CN103789355A - Method for preparing ethanol from cellulose-containing raw material - Google Patents
Method for preparing ethanol from cellulose-containing raw material Download PDFInfo
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- CN103789355A CN103789355A CN201210434785.4A CN201210434785A CN103789355A CN 103789355 A CN103789355 A CN 103789355A CN 201210434785 A CN201210434785 A CN 201210434785A CN 103789355 A CN103789355 A CN 103789355A
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- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E50/00—Technologies for the production of fuel of non-fossil origin
- Y02E50/10—Biofuels, e.g. bio-diesel
Abstract
The invention discloses a method for preparing ethanol from a cellulose-containing raw material, which comprises the following steps: in the presence of water, mixing a cellulose-containing raw material with enzyme, carrying out enzymolysis to obtain an enzymolysis product, and fermenting the enzymolysis product. The enzymolysis is characterized by comprising a main enzymolysis stage and an intermitted enzymolysis stage after the main enzymolysis stage which are continuously performed, wherein in the main enzymolysis stage, proper amounts of the cellulose-containing raw material and enzyme are continuously added into an enzymolysis tank so that the monosaccharide content in the enzymolysis product in the main enzymolysis stage is 50-100 g/L, and the enzymolysis product of the main enzymolysis stage sequentially and continuously flows into the enzymolysis tank of the subsequent stage to perform enzymolysis until the monosaccharide content in the enzymolysis product at the enzymolysis end point is greater than or equal to 105 g/L. The method effectively enhances the saccharide conversion rate and enzymolysis efficiency of the raw material, and therefore, greatly enhances the yield of ethanol and shortens the production cycle.
Description
Technical field
The present invention relates to a kind of method that adopts cellulose containing raw material to prepare ethanol.
Background technology
Prior art by cellulose containing raw material, as straw mainly comprises three steps for the method for ethanol: 1, the pre-treatment of cellulose containing raw material, 2, cellulosic enzymolysis, 3, the fermentation ethanol processed of sugar.
Out exposed through the Mierocrystalline cellulose in pretreated cellulose containing raw material, after mixing with cellulase, be commonly referred to enzyme digestion reaction by the reaction of cellulase hydrolysis, can be called again saccharification react, the primary product of enzymolysis is monose.Mierocrystalline cellulose can change into glucose under the effect of cellulase, hemicellulose can change into the monose such as wood sugar under the effect of hemicellulase, glucose and xylose may be used to fermentative production of ethanol, such as yeast saccharomyces cerevisiae can be prepared ethanol by glucose fermentation, pichia stipitis can be prepared ethanol by xylose-fermenting.Cellulosic non-crystalline structure is easy to be broken, and it can degradable one-tenth glucose, then becomes ethanol by glucose fermentation.
Prepare in the method for ethanol at traditional employing cellulose containing raw material, enzymolysis step adopts batch operation conventionally, all join in an enzymatic vessel and mix by cellulose containing raw material and enzyme, under suitable enzymatic hydrolysis condition, being maintained until enzymolysis terminal, obtaining enzymolysis product.The energy consumption of described traditional intermittent type enzyme solution is higher, and the functioning efficiency of enzyme is low, and the enzymolysis cycle is long, and plant factor is low, therefore can cause adopting existing cellulose containing raw material to prepare the alcohol yied that ethanol obtains lower.
Summary of the invention
The object of the invention is to overcome the lower defect of alcohol yied that method that existing employing cellulose containing raw material prepares ethanol prepares, provide employing cellulose containing raw material that a kind of alcohol yied is higher to prepare the method for ethanol.
The present inventor finds, the employing cellulose containing raw material of prior art is prepared in the method for alcohol fuel, cellulose containing raw material, as stalk normally exists with the form of liquid slurry, in the time that whole stalks of slurries shape are directly mixed with enzyme, can make enzyme concn reduce, enzyme activity is declined.Moreover, by being generally through pretreated stalk and the method for enzyme mixed enzymolysis, broken stalk particle is once all joined in the mixed solution of enzyme and water and mixed with enzyme liquid, carry out enzymatic saccharification reaction, or, first by reaction mass used---pretreated stalk particle mixes with water in retort, then under hydrolysis temperature, enzyme is directly joined in retort and reacted.Although above-mentioned mixing is carried out under agitation condition, stalk particle is still not easy to mix with enzyme.Because, diminish through pretreated stalk granularity, particle and clastic stalk particle are easy to mutual adhesion and reunion, therefore once whole stalks are mixed with enzyme completely, only there is part stalk fully to contact with enzyme, can not fully contact with enzyme because the adhesion between stalk also has part stalk with reunion, even under agitation, can not completely stalk be broken up.Therefore, after enzymolysis, cellulose conversion is sugared low conversion rate, and the productive rate of the ethanol that sugar-fermenting obtains is lower.In addition, owing to once whole stalks being mixed with enzyme completely, stalk can not fully contact with enzyme, and therefore, the cycle of enzymolysis is longer, and enzymolysis efficiency is lower, causes the productive rate of the ethanol that sugar-fermenting obtains lower.
To achieve these goals, the invention provides a kind of method that adopts cellulose containing raw material to prepare ethanol, the method is included under the existence of water, cellulose containing raw material is mixed with enzyme, enzymolysis, obtain enzymolysis product, and this enzymolysis product that ferments, wherein, described enzymolysis is divided into continuous multiple enzymolysis stages to carry out, the described multistage comprises the enzymolysis stage after apoenzyme solution stage and apoenzyme solution stage, in the apoenzyme solution stage, in enzymatic vessel, add continuously cellulose containing raw material and enzyme, contents of monosaccharides in the enzymolysis product that the add-on of described cellulose containing raw material and the add-on of enzyme make to obtain through this apoenzyme solution stage is 50-100g/L, and make to continuously flow into successively in the enzymatic vessel in the enzymolysis stage after the apoenzyme solution stage and carry out enzymolysis through the enzymolysis product that this apoenzyme solution stage obtains, in the enzymolysis product of enzymolysis terminal, the content of monose is for being more than or equal to 105g/L.
Method of the present invention is by mixing cellulose containing raw material continuously with enzyme, make the cellulose containing raw material adding continuously mix and fully to contact with enzyme, and in reaction process, the concentration of enzyme remains on higher level always, therefore, cellulose containing raw material can fully react with enzyme, thereby has effectively improved sugared transformation efficiency and the enzymolysis efficiency of raw material, has therefore greatly improved the productive rate of ethanol and has shortened the production cycle.For example, in the case of other steam explosion condition is all identical, the alcohol yied of embodiment 1 reaches 18.52%, the enzymolysis cycle is 72 hours, and the alcohol yied of comparative example 1 is only 17.35%, the enzymolysis cycle is 88 hours, and alcohol yied increase rate is up to 6.74%, the enzymolysis cycle has shortened more than 16 hours, and has improved plant factor simultaneously and reduced comprehensive energy consumption.
Other features and advantages of the present invention are described in detail the embodiment part subsequently.
Embodiment
Below the specific embodiment of the present invention is elaborated.Should be understood that, embodiment described herein only, for description and interpretation the present invention, is not limited to the present invention.
According to the present invention, the method is included under the existence of water, cellulose containing raw material is mixed with enzyme, enzymolysis, obtain enzymolysis product, and this enzymolysis product that ferments, wherein, described enzymolysis is divided into continuous multiple enzymolysis stages to carry out, the described multistage comprises the enzymolysis stage after apoenzyme solution stage and apoenzyme solution stage, in the apoenzyme solution stage, in enzymatic vessel, add continuously cellulose containing raw material and enzyme, contents of monosaccharides in the enzymolysis product that the add-on of described cellulose containing raw material and the add-on of enzyme make to obtain through this apoenzyme solution stage is 50-100g/L(5-10%), and make to continuously flow into successively in the enzymatic vessel in the enzymolysis stage after the apoenzyme solution stage and carry out enzymolysis through the enzymolysis product that this apoenzyme solution stage obtains, in the enzymolysis product of enzymolysis terminal, the content of monose is for being more than or equal to 105g/L(10.5%).Wherein, the content of monose in the enzymolysis product that the contents of monosaccharides in the enzymolysis product that obtains of this apoenzyme solution stage refers to flow out from last enzymatic vessel in apoenzyme solution stage; The content of monose in the final enzymolysis product that in the enzymolysis product of enzymolysis terminal, the content of monose refers to obtain after apoenzyme solution stage and follow-up enzymolysis stage.
According to the present invention, the described apoenzyme solution stage is the stage of carrying out continuously enzymolysis, in this apoenzyme solution stage, in enzymatic vessel, add continuously cellulose containing raw material and enzyme, can guarantee fully the contacting of enzyme and cellulosic material, mixing, and monose in the enzymolysis product that guarantees to obtain through the apoenzyme solution stage reaches certain concentration, thereby be beneficial to the optimization in enzymolysis cycle.Under preferable case, the contents of monosaccharides in the enzymolysis product that the add-on of cellulose containing raw material and the add-on of enzyme make to obtain through this apoenzyme solution stage is 60-80g/L.
According to the present invention, in the apoenzyme solution stage, the add-on of the described cellulose containing raw material adding continuously and enzyme is as long as the contents of monosaccharides in the enzymolysis product that guarantees to make to obtain through this apoenzyme solution stage is 50-100g/L(5-10%), more preferably 60-80g/L(6.0-8.0%), and the add-on of described cellulose containing raw material can be determined according to throughput, for example, can be 10-300 kg/hr.
According to the present invention, the described multistage comprises continuous multiple enzymolysis stages,, the described multistage comprises successively the enzymatic vessel (comprise apoenzyme solution stage and apoenzyme solution stage after enzymolysis stage) in multiple enzymolysis stages of series connection,, a corresponding enzymatic vessel of each enzymolysis stage in described continuous multiple enzymolysis stages, has no particular limits for kind and the quantity of described enzymatic vessel, can be various enzymatic vessels conventional in this area.Their position can, in a highly identical plane or in highly different planes, be step type.The preferred multiple enzymatic vessels of the present invention are in one plane connected in series.
According to the present invention, the described apoenzyme solution stage preferably includes 2-3 the enzymolysis stage of carrying out continuously,, comprises successively two or three enzymatic vessels of series connection that is; Cellulose containing raw material is added continuously in the enzymatic vessel in the first enzymolysis stage in apoenzyme solution stage.More abundant for what the enzymolysis in described apoenzyme solution stage was carried out, enzyme is joined respectively continuously in the enzymatic vessel in the first enzymolysis stage and the enzymatic vessel in the second enzymolysis stage of series connection with it in apoenzyme solution stage, in described the second enzymatic vessel, add the mode of enzyme, preferably, the enzymolysis product obtaining until the first enzymolysis stage adds enzyme after flowing into the enzymatic vessel in the second enzymolysis stage more continuously in the enzymatic vessel in the second enzymolysis stage.
According to the present invention, quantity for the enzymolysis stage after the apoenzyme solution stage has no particular limits, consider from aspects such as the shortening of abundant enzymolysis and production cycle and the utilization ratios of equipment, preferably, the enzymolysis stage after the described apoenzyme solution stage comprises 1-3 enzymatic vessel of series connection successively.
According to the present invention, in the described apoenzyme solution stage, the enzymatic vessel in multiple enzymolysis stages of described series connection carries the mode of enzymolysis product mostly to be overflow mode, and the Degree of Enzymatic Hydrolysis in each enzymolysis stage is also relevant with flow and the tank volume of cellulosic material and enzyme.
Particularly, in the described apoenzyme solution stage, the material inlet of the enzymatic vessel in a rear enzymolysis stage is connected with the material outlet of the enzymatic vessel in the last enzymolysis stage being adjacent.The material inlet of the enzymatic vessel in each enzymolysis stage can be positioned at the top of enzymatic vessel, and corresponding with it, the material outlet in each enzymolysis stage can be positioned at the bottom of enzymatic vessel; Or the material inlet of the enzymatic vessel in each enzymolysis stage also can be positioned at the bottom of enzymatic vessel, corresponding with it, the material outlet of each enzymatic vessel also can be positioned at the top of enzymatic vessel.In the described apoenzyme solution solution stage, add continuously cellulose containing raw material and enzyme from the material inlet of the enzymatic vessel in the first enzymolysis stage, make cellulose containing raw material enzymolysis, the enzymolysis product for the treatment of for the first enzymolysis stage flows out and enters the enzymatic vessel in the second enzymolysis stage from the material outlet of enzymatic vessel, enzyme is added continuously in the enzymatic vessel in the second enzymolysis stage, thereby mix with the enzymolysis product of the first enzymolysis stage enzymolysis, continue enzymolysis, enzymolysis product through the second enzymolysis stage enzymolysis flows out the enzymatic vessel that optionally entered for the 3rd enzymolysis stage and continues abundant enzymolysis from the material outlet of the second enzymatic vessel, then enzymolysis product is continuously flowed into successively with it in the enzymatic vessel in the follow-up enzymolysis stage being communicated with and carry out continuous enzymolysis, until the terminal enzymolysis product that enzymolysis completes flows out from the material outlet of the enzymatic vessel in last enzymolysis stage.
In addition, because enzymolysis product viscosity is larger, mobility is poor, therefore, the material inlet of the enzymatic vessel in a rear enzymolysis stage can be arranged to slightly lower than the material inlet of the enzymatic vessel in described last enzymolysis stage.In addition, and can help the enzymolysis product of thickness successfully to flow in next enzymatic vessel by pumping.
The mode that is connected in series of the structure of described enzymatic vessel and enzymatic vessel is all well known in the art, does not repeat them here.In each tank, the initial loading liquid measure of material is the 50-70% of each enzymatic vessel volume; When inflow and the outflow of material reach after balance, the liquid amount of each tank is adjusted to 80% left and right.
Because the present invention only relates to the improvement to mode of action, therefore other step of the method for preparing ethanol with the raw material of cellulose is had no particular limits.
According to the present invention, the enzyme that described enzymolysis uses comprises cellulase.Described cellulase can obtain by variety of way, is for example commercially available, or by using microbes producing cellulase secretion to obtain.
Can contain various by products owing to using microbes producing cellulase to secrete the enzyme obtaining, therefore preferably directly add enzyme.The consumption of described enzyme is The more the better, and for cost consideration, preferably, with the dry weight basis of every gram of cellulose containing raw material, the consumption of described cellulase is 8-20 enzyme activity unit, more preferably 10-15 enzyme activity unit.
For example, when preferably take the add-on of the described cellulose containing raw material of dry weight basis as 300-350 kg/hr, more preferably 310-330 kg/hr, in the described apoenzyme solution stage, the total amount that adds of described cellulase is 2.4 × 10
6-7.0 × 10
6enzyme activity unit/hour, more preferably 3.0 × 10
6-5.25 × 10
6enzyme activity unit/hour (cellulase add total amount comprise the apoenzyme solution stage to multiple enzymatic vessels, as the total amount of the cellulase adding in the first enzymatic vessel and the second enzymatic vessel).
