FR2560898A1 - Process for destructuring lignocellulosic matter - Google Patents

Abstract

Process for destructuring lignocellulosic matter originating from agricultural waste and scrap timber using an oxidising alkaline treatment. According to the process the cellulose substrate is subjected to a treatment with an alkaline aqueous solution of a peroxide compound: hydrogen peroxide and its solid derivatives capable of reconstituting the H2O2 molecule in an aqueous medium, by itself or mixed - activated by a compound chosen from the class of cyanamides and derivatives, the cyanamide active principle CN2 being used in a proportion by weight of between 0.2 and 3 % relative to the solids content of the substrate. Application of the lignocellulosic matter destructured according to the process in feeding ruminants, in biochemical processes for conversion into sugar, alcohol and protein and for a subsequent bacterial delignification of papermaking pulp.

Description

<Tb>

"<SEP>SEP>SEP>SEP><SEP> MATERIAL <SEP> LIGNOCELLULOSIC
<tb> Invention <SEP> of <SEP> Michel <SEP> GRANGER, <SEP> R, <SEP> Marie-Jeanne <SEP> DESMURS <SEP> and <SEP> Marie-Dominique <SEP> STEFAN
<tb> At <SEP> name <SEP> of <SEP> the <SEP> company <SEP> says: AIRLiUIDE <SEP> COMPANY <SEP> ANONYMOUS <SEP> FOR <SEP> STUDY <SEP> AND
<tb> s <SEP> EXPLOITATW <SEP> 1 <SEP> n <SEP> concern <SEP> a <SEP> process <SEP> of <SEP> destructura tion of lignocellulosic materials.

 Agriculture and wood industry waste, such as cereal straw, grass stems and tops, oilseed husks and hulls, sawdust, etc., are a very important source of potential food for the ruminant. based on cellulosic carbon hydrates.

 Unfortunately, these wastes can not be assimilated directly as they are for various reasons. Lignin acts as a barrier between carbohydrates and rumen cellulosic enzymes, on the other hand, crude cellulose is too crystalline and its accessibility to the enzyme and microorganisms is poor, and silica inhibits the digestibility of carbohydrates.

 Lignin is one of the fundamental constituents of the plant cell wall where it appears during a so-called "lignifioation" growth phase, which is essentially associated with the development of the vascular system. climatic conditions that are not conducive to rapid growth of the plant favor the lignification of plant tissues. The proportion of lignin in the fiber can vary between 3 and 30%.

 Chemically, lignin is a highly complex, non-saccharide polymer based on phenylpropane aromatic molecular units. The complexity of the lignin molecule depends on the one hand, the way the C6-C3 units are connected to each other and, on the other hand, the fact that these units are not ohimically identical. carbohydrate digestion by cellulolytic enzymes of the rumen because its digestibility is very low, but also by the protective effect that it exerts in the form of incrustations on cellulose and hemicellulose. Also, a delignification of this vegetable waste, must promote the penetration of enzymes and thus increase the digestibility of the treated substrate.

 Various means have been advocated to increase the nutritional value of cellulosic waste for the feeding of ruminants. The best known is the treatment with aloalis: souda, ammonia, lime.

 The treatment with soda has received particular attention especially on straws.

From 1921, Beckmann (Festschr Kaiser Wilhelm Ges.Forderung
Wiss. zehnjahrigen Jubilaum, p.18 - 26, 1921) has demonstrated the effectiveness of soaking in a dilute aqueous solution of sodium hydroxide.

This wet immersion technique has been successfully applied, but it has serious drawbacks: 20 to 5% of cellulosic substrate is lost in the alkaline liquor and in the washings intended to evacuate the unreacted soda. This poses a pollution problem, and if you want to keep the product, you have to dry it.

 More recently, Wilson and Pigden (Can J. Animal Sci 44, pp. 122-123, 1964) have proposed an improvement to this technique of spraying an alkaline liquor more concentrated on the cellulosic substrate and allowing it to air dry. ambient. The implementation is greatly facilitated but the efficiency is lower.

 Despite the fact that it is universally used for pulping wood in the paper industry, the delignifying action of soda is not very sensitive at ambient temperature; only a small part of the lignin is solubilized and the alkaline agent acts rather on the crystallinity of the cellulose which it reduces by causing a swelling of the fibrous network and by reducing the strength of the intermolecular hydrogen bonds which bind the cellulose cycles between them . Thus accessibility to cellular enzymes is facilitated.

 Hydrogen peroxide must amplify the delignifying action of soda. But its effect is limited, too, at room temperature.

 Since it is undesirable to heat the treated cellulosic substrate in large quantities and under particular conditions, except by the reaction energy of the treatment itself, it has been found that the addition to peroxide and sodium hydroxide a certain type of activator made it possible to obtain lignin degradation and dislocation of the lignocellulosic skeleton leading to better penetration of microorganisms and enzymes during the subsequent bacterial fermentation, whether it is carried out with the aim of producing proteins in vitro or in vivo with the objective of feeding ruminant animals.

 According to the invention, the treatment of lignocellulosic material with an alkaline aqueous solution of a peroxidized compound activated by a compound chosen from the class of cyanamides and derivatives leads to the destructuration of said material under the desired conditions; which allows its use- in the feeding of ruminants, or in biochemical processes of transformation into sugar, alcohol and proteins, if it is vegetable waste, and for a subsequent bacterial delignification if it is is pulp.

The alkaline solution used is obtained from alkali or ammonium hydroxides. The proportion of alkaline agent recommended is between 8.5 and 10% (expressed as alkaline agent 100, such as sodium hydroxide NaOH) relative to the dry matter, preferably 1 to 6% and in particular close to 5%.
The peroxidized compound is hydrogen peroxide used alone or as a mixture, in a weight ratio of between 0.5 and 10% (expressed as peroxidized compound 100%) relative to the dry matter, preferably d at 6%.
The hydrogen peroxide solution is selected from commercial products grading 30 percent. 35 or 50% by weight or obtained by dilution of the 70% commercial solution, preferably preferably the proportion of H 2 O 2 used is around 4%.

 Hydrogen peroxide can also be used in the form of its solid derivatives which generate the H 2 O 2 molecule in an aqueous medium. These compounds capable of recovering the molecule of hydrogen peroxide in an aqueous medium may be chosen from perborates, percarbonates, perpyrophosphates, urea peroxide (per carbamide), etc.

The hydrogen peroxide activator in this process of destructuring cellulosic substrates is chosen from the class of cyanamide functional products, such as, for example, H 2 CN 2,
Na2CN2, NaHCN2, K2CN2, haloformamidine salts, etc.

 Disodium cyanamide, Na 2 CN 2, is an activator particularly well suited to the process of destructuring cellulosic line materials and leads to quite satisfactory results. The sub-acidic cyanamide is also of interest and may be used in place of disodium cyanamide.

Sodium cyanamide being used in solution, it can be obtained from calcium cyanamide, a technique commonly used as fertilizer by any appropriate means
A convenient and inexpensive way to prepare a usable solution for the treatment under consideration is to treat the technical calcium cyanamide with a solution of disodium phosphate obtained by dissolving in water the commercial product dihydrate Na2EP04.2R20 or by using sodium hydroxide solution and phosphoric acid in stoichiometric proportions. For example, after rough grinding of the CaCN 2 granules, the phosphate solution can be stirred at 450 ° C. for 4 hours.

 The isodic cyanamide solution being unstable should be used rather quickly after its preparation; a storage time not exceeding two hours leads to the best results.

 The proportion of cyanamide ON2 active ingredient to be used will be between 0.2 and 3%, preferably close to 1.5% by weight relative to the dry matter of the substrate.

 Advantageously, the H2O2 / Na2CN2 weight ratio is between 1 and 1.4.

 The byproduct of the action of cyanamides on peroxide, after the minceracid has reacted on the reducing lignin and cellulose, is urea, which is strongly recommended for supplementation for animals fed with treated straw. Urea is a source of nonprotein nitrogen and especially has a beneficial effect on the voluntary consumption by the animal of treated straw.

 In some cases, it has been found that the result can also be improved by addition of urea, added at the time of treatment in a proportion of between 0.1% and 5% by weight relative to the dry matter, and preferably around 20%. The commercial technical product usually used as fertilizer and in the diet of ruminants is an excellent source of urea.

The practical implementation of the process consists in impregnating the cellulosic substrate, in a fairly divided form, by any appropriate means with an alkaline solution, then with a solution of hydrogen peroxide or with an H 2 O 2 generating compound, then with a activator solution. This "dry" technique is preferably carried out in the form of an impregnation in a consistency range of between 0.45 and 0.5% (solid / solid + liquid weight), but conventional soaking techniques are also possible.
It is then allowed to continue the chemical reactions carried out for at least a period of about seven hours.

 It can be heated during the treatment, but it is preferable to operate at ambient temperature which facilitates an on-site prevention in the case of on-farm trash treatment.

 By way of illustration, an example of implementation of the process for the treatment of 10 kg of oat straw is given under the conditions indicated below: a - Reagents used: 0.7 liter of soda at 30% by weight 0.9 liter of 35% by weight hydrogen peroxide (obtained by dilution with water of 70% H 2 O 2 commercial); and 10 liters of concentrated cyanamide solution.

b) - Preparation of the cyanamide solution: Dens a container with a capacity of about 50 liters equipped with efficient stirring, heated to 45 C 12 liters of water. With stirring, 1.15 kg of premilled black calciun cyanamide is poured. 1 mg of disodium orthophosphate or, better still, a solution prepared from NaOH and H 3 PO 4 are added with stirring. In this case, the quantity of water initially heated must be reduced accordingly. The mixture is kept at 45 ° C. with stirring for 4 hours. 10 liters of a clear, slightly yellowish solution of concentrated cyanamide are collected and recovered, which must be used within 2 hours for the treatment of the cellulosic substrate.

c) - Treatment of oat straw The milled straw is introduced into a rotary mixer; after homogenization, the sodium hydroxide solution is added to the mixer preferably continuously and at a rate such that it requires a duration of at least 13 minutes. Once the sodium hydroxide is added, the mixture is stirred for a further 5 minutes at least. The peroxide solution is then preferably introduced continuously in at least 15 minutes. The temperature rise of the substrate must not exceed 10 degrees, otherwise it is the proof of an inadvertent decomposition of the peroxide which will necessarily lead to a less effective treatment. Various means can be implemented to overcome this problem. decomposition. The stirring is maintained for 5 to 10 minutes and then the concentrated solution of cyanamide is introduced into the mixer, preferably continuously. A rise in the temperature of the substrate from 15 to 20 ° C. is normal. above. Once the cyanamide solution is completely introduced, stirring is continued for at least 30 minutes. As a result, the substrate can be unloaded and put in piles. In order for the action of the reagents to be optimal, it is necessary to leave under these conditions at least 72 hours. At the end of this time, the straw can be used or stored as it is or dried for later use.

 In the specific case where it has been prepared for feeding ruminant, it can be incorporated in straw molasses at a rate of the order of 10 percent.

 The results of the treatment described above were found at least as good as those reported below and which were carried out at the laboratory scale.

 The effectiveness of the treatments is determined by carrying out measurements of disappearance of dry matter by 3 methods: enzymatic attack in vitro, rumen in vitro and nylon bags in vivo.

 The principle of the so-called enzymatic etching measurement consists in subjecting the lignocellulosic sample to the successive attack of 2 enzymatic preparations: pepsin for 24 hours then a cellulase for 48 hours. The solid part resistant to these attacks is separated by filtration on sintered glass and put in the summer ve for determination of the dry matter.

 The results are expressed in terms of in vivo digestibility evaluated, many studies having shown that the latter is linearly related to solubilized dry matter in vitro by enzymatic attack. Since some treatment reagents may artificially increase the digestibility of the treated substrate even if they have not reacted since they are soluble, "corrected" digestibility has been used for the expression of the results. This correction should contribute to slightly underestimating the effectiveness of the treatment since it does not include a final water washing step.

 The in vitro rumen technique simulates the two stages of the digestive process in ruminants. The food is first digested by anaerobic microorganisms from rumen fistulated sheep, then attacked in an acid medium by pepsin. During the first stage, the sugars of the plant membranes are partly transformed by the enzymes of the microorganisms into soluble products. In a second step, the conversion of the proteins into water-soluble compounds is carried out by treatment with hydrochloric acid and a proteolytic enzyme, pepsin. The undissolved material is dried and calcined.

 The in vivo nylon bag method involves simulating the main stages of ruminant digestion. The test food is placed in a bag of nylon cloth that is introduced into the rumen of fistulated ruminants. The microorganisms present can cross the wall of the bag and partially degrade the food. The bag is then removed from the runian and placed in a pepsin solution. The total disappearance of dry matter after these two stages is in correlation with the digestibility of the dry matter "in vivo".

 It is given without limitation, some examples of application that show the effectiveness of the treatment. In all the examples from 1 to 15, the effectiveness of the treatment by the first method is measured: enzymatic attack in vitro; in Example 16, the 3 methods are compared.

EXAMPLE 1 In a mixing bowl, the equivalent of 100 g of oat straw solids is added and 5% of NaOH is added dropwise with stirring (expressed by weight relative to each other). to the dry matter). The substrate thus impregnated is stored in a polyethylene bag at room temperature and analyzed after 72 hours. The estimated digestibility of oat straw increased from 43% to 63%.

 The same treatment is applied to the same straw, but 5% of sodium hydroxide is added 5% H2O2 always with respect to the dry matter. Digestibility, in this case, increases from 43 to 55.5%.

 The presence of hydrogen peroxide seems to reduce the effectiveness of the soda.

Example 2: By way of comparison, the treatment described in Example 1 is carried out on the same oat straw without soda, but in the presence of: = 4% of H2O2: the digestibility reached is 46%,
= 4% peracetic acid: the digestibility goes to 5%
It is found that the hydrogen peroxide used alone is
less effective than coupled with soda and there is no synergy
between the fraction of the soda and that of the peroxide, which is
(OH + H2O2) is less than the sum of the efficiencies of the
treatments with NaOH and H2O2 carried out separately. Otherwise,
the action of peracetic acid is better than that of H2O2 but
less than that of NaOH.

Example 3 The Treatment Described in Example 1 Is Implemented
according to the invention on the same oat straw with 5% NaOH + 2%
H2O2 + 3.2% Na2ON2. The digestibility obtained is 67%. Thus the addition of Na2CN2 coupled to H2O2 / OH makes it possible to exceed the efficiency of @aOH alone.

Example 4: On oak sawdust initial digestibility 42 jo and treatment with 5% sodium hydroxide provides a gain of 6 digestibility points (digestibility after treatment with sodium hydroxide 48%), is carried out a treatment according to the operating protocol of Example 1 and this with 5 D NaOH + 45 ', E202 + 3.2% NaCN2. The digestibility obtained is 54% which corroborates on another substrate the effectiveness of the OH / H2O2 / Na2CN2 mixture.

EXAMPLE 2 Using the same technique as that described in Example 1, sunflower shells and bagasse tops are successively treated with the oxidizing mixture of Example 4.

 The digestibility obtained for the sunflower hulls is 55% as against 40 for the raw substrate and 48 for the substrate treated with soda. For the initial digestibility bagasse of 43, the oxidizing treatment brings a gain of 15 points against 5 for soda.

 The effectiveness of the oxidizing treatment is variable according to the cellulosic substrate.

Example 6: Keeping the conditions of Example 3, with regard to the mode of treatment and the amounts of reagent involved, but starting from another oat straw of digestibility. Initial 44.5 was used CaCN2 (3.1%) and H2CN2 (1.6%) replacing Na2CN2.

The digestibilities corrected were respectively:
64% for Na2CN2 (5% sodium hydroxide: digestibility 57)
58% for CaCN2
60% for R20N2
Example 7s A sample of oak sawdust is brought into contact with a solution of NaOH (5%), H2O2 (2%) and NaHCN2 (2.5%) in a sealed polyethylene bag, which is immersed in a water bath. 70CC for one hour. The consistency of the reactive substrate mixture is 15 seconds, that is, the treatment is more "wet" than in the previous 6 examples. The substrate is then rinsed and neutralized before being filtered and dried at 30-50 ° C. for at least one night. The digestibility of the sawdust treated under these conditions increases from 42% to 52%, compared with 47% for the treatment. to sodium hydroxide (5%), so sodium cyanamide acid can be used in place of disodium cyanamide.

EXAMPLE 8 The treatment described in Example 1 is carried out by replacing 45% of H 2 O 2 with 18% of sodium perborate tetrahydrate, the moisture content being kept the same as in Tests 1 to 6.

The corrected digestibility obtained under these conditions is 62% against 64% with H2O2. The sodium perborate can therefore be used as a replacement for H2O2.

Example 9: Example 3 is repeated replacing the hydrogen peroxide with urea peroxide equivalent amount of active oxygen. The corrected digestibility of the soluble reagents is found to be 69%.

Urea peroxide advantageously replaces hydrogen peroxide.

Example 10: 8 tests are carried out from urea peroxide (PC3) in the same way as the test 9 but by varying the activation ratio that is to say the respective amounts of PCB and Na2CN2.

<Tb>

<SEP> Equivalent <SEP> PCB <SEP> Na2CN2 <SEP> Activation <SEP> Report <SEP> Digestibility
<tb><SEP> H2O2 <SEP> (%) <SEP> (%) <SEP> (%) <SEP> corrected <SEP> (%)
<tb> 0 <SEP> 0 <SEP> 0 <SEP> - <SEP> 61.0
<tb><SEP> 2.1 <SEP> 5.7 <SEP> 3.2 <SEP> 1.8 <SEP> 64.6
<tb><SEP> 7.2 <SEP> 19.9 <SEP> 3.2 <SEP> 6.2 <SE> 72.8
<tb><SEP> 10.3 <SEP> 28.5 <SEP> 3.2 <SEP> 8.9 <SEP> 74.2
<tb><SEP> 4.1 <SEP> 11.4 <SEP> 1.5 <SEP> 7.6 <SEP> 66.4
<tb><SEP> 4.1 <SEP> 11.4 <SEP> 3.2 <SEP> 3.6 <SEP> 68.8
<tb><SEP> 4.1 <SEP> 11.4 <SEP> 6 <SEP> 1.9 <SEP> 71.8
<tb><SEP> 4.1 <SEP> 11.4 <SEP> 11.4 <SEP> 1 <SEP> 72.4
<Tb>
It can be seen that the activation of H2O2 by Na2CN2 can make it possible to convert a straw or a good hay from the point of view of its nutritional value for the ruminant.

 There is no optimal ratio of activation (oxidant) / (activator), that is to say that when the amount of one of the reagents (oxidizer or activator) is fixed and when the other, the digestibility of the treated substrate increases.

Example 11: On an oat straw, the effect of a treatment of the type of Example 3 was compared in which, in addition to Na 2 CN 2, urea was added and during which the treated substrate was not allowed to stand for 72 hours at room temperature, but was heated for 1 hour at 80 C. In these tests, the amounts of reagents used were 5% NaOH,
4% H2O2, 1.83% Na2CN2, 4% urea. The digestibility after 72 hours at room temperature was found to be 75% or only 1 point higher than that found after 1 hour at 80 C. It is therefore possible to play on the temperature to considerably reduce the duration of treatment. is lying.

Example 12: On crushed sunflower shells and according to the technique of Example 1, two treatments involving 5% NaOH, 2% H2O2 and either 3% or 4% urea were carried out. The corrected digestibilities obtained are respectively 52 and 55 5'a, which proves the interest of an addition of urea during the treatment with the activated formula of alkaline peroxide.

Example 13: On an oat straw, according to the treatment technique of Example 1, a series of impregnation is carried out by varying the total amount of liquid involved. The results are as follows

<tb> Processing <SEP> volume <SEP> total <SEP> of <SEP> digestibility
<tb><SEP> liquid <SEP> (ml) <SEP> corrected <SEP> (%)
<tb> NaOH <SEP> 5%, <SEP> H2O2 <SEP> 4%, <SEP> Na2CN2 <SEP> 3.2 <SEP>% <SEP> 27.1 <SEP> 56.3
<tb><SEP>"<SEP> 61.7 <SEP> 66.9
<tb><SEP> n <SEP> 66.7 <SEP> 71
<tb><SEP> N <SEP> 71.7 <SEP> 70.6
<tb><SEP> 100 <SEP> 71.1
<tb><SEP> 150 <SEP> 66.9
<Tb>
It can be seen that if it is desired to obtain a corrected digestibility of at least 70%, it is necessary to carry out the treatment in the consistency range 0.6-0.46 (solid / solid + liquid weight).

Example 14 1.1 kg ground oat straw was placed in a rotary mixer and the amounts of sodium hydroxide (5), H2O2 (4%), Na2CN2 (3.2%) and water-either in order: 167 ml of NaOR at 30% w / v; 100 ml of 35% H 2 O 2 32 g of Na 2 CN 2 in 100 ml of water; 300 ml of water (consistency 0.6) were added gradually to the rotating substrate in about one hour. The mixture was then left in a heap at room temperature for 3 days, after which the digestibility was found to be 68% or 20 digestibility points brought by the treatment.

Example 15: The foregoing examples used Na2CN2 of> 95% purity.

An experiment similar to that of Example 14 was carried out with a solution of Na2CN2 at 45 g / l obtained by reaction of the disodium orthophosphate on calcium cyanamide. The consistency in this case was 0.51. By following the same treatment conditions, the digestibility of the treated straw was found to be 68%, a gain similar to that obtained from crystallized Na 2 CN 2.

Example 16: The digestibility of treated and untreated substrates was evaluated by the three methods mentioned above. The consistency of the results and the effectiveness of the peroxide treatments are shown in the following table

<SEP> bag of
<tb><SEP> Study Method <SEP> Cellulase <SEP> Nylon <SEP> Rumen <SEP> in <SEP> vitro <SEP> Mean
<tb> digest. <SEP> digest. <SEP> digest. <SEP> digest. <SEP> digest.
<Tb>

<SEP> topic <SEP> topic <SEP> topic <SEP> topic <SEP> subject
<tb><SEP> Products <SEP> dry <SEP> dry <SEP> dry <SEP> orga. <SEP> dry
<tb><SEP> evaluated <SEP> evaluated <SEP> evaluated <SEP> evaluated <SEP> estimated
<tb><SEP> (%) <SEP> (%) <SEP> (%) <SEP> (%) <SEP> (%)
<tb> Straw <SEP> no
<tb><SEP> treated <SEP> 42.7 <SEP> 42.4 <SEP> 37.2 <SEP> 36.6 <SE> 40.8
<tb><SEP> Straw <SEP> + <SEP> 5% <SEP> NaOH
<tb><SEP> 4% <SEP> H2O2 <SEP> + <SEP> 3.2 <SEP>%
<tb><SEP> 66.6 <SEP> 63.6 <SEP> 68.8 <SEP> 62.0 <SEP> 66.3
<tb> Na2CN2
<tb> Straw <SEP> + <SEP> 5% <SEP> NaOH
<tb> + <SEP> 11.4 <SEP>% <SEP> PCB
<tb> 72.1 <SEP> 64.9 <SEP> 70.8 <SEP> 69 <SEP> 69.2
<tb><SEP> + <SEP> 3.2 <SEP>% <SEP> Na2CN2
<tb><SEP> Sawdust <SEP> no <SEP> 14.2 <SEP> 4.3 <SEP> 9.2 <SEP> 9-10
<tb><SEP> processed
<tb><SEP> Sawdust <SEP> + <SEP> 5% <SEP> NaOH
<tb> + <SEP> 4 <SEP>% <SEP> H2O2 <SEP> +
<tb><SEP> 53.7 <SEP> 46.4 <SEP> 44.7 <SEP> 40.7 <SE> 48.3
<tb><SEP> 3.2 <SEP>% <SEP> Na2CN2
<tb><SEP> Sawdust <SEP> + <SEP> 5% <SEP> NaOH
<tb> + <SEP> 11.4 <SEP>% <SEP> PCB
<tb><SEP> 54.6 <SEP> 53.2 <SEP> 51.7 <SEP> 49.3 <SEP> 53.2
<tb> + <SEP> 3.2 <SEP>% <SEP> Na2CN2
<Tb>
Electron microscopic examination of samples of treated substrates showed that - following the NaOH / H2O2 / Na2CN2 treatment, straw was observed on the ends of the fragments under study and generalized swelling of the structures. a large misalignment but no swelling The wood vessels are not degraded.

- following treatment NaOH / PCB / Na2CN2, there is observed on the straw an important cellular development, probably due to the dissolution or the extraction of the pectic cement. The wood vessels are destroyed. For sawdust, there is a cellular breakdown by dissolving the pectic cement and destroying the lignified conductive vessels.

 X-ray diffraction examination shows that, in the case of straw, the crystallinity or organization decreases when straw is changed from straw to treated straw. For sawdust it is a little different, since sawdust treated PCB is more "crystalline" than that treated with H2O2. This may be due to a significant disappearance of lignin which would reveal the diffraction pattern of this cellulose present.

Indeed, treatments with alkaline oxidants activated by carbimides show that the increase in digestibility is generally accompanied by a decrease in the lignin content of the substrate.

<SEP> substrate <SEP> treated <SEP> or <SEP> no <SEP> lignin <SEP> from <SEP> Van <SEP> Soest (%) <SEP>
<tb><SEP> Straw <SEP> oats <SEP> no <SEP> processed <SEP> 8
<tb><SEP> Straw <SEP> + <SEP> 5 <SEP>% <SEP> NaOH <SEP> + <SEP> 4 <SEP>% <SEP> H202 <SEP> 5.6
<tb><SEP> + <SEP> 3,2 <SEP>% <SEP> Na2CN2 <SEP>
<tb><SEP> Sawdust <SEP> of <SEP> oak <SEP> no <SEP> treated <SEP> 12 <SEP> 3
<tb><SEP> Sawdust <SEP> + <SEP> 5 <SEP>% <SEP> NaOR <SEP> + <SEP> It <SEP>% <SEP> POB <SEP> + <SEP> 3,2 <SEP>%<SEP> Na2CN2 <SEP> 9.6
<tb><SEP> Cocues <SEP> of <SEP> sunflower <SEP> no <SEP> treated <SEP> 22
<tb><SEP> Shells <SEP> + <SEP> 5 <SEP>% <SEP> NaOH <SEP> + <SEP> 2 <SEP>% <SEP> H2O2 <SEP> + <SEP> 3,2 <SEP>%<SEP> Na2CN2 <SEP> 13.8
<tb><SEP> Bagasse <SEP> No <SEP> Processed <SEP> 12.3 <SEP>
<tb><SEP> Bagasse <SEP> + <SEP> 5 <SEP>% <SEP> NaOH <SEP> + <SEP> 4 <SEP>% <SEP> H2O2
<tb> 11
<tb> + <SEP> 3.2 <SEP>% <SEP> Na2CN2
<Tb>

Claims (10)

 1. A process for destructuring lignocellulosic materials from agricultural waste and wood waste by an alkaline oxidizing treatment, characterized in that the cellulosic substrate is subjected to treatment with an aqueous alkaline solution of a peroxidized compound activated by a compound selected from the class of cyanamides and derivatives.  2. Process for destructuring lignocellulosic materials according to claim 1, characterized in that the activator is chosen from the class of cyanamide compounds, such as H 2 CN 2, Na2CN2, NaHCN2, K2CN2, ZnCN2, and derivatives capable of restoring the cyanamide function in aqueous solution, such as the haloformamidine salts, the peroxidized compound being hydrogen peroxide and its solid derivatives capable of recovering the peroxide molecule. hydrogen in an aqueous medium, alone or as a mixture  3. Process for structuring lignocellulosic materials according to claim 1 or 2, characterized in that the Cy2 active cyanamide active pe is used in a proportion of between 0.2 and 3% by weight, relative to the dry matter. of the substrate preferably close to 1.55 "o  4.Procedure for destructuring lignocellulosic material according to any one of claims 1 to 3, characterized in that the activator is disodium cyanamide in solid or in solution form obtained from technical calcium cyanamide, the weight ratio H2O2 / Na2CN2 being understood between 1 and 1.4.  5. Process for destructuring lignocellulosic materials according to claim 3, wherein the peroxidized compound (expressed as 100% H2O2) is used in a proportion of between 0.5 and 10% by weight relative to the dry substance, the alkaline agent, selected from the group of alkaline hydroxides and ammonium is used in a proportion of between 0.5 and 10% by weight (expressed as alkaline agent 100%) relative to the material dry, preferably 1 to 6%.  6. A process for destructuring lignocellulosic materials according to any one of claims 1 to 5, characterized in that the hydrogen peroxide is used in the form of either commercial aqueous solutions of less than 70% titre, or of its solid derivatives capable of returning the hydrogen peroxide molecule to an aqueous medium, such as perborate, percarbonate, perpyrophosphate, urea peroxide (percarbamide).  7. Process for destructuring lignocellulosic materials according to any one of claims 1 to 6, characterized in that the treatment is carried out in the presence of urea.  8. Process for destruoturation of lignocellulosic materials according to claim 7, characterized in that the urea is added at the time of treatment in a proportion of between 5% and 5% by weight relative to the dry matter, preferably around 2%.  9. A method of destructuring lignocellulosic material according to any one of claims 1 to 8, characterized in that one proceeds to the impregnation of the cellulosic substrate in fairly divided form, in a consistency range between 0.45 and 0, 6 (solid / solid weight + liquid) by the alkaline solution, then by the solution of the peroxidized compound and by the activator solution, the chemical reactions used are then allowed to continue for at least one duration of the order about seven hours at room temperature.  10. Application of the degraded lignocellulosic material according to the method of any one of claims 1 to 9, for use in feeding ruminants in biochemical processes for processing sugar, alcohol and proteins and for subsequent bacterial delignification of pulp paper.