PULVERULENT SUBSTRATE OPTAINED BY STEAM CRACKING OF A BIOMASS WIITHOUT CHEMICAL AUZILIARY AGENT, AND USES THEREOF

Abstract

An energy substrate is obtained by steam cracking of a biomass. More specifically, the disclosure relates to a steam-cracked biomass in the form of dry powder and devoid of any chemical additive, to a method for the production thereof and to the use thereof as a substrate for green chemistry and biotechnological methods such as enzymatic hydrolysis and fermentation.

Claims

1. A pulverulent carbon substrate of chemical or biochemical reaction, formed by a process comprising continuous steam-cracking of a lignocellulosic biomass at a humidity level of between 5% and 27% without any chemical auxiliary, by applying a severity factor of between 3 and 5.

2. A ready-to-use dry composition, comprising: a pulverulent substrate as defined in claim 1; and at least one enzyme.

3. A ready-to-use dry composition, comprising: a pulverulent substrate as defined in claim 1; and at least one microorganism.

4. A ready-to-use dry composition, comprising: a pulverulent substrate as defined in claim 1; at least one enzyme; and at least one microorganism.

5. The composition of claim 3, wherein the at least one microorganism is a microbial biomass.

6. The composition of claim 3, wherein the at least one microorganism is micro-algae.

7. A method, comprising: providing a substrate as defined in claim 1; and using the substrate as a support for a chemical reaction.

8. The method of claim 7, wherein using the substrate as a support for a chemical reaction further comprises using the substrate as a production support for a culture of microorganisms.

9. A method for obtaining sugars from lignocellulosic biomass, comprising: (i) subjecting a pulverulent carbon substrate as defined in claim 1 to enzymatic hydrolysis, or (ii) cultivating a composition comprising a pulverulent carbon substrate as defined in claim 1 and one or more of a microorganism, an enzyme, a microbial biomass, or a micro-algae.

10. A method of producing molecules of interest, comprising: (i) subjecting a pulverulent carbon substrate as defined in claim 1 to fermentation; or (ii) cultivating a composition comprising a pulverulent carbon substrate as defined in claim 1 and one or more of a microorganism, an enzyme, a microbial biomass, or a micro-algae.

11. The method of claim 10, wherein the molecules of interest are intended to be used in the field of bioenergies or bioplastics or bioproducts.

12. A method of continuous preparation of a pulverulent substrate for a chemical reaction, other than combustion, comprising: continuously steam-cracking a lignocellulosic biomass at a humidity level of between 5% and 27% without any chemical auxiliary while applying a severity factor of between 3 and 5 to the lignocellulosic biomass.

13. A method of forming a pulverulent substrate of chemical reaction, comprising continuously steam-cracking a lignocellulosic biomass at a humidity level of between 5% and 27% without any chemical auxiliary while applying a severity factor of between 3 and 5 to the lignocellulosic biomass

Description

DETAILED DESCRIPTION

[0023] A first object of the disclosure relates to a pulverulent carbon substrate of chemical or biochemical reaction, obtained by continuous steam-cracking of a lignocellulosic biomass at a humidity level of between 5% and 27% without any chemical auxiliary.

[0024] In a preferred embodiment, the steam-cracking is carried out by applying a severity factor of between 3 and 5.

[0025] Within the meaning of the present disclosure, “chemical reaction” means any reaction, including biochemical reactions such as fermentation, enzymatic hydrolyses, biotechnological methods, in addition to conventional chemical transformations. The concept of a chemical reaction does not include a combustion reaction.

[0026] Within the meaning of the present disclosure, “pulverulent substrate” means a substrate in powder form or in the form of pellets, or pellets having a low degree of compression, also referred to as “granulettes.” The granulettes correspond to a form of compressed powder, so as to give the powder the form of a pellet, but that rapidly releases a powder by soaking (little pelletization). This form can be adopted during packaging of the product in order to facilitate the handling thereof, but the characteristics thereof are those of a powder from the moment the substrate is impregnated by a solution (enzymatic, acidic, etc.).

[0027] The biomass powder obtained by steam-cracking comprises at least 50% pulverulent compounds having a cross section of less than 0.5 millimeters, and at least 10% of fibrous compounds having a length of over 1 millimeter.

[0028] The pellets are cylindrical in shape. The length thereof may be defined as being 99.9% less than 5 cm, and 99.0% less than 4 cm, and less than 10% less than 1 cm. Furthermore, at least 99.0% of the pellets have a diameter of greater than or equal to the diameter selected, i.e., for example, 6, 8 or 10 mm. Finally, the bulk density thereof (with a cylinder having a volume of 5 liters of pellets, tapped 3 times by falling from a height of 20 cm) is between 600 g/l and 700 g/l.

[0029] The granulettes have dimensions equivalent to those of the pellets, but have a density of less than 600 g/l, generally between 300 and 600 g/l.

[0030] The pulverulent substrate is particularly suitable for implementing biochemical reactions such as enzymatic hydrolysis, fermentation, or any other chemical or biochemical reaction.

[0031] The fact that the substrate is present in powder form implies that it is in dry form, preferably between 5% and 27% humidity. This feature distinguishes it from other forms of biomass used for biochemical reactions, which are in liquid form. Indeed, the biomasses of the prior art are impregnated, in particular with chemical auxiliaries, prior to treatment, and are treated in a liquid environment following steam-cracking, in order to eliminate the auxiliaries. Even if presentation in liquid or wet form may be suitable for biochemical applications, this is problematic for preserving the biomass, which will necessarily ferment.

[0032] The substrate according to the disclosure thus has the advantage of being dry, by virtue of a method of preparation by means of steam-cracking without prior impregnation, i.e., from biomass having a humidity level that is preferably between 5 and 27% (directly, or optionally after drying). Moreover, the method does not involve the addition of chemical auxiliaries (or additives), producing a clean substrate.

[0033] Within the meaning of the disclosure, a “chemical auxiliary” means any compound or any solution that may rest in the steam-cracked product or in the effluents. The auxiliaries create impurities in the steam-cracked product, in terms of the uses thereof and pollutants in the effluents to be rejected. Chemical auxiliaries of this kind are, for example, acids, bases, organic solvents or organic molecules, salts, etc. Products such as lime, carbon dioxide, and renewable dissociated forms of carbon dioxide are not considered chemical auxiliaries, because they are inert with respect to the intended uses and the environment.

[0034] The severity factor depends on the pressure, the temperature, and the treatment duration. In a preferred embodiment, a severity factor is between 3 and 5. In a particular embodiment of the disclosure, the severity factor corresponds to a treatment for several minutes (generally between 5 and 30 minutes).

[0035] A second object of the disclosure relates to a “ready-to-use” dry composition comprising a pulverulent substrate as defined above, and at least one enzyme.

[0036] The dry composition can be preserved and transported; it is stable.

[0037] The enzymes allow for hydrolysis of the biomass, once it is impregnated, by the user. Indeed, the enzymes in the dry environment (the biomass in powder form) are inactive, and the activation thereof is initiated by wetting, indeed soaking, the composition.

[0038] The enzymes that can be associated with the biomass in a composition of this kind can, for example, be selected from cellulases, a beta-glucosidase, hemicellulases, etc.

[0039] A third object of the disclosure relates to a “ready-to-use” dry composition comprising a pulverulent substrate as defined above, and at least one microorganism.

[0040] The dry composition can be preserved and transported; it is stable.

[0041] The microorganisms allow for the fermentation of the biomass, once it is impregnated, by the user. Indeed, the microorganisms are not active in the dry environment (the biomass in powder form), and the metabolism thereof is activated by wetting, indeed soaking, the composition.

[0042] The microorganisms associated with the substrate may be of different types, in particular a microbial biomass or microalgae. The microbial biomass may contain bacteria, yeasts, fungi, or any other type of cell.

[0043] In a particular embodiment, the disclosure relates to a “ready-to-use” dry composition comprising a pulverulent substrate, at least one enzyme, and at least one microorganism.

[0044] A third object of the disclosure relates to the use of a substrate as defined above, as a support for a chemical reaction.

[0045] In a particular embodiment, the substrate is used as a production support for the culture of microorganisms.

[0046] It is a case of using the substrate in order to provide the microorganisms, making up the biomass, with the nutrients necessary for the multiplication thereof. It is sufficient to mix a sample of biomass with the substrate in appropriate conditions (humidity, temperature, etc.) in order to grow microorganisms.

[0047] A fourth object of the disclosure relates to a method for obtaining sugars from lignocellulosic biomass, consisting in subjecting a pulverulent carbon substrate to enzymatic hydrolysis, or in cultivating a “ready-to-use” dry composition comprising a pulverulent substrate and enzymes.

[0048] The substrate obtained from biomass may undergo enzymatic hydrolysis in order to provide high added-value sugars such as xylose, glucose, etc.

[0049] The enzymatic and fermentation reactions furthermore generate co-products that must be able to be exploited, such as the hydrolysis or fermentation residue, which contains lignin and fibers having a significant LCV, resinous or terpenic derivatives, phenolic compounds (coumaric, ferulic), condensates rich in furfuraldehyde (polymerization monomer), in acetic and formic acid, etc. The soluble or insoluble lignin co-products can be used as materials (resins, binding agents, feedstocks).

[0050] A fifth object of the disclosure relates to a method for obtaining molecules of interest from lignocellulosic biomass, that includes (i) subjecting a pulverulent carbon substrate to fermentation, or (ii) cultivating a “ready-to-use” dry composition comprising a pulverulent substrate and at least one microorganism, or (iii) subjecting a pulverulent substrate to a (conventional) chemical transformation method.

[0051] The molecules of interest that can be obtained are intended, for example, for the field of bioenergies (biofuel oils, biogas, etc., such as bioethanol, biomethanol, biomethane, etc.) or bioplastics (biomaterials, biocomposites) or bioproducts (proteins, solvents, any other chemical molecule, etc.).

[0052] The substrate according to the disclosure can be used in numerous applications: by manufacturers seeking to produce bioethanol and biobutanol and isobutene and farnesene to make liquid biofuels (biofuel oils in particular, toward light-duty or heavy-duty vehicles such as BP, SHELL, toward aviation such as TOTAL); by biotechnologists wishing to ferment 2G sugars (cellulosic glucose and xylose) toward basic synthons (building blocks) of industry, bioplastics or bioproducts (methane, methanol, formic acid, formol, ethanol, ethylene, acetic acid, oxalic acid, ethanal, propanol, propanediol, acetone, propionic acid, lactic acid, maleic acid, malic acid, fumaric acid, succinic acid, butanol, butanediol, isobutene, butyric acid, hydroxybutyric acid, valeric acid, glutaric acid, capric acid, caproic acid, caprylic acid, amino acids, etc.); by producers of microorganisms (start-up or spinoff) who plan to produce microbial biomass of non-food origin (yeasts rich in proteins, or in oils, or heterotrophic microalgae without light).

[0053] A sixth object relates to a continuous preparation method of a pulverulent substrate of chemical reaction as defined above, by steam-cracking of a lignocellulosic biomass, characterized in that the method is carried out: [0054] at a humidity level of between 5 and 27%, and [0055] without a chemical auxiliary.

[0056] In a preferred embodiment, the method allows for the preparation of a pulverulent substrate of chemical reaction, except for combustion.

EXAMPLES

Example 1: Implementation of a Steam-Cracking Method Making it Possible to Obtain a Pulverulent Carbon Substrate

[0057] The production of a pulverulent carbon substrate according to the present disclosure can be achieved proceeding from wood, by implementing the following steps: [0058] obtaining wood fragments of wood of a size of between 0.5 and 14 mm having a humidity level of between 5 and 27%; [0059] continuously introducing a predetermined volume per minute of the wood fragments obtained, into a pressurized reactor, the reactor being fed with substantially saturated water vapor, the pressure of which is between 10 and 25 bar, and the temperature of which is between 180° C. and 220° C.; [0060] exposing wood fragments, introduced into the reactor, to the water vapor for a period sufficient to achieve steam-cracking of between 5 and 30 minutes, the value of the exposure period and the value of the temperature of the substantially saturated vapor being selected such that the severity factor is between 3 and 5, preferably between 3.5 and 4; [0061] continuously extracting, from the reactor, the same predetermined volume of wood fragments per minute, through a plurality of openings leading into a channel that is substantially at atmospheric pressure, so as to bring about explosive decompression of the wood fragments extracted from the reactor in the channel; [0062] separating the steam-cracked powder and the residual vapor extracted from the reactor, the steam-cracked wood powder obtained following separation forming the pulverulent substrate.