According to the present invention, under preferable case, in the described apoenzyme solution stage, in order to there is certain contents of monosaccharides at the enzymolysis product that in the short time, assurance obtains of trying one's best, the enzyme adding to the enzymatic vessel in the first enzymolysis stage continuously accounts for the 50%-70% of the total add-on of enzyme, and the enzyme adding to the enzymatic vessel in the second enzymolysis stage accounts for the 30%-50% of the total add-on of enzyme.Therefore,, under the prerequisite of the feeding quantity of above-mentioned cellulose containing raw material, the add-on that adds continuously the cellulase of the enzymatic vessel in the first enzymolysis stage is 1.2 × 10
6-4.9 × 10
6enzyme activity unit/hour, the add-on that adds continuously the cellulase of the enzymatic vessel in the second enzymolysis stage is 0.72 × 10
6-3.5 × 10
6enzyme activity unit/hour.
The enzyme activity of cellulase of the present invention is according to American National renewable energy source laboratory (National Renewable Energy Laboratory, NREL) standard method providing---cellulase activity is measured NREL LAP-006 and is measured, the enzyme activity unit of described cellulase is under the condition determination of this standard method regulation, in 1 minute, 1 gram of Whatman No.1 filter paper is converted into the micrograms of the required enzyme of glucose.
According to the present invention, under preferable case, in the described apoenzyme solution stage, in order to there is certain contents of monosaccharides at the enzymolysis product that in the short time, assurance obtains of trying one's best, the enzyme adding to the enzymatic vessel in the first enzymolysis stage continuously accounts for the 50%-70% of the total add-on of enzyme, and the enzyme adding to the enzymatic vessel in the second enzymolysis stage accounts for the 30%-50% of the total add-on of enzyme.Therefore,, under the prerequisite of the feeding quantity of above-mentioned cellulose containing raw material, the add-on that adds continuously the cellulase of the enzymatic vessel in the first enzymolysis stage is 1.2 × 10
6-4.9 × 10
6enzyme activity unit/hour, the add-on that adds continuously the cellulase of the enzymatic vessel in the second enzymolysis stage is 0.72 × 10
6-3.5 × 10
6enzyme activity unit/hour.
Under preferable case, the enzyme that described enzymolysis uses also comprises hemicellulase.Because hemicellulase can degradation of hemicellulose become water-soluble wood sugar, so the enzyme that enzymolysis uses comprises hemicellulase, one side exposed fibers element more fully, increase the contact probability of Mierocrystalline cellulose and cellulase, hemicellulose degraded product wood sugar can be generated ethanol by pichia stipitis fermentation on the other hand, and two aspect effects can increase alcohol yied.
Method of the present invention was also included in the apoenzyme solution stage, and with the dry weight basis of every gram of cellulose containing raw material, the consumption of described hemicellulase is 4.4-8.8 enzyme activity unit.More preferably in situation, hemicellulase is added respectively continuously in the enzymatic vessel and the enzymatic vessel in the second enzymolysis stage in the first enzymolysis stage, the add-on that adds continuously the hemicellulase of the enzymatic vessel in the first enzymolysis stage is 0.66 × 10
6-2.156 × 10
6enzyme activity unit/hour, the add-on that adds continuously the cellulase of half enzymatic vessel in the second enzymolysis stage is 0.396 × 10
6-1.54 × 10
6enzyme activity unit/hour.
Because the present invention only relates to the improvement to mode of action, therefore other step of the method for preparing ethanol with the raw material of cellulose is had no particular limits.
Wherein, described cellulase is prozyme, at least comprises C
1fiber type element enzyme, Cx fiber type element enzyme and three kinds of enzymes of cellobiase.
C
1enzyme can make the Mierocrystalline cellulose of crystallization change amorphous Mierocrystalline cellulose into.
C
xfiber type element enzyme is divided into again C
x1fiber type element enzyme and C
x2two kinds of fiber type element enzymes.C
x1fiber type element enzyme is endo-type cellulase, can, from hydration amorphous cellulose element intramolecular action in β-Isosorbide-5-Nitrae-glycosidic link, generate cellodextrin and cellobiose.C
x2fiber type element enzyme is a kind of circumscribed-type cellulase, can act on β-Isosorbide-5-Nitrae-glycosidic link from the non-reducing end of hydration non-cellulose molecule, cuts off one by one β-Isosorbide-5-Nitrae-glycosidic link and generates glucose.
Cellobiase acts on cellobiose, generates glucose.
The enzyme activity unit (U) of hemicellulase of the present invention is under 50 ℃, pH=4.8 condition, and it is that 1 % by weight xylan solution produces the required enzyme amount of 1 microgram reducing sugar (in wood sugar) that per minute decomposes concentration.
The vigor of hemicellulase of the present invention refers to the unit of activity that every gram of hemicellulase has.The vigor of described hemicellulase utilizes the Water Under solution 1 % by weight xylan that hemicellulase is 4.8 at 50 ℃, pH to produce reducing sugar (in wood sugar), gained reducing sugar and excessive 3, there is color reaction in 5-dinitrosalicylic acid (DNS), records the proportional mensuration of growing amount of absorbance value and the reducing sugar (in wood sugar) of reaction solution 550 nanometers with spectrophotometer.Concrete measuring method is as follows:
Accurately take 1.000 grams of xylans, with 0.1 mol/L acetic acid-sodium acetate buffer solution dissolving of 0.5 milliliter of pH=4.8, then use deionized water constant volume to 100 milliliter, obtain 1 % by weight xylan solution;
Take 30 grams of Rochelle salts and put into 500 milliliters of Erlenmeyer flasks, add after 16 grams of NaOH, add 50 ml deionized water, dissolve with speed heating in water bath to the solid matter of 5 ℃/min, add 1 gram 3,5-dinitrosalicylic acid, to dissolving, be cooled to room temperature, be settled to 100 milliliters with deionized water, can obtain 3,5-dinitrosalicylic acid (DNS) solution;
80 ℃ of wood sugars are dried to constant weight, accurately take 1.000 grams and be dissolved in 1000 ml waters, add 10 milligrams of sodiumazide anticorrosion, obtain the normal wood sugar soln of 1 mg/ml;
Accurately take 1.000 grams of solid hemicellulases or pipette 1 milliliters of liquid hemicellulase stoste, with 0.1 mole of acetic acid-sodium acetate buffer solution dissolving of 0.5 milliliter of pH=4.8, then use deionized water constant volume to 100 milliliter, obtain diluting the enzyme liquid to be measured of 100 times;
Respectively by 50 ℃ of heating in water bath, 2 milliliters of wood sugar gradient standardized solution (0.1 mg/ml of 60 minutes, 0.2 mg/ml, 0.3 mg/ml, 0.4 mg/ml and 0..5 mg/ml, described wood sugar gradient standardized solution is mixed with the normal wood sugar soln of deionized water and 1 mg/ml) or deionized water (wood sugar blank), with 2 milliliters of DNS mixing boiling water baths 5 minutes, cooling, after 15 milliliters of deionized water constant volumes, with spectrophotometer absorbance value of wood sugar gradient standardized solution after assaying reaction respectively under 550 nanometers, take absorbance value as X-coordinate, xylose concentration is ordinate zou drawing standard curve.Can obtain regression equation y=bx+a by this typical curve, wherein, x is absorbance value, and y is xylose concentration, and a is the intercept of gained straight-line equation, and b is the slope of gained straight-line equation;
Get 0.1 mol/L acetic acid-sodium acetate buffer solution (xylan blank) of 0.2 milliliter of enzyme liquid to be measured and 1.8 milliliters of described 1 % by weight xylan solutions or pH=4.8, according to the step test light absorption value identical with above-mentioned wood sugar gradient standardized solution.And calculate according to the following formula the vigor of hemicellulase:
In formula, x is the absorbance value of enzyme liquid to be measured, b is consistent to the b in the regression equation of absorbance value and a with xylose concentration with a, n is the extension rate of enzyme, and 60 times that are expressed as enzymatic reaction were 60 minutes, and 5 is sampling multiple (having taken out 0.2 milliliter here from 1 milliliter of enzyme liquid to be measured tests).
Can determine the vigor of concrete hemicellulase according to aforesaid method, and then calculate the consumption of hemicellulase.
According to the present invention, the temperature of described enzymolysis can be any optimum temperature of cellulase, is generally 45-55 ℃, more preferably 48-52 ℃.The time of described enzymolysis is as long as the content that guarantees monose in the enzymolysis product of the enzymolysis terminal obtaining after the enzymolysis in the enzymolysis in apoenzyme solution stage and follow-up enzymolysis stage is for being more than or equal to 105g/L(10.5%), adopt after mode of action of the present invention, compare with traditional single tank enzyme solution, the enzymolysis cycle can shorten more than 16 hours.In described enzymolysis cyclical theory, the longer the better, considers plant factor, and the preferred described enzymolysis cycle is 56-80 hour, more preferably 64-72 hour.Described enzymolysis week index futures start calculating when enzyme is mixed with cellulose containing raw material until the enzymolysis product of enzymolysis terminal monosaccharide concentration reach the requirement time used.
In order to guarantee that enzyme has best reactive behavior, before cellulose containing raw material is mixed with enzyme, regulate the pH value of cellulose containing raw material to be less than 7 for being greater than 3, be preferably 4.0-6.0, after cellulose containing raw material is mixed with enzyme, enzyme has best reactive behavior.The method of described adjusting reaction mass pH value can adopt and well known to a person skilled in the art the whole bag of tricks.As according to the pH value of gained cellulose containing raw material, in this cellulose containing raw material, add acidic substance or alkaline matter.For example, described acidic substance can be one or more in sulfuric acid, hydrochloric acid and phosphoric acid; Described alkaline matter can be sodium hydroxide and/or potassium hydroxide.
More even for what enzyme was mixed with reaction raw materials, the enzymolysis of described cellulose containing raw material preferably carries out under water existence condition, therefore, for charging convenience, more preferably first add water to the enzymatic vessel that is arranged in apoenzyme solution stage first place, and add continuously cellulose containing raw material and enzyme, so that cellulose containing raw material and water are mixed to get suspension, be more conducive to the reduction of the material viscosity of the enzymatic vessel that is arranged in apoenzyme solution stage first place.Amount to added water is not particularly limited, and under preferable case, the add-on of described water is 1:1-3 with the weight ratio of whole cellulose containing raw materials.
Described cellulose containing raw material can be stalk, the herbal cane etc. of various farm crop, as maize straw, straw, wheat stalk, sorghum stalk etc.Because the main component of stalk comprises Mierocrystalline cellulose, hemicellulose and xylogen, in order to make cellulase fully contact and carry out abundant enzymolysis with hemicellulose with the Mierocrystalline cellulose in stalk with hemicellulase when the enzymolysis, before enzymolysis, preferably also cellulose containing raw material is carried out to pre-treatment so that Mierocrystalline cellulose, hemicellulose and lignin separation are opened.
The pretreatment process of described cellulose containing raw material can be the method that well known to a person skilled in the art, for example, and acid treatment method and/or steam explosion method.Described acid treatment method comprises mixes cellulose containing raw material to make it with dissolved lignin to separate with hemicellulose with Mierocrystalline cellulose with acid.The described sour kind for the xylogen that dissolves cellulose containing raw material is conventionally known to one of skill in the art, as: as described in acid can be the various acid of this area routine, as, be selected from one or more in sulfuric acid, hydrochloric acid and phosphoric acid; Consumption and the concentration of described acid are not particularly limited, and in the cellulose containing raw material that can dissolve as required, the amount of xylogen is controlled sour consumption and concentration.
Described steam explosion method comprises after cellulose containing raw material is mixed with water and carries out steam explosion or directly cellulose containing raw material is placed in to steam blasting device carrying out steam explosion.Because steam explosion method is more conducive to destroy the reticulated structure between Mierocrystalline cellulose in cellulose containing raw material, hemicellulose and xylogen, Mierocrystalline cellulose can fully be separated, be conducive to the effect of cellulase at cellulose surface, improve the productive rate of cellulosic percent hydrolysis and sugar.Therefore, the pretreatment process of the preferred described cellulose containing raw material of the present invention is steam explosion method, and described cellulose containing raw material is preferably cellulose containing raw material and/or the acid-treated cellulose containing raw material of steam explosion.
The steam explosion that adopts the steam explosion condition of prior art routine to carry out can reach goal of the invention of the present invention, for example, the temperature of described steam explosion is 160-200 ℃, and the pressure of described steam explosion is 0.6-1.6 MPa, the holding time as 3-10 minute of described steam explosion pressure.More preferably the temperature of described steam explosion is 160-180 ℃, and the pressure of described steam explosion is 0.6-1.0 MPa, the holding time as 4-8 minute of described steam explosion pressure.
Can ferment pentoses and/or the microorganism of hexose may be used to fermenting process of the present invention, because yeast saccharomyces cerevisiae is the general microorganism of the zymohexose that ethanol-tolerant, by product are few, alcohol yied is high of application in wine industry; Pichia stipitis be both can ferment pentoses also can zymohexose microorganism (referring to " pichia stipitis continuously ferment pentose and hexose generate alcohol ", Ji Gengsheng etc., Nanjing Forestry University's journal natural science edition, the 28th the 3rd phase of volume, 9-13 page, 2004), the yeast that therefore preferred described fermentation is used is pichia stipitis and/or yeast saccharomyces cerevisiae.In every gram of enzymolysis product, the inoculum size of the yeast that described fermentation is used is 10
3-10
8colony-forming unit, more preferably 10
4-10
6colony-forming unit.The yeast using is fermented in the present invention can be for being purchased yeast solids preparation (such as dried yeast powder) or barms (such as the cereuisiae fermentum of ATCC numbering 2601).The colony-forming unit of described yeast can be measured by means commonly known in the art, such as methylene blue staining viable bacteria counting method.The concrete grammar of methylene blue staining viable bacteria counting method is as follows:
1 gram of dried yeast powder is dissolved in 10 ml sterile waters, or 1 milliliter of actication of culture liquid is diluted to 10 milliliters with sterilized water, add 0.5 milliliter of 0.1 % by weight methylene blue, at 35 ℃, be incubated 30 minutes.Under 10 times of opticmicroscopes, with the number (dead bacterium dyeing, viable bacteria is not dyeed) of viable bacteria in the solution after the insulation of blood counting chamber counting, can obtain the number of viable bacteria in 1 gram of dry yeast or 1 milliliter of actication of culture liquid, i.e. colony forming single-digit.
Described yeast can adopt the inoculation of conventional method, for example, to the seed liquor that adds 5-15 volume % in enzymolysis product.Described seed liquor can be the aqueous solution or the culture medium solution of dry yeast, can be also dry yeast or the activated seed liquid that is purchased bacterial classification.The temperature of described fermentation can be any temperature that is suitable for yeast growth, is preferably 30-36 ℃, more preferably 32-35 ℃.The time of described fermentation can be for starting to occur to the decline phase of yeast growth the time of (being that fermentation time is that lag phase, logarithmic phase add stationary phase) from inoculation, preferably the time of fermentation is 32-48 hour, more preferably 36-40 hour.Tunning ethanol can, by conventional method, separate and refine according to the requirement of different Industrial products (reaching more than 99% such as fuel alcohol requires the purity of ethanol), such as distilling, concentrate, dewatering.
In addition, the pressure and temperature of steam explosion can sterilizing, and acid treatment also can be played the effect of sterilization.Pollute the toxin of the enzyme activity that exerts an influence for preventing miscellaneous bacteria in enzymolysis process (being mainly bacterium), and prevent that living contaminants during the fermentation from affecting the growth of yeast, preferably before enzymolysis, add the bacteria antibiotic such as industrial penicillin, described microbiotic does not act on yeast but can suppress the growth of miscellaneous bacteria.Take every milliliter of enzymolysis solution or fermented liquid as benchmark, described antibiotic add-on is 1-10 unit.Described enzymolysis solution comprises steam explosion products, enzyme and water, and described fermented liquid comprises the yeast of enzymolysis product and inoculation.
Owing to may containing sandstone impurity and iron contamination in cellulose containing raw material, can cause damage to steam explosion equipment, therefore the method for preparing ethanol of the present invention, before can being included in steam explosion, cellulose containing raw material is removed to stone deironing routine operation, such as removing stone deironing with the method for " wind send " cellulose containing raw material attraction.Sandstone, because quality is large, can not be delivered in steam explosion equipment by wind, and iron contamination is because the attraction of magnet also can not enter in steam explosion equipment with raw material, thereby can complete except stone deironing.In addition, because cellulose containing raw material itself easily tangles and occluding device pipeline, therefore, entering before steam explosion equipment, the size that preferably makes described cellulose containing raw material is 0.5-3 cm x 0.2-1 cm x 0.2-1 centimetre, and the size that more preferably makes described cellulose containing raw material is 1-2 cm x 0.4-0.6 cm x 0.5-1 centimetre.
Below in conjunction with embodiment, the present invention will be described in more detail.
In following embodiment, the enzymatic vessel using is that the model that Yixing City pharmaceutical equipment factory produces is φ 2800 × 3500, the enzymatic vessel that ss304, capacity are 21500L, the cellulase using is the cellulase that the trade mark of letter zymin company of Novi production is NS50010, the hemicellulase using in the present invention is the hemicellulase that the trade mark of letter zymin company of Novi production is NS50013, and yeast saccharomyces cerevisiae used in the present invention is the super highly active dry yeast in Angel that Hubei Angel Yeast stock company produces.
Embodiment 1
The present embodiment is prepared the method for ethanol for employing cellulose containing raw material of the present invention is described.
(1) pre-treatment of cellulose containing raw material
Do not have the maize straw (water content 10 % by weight) of impurity to be cut into the segment that is no more than 1.0 centimetres of 1.2 cm x 0.5 cm x 1000Kg, maintain the pressure 5 minutes of 1.0 MPas at 180 ℃, then pressure release, completes steam explosion.Obtain altogether 1800Kg steam explosion products (water content is 50 % by weight).
The mensuration of Mierocrystalline cellulose gross weight and hemicellulose gross weight in gained solid steam explosion products:
Get 10 grams of above-mentioned steam explosion products and at 45 ℃, dry to 5 grams of constant weights, weigh 300.0 milligrams of these dried steam explosion products, be positioned in 100 milliliters of dry Erlenmeyer flasks of heavy 80 grams.Be the sulphuric acid soln of 72 % by weight to adding 3.00 ml concns in described Erlenmeyer flask, stir 1 minute.Then Erlenmeyer flask is placed 60 minutes in the water-bath of 30 ℃, stirred once to guarantee even hydrolysis every 5 minutes.After hydrolysis finishes, make the concentration dilution of sulfuric acid to 4 % by weight with deionized water, then filter with Büchner funnel, obtain altogether 84 milliliters of filtrates.20 milliliters of filtrates are transferred in the dry triangular flask of 50 milliliters.Use 2.5 grams of calcium carbonate to regulate the pH value to 5.5 of this filtrate, leave standstill 5 hours, collect supernatant liquid.The supernatant liquid of collecting with 0.2 micron of membrane filtration, gained filtrate is analyzed with Biorad AminexHPX-87P high performance liquid chromatography (HPLC).HPLC condition: sample size 20 microlitres; Moving phase is 0.2 micron of membrane filtration and the degassed HPLC ultrapure water of sonic oscillation; Flow velocity is 0.6 ml/min; Column temperature 80-85 ℃; Detector temperature 80-85 ℃; Detector is refractive index detector; Be 35 minutes working time.Using the D-(+ of 0.1-4.0 mg/ml concentration range) glucose and 0.1-4.0 mg/ml concentration range D-(+) wood sugar is as standard model.HPLC analyzes and obtains glucose concn in steam explosion products acid hydrolysis liquid is 2.7 mg/ml, can be calculated 1 gram of described steam explosion products acid hydrolysis, to obtain weight be the glucose of 0.224 gram, because the sulphuric acid soln that concentration is 72 % by weight can all be hydrolyzed into glucose by the Mierocrystalline cellulose of the product of steam explosion, therefore the weight of gained glucose is 1.11 times of cellulose in steam explosion products, i.e. 0.202 gram of cellulose in 1 gram of described steam explosion products, cellulose 363Kg altogether in 1800Kg steam explosion products.HPLC analyzes and obtains xylose concentration in steam explosion products acid hydrolysis liquid is 0.67 mg/ml, can be calculated 1 gram of steam explosion products acid hydrolysis after described washing, to obtain weight be the wood sugar of 0.057 gram, because the sulphuric acid soln that concentration is 72 % by weight can all be hydrolyzed into wood sugar by the hemicellulose of the product of steam explosion, therefore the weight of gained wood sugar is 1.14 times of hemicellulose weight in steam explosion products, in 1 gram of described steam explosion products, contain 0.048 gram of hemicellulose, in 1800Kg steam explosion products, contain altogether hemicellulose 87Kg.
(2) enzymolysis
Described enzymolysis divides the multistage to carry out, the described multistage comprises the enzymolysis stage after apoenzyme solution stage and the apoenzyme solution stage of carrying out continuously, the described apoenzyme solution stage comprises the enzymatic vessel in 2 enzymolysis stages of series connection successively, the follow-up enzymolysis stage comprises the enzymatic vessel in 3 enzymolysis stages of series connection successively, between 5 enzymatic vessels, is all to connect successively.
First remaining steam explosion products after step (1) sampling and testing is mixed with the weight ratio of 1.42:1 with water, regulating the pH value of mixture is 5, then under agitation condition, the mixture that regulates the rear gained of pH value is joined in the enzymatic vessel in the first enzymolysis stage continuously with the speed of 42.58Kg/ hour, simultaneously with 1.25 × 10
5enzyme activity unit/hour speed in the enzymatic vessel in the first enzymolysis stage, add cellulase, the hydrolysis temperature of the enzymatic vessel in described the first enzymolysis stage remains on 52 ℃, hydrolysis temperature in the enzymatic vessel in follow-up enzymolysis stage is identical in this, enzymolysis product through the first enzymolysis stage flows out and flow into the enzymatic vessel in the second enzymolysis stage from the outlet of the enzymatic vessel in described the first enzymolysis stage, add entrance from the enzyme being connected with the influx of the enzymatic vessel in described the second enzymolysis stage and add continuously cellulase to the enzymatic vessel in described the second enzymolysis stage, it is 6.25 × 10 that cellulase adds speed
4enzyme activity unit/hour, with the dry weight basis of every gram of cellulose containing raw material, the consumption of the cellulase adding in the first enzymatic vessel and the second enzymatic vessel is 15 enzyme activity units, enzymolysis product through the second enzymolysis stage flows out from the spout of the enzymatic vessel in described the second enzymolysis stage, complete the apoenzyme solution stage with this, by the enzymolysis product sampling (duration in apoenzyme solution stage is every tank 12 hours) of flowing out in the enzymatic vessel in the second enzymolysis stage of apoenzyme solution stage, filter, 20 milliliters of filtrates are transferred in the triangular flask that is dried 50 milliliters, leave standstill 5 hours, collect supernatant liquid.0.2 micron of supernatant liquid that membrane filtration is collected, according to the described high performance liquid phase condition of above-mentioned steps (1), the glucose content in the enzymolysis product in apoenzyme solution stage is 75g/L(7.5%).
Then continuously flow into successively the enzymatic vessel of three follow-up series connection through the enzymolysis product of apoenzyme solution stage enzymolysis, enzymolysis completely enzymolysis product flows out from last enzymatic vessel, the whole enzymolysis cycle has been experienced 72 hours, by enzymolysis completely final enzymolysis product filter, according to the method described above measure and calculation go out through the enzymolysis of follow-up phase completely in final enzymolysis product glucose content be 112g/L, the glucose calculating described enzymolysis product from the cumulative volume of the enzymolysis product of the complete enzymolysis that obtains is 343.34Kg.The glucose weight that described enzymolysis obtains, divided by 1.11, is total to 309.32Kg by the cellulosic weight of enzymolysis in steam explosion products, calculates according to the following formula cellulose conversion rate and monose productive rate, and calculation result is in table 1.
Cellulose conversion rate=100% × by the cellulosic weight of enzymolysis/cellulosic gross weight
Glucose weight/stalk dry weight that monose productive rate=100% × enzymolysis obtains
(3) fermentation
Make enzymolysis completely the temperature of enzymolysis solution be down to 35 ℃, with the weighing scale of every gram of enzymolysis solution, inoculation 10
5the yeast saccharomyces cerevisiae of colony-forming unit, gained mixture at 32 ℃ in fermentor tank stir culture 40 hours.At 100 ℃ of distillation gained tunnings, gained distillation fraction second distillation at 78.3 ℃ can obtain ethanol 166.67Kg, calculates according to the following formula alcohol yied, and calculation result is in table 1.
Alcohol yied=100% × ethanol weight/stalk dry weight
Comparative example 1
The explanation of this comparative example adopts cellulose containing raw material to prepare the reference method of ethanol.
Method according to embodiment 1 is prepared ethanol, different is, in enzymolysis step (2), remaining steam explosion products after step (1) sampling and testing is once all joined in moisture enzymatic vessel, then mix (all the weight ratio of steam explosion products and water is 1.42:1) with enzyme, enzymolysis time is 88 hours; Second distillation obtains ethanol 156.11Kg, and calculates cellulose conversion rate, monose productive rate and alcohol yied according to the method for embodiment 1 and formula, and calculation result is in table 1.
Embodiment 2
The present embodiment is prepared the method for ethanol for employing cellulose containing raw material of the present invention is described.
Method according to embodiment 1 is prepared ethanol, different, in enzymolysis step, the mixture that regulates the rear gained of pH value is joined in the enzymatic vessel in the first enzymolysis stage continuously with the speed of 47.89Kg/ hour, simultaneously with 9.4 × 10
4enzyme activity unit/hour speed in the enzymatic vessel in the first enzymolysis stage, add cellulase, it is 4.7 × 10 that the cellulase that joins the second enzymatic vessel adds speed
4enzyme activity unit/hour, with the dry weight basis of every gram of cellulose containing raw material, the consumption of the cellulase adding in the first enzymatic vessel and the second enzymatic vessel is 10 enzyme activity units, glucose content in the enzymolysis product in apoenzyme solution stage is 60g/L(6.0%), (duration in apoenzyme solution stage is every tank 12 hours), whole enzymolysis process has experienced 64 hours, enzymolysis completely in final enzymolysis product glucose content be 110.8g/L, the glucose calculating described enzymolysis product from the cumulative volume of the enzymolysis product of the complete enzymolysis that obtains is 339.63Kg.The glucose weight that described enzymolysis obtains is divided by 1.11, be by the cellulosic weight of enzymolysis 305.97Kg altogether in steam explosion products, second distillation obtains ethanol 164.87Kg, and calculate cellulose conversion rate, monose productive rate and alcohol yied according to the method for embodiment 1 and formula, calculation result is in table 1.
Embodiment 3
The present embodiment is prepared the method for ethanol for employing cellulose containing raw material of the present invention is described.
Method according to embodiment 1 is prepared ethanol, different, in enzymolysis step, the mixture that regulates the rear gained of pH value is joined in the enzymatic vessel in the first enzymolysis stage continuously with the speed of 45.08Kg/ hour, simultaneously with 1.06 × 10
5enzyme activity unit/hour speed in the enzymatic vessel in the first enzymolysis stage, add cellulase, it is 5.3 × 10 that the cellulase that joins the second enzymatic vessel adds speed
4enzyme activity unit/hour, with the dry weight basis of every gram of cellulose containing raw material, the consumption of the cellulase adding in the first enzymatic vessel and the second enzymatic vessel is 12 enzyme activity units, glucose content in the enzymolysis product in apoenzyme solution stage is 65g/L(6.5%), (duration in apoenzyme solution stage is every tank 12 hours), whole enzymolysis process has experienced 68 hours, enzymolysis completely in final enzymolysis product glucose content be 111.5g/L, the glucose calculating described enzymolysis product from the cumulative volume of the final enzymolysis product of the complete enzymolysis that obtains is 341.68Kg.The glucose weight that described enzymolysis obtains is divided by 1.11, be by the cellulosic weight of enzymolysis 307.82Kg altogether in steam explosion products, second distillation obtains ethanol 165.87Kg, and calculate cellulose conversion rate, monose productive rate and alcohol yied according to the method for embodiment 1 and formula, calculation result is in table 1.
Embodiment 4
The present embodiment is prepared the method for ethanol for employing cellulose containing raw material of the present invention is described.
Method according to embodiment 1 is prepared ethanol, different, in enzymolysis step, the mixture that regulates the rear gained of pH value is joined in the enzymatic vessel in the first enzymolysis stage continuously with the speed of 41.43Kg/ hour, simultaneously with 6.5 × 10
4enzyme activity unit/hour speed in the enzymatic vessel in the first enzymolysis stage, add cellulase, it is 3.2 × 10 that the cellulase that joins the second enzymatic vessel adds speed
4enzyme activity unit/hour, with the dry weight basis of every gram of cellulose containing raw material, the consumption of the cellulase adding in the first enzymatic vessel and the second enzymatic vessel is 8 enzyme activity units, glucose content in the enzymolysis product in apoenzyme solution stage is 52g/L(5.2%), (duration in apoenzyme solution stage is every tank 12 hours), whole enzymolysis process has experienced 74 hours, enzymolysis completely in final enzymolysis product glucose content be 110.11g/L, the glucose calculating described enzymolysis product from the cumulative volume of the enzymolysis product of the complete enzymolysis that obtains is 337.53Kg.The glucose weight that described enzymolysis obtains is divided by 1.11, be by the cellulosic weight of enzymolysis 304.09Kg altogether in steam explosion products, second distillation obtains ethanol 163.86Kg, and calculate cellulose conversion rate, monose productive rate and alcohol yied according to the method for embodiment 1 and formula, calculation result is in table 1.
Embodiment 5
The present embodiment is prepared the method for ethanol for employing cellulose containing raw material of the present invention is described.
Method according to embodiment 1 is prepared ethanol, different is, in enzymolysis step, first remaining steam explosion products after step (1) sampling and testing is mixed with the weight ratio of 1.42:1 with water, regulating the pH value of mixture is 6, the hydrolysis temperature of the enzymatic vessel in described the first enzymolysis stage remains on 55 ℃, glucose content in the enzymolysis product in apoenzyme solution stage is 65g/L, (duration in apoenzyme solution stage is every tank 12 hours), whole enzymolysis process has experienced 78 hours, enzymolysis completely in enzymolysis product glucose content be 108.2g/L, the glucose calculating described enzymolysis product from the cumulative volume of the enzymolysis product of the complete enzymolysis that obtains is 331.69Kg.The glucose weight that described enzymolysis obtains is divided by 1.11, be by the cellulosic weight of enzymolysis 298.82Kg altogether in steam explosion products, second distillation obtains ethanol 161.02Kg, and calculate cellulose conversion rate, monose productive rate and alcohol yied according to the method for embodiment 1 and formula, calculation result is in table 1.
Embodiment 6
The present embodiment is prepared the method for ethanol for employing cellulose containing raw material of the present invention is described.
Method according to embodiment 1 is prepared ethanol, different is, use in the present embodiment 3 enzymatic vessels that are connected in series, the apoenzyme solution stage comprises two enzymatic vessels, the follow-up enzymolysis stage comprises an enzymolysis stage, first remaining steam explosion products after step (1) sampling and testing is mixed with the weight ratio of 1.42:1 with water, regulating the pH value of mixture is 5, then under agitation condition, the mixture that regulates the rear gained of pH value is joined in the enzymatic vessel in the first enzymolysis stage continuously with the speed of 54.74Kg/ hour, simultaneously with 1.8 × 10
5enzyme activity unit/hour speed in the enzymatic vessel in the first enzymolysis stage, add cellulase, add entrance from the enzyme being connected with the influx of the enzymatic vessel in described the second enzymolysis stage and add continuously cellulase to the enzymatic vessel in described the second enzymolysis stage, it is 9.1 × 10 that cellulase adds speed
4enzyme activity unit/hour, with the dry weight basis of every gram of cellulose containing raw material, the consumption of the cellulase adding in the first enzymatic vessel and the second enzymatic vessel is 17 enzyme activity units, glucose content in the enzymolysis product in apoenzyme solution stage is 62g/L(6.2%), (duration in apoenzyme solution stage is every tank 12 hours), then flow into successively the enzymatic vessel of 1 in follow-up enzymolysis stage through the enzymolysis product of apoenzyme solution stage enzymolysis, enzymolysis completely enzymolysis product flows out from this enzymatic vessel, whole enzymolysis process has experienced 56 hours, through the enzymolysis of follow-up phase completely in enzymolysis product glucose content be 107g/L, the glucose calculating described enzymolysis product from the cumulative volume of the enzymolysis product of the complete enzymolysis that obtains is 328.23Kg.The glucose weight that described enzymolysis obtains is divided by 1.11, be by the cellulosic weight of enzymolysis 295.70Kg altogether in steam explosion products, second distillation obtains ethanol 159.34Kg, and calculate cellulose conversion rate, monose productive rate and alcohol yied according to the method for embodiment 1 and formula, calculation result is in table 1.
Embodiment 7
The present embodiment is prepared the method for ethanol for employing cellulose containing raw material of the present invention is described.
Method according to embodiment 1 is prepared ethanol, different is, use in the present embodiment 5 enzymatic vessels that are connected in series, the apoenzyme solution stage comprises 3 enzymatic vessels, the follow-up enzymolysis stage comprises 2 enzymatic vessels, first remaining steam explosion products after step (1) sampling and testing is mixed with the weight ratio of 1.42:1 with water, regulating the pH value of mixture is 5, then under agitation condition, the mixture that regulates the rear gained of pH value is joined in the enzymatic vessel in the first enzymolysis stage continuously with the speed of 38.32Kg/ hour, simultaneously with 7.5 × 10
4enzyme activity unit/hour speed in the enzymatic vessel in the first enzymolysis stage, add cellulase, enter the second enzymatic vessel and carry out the enzymolysis in the second enzymolysis stage through the enzymolysis product in the first enzymolysis stage, add entrance from the enzyme being connected with the influx of the enzymatic vessel in described the 3rd enzymolysis stage and add continuously cellulase to the enzymatic vessel in described the 3rd enzymolysis stage, it is 3.75 × 10 that cellulase adds speed
4enzyme activity unit/hour, with the dry weight basis of every gram of cellulose containing raw material, the consumption of the cellulase adding in the first enzymatic vessel and the 3rd enzymatic vessel is 10 enzyme activity units, the 3rd enzymatic vessel carries out the enzymolysis in the 3rd enzymolysis stage, complete the apoenzyme solution stage with this, glucose content in the enzymolysis product in apoenzyme solution stage is 72g/L, then flow into successively the enzymatic vessel of 2 in follow-up enzymolysis stage through the enzymolysis product of apoenzyme solution stage enzymolysis, enzymolysis completely enzymolysis product flows out from last enzymatic vessel, whole enzymolysis process has experienced 80 hours, through the enzymolysis of follow-up phase completely in enzymolysis product glucose content be 109.52g/L, the glucose calculating described enzymolysis product from the cumulative volume of the enzymolysis product of the complete enzymolysis that obtains is 335.72Kg.The glucose weight that described enzymolysis obtains is divided by 1.11, be by the cellulosic weight of enzymolysis 302.45Kg altogether in steam explosion products, second distillation obtains ethanol 162.98Kg, and calculate cellulose conversion rate, monose productive rate and alcohol yied according to the method for embodiment 1 and formula, calculation result is in table 1.
Embodiment 8
The present embodiment is prepared the method for ethanol for employing cellulose containing raw material of the present invention is described.
(1) pre-treatment of cellulose containing raw material
Do not have the maize straw (water content 10%) of impurity to be cut into the segment that is no more than 1.0 centimetres of 1.5 cm x 0.4 cm x 1000Kg, by stalk section water logging after 5 minutes (weight ratio of stalk and water is 1:25), and at 190 ℃, maintain the pressure 3 minutes of 1.25 MPas, then pressure release, completes steam explosion.Obtain altogether 1925Kg steam explosion products (water content is 53.25 % by weight).
Analyze the method for sulphuric acid hydrolysis steam explosion products according to HPLC described in embodiment 1, obtaining glucose concn in steam explosion products acid hydrolysis liquid is 2.52 mg/ml, can be calculated 1 gram of described steam explosion products acid hydrolysis and can obtain the glucose that weight is 0.209Kg, because the sulphuric acid soln that concentration is 72 % by weight can all be hydrolyzed into glucose by the Mierocrystalline cellulose of the product of steam explosion, therefore the weight of gained glucose is 1.11 times of cellulose in steam explosion products, i.e. 0.189 gram of cellulose in 1 gram of described steam explosion products, in 1925Kg steam explosion products, be total to cellulose 363Kg.HPLC analyzes and obtains xylose concentration in steam explosion products acid hydrolysis liquid is 0.64 mg/ml, can be calculated 1 gram of described steam explosion products acid hydrolysis, to obtain weight be the wood sugar of 0.052 gram, because the sulphuric acid soln that concentration is 72 % by weight can all be hydrolyzed into wood sugar by the hemicellulose of the product of steam explosion, therefore the weight of gained wood sugar is 1.14 times of hemicellulose weight in steam explosion products, in 1 gram of described steam explosion products, contain 0.045 gram of hemicellulose, in 1925Kg steam explosion products, contain altogether hemicellulose 87Kg.
