A wood-derived carbohydrate composition and the use thereof

Abstract

Disclosed is a wood-derived carbohydrate composition, wherein - the carbohydrate composition comprises at least 30 weight-% of carbohydrates based on the total dry matter content of the carbohydrate composition, and wherein 5 – 80 weight-% of the carbohydrates are oligosaccharides; and - the carbohydrate composition comprises protein in a total amount of 2 – 15 weight-% based on the total dry matter content of the carbohydrate composition. Further is disclosed the use of the wood-derived carbohydrate composition and an animal feed additive.

Description

[0001] A WOOD-DERIVED CARBOHYDRATE COMPOSITION AND THE USE

[0002] THEREOF

[0003] TECHNICAL FIELD

[0004] The present disclosure relates to a wood- derived carbohydrate composition . Further, the present disclosure relates to the use of the wood-derived carbohydrate composition . Further, the present disclosure relates to an animal feed additive .

[0005] BACKGROUND

[0006] Different methods are known for converting biobased raw material , such as lignocellulosic biomass , into a liquid stream of various sugars . Being able to provide sufficiently pure carbohydrate composition with properties suitable for different applications has still remained as a task for researchers .

[0007] SUMMARY

[0008] Disclosed is a wood-derived carbohydrate composition, wherein :

[0009] - the carbohydrate composition comprises at least 30 weight-% of carbohydrates based on the total dry matter content of the carbohydrate composition, and wherein 5 - 80 weight-% of the carbohydrates are oligosaccharides ; and the carbohydrate composition comprises protein in a total amount of 2 - 15 weight-% based on the total dry matter content of the carbohydrate composition .

[0010] Further is disclosed the use of the wood- derived carbohydrate composition as disclosed in the current specification for the production of ethanol , biogas , or animal feed additive . Further is disclosed an animal feed additive comprising or consisting of the wood-derived carbohydrate composition as disclosed in the current specification .

[0011] BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The accompanying drawings , which are included to provide a further understanding of the embodiments and constitutes a part of this specification, illustrate embodiments . In the drawing :

[0013] Fig . 1 presents a set-up of the improved s imulated moving bed chromatography ( I SMB) process used in example 1 , and

[0014] Figs . 2 and 3 present the test results from example 2 .

[0015] DETAILED DESCRIPTION

[0016] The present disclosure relates to a wood- derived carbohydrate composition, wherein :

[0017] - the carbohydrate composition comprises at least 30 weight-% of carbohydrates based on the total dry matter content of the carbohydrate composition, and wherein 5 - 80 weight-% of the carbohydrates are oligosaccharides ; and the carbohydrate composition comprises protein in a total amount of 2 - 15 weight-% based on the total dry matter content of the carbohydrate composition .

[0018] The present disclosure further relates to the use of the wood-derived carbohydrate composition as disclosed in the current specification for the production of ethanol , biogas , or animal feed additive .

[0019] The present disclosure further relates to an animal feed additive comprising or consisting of the wood-derived carbohydrate composition as disclosed in the current specification . The inventors surprisingly found out that the specific combination of carbohydrates together with protein enable the wood-based carbohydrate composition to be used as an animal feed additive . Oligosaccharides are components that may be easily digested by animals . Also , oligosaccharides may absorb slower into the blood during digestion than monosaccharides do , whereby the energy uptake from the carbohydrate composition as disclosed in the current disclosure is more even as the blood sugar level is not increased too fast after the intake of the carbohydrate composition .

[0020] The animal feed additive may e . g . be blended in or mixed with animal feed to be given to animal . The animal feed additive may be fed to e . g . piglets . In one embodiment , the animal feed additive is a piglet feed additive .

[0021] In one embodiment , the wood-derived carbohydrate composition is a liquid wood-derived carbohydrate composition . In one embodiment , the wood- derived carbohydrate composition is in liquid form .

[0022] The wood-derived carbohydrate composition, or the carbohydrate composition as also used in the current disclosure , as disclosed in the current specification relates to a composition that comprises carbohydrates but may also in addition comprise additional components and / or elements e . g . as disclosed in the current specification . Thus , the "wood-derived carbohydrate composition" may be considered as a "wood-derived carbohydrate-containing composition" or a "wood-derived composition comprising carbohydrates" .

[0023] The wood-derived carbohydrate composition may be prepared starting or derived from wood . In one embodiment , the wood-derived carbohydrate composition is a hardwood-derived carbohydrate composition . The wood-derived carbohydrate composition may be prepared starting from wood species such as beech, birch, ash, or their combination .

[0024] In one embodiment , the carbohydrate composition comprises 30 - 90 weight-% , or 35 - 80 weight-% , or 40 - 70 weight-% , of carbohydrates based on the total dry matter content of the carbohydrate composition . When used as an animal feed additive , the high amount of carbohydrates in the carbohydrate composition may be beneficial for the intake of energy . In addition, a high amount of carbohydrates is of relevance when producing ethanol or biogas as the carbohydrates are the reacting part of the composition in such a production process . The high amount of carbohydrates is of use during the fermentation process when producing ethanol as is the presence of nitrogen , both of which can be used by the fermenting microorganisms . Thus , the wood-derived carbohydrate composition has the added utility of being a low-cost raw material for ethanol production as well as for biogas production .

[0025] The amount of monomeric carbohydrates , such as the amount of monomeric C5 sugars and monomeric C6 sugars , may be determined both qualitatively and quantitatively by high-performance liquid chromatography (HPLC) by comparing to standard samples . Examples of analysis methods can be found in e . g . Sluiter, A . , et al . , "Determination of sugars , byproducts , and degradation products in liquid fraction process samples" , Technical Report , National Renewable Energy Laboratory, 2008 , and Sluiter, A . , et al . , "Determination of Structural Carbohydrates and Lignin in Biomass" , Technical Report , National Renewable Energy Laboratory, revised 2012 .

[0026] The amount of oligosaccharides may be determined with acid hydrolysis pretreatment and high- performance liquid chromatography (HPLC) analysis . In the pretreatment , a sample of the carbohydrate composition is contacted with 72 weight-% sulfuric acid and kept at 30 ° C temperature for 30 min . After this the same is put to an autoclave and kept there at a temperature of 121 ° C for 1 h . Thereafter, the amount of monosaccharides in the treated sample may be determined using the above HPLC method . Prior to the analysis of the monosaccharides , the acidic solution is neutrali zed with calcium carbonate (CaCCg ) and filtered . The amount of oligosaccharides in the original sample may be obtained by subtracting the amount of monosaccharides determined from the sample before the acid hydrolysis pretreatment from the amount of monosaccharides determined from the acid hydrolysis pretreated sample .

[0027] As used herein, any weight-percentages are given as percent of the total dry matter content of the carbohydrate composition unless specified otherwise . Similarly, other fractions of weight (ppm etc . ) may also denote a fraction of the total dry matter content of the carbohydrate composition unless specified otherwise .

[0028] By the expression "oligosaccharide" or that the sugar is "oligomeric" should be understood in this specification, unless otherwise stated, as referring to a sugar molecule consisting of two or more monomers coupled or connected to each other .

[0029] By the expression "monosaccharide" or that the sugar is "monomeric" should be understood in this specification, unless otherwise stated, as referring to a sugar molecule present as a monomer, i . e . not coupled or connected to any other sugar molecule ( s ) .

[0030] In the current specification the amounts of different components / elements in the wood-derived carbohydrate composition are presented in weight-% based on the total dry matter content of the carbohydrate composition . In this specification the term "total dry matter content of the carbohydrate composition" may refer to the weight of the carbohydrate composition as determined by allowing a sample of the carbohydrate composition to be absorbed on a glass fiber filter placed in an aluminium cup. The aluminium cup with the glass fiber filter is weighted before and after the sample has been absorbed. The sample in the aluminium cup is allowed to dry in an oven overnight at a temperature of 60 °C. Immediately after this, the dried sample absorbed in the glass fiber is weighted with the cup. Dry solids content is calculated from the difference in mass of the wet and dried samples. The expression "total dry matter content" may refer to the total amount of solids including suspended solids and soluble or dissolved solids .

[0031] As is clear to the skilled person, the total amount of the different components / elements in the wood- derived carbohydrate composition may not exceed 100 weight-%. The amount in weight-% of the different components / elements in the wood-derived carbohydrate composition may vary within the given ranges.

[0032] In one embodiment, 7.5 - 70 weight-%, or 10 - 60 weight-%, or 15 - 50, of the carbohydrates are oligosaccharides. In one embodiment, 15 - 80 weight-%, or 25 - 70 weight-%, or 35 - 60 weight-%, or 40 - 55 weight-%, of the carbohydrates are oligosaccharides. The high amount of oligosaccharides in the carbohydrate composition has the added utility of enhancing digestion when used as an animal feed additive.

[0033] In one embodiment, at least 60 weight-%, or at least 70 weight-%, or at least 80 weight-%, or at least 90 weight-%, of the carbohydrates are C6 sugars. By the expression "C6 sugars" should be understood in this specification, unless otherwise stated, as referring to glucose, galactose, mannose, fructose, or any mixture or combination thereof. The C6 sugars may be monomeric C6 sugars and / or oligomeric C6 sugars.

[0034] In one embodiment, at least 80 weight-%, or at least 85 weight-%, or at least 90 weight-%, of the C6 sugars are glucose . The glucose may be in monomeric glucose and / or oligomeric glucose .

[0035] In one embodiment , at least 85 weight-% , or at least 90 weight-% , or at least 95 weight-% , of the oligosaccharides are C6 oligosaccharides .

[0036] In one embodiment , the carbohydrate composition comprises protein in a total amount of 3 - 12 weight-% , or 4 - 10 weight-% , or 5 - 8 weight-% , based on the total dry matter content of the carbohydrate composition . The amount of protein present in the carbohydrate composition may evidence that enzymatic hydrolysis has been used during the production process of the carbohydrate composition . Enzymes are used during enzymatic hydrolysis from which the amount of protein may originate .

[0037] The amount of protein may be determined based on the total amount of nitrogen . The amount of protein may be obtained by multiplying the total amount of nitrogen with a factor of 6 . 25 . This factor is based on the commonly used literature value for the amount of nitrogen in protein, i . e . 16 % ( 100 % / 16 % = 6 . 25 ) . The total amount of nitrogen in a sample may be determined using a Total Organic Carbon / Total Nitrogen analyzer such as Shimadzu TOC-LCSH instrument equipped with TNM-L module according to standard method SFS-EN 12260 : 2003 . The sample is burned in the instrument furnace at a temperature of 720 °C in which nitrogen forms nitrogen monoxide . This reacts with ozone and forms nitrogen dioxide while excited to a higher energy state . Upon discharge of this excitation state , chemiluminescent radiation is generated, and it may be detected by a chemiluminescent detector .

[0038] The presence of protein in the carbohydrate composition has the added util ity of the composition being suitable to be used as an animal feed additive .

[0039] In one embodiment , the carbohydrate composition comprises soluble lignin in a total amount of 6 - 20 weight-%, or 8 - 18 weight-%, or 10 - 16 weight-%, based on the total dry matter content of the carbohydrate composition. The presence of soluble lignin in the carbohydrate composition may evidence that the carbohydrate composition is derived from wood. The presence of soluble lignin in the carbohydrate composition has the added utility of providing the carbohydrate composition with antioxidant properties when used e.g. as an animal feed additive. The presence of soluble lignin may thus improve the preservation of the carbohydrate composition.

[0040] The amount of soluble lignin may be determined by UV-VIS absorption spectroscopy in the following manner: The amount of soluble lignin present in the carbohydrate composition is determined by diluting a sample of carbohydrate composition so that its absorbance at 205 nm is 0.2 - 0.7 AU when compared to a reference sample of pure water and using a cuvette with a path length of 1 cm. The soluble lignin content of the sample in mg / 1 may then be calculated using the following equation where

[0041] A is absorbance of the sample, a is the absorptivity coefficient 0.110 1 / mgcm, and D is a dilution factor.

[0042] In one embodiment, the carbohydrate composition comprises sulphur in a total amount of 0.05 - 1.0 weight-%, or 0.1 - 0.6 weight-%, or 0.2 - 0.4 weight-%, based on the total dry matter content of the carbohydrate composition. The amount of sulphur may be determined according to standard SFS-EN ISO 11885 (2009) .

[0043] In one embodiment, the conductivity of a 30 % aqueous solution of the carbohydrate composition is 1 - 5 mS / cm, or 2 - 3.5 mS / cm, when determined according to SFS-EN 27888. The conductivity of the carbohydrate composition correlates with the amount of sodium present in the carbohydrate composition. The low conductivity of the carbohydrate composition may thus indicate that the carbohydrate composition comprises only a small amount of salts. A higher amount of salts could be harmful e.g. when using the carbohydrate composition for fermentation during ethanol production.

[0044] In one embodiment, the ICUMSA color value of an aqueous solution of the carbohydrate composition is 100000 - 300000 IU, or 125000 - 250000 IU, or 150000 - 200000 IU. In one embodiment, the ICUMSA color value of an aqueous solution of the carbohydrate composition is 100000 - 300000 IU, or 125000 - 250000 IU, or 150000 - 200000 IU, when measured using a modified ICUMSA GS1 method without adjusting the pH of the sample to be analyzed and filtering the sample through a 0.45 pm filter before analysis. The ICUMSA color value may be used as an indication about the amount of soluble lignin present in the carbohydrate composition. The ICUMSA color value correlates with the color of the carbohydrate composition.

[0045] In one embodiment, the pH of the carbohydrate composition is 4 - 7, or 4.5 - 6.5, or 5 - 6.

[0046] In one embodiment, the carbohydrate composition comprises ash in a total amount of 7.5 - 35 weight-%, or 10 - 30 weight-%, or 15 - 25 weight-%, based on the total dry matter content of the carbohydrate composition. The amount of ash may be determined as follows: 1-2 g of sample is placed on an annealed crucible and weighted. The sample in the crucible is then dried in an oven at 105 °C temperature for overnight. Weight of the dried sample is then determined. The dried sample in the crucible is then placed into an oven at 525 °C temperature for at least 5 h (3 h heating period, 2 h constant temperature period) . The sample in the crucible is then placed into a desiccator for cooling. If the sample was not completely turned to ash (e.g. black particles can be seen in the ash) , 1-2 ml hydrogen peroxide (30 %) is dropped on the cooled sample. The sample is then put to oven at 525 °C temperature for 30 min. Cooling of the samples in the crucible is done in a desiccator. This treatment is repeated until the ash in crucible has a pale color (e.g. no black particles can be seen) . The ash content can be calculated from mass of ash in the crucible, g

[0047] Ash content (%) = mass of dried sample, g

[0048] In one embodiment, the carbohydrate composition comprises sodium in a total amount of 14 - 60 g / kg, or 16 - 45 g / kg, or 18 - 30 g / kg, or 20 - 25 g / kg, based on the total dry matter content of the carbohydrate composition. The amount of sodium may be determined analyzed using inductively coupled plasma- optical emission spectroscopy (ICP-OES) according to standard SFS-EN ISO 11885:2009. The amount of sodium of the carbohydrate composition is on a suitable level for fermentation purposes during ethanol production. A too high amount of sodium may be of harm for fermentation.

[0049] Organic acids may be mentioned as examples of organic impurities that may be present in the carbohydrate composition. In one embodiment, the carbohydrate composition comprises organic acids in a total amount of 0.1 - 8 weight-%, or 0.2 - 6 weight-%, or 0.3 - 4 weight-%, or 0.4- 2 weight-%, based on the total dry matter content of the carbohydrate composition. Non-limiting examples of organic impurities are oxalic acid, citric acid, succinic acid, formic acid, acetic acid, levulinic acid, 2-furoic acid, 5-hydroxymethylfurfural (5-HMF) , furfural, glycolaldehyde, glyceraldehyde, as well as various acetates, formiates, and other salts or esters. The quality and quantity of organic impurities in the carbohydrate composition may be determined using e.g. a HPLC coupled with e.g. a suitable detector, infrared (IR) spectroscopy, ultraviolet-visible (UV-VIS) spectroscopy, or nuclear magnetic resonance (NMR) spectrometry .

[0050] In one embodiment, the carbohydrate composition comprises uronic acids in an amount of 0.2 - 4 weight-%, or 0.5 - 3 weight-%, or 1.0 - 2.5 weightin one embodiment, the carbohydrate composition comprises 5-HMF in an amount of 0 - 1 weight- %, or 0.05 - 0.2 weight-%.

[0051] One example of providing the wood-based carbohydrate composition as disclosed in the current specification may include the following:

[0052] Firstly, a feedstock of wood chips, such as hardwood chips, softwood chips, or a combination thereof, may be subjected to a pretreatment. The pretreatment may comprise pre-steaming of a wood-based feedstock with steam having a temperature of 100 - 130 °C at atmospheric pressure. The pretreatment may further comprise subjecting the wood-based feedstock to at least one impregnation treatment with impregnation liquid to form an impregnated wood-based feedstock. The impregnation liquid may comprise water, at least one acid, at least one alkali, at least one alcohol, or any combination or mixture thereof. The at least one acid may be selected from a group consisting of inorganic acids, such as sulphuric acid (H2SO4) , nitric acid, phosphoric acid; organic acids, such as acetic acid, lactic acid, formic acid, carbonic acid; and any combination or mixture thereof. In one embodiment, the impregnation liquid comprises sulphuric acid, e.g. dilute sulphuric acid. The concentration of the acid may be 0.3 - 5.0 % w / w, 0.5 - 3.0 % w / w, 0.6 - 2.5 % w / w, 0.7 - 1.9 % w / w, or 1.0 - 1.6 % w / w. The impregnation liquid may act as a catalyst in affecting the hydrolysis of the hemicellulose in the wood-based feedstock. The impregnation treatment may be carried out at a temperature of 20 - 99 °C for 5 seconds - 60 minutes, or 0.5 - 45 minutes, or 1 - 30 minutes. A higher impregnation time has the added utility of increasing the conversion during the steam explosion treatment making the hemihydrolysis efficient .

[0053] The impregnated feedstock may then be subjected to steam explosion treatment. The steam explosion treatment may be carried out by treating the impregnated wood-based feedstock with steam having a temperature of 130 - 240 °C, or 180 - 200 °C, or 185 - 195 °C under a pressure of 0.17 - 3.25 MPaG followed by a sudden, explosive decompression of the feedstock. The feedstock may be treated with the steam for 1 - 20 minutes, or 1 - 18 minutes, or 2 - 15 minutes, or 4 - 13 minutes, or 3 - 10 minutes, or 3 - 8 minutes, before the sudden, explosive decompression of the steam-treated feedstock. As a result of the hemihydrolysis of the feedstock affected by the steam explosion treatment, the hemicellulose present in the wood chips of feedstock may become hydrolyzed or degraded into e.g. xylose oligomers and / or monomers. The hemicellulose comprises polysaccharides such as xylan, mannan and glucan. Xylan is thus hydrolyzed into xylose that is a monosaccharide.

[0054] In one embodiment, the amount of sulphuric acid in the steam explosion treatment may be 0.10 - 0.75 weight-% based on the total dry matter content of the wood-based feedstock. The amount of acid present in the steam explosion treatment may be determined by measuring the sulphur content of the liquid of the steam-treated wood-based feedstock or the liquid part of the steam- treated wood-based feedstock after steam explosion treatment. The amount of sulphuric acid in the steam explosion reactor may be determined by subtracting the amount of sulphur in the wood-based feedstock from the measured amount of total sulphur in the steam-treated wood-based feedstock .

[0055] Thus , steam explosion of the feedstock may result in the formation of an output stream . The output stream from the steam explosion may be subj ected to steam separation . The output stream from the steam explosion may be mixed or combined with a liquid, e . g . water, to form a slurry . The slurry may comprise a liquid phase and a solid phase . The slurry may be separated into a liquid fraction and a fraction compri sing solid cellulose particles . The liquid fraction may then be subj ected to concentration, e . g . by evaporation, and, if neces sary, the pH of the liquid fraction may be adj usted to 5 . 5 - 6 , e . g . with sodium hydroxide (NaOH) or potassium hydroxide (KOH) , to provide a crude liquid fraction . The separated crude liquid fraction may thus comprise 05 sugars from hydrolyzed hemicellulose as well as soluble lignin and other by-products .

[0056] The fraction comprising solid cellulose particles may have a total dry matter content of 15 - 50 weight-% . The fraction comprising solid cellulose particles may, in addition to cellulose , comprise lignin . As the 05 sugars are efficiently removed with the crude liquid fraction, the fraction comprising solid cellulose particles may comprise carbohydrates such as solid 06 sugars . The fraction comprising solid cellulose particles may also comprise other carbohydrates and other components . The fraction comprising solid cellulose particles may also comprise some amount of 05 sugars .

[0057] The separated and recovered fraction comprising solid cellulose particles may be further purified or washed before being subj ected to enzymatic hydrolysis . The separated fraction comprising solid cellulose particles may be di luted to a total dry matter content of 8 - 22 weight-% , or 10 - 20 weight-% , or 12 - 18 weight-% . Then the separated fraction comprising solid cellulose particles may be subjected to enzymatic hydrolysis to form a hydrolysis product. The enzymatic hydrolysis may be carried out at a temperature of 30 - 70 °C, or 35 - 65 °C, or 40 - 60 °C, or 42 - 59 °C, or 45 - 58 °C, or 47 - 57 °C, at atmospheric pressure for 20 - 120 h, or 30 - 90 h, or 40 - 80 h. The pH of the fraction comprising solid cellulose particles may be kept at a pH value of 3.5 - 6.5, or 4.0 - 6.0, or 4.5 - 5.5. Enzymes are catalysts for the enzymatic hydrolysis. At least one enzyme may be used for carrying out the enzymatic hydrolysis. The at least one enzyme may be selected from a group consisting of cellulases, hemicellulases, laccases, lytic polysaccharide monooxygenases (LPMO) , and lignolytic peroxidases. Cellulases are multi-protein complexes consisting of synergistic enzymes with different specific activities that can be divided into exo- and endo-cellulases (glucanase) and [3-glucosidase (cellobiose) . The enzymes may be either commercially available cellulase mixes or on-site manufactured .

[0058] The enzymatic reaction decreases the pH and by shortening the length of the cellulose fibers it may also decrease the viscosity. Subjecting the fraction comprising solid cellulose particles to enzymatic hydrolysis may result in cellulose being transformed into glucose monomers with enzymes. Lignin present in the fraction comprising solid cellulose particles may remain essentially in solid form.

[0059] Enzymatic hydrolysis may result in the formation of hydrolysis product. The hydrolysis product may be separated into a solid fraction comprising lignin and a liquid carbohydrate fraction e.g. by a solid-liquid separation process to recover the liquid carbohydrate fraction .

[0060] The liquid carbohydrate fraction may be concentrated and / or the pH thereof may be adjusted. The concentrated liquid carbohydrate fraction may have a total dry matter content of 40 - 60 weight-% , or 45 - 55 weight-% . The pH of the liquid carbohydrate fraction may be in range of 5 . 5 - 6 .

[0061] The liquid carbohydrate fraction may then be subj ected to chromatographic treatment . A strong acid cation exchange ( SAC) resin may be used as a separation material . The SAC resin is a bead-like product , which has a sulfonic acid group in a cross-linked styrene frame . The resin may be in Na+form or in K+ form . The form of the resin may depend on the alkaline chemical (NaOH or KOH) used when adj usting the pH of the liquid carbohydrate fraction .

[0062] In one embodiment , the strong acid cation-ex- change resin is in the Na+form . The strong acid cationexchange resin in the Na+form may have a polystyrene structure where to divinyl benzene groups are crosslinked . The average particle si ze may be about 280 pm .

[0063] The cut-points for the fractionation of the target liquid carbohydrate composition fraction ( i . e . the wood-derived carbohydrate composition as disclosed in the current specification) using chromatographic separation can be determined from lignin yield determined based on the elution profiles obtained with a single column batchwise chromatography process . The production of wood-derived carbohydrate composition can be carried out using a simulated moving bed ( SMB) chromatography, or with any variation of simulated moving bed chromatography with water as elution solution . Improved simulated moving bed chromatography ( I SMB) and sequential simulated moving bed chromatography ( SSMB) may be mentioned as examples of such variations . The flow rate through columns may be 1-4 bed volumes per hour . The chromatographic treatment may be carried out in a single step, i . e . the liquid carbohydrate fraction is subj ected to the chromatographic treatment one time . After the chromatographic treatment , the wood- derived carbohydrate composition may be evaporated to a predetermined dry matter content .

[0064] The wood-derived carbohydrate composition has the added utility of comprising a high amount of oligosaccharides together with high amount of protein . The wood-based carbohydrate composition may thus find added utility in being usable as an animal feed additive .

[0065] The wood-derived carbohydrate composition has the added utility of being an easy-to-use liquid composition having a high concentration of carbohydrates and especially oligosaccharides . The high concentration of carbohydrates present in the composition increases the preservation of the carbohydrate composition resulting from the carbohydrates sucking up moisture from the composition whereby the preservability of the carbohydrate composition is increased . The wood-derived carbohydrate composition may thus not serve as a growth medium for harmful micro-organisms .

[0066] The wood-derived carbohydrate composition has the added utility of being a liquid composition that may be easy to process and transport . The wood-derived carbohydrate composition may be e . g . pumped from one tank to another and i s also easy to measure out for further use .

[0067] The wood-derived carbohydrate composition has the further added utility of not crystalli zing, not even when being stored in a freezer .

[0068] Further, the wood-derived carbohydrate composition has a pleasant odour .

[0069] EXAMPLES

[0070] Reference will now be made in detail to the embodiments of the present disclosure , an example of which is illustrated in the accompanying drawing .

[0071] The description below discloses some embodiments in such a detail that a person skilled in the art is able to utilize the wood-derived carbohydrate composition based on the disclosure. Not all steps of the embodiments are discussed in detail, as many of the steps will be obvious for the person skilled in the art based on this disclosure.

[0072] Example 1 - Producing a wood-derived carbohydrate composition

[0073] In this example, a liquid carbohydrate fraction was provided as described above in the current disclosure. The liquid carbohydrate fraction had the following properties (see also table 1 below) : total dry matter content: 49.6 weight-% soluble lignin content: 1.6 weight-%

[0074] ICUMSA color value: 28 000 IU (pH 5.8)

[0075] The provided liquid carbohydrate fraction was subjected to chromatographic treatment. A four column ISMB (Improved Simulated Moving Bed) chromatographic process was used. The unit consisted of four columns where each had a volume of 5.34 1. The feed and eluent flowrates were 2 bed volumes per hour. One cycle of the ISMB process consisted of four steps (1-4) between which the inlet and outlet points from the process were shifted in the direction of the liquid flow (simulation of the counter current movement of the liquid and separation material) . Each of the steps were divided into four sub-steps A-D as is presented in Fig 1. The target liquid carbohydