Utilize alkali extracting biomass residue to prepare the enzymatic acidification method technology of glucoseTechnical field
The present invention relates to the Technology field of plant cellulose hydrolysis, particularly utilize alkali extracting biomass residue to prepare the enzymatic acidification method technology of glucose.
Background technology
Modern industry made the development of human civilization be equivalent to progress in several thousand in the past in short 100 years, had also consumed a large amount of fossil resources simultaneously, and the development and utilization of renewable energy source has become the human Critical policies that solves the energy and environment problem.The utilization of water energy, wind energy, sun power and biomass energy has become the heat subject of current society, is the renewable energy resources but wherein have only biomass, is again the important carbon resource that contains.
The about 1,000 hundred million tons of CO of the annual absorption of plant on the earth2, they are emitting a large amount of O2The time produce 1,500 hundred million tons of biomass, its main component comprises Mierocrystalline cellulose, hemicellulose and xylogen are referred to as lignocellulose.Require lowly owing to generate land resources that lignocellulose consumes, the space that provides to human being's production is bigger relatively, and not only Mierocrystalline cellulose generation process absorbs CO2Help CO in the atmosphere2Balance, and the existence of a large amount of lignocelluloses also will provide more opportunity for following industrial chemicals and liquid fuel production.For example, though it is high to utilize cellulose raw to produce thing alcoholic acid cost, use bio-ethanol can reduce greenhouse gases CO2About 200 dollars/ton of Environmental costs are saved in discharging.Therefore, cellulose resource such as straw in the waste agronomic crop if can be converted into the human energy, food and the industrial chemicals of being badly in need of, will solve environmental pollution to human society, be short of food and energy dilemma is of great immediate significance.Especially after cellulose degradation was monose, the glucose of acquisition not only can directly be other number of chemical product as the platform compound deriving, and its biological alcohol that obtains through fermentative production more more can be used as oil substitutes and is applied in a plurality of fields.
But the efficient greatest problem that faces of utilizing of biomass resource is exactly that Mierocrystalline cellulose stable structure and physico-chemical property have caused very big obstacle to its degraded utilization, the bottleneck that has become cellulose industry to use.With the xylogen is binding agent, and hemicellulose is a weighting material, and Mierocrystalline cellulose is that the lignocellulose of skeleton be combined into is considered to occurring in nature to one of the strongest material of chemical action and biological action resistance.The natural cellulose hydrolysis prepares the committed step that glucose is cellulose degradation and utilization.The yield of cellulose conversion rate and glucose directly influences the cost and the economic benefit of whole biomass degradation technology.The method that with biomass is feedstock production glucose at present is mainly by enzymic hydrolysis and acid-hydrolysis method two big classes are arranged: acidic hydrolysis generally is divided into hydrolysis of diluted acid high-temperature pressurizing and the hydrolysis of concentrated acid low-temperature atmosphere-pressure.The former acid consumption is few, but energy consumption is higher, needs withstand voltage and acid-resistant system, invests bigger; The concentrated acid hydrolysis can make the Mierocrystalline cellulose complete hydrolysis, but bigger owing to the consumption acids amount in actual production, cost is higher, pollutes bigger.The both is difficult to satisfactory.The great advantage of the biological enzymolysis of Mierocrystalline cellulose is that hydrolytic process only generates by product seldom, and purification process is simple relatively, is the main flow trend of fiber degradation at present.But biomass need pre-treatment in this technology, and there is the obvious suppression effect in the accumulation of hydrolytic process intermediate product oligosaccharide to catalyzed reaction, influenced the glucose yield of degraded, need the extra beta-glucosidase that adds to eliminate inhibition, cause the production cost height of whole technology enzyme, the hydrolysis cycle is long, and process cost is too high.
Summary of the invention
The objective of the invention is provides a kind of easy elimination enzymolysis process oligosaccharide restraining effect at above-mentioned technical problem, and the alkali extracting biomass residue that utilizes that improves hydrolytic process glucose yield prepares the enzymatic acidification method technology of glucose.
The theoretical basis of technical solution of the present invention:
Alkali extracting biomass residue is a kind of agriculture and forestry organic waste material, the xylo-oligosaccharide that the liquid phase that the alkali extracting obtains makes through enzymolysis by successful Application at fodder industry, and its residue belongs to the waste plant fiber of a kind of agricultural byproducts after deep processing, and main component is a Mierocrystalline cellulose.Therefore, the hydrolytic process of alkali extracting biomass residue just cellulose degradation be the process of glucose.
Utilizing hydrolytic process is out-phase system and the soluble principle of intermediate product oligosaccharide, remove the intermediate product accumulation by simple solid-liquid separation, because cellulase has CBM fiber adsorption zone, think after the solid-liquid separation and can further be utilized degraded solid phase residue under given conditions by a large amount of cellulase of absorption on the solid phase residue of cellulase hydrolysis.
Merge the hydrolyzed solution in each hydrolytic process, mainly contain glucose and oligosaccharide this moment, all oligosaccharides thoroughly can be hydrolyzed to glucose by simple acid treatment, thereby reach the purpose that improves cellulose conversion rate and glucose yield.
The objective of the invention is to realize by following technical measures:
A kind of enzymatic acidification method technology of utilizing the pretreated biomass residue of alkali extracting to prepare glucose, this technology may further comprise the steps:
A. be raw material with the pretreated biomass residue of alkali extracting, biomass residue is added in the hydrolysis reactor, it is miscible to add the pH damping fluid, and adding cellulase, the cellulase consumption of every g biomass residue is controlled at 4～10 FPIU of filter paper enzyme activity unit, regulating biomass residue concentration is 10～100g/L, and pH is 4.5～5.5, carries out enzymolysis then under 40～65 ℃ of conditions; Enzymolysis carries out solid-liquid separation after finishing, and the gained liquid phase is labeled as solution I, and gained solid phase residue is labeled as residual II;
B. add the pH damping fluid of 1～5 times of amount by residual II weight, pH is controlled at 4.5～5.5, and hydrolysis 16～30 hours is continued at the cellulase that 40～65 ℃ of utilizations are adsorbed on the residual II in the back that suspends, and carries out solid-liquid separation, obtains solution II;
C. solution I and solution II are merged, adding mineral acid to sour final concentration is 0.5%～5wt%, and 100～140 ℃ were reacted 0.5～6 hour, collects glucose and gets final product.
Described method, wherein biomass are one or more in corn cob, maize straw, straw, rice straw, the birch.
Described method, wherein cellulase is selected from one or more in Trichodermareesei (Trichoderma reesei), viride (Trichoderma viride), aspergillus niger (Aspergillus niger), the koning trichoderma (Trichoderma koningii).
It is the phosphoric acid-sodium phosphate buffer of 0.05-0.2mol/L or the citric acid-sodium citrate damping fluid that concentration is 0.05-0.2mol/L in 4.5～5.5 concentration that described method, wherein said pH damping fluid are selected from the pH scope.
Described method adds among the step a wherein that the time of enzymolysis is 16～48 hours behind the cellulase.
Described method, wherein the mineral acid of Jia Ruing is sulfuric acid or hydrochloric acid.
Described method, wherein the method for alkali extracting biomass residue is that a certain amount of biomass are added appropriate alkaline liquor extracting 30～60min, and is centrifugal, can obtain the biomass residue after the alkali extracting.
Beneficial effect of the present invention:
The present invention compares with the method that present biomass by hydrolyzation prepares reductive monosaccharide, not only can improve the efficient that cellulose conversion is a reducing sugar, make its under the situation of not adding beta-glucosidase in the raw material cellulose conversion be that the reducing sugar yield brings up to 97.60% from 90.11%, and finish the back at enzymolysis and adopt the acid treatment enzymolysis solution, oligosaccharide all can be converted into glucose, Mierocrystalline cellulose generation glucose yield reaches 91% in the raw material.
Embodiment
The invention will be further elaborated by the following examples.
The method of alkali extracting biomass of the present invention is referring to big vast maple, (the xylan composition influences the zytase synthetic people such as surplus generation Yuan at document, " Mierocrystalline cellulose science and technology ", 1999,7 (2): 42-47) disclosed method is an example with corn cob alkali extracting pre-treatment, the extracting of a certain amount of corn cob water, adding concentration at 1: 10 by the solid-liquid weight ratio then is the NaOH of 5-10%, and behind 100 ℃ of left and right sides extracting 30-60min, centrifugal 3500rpm 15 min obtain alkali extracting corn cob slag.
Embodiment 1
1, take by weighing alkali extracting corn cob residue 0.6g, put into the 50ml Erlenmeyer flask, adding the work of 5ml enzyme is 1 FPIU/mL cellulase solution (Trichodermareesei) and 15ml 0.05M citric acid-sodium citrate damping fluid (pH 4.5), shakes up, and makes pH at 4.5-5.5.
2, enzymolysis for the first time: put into 50 ℃ of water bath with thermostatic control vibrator enzyme digestion reactions 24 hours, oscillation amplitude is 100r/min.
3,3500rpm carried out solid-liquid separation in centrifugal 15 minutes, and supernatant liquor is labeled as solution I, shifts out reaction system, and is standby, and the solid phase residue is labeled as residual II.
4, enzymolysis for the second time: residual II is refunded former Erlenmeyer flask, weigh, the 0.05M citric acid-sodium citrate damping fluid (pH4.5) that adds 1～5 times of amount, make pH at 4.5-5.5,100r/min vibration in 50 ℃ of water bath with thermostatic control vibrators, carry out enzyme digestion reaction 24h, reaction is carried out solid-liquid separation after finishing, and liquid phase is denoted as solution II.
5, solution I and solution II are merged, adding sulfuric acid to vitriolic final concentration is 2wt%, continues hydrolysis 2h at 110 ℃, termination reaction, and measuring cellulose conversion is 97.60% for the reducing sugar yield, the glucose yield reaches 91%.
Embodiment 2
1, takes by weighing alkali extracting maize straw residue 0.6g, put into the 50ml Erlenmeyer flask, and add the 5ml enzyme respectively and live and to be 1.5FPIU/mL cellulase solution (aspergillus niger) and 15ml 0.05M citric acid-sodium citrate damping fluid (pH 4.5), shake up, make pH at 4.5-5.5.
2, enzymolysis for the first time: put into 50 ℃ of water bath with thermostatic control vibrator enzyme digestion reactions 48 hours, oscillation amplitude is 100r/min.
3,3500rpm carried out solid-liquid separation in centrifugal 15 minutes, and supernatant liquor is labeled as solution I, shifts out reaction system, and is standby, and the solid phase residue is labeled as residual II.
4, enzymolysis for the second time: residual II is refunded former Erlenmeyer flask, weigh, the pH 4.5 0.05M citric acid-sodium citrate damping fluids that add 1～5 times of amount, make pH at 4.5-5.5,100r/min vibration in 50 ℃ of water bath with thermostatic control vibrators, enzyme digestion reaction 24h takes place, and reaction is carried out solid-liquid separation after finishing, and liquid phase is denoted as solution II.
5, solution I and solution II are merged, adding sulfuric acid to vitriolic final concentration is 1wt%, continues hydrolysis 4h, termination reaction at 110 ℃.Measuring cellulose conversion is 98.66% for the reducing sugar yield, and cellulose raw malaga sugar yield reaches 93%.
Embodiment 3
1, takes by weighing alkali extracting birch residue 1.0g, put into the 50ml Erlenmeyer flask, and add the work of 5ml enzyme respectively, shake up, make pH at 4.5-5.5 at 1.5FPIU/mL cellulase solution (viride) and 15ml 0.05M citric acid-sodium citrate damping fluid (pH4.5).
2, enzymolysis for the first time: put into 50 ℃ of water bath with thermostatic control vibrator enzymolysis 24 hours, oscillation amplitude is 100r/min.
3,3500rpm carried out solid-liquid separation in centrifugal 15 minutes, and supernatant liquor is labeled as solution I, shifts out reaction system, and is standby, and the solid phase residue is labeled as residual II.
4, enzymolysis for the second time: residual II is refunded former Erlenmeyer flask, weigh, the 0.05M citric acid-sodium citrate damping fluid that adds 1～5 times of amount, make pH at 4.5-5.5, be put into 100r/min vibration in 50 ℃ of water bath with thermostatic control vibrators, enzyme digestion reaction 36h, reaction is carried out solid-liquid separation after finishing, and liquid phase is denoted as solution II.
5, solution I and solution II are merged, adding sulfuric acid to final concentration is that 1wt% continues hydrolysis 6h, termination reaction at 110 ℃.Measuring cellulose conversion is 99.13% for the reducing sugar yield, and cellulose raw malaga sugar yield reaches 95%.