Carry out enzymolysis step (2) according to the method identical with embodiment 1, different is, in adding cellulase to first enzymatic vessel in apoenzyme solution stage, also add continuously hemicellulase, when enzymolysis product in the first enzymatic vessel starts to flow in the enzymatic vessel in the second enzymolysis stage, when cellulase being added continuously in the enzymatic vessel in this second enzymolysis stage, also add continuously hemicellulase, the add-on that adds continuously the cellulase in the first enzymatic vessel and the second enzymatic vessel is identical with embodiment's 1, the add-on that adds continuously the hemicellulase of the first enzymatic vessel be 48750 enzyme activity units/hour, the add-on that adds continuously the hemicellulase of the enzymatic vessel in the second enzymolysis stage be 24375 enzyme activity units/hour, with the dry weight basis of every gram of cellulose containing raw material, the consumption that adds continuously the described hemicellulase in the first enzymatic vessel and the second enzymatic vessel is 5 enzyme activity units.According to the described high performance liquid phase condition of above-mentioned steps (1), show that the glucose content in the enzymolysis product in apoenzyme solution stage is 72g/L(7.2%).
And according to the described high performance liquid phase condition of embodiment 1 step (1), through the enzymolysis of follow-up phase completely in enzymolysis product glucose content be 155g/L, the glucose calculating described enzymolysis product from the cumulative volume of the enzymolysis product of the complete enzymolysis that obtains is 343.34Kg.The glucose weight that described enzymolysis obtains is divided by 1.11, be by the cellulosic weight of enzymolysis 309.31Kg altogether in steam explosion products, measure and calculate the wood sugar 74.66Kg altogether in enzymolysis product, the weight of the wood sugar that described enzymolysis obtains, divided by 1.14, is total to 65.49Kg by the weight of the hemicellulose of enzymolysis in steam explosion products; And calculate according to the following equation Mierocrystalline cellulose, hemicellulose transformation efficiency and monose productive rate, calculation result is in table 1.
Cellulose conversion rate=100% × by the cellulosic weight of enzymolysis/cellulosic gross weight
Hemicellulose transformation efficiency=100% × by the gross weight of the weight/hemicellulose of the hemicellulose of enzymolysis
Monose productive rate=100% × (the wood sugar weight that glucose weight+enzymolysis that enzymolysis obtains obtains)/stalk dry weight
(3) fermentation
Make enzymolysis completely the temperature of enzymolysis solution be down to 35 ℃, with the weighing scale of every gram of enzymolysis solution, inoculation 10
5the yeast saccharomyces cerevisiae of colony-forming unit, gained mixture at 32 ℃ in fermentor tank stir culture 40 hours.At 100 ℃ of distillation gained tunnings, gained distillation fraction second distillation at 78.3 ℃ can obtain ethanol 202.92Kg, calculates according to the following formula alcohol yied, and calculation result is in table 1.
Alcohol yied=100% × ethanol weight/stalk dry weight
Comparative example 2
The explanation of this comparative example adopts cellulose containing raw material to prepare the reference method of ethanol.
Method according to embodiment 8 is prepared ethanol, different is, in enzymolysis step (2), remaining steam explosion products after step (1) sampling and testing is once all joined in moisture enzymatic vessel, then mix (all the weight ratio of steam explosion products and water is 1.7:1) with enzyme, enzymolysis time is 80 hours; Second distillation obtains ethanol 191.44Kg, and calculates Mierocrystalline cellulose, hemicellulose transformation efficiency and monose productive rate and alcohol yied according to the method for embodiment 8 and formula, and calculation result is in table 1.
Table 1
Data in upper table 1 can find out, the productive rate of ethanol that the method that adopts employing cellulose containing raw material of the present invention to prepare ethanol obtains and the productive rate of monose are all apparently higher than the productive rate of the ethanol being obtained by reference method and the productive rate of monose.
Claims (11)
1. a method that adopts cellulose containing raw material to prepare ethanol, the method is included under the existence of water, cellulose containing raw material is mixed with enzyme, enzymolysis, obtain enzymolysis product, and this enzymolysis product that ferments, it is characterized in that, described enzymolysis is divided into continuous multiple enzymolysis stages to carry out, the described multistage comprises the enzymolysis stage after apoenzyme solution stage and apoenzyme solution stage, in the apoenzyme solution stage, in enzymatic vessel, add continuously cellulose containing raw material and enzyme, contents of monosaccharides in the enzymolysis product that the add-on of described cellulose containing raw material and the add-on of enzyme make to obtain through this apoenzyme solution stage is 50-100g/L, and make to continuously flow into successively in the enzymatic vessel in the enzymolysis stage after the apoenzyme solution stage and carry out enzymolysis through the enzymolysis product that this apoenzyme solution stage obtains, in the enzymolysis product of enzymolysis terminal, the content of monose is for being more than or equal to 105g/L.
2. method according to claim 1, wherein, the contents of monosaccharides in the enzymolysis product that the add-on of described cellulose containing raw material and the add-on of enzyme make to obtain through the described apoenzyme solution stage is 60-80g/L.
3. method according to claim 1, wherein, the described multistage comprises the enzymatic vessel in multiple enzymolysis stages of series connection successively; The apoenzyme solution stage comprises 2-3 enzymatic vessel of series connection successively, cellulose containing raw material is added continuously in the enzymatic vessel in the first enzymolysis stage in apoenzyme solution stage, enzyme is added respectively continuously in the enzymatic vessel in the first enzymolysis stage and the enzymatic vessel in the second enzymolysis stage of series connection with it in apoenzyme solution stage.
4. method according to claim 3, wherein, the enzymolysis stage after the described apoenzyme solution stage comprises 1-3 enzymatic vessel of series connection successively.
5. method according to claim 4, wherein, the enzyme that the enzymatic vessel in continuous the first enzymolysis stage to the apoenzyme solution stage adds accounts for the 50-70% of the total add-on of enzyme, and the enzyme adding to the enzymatic vessel in the second enzymolysis stage continuously accounts for the 30-50% of the total add-on of enzyme.
6. according to the method described in any one in claim 1-5, wherein, the enzyme that enzymolysis uses comprises cellulase, and with the dry weight basis of every gram of cellulose containing raw material, the consumption of described cellulase is 8-20 enzyme activity unit.
7. according to the method described in any one in claim 1-5, wherein, the enzyme that described enzymolysis uses also comprises hemicellulase, and with the dry weight basis of every gram of cellulose containing raw material, the consumption of described hemicellulase is 4.4-8.8 enzyme activity unit.
8. method according to claim 1, wherein, the temperature of described enzymolysis is 45-55 ℃, the pH value of described enzymolysis is 4-6.
9. method according to claim 1 and 2, wherein, the cellulose containing raw material that described cellulose containing raw material is steam explosion and/or acid-treated cellulose containing raw material.
10. method according to claim 9, wherein, described cellulose containing raw material is stalk.
11. methods according to claim 1, wherein, the yeast that described fermentation is used is pichia stipitis and/or yeast saccharomyces cerevisiae; The enzymolysis product obtaining in every gram of enzymolysis terminal, the inoculum size of the yeast that described fermentation is used is 10
3-10
8colony-forming unit, the temperature of described fermentation is 30-36 ℃, the time of fermentation is 32-48 hour.
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| CN105886553A (en) * | 2015-01-26 | 2016-08-24 | 中粮营养健康研究院有限公司 | Synchronous diastatic fermentation process of cellulose-containing raw materials |
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| CN105886553A (en) * | 2015-01-26 | 2016-08-24 | 中粮营养健康研究院有限公司 | Synchronous diastatic fermentation process of cellulose-containing raw materials |
| CN105154494A (en) * | 2015-09-30 | 2015-12-16 | 河南天冠纤维乙醇有限公司 | Method for continuous enzymolysis of lignocellulose for improving sugar concentration |
| CN105154494B (en) * | 2015-09-30 | 2019-06-07 | 河南天冠纤维乙醇有限公司 | A kind of method that lignocellulosic continuous enzymolysis mentions high glucose concentration |
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