研究，而稀酸预处理是目前被广泛应用的预处理方法，成本低且效率高，具有很好的发展前景。稀酸预处理能够成功的脱除半纤维素，将其转化为木糖，利于后续的纤维素水解。 Many pretreatment methods have been studied, and dilute acid pretreatment is a pretreatment method widely used at present, with low cost and high efficiency, and has a good development prospect. Dilute acid pretreatment can successfully remove hemicellulose and convert it into xylose, which is beneficial to the subsequent hydrolysis of cellulose. the

所谓的稀酸预处理就是对生物质原料进行稀酸水解。在纤维素类生物质的稀酸水解过程中，反应温度和反应时间是两个相关的参数。当采用较高的温度时，可以用较短的反应时间；而当采用较低的温度时，就必须用较长的反应时间。 The so-called dilute acid pretreatment is dilute acid hydrolysis of biomass raw materials. During dilute acid hydrolysis of cellulosic biomass, reaction temperature and reaction time are two relevant parameters. When higher temperatures are used, shorter reaction times can be used; when lower temperatures are used, longer reaction times must be used. the

传统稀酸预处理工艺中，酸水解和酶水解是在不同反应器内进行的，为了提高酸水解反应器的利用率，常采用较高的反应温度，故要用价格较贵的高压或中压水蒸气作为热源。另外传统稀酸水解对设备的要求较高。 In the traditional dilute acid pretreatment process, acid hydrolysis and enzymatic hydrolysis are carried out in different reactors. In order to improve the utilization rate of the acid hydrolysis reactor, a higher reaction temperature is often used, so more expensive high-pressure or medium Pressurized steam as a heat source. In addition, traditional dilute acid hydrolysis has higher requirements on equipment. the

发明内容Contents of the invention

本发明的目的在于提出一种能在较缓和的条件下由木质纤维素类生物质制备还原性单糖的方法，解决传统稀酸水解预处理反应条件苛刻，对设备要求高及酸水解和酶水解必须在不同反应器内进行的问题。 The purpose of the present invention is to propose a method that can prepare reducing monosaccharides from lignocellulosic biomass under relatively mild conditions, so as to solve the problem of harsh reaction conditions of traditional dilute acid hydrolysis pretreatment, high requirements for equipment and acid hydrolysis and enzymes. The problem that the hydrolysis must be carried out in different reactors. the

本发明的构思： Design of the present invention:

发明人认为，相对于酶水解常要几十小时，酸水解所需的时间要短得多，即使是在相对较低的温度下也是如此。使稀酸预处理和酶水解在同一反应器内进行，并不会明显降低酶水解反应器的利用率。由于省略了一次固体出料和一次固体进料，总的效率可以明显增加。酸水解反应在相对较低的温度下进行，就可以用较廉价的低压水蒸气作为热源。由于反应在常压或接近常压下进行，水解过程中可补加部分生物质原料，以提高水解液中的糖浓度，对反应器的材料和制造要求也比较低。另外由于酶水解需要在一定的酸度下进行(pH在5左右)，对酸水解固体残渣的洗涤也比较容易。为此本发明人提出了生物质在同反应器内酸-酶串联水解制取还原性单糖的工艺。 The inventors believe that the time required for acid hydrolysis is much shorter than that for enzymatic hydrolysis, which usually takes tens of hours, even at relatively low temperatures. The dilute acid pretreatment and enzymatic hydrolysis are carried out in the same reactor, and the utilization rate of the enzymatic hydrolysis reactor will not be significantly reduced. Since a solid discharge and a solid feed are omitted, the overall efficiency can be significantly increased. The acid hydrolysis reaction is carried out at a relatively low temperature, and a relatively cheap low-pressure steam can be used as a heat source. Since the reaction is carried out at or near normal pressure, some biomass raw materials can be added during the hydrolysis process to increase the sugar concentration in the hydrolyzate, and the requirements for the material and manufacture of the reactor are relatively low. In addition, because the enzymatic hydrolysis needs to be carried out under a certain acidity (pH around 5), it is also relatively easy to wash the solid residue of acid hydrolysis. For this reason, the present inventors proposed a process for preparing reducing monosaccharides by acid-enzyme serial hydrolysis of biomass in the same reactor. the

本发明的工艺包括如下步骤： Technology of the present invention comprises the steps:

(1)稀酸水解： (1) dilute acid hydrolysis:

将经过初步粉碎的木质纤维素类生物质原料置于带有搅拌装置的反应器中，先通入低压蒸汽进行预热，再加入一定量的稀盐酸或稀硫酸溶液。液体加完后继续通入低压蒸汽加热，同时开始搅拌。当温度达到预定值(该值在90～110℃)后，在此温度下水解1～3小时，反应过程中保持一定的搅拌速率。水解中所用酸浓度为1～3％，酸溶液与固体原料的质量比为6～10，这二者均为考虑了蒸汽冷凝后的数值。水解过程中可补加部分生物质原料，其量为原料初始量的15～40％，根据原料中半纤维素的含量决定。可以一次补加，也可以分几次补加。补加后可以通入少量蒸汽以控制温度。 The lignocellulosic biomass material that has been preliminarily crushed is placed in a reactor with a stirring device, firstly fed with low-pressure steam for preheating, and then a certain amount of dilute hydrochloric acid or dilute sulfuric acid solution is added. After the liquid is added, continue to feed low-pressure steam to heat, and start stirring at the same time. When the temperature reaches a predetermined value (the value is 90-110° C.), hydrolyze at this temperature for 1-3 hours, and maintain a certain stirring rate during the reaction. The acid concentration used in the hydrolysis is 1-3%, and the mass ratio of the acid solution to the solid raw material is 6-10, both of which are values after steam condensation is considered. During the hydrolysis process, some biomass raw materials can be added, and the amount is 15-40% of the initial amount of raw materials, which is determined according to the content of hemicellulose in the raw materials. It can be added at one time, or it can be added several times. After adding, a small amount of steam can be introduced to control the temperature. the

洗涤与中和： Washing and Neutralization:

反应完成后停止搅拌，放出酸水解液，用一定量的液体洗涤酸水解固体残渣，得到洗涤液1。这里所说的液体在第一批原料的处理时用的是清水，在以后批原料的处理时用的是上一批次原料处理中得到的酶水解残渣洗涤水。 After the reaction is completed, the stirring is stopped, the acid hydrolyzate is released, and the acid hydrolyzed solid residue is washed with a certain amount of liquid to obtain the washing solution 1. The liquid mentioned here used clear water when the first batch of raw materials were processed, and used the enzyme hydrolysis residue washing water obtained in the previous batch of raw materials processing when the subsequent batches of raw materials were processed. the

对得到的酸溶液用氢氧化钠或氢氧化钙中和，得到中和液。可用于下一批次原料处理中的酶水解。 The obtained acid solution is neutralized with sodium hydroxide or calcium hydroxide to obtain a neutralized solution. It can be used for enzymatic hydrolysis in the next batch of raw material processing. the

得到的洗涤液1经过中和后作为水解产品。 The obtained washing liquid 1 is used as a hydrolyzed product after being neutralized. the

酶水解： Enzymatic hydrolysis:

向反应器中加入一定量的液体和一定量的纤维素酶，这里所说的液体在第一批原料处理时用的是清水，在以后批原料的处理时用的是上一批次原料处理中得到的中和液。纤维素酶用量控制在每克固体原料用10～20滤纸酶活。 Add a certain amount of liquid and a certain amount of cellulase into the reactor. The liquid mentioned here is clear water when the first batch of raw materials are processed, and the previous batch of raw materials is used for the processing of subsequent batches of raw materials. The neutralizing solution obtained in The amount of cellulase is controlled at 10-20 filter paper enzyme activities per gram of solid raw material. the

调节溶液pH＝5后开始搅拌，对固体残渣进行酶水解。反应过程中控制温度为45～55℃。水解进行12～48小时后停止搅拌，放出酶水解液，用一定量的清水洗涤酶水解固体残渣，并将残渣压干。得到洗涤液2。 Stirring is started after adjusting the pH of the solution to 5, and the solid residue is subjected to enzymatic hydrolysis. During the reaction, the temperature is controlled at 45-55°C. After the hydrolysis is carried out for 12 to 48 hours, the stirring is stopped, the enzyme hydrolyzate is released, the solid residue of the enzyme hydrolysis is washed with a certain amount of water, and the residue is pressed dry. Wash solution 2 was obtained. the

得到的酶水解液和经过中和的洗涤液1一起作为水解产品。 The obtained enzymatic hydrolyzate and the neutralized washing solution 1 together serve as hydrolyzed products. the

洗涤液2可用于下一批次原料处理中的酸水解残渣的洗涤。 The washing liquid 2 can be used for washing the acid hydrolysis residue in the next batch of raw material treatment. the

本发明中所用反应器为适用于液固反应的搅拌搅拌反应装置，同时要能够耐本发明的适用酸度和温度范围，材料为搪玻璃或内衬聚四氟乙烯的碳钢。 The reactor used in the present invention is a stirring and stirring reaction device suitable for liquid-solid reaction, and should be able to withstand the applicable acidity and temperature range of the present invention, and the material is glass-lined or carbon steel lined with polytetrafluoroethylene. the

具体实施方式Detailed ways

实施例1 Example 1

原料和分析方法： Raw materials and analytical methods:

所用原料为甘蔗渣，其组成为：水分6.3％，半纤维素31.2％，纤维素41.2％，木质素13.9％，灰分1.3％，中性洗涤物6.1％。 The raw material used is bagasse, and its composition is: 6.3% of moisture, 31.2% of hemicellulose, 41.2% of cellulose, 13.9% of lignin, 1.3% of ash, and 6.1% of neutral detergent. the

水解后得到的单糖含量用液相谱法分析。水解液中单糖收率的计算方法如下： The monosaccharide content obtained after hydrolysis was analyzed by liquid chromatography. The calculation method of monosaccharide yield in the hydrolyzate is as follows:

$\mathrm{<span><span>Y</span>Y</span>}<span><span>=</span>=</span>\frac{\mathrm{<span><span>CV</span>cv</span>}}{\mathrm{<span><span>1.1</span>1.1</span>}\mathrm{<span><span>A</span>A</span>}<span><span>\&times;</span>\&times;</span>\mathrm{<span><span>M</span>m</span>}}<span><span>\&times;</span>\&times;</span>\mathrm{<span><span>100</span>100</span>}<span><span>\%</span>\%</span>$

式中Y表示单糖收率(％)；C表示水解液中单糖浓度(g/L)；A表示原料中半纤维素加纤维素质量分率；V表示水解液的体积(L)；M表示原料的质量(g)。 In the formula, Y represents the monosaccharide yield (%); C represents the monosaccharide concentration (g/L) in the hydrolyzate; A represents hemicellulose in the raw material and cellulose mass fraction; V represents the volume (L) of the hydrolyzate; M represents the mass (g) of the raw material. the

稀酸水解： Dilute acid hydrolysis:

称取50克甘蔗渣置于装有温度计的搅拌反应器中，再加入400毫升2％的盐酸溶液。用油浴加热，使温度快速升至100℃，在此温度下水解1小时后补加10克甘蔗渣，在1小时后反应完成，反应过程中控制搅拌速率为80转/分。 Weigh 50 grams of bagasse and place it in a stirred reactor equipped with a thermometer, and then add 400 milliliters of 2% hydrochloric acid solution. Heat with an oil bath to rapidly raise the temperature to 100° C., add 10 grams of bagasse after hydrolysis at this temperature for 1 hour, and the reaction is completed after 1 hour. During the reaction, the stirring rate is controlled to be 80 rpm. the

洗涤与中和： Washing and Neutralization:

反应完成后停止搅拌，放出酸水解液，用150毫升清水洗涤酸水解固体残渣，得到洗涤液1。 After the reaction was completed, the stirring was stopped, and the acid hydrolyzed solution was released, and the acid hydrolyzed solid residue was washed with 150 ml of water to obtain Washing Solution 1. the

对得到的酸溶液用氢氧化钠中和，得到中和液。 The obtained acid solution was neutralized with sodium hydroxide to obtain a neutralized solution. the

酶水解： Enzymatic hydrolysis:

向反应器中加入300毫升清水和500滤纸酶活的纤维素酶，调节溶液pH＝5，然后对固体残渣进行酶水解。反应过程中控制温度为50℃，搅拌速率为80转/分。水解进行24小时后停止搅拌，放出酶水解液，用120毫升清水 洗涤酶水解固体残渣，并将残渣压干。得到洗涤液2。 Add 300 ml of clear water and 500 g of cellulase with filter paper enzyme activity to the reactor, adjust the pH of the solution to 5, and then carry out enzymatic hydrolysis of the solid residue. During the reaction, the temperature was controlled at 50° C., and the stirring rate was 80 rpm. After hydrolysis was carried out for 24 hours, the stirring was stopped, the enzyme hydrolyzate was released, and the solid residue of enzyme hydrolysis was washed with 120 milliliters of clear water, and the residue was pressed dry. Wash solution 2 was obtained. the

实验结果： Experimental results:

总糖回收率为79.3％。它包括酸水解中和液，酶水解液，洗涤液1和洗涤液2中所得到的全部单糖。平均糖浓度39.9克/升。 The total sugar recovery was 79.3%. It includes all the monosaccharides obtained in acid hydrolysis neutralization solution, enzymatic hydrolysis solution, wash solution 1 and wash solution 2. The average sugar concentration is 39.9 g/l. the

实施例2 Example 2

原料和分析方法： Raw materials and analytical methods:

同实施例1。 With embodiment 1. the

稀酸水解： Dilute acid hydrolysis:

同实施例1。 With embodiment 1. the

洗涤与中和： Washing and Neutralization:

其他条件同实施例1，但用于洗涤酸水解固体残渣的不是清水，而是实施例1中的洗涤液2。 Other conditions are the same as in Example 1, but what is used for washing the acid hydrolysis solid residue is not clear water, but the washing solution 2 in Example 1. the

酶水解： Enzymatic hydrolysis:

其他条件同实施例1。但用于酶水解的不是清水，而是实施例1中的中和液。 Other conditions are with embodiment 1. But what is used for enzymatic hydrolysis is not clear water, but the neutralizing solution in Example 1. the

实验结果： Experimental results:

总糖回收率为75.4％。它包括酶水解液和洗涤液1中所得到的全部单糖。平均糖浓度72.1克/升。 The total sugar recovery was 75.4%. It includes all monosaccharides obtained in the enzymatic hydrolysis solution and wash solution 1. The average sugar concentration is 72.1 g/L. the

实施例3 Example 3

原料和分析方法： Raw materials and analytical methods:

同实施例1。 With embodiment 1. the

稀酸水解： Dilute acid hydrolysis:

同实施例1。 With embodiment 1. the

洗涤与中和： Washing and Neutralization:

其他条件同实施例1，但用于洗涤酸水解固体残渣的不是清水，而是实施例2中的洗涤液2。 Other conditions are the same as in Example 1, but what is used for washing the acid hydrolysis solid residue is not clear water, but the washing solution 2 in Example 2. the

酶水解： Enzymatic hydrolysis:

其他条件同实施例1。但用于酶水解的不是清水，而是实施例2中的中和液。 Other conditions are with embodiment 1. But what is used for enzymatic hydrolysis is not clear water, but the neutralization solution among the embodiment 2. the

实验结果： Experimental results:

总糖回收率为75.7％。它包括酶水解液和洗涤液1中所得到的全部单糖。平均糖浓度72.4克/升。 The total sugar recovery was 75.7%. It includes all monosaccharides obtained in the enzymatic hydrolysis solution and wash solution 1. The average sugar concentration is 72.4 g/L. the

Claims (5)

Translated fromChinese

1.一种由木质纤维素类生物质水解制备还原性单糖的方法，其特征在于，包括如下步骤：将生物质原料置于搅拌反应器中，以稀酸为催化剂，在常压或接近常压的条件下进行水解。水解完成后洗涤残渣，并在同一反应器内对其进行酶水解。1. A method for preparing reducing monosaccharides by lignocellulosic biomass hydrolysis, is characterized in that, comprises the steps: biomass raw material is placed in stirring reactor, with dilute acid as catalyst, under normal pressure or near Hydrolysis was carried out under atmospheric conditions. After the hydrolysis is complete, the residue is washed and subjected to enzymatic hydrolysis in the same reactor.2.根据权利要求1所述的方法，其特征在于，所用无机酸为盐酸或硫酸，酸浓度为1～3％，所用酸液与固体原料的质量比为6～10。2. The method according to claim 1, characterized in that the inorganic acid used is hydrochloric acid or sulfuric acid, the acid concentration is 1 to 3%, and the mass ratio of the acid liquid to the solid raw material is 6 to 10.3.根据权利要求1所述的方法，其特征在于，酸水解反应时间为1～3小时，反应温度为90～110℃；酶水解反应时间为12～48小时，反应温度为40～70℃。3. The method according to claim 1, characterized in that, the acid hydrolysis reaction time is 1 to 3 hours, and the reaction temperature is 90 to 110° C.; the enzymatic hydrolysis reaction time is 12 to 48 hours, and the reaction temperature is 40 to 70° C. .4.根据权利要求1所述的方法，其特征在于，水解过程中要补加部分生物质原料，其量相当于初始加料量的15～40。4. The method according to claim 1, characterized in that, during the hydrolysis process, part of the biomass raw material is added, and the amount is equivalent to 15-40% of the initial feeding amount.5.根据权利要求1所述的方法，其特征在于，还包括如下步骤：5. The method according to claim 1, further comprising the steps of:(1)放出的酸液经中和后用于下一批原料的酶水解。(1) The released acid solution is used for enzymatic hydrolysis of the next batch of raw materials after neutralization.(2)酶水解后的残渣洗涤水用于下一批原料酸水解后的残渣洗涤，酸水解后的洗涤液也作为产品。 (2) The residue washing water after enzymatic hydrolysis is used for washing the residue after acid hydrolysis of the next batch of raw materials, and the washing solution after acid hydrolysis is also used as a product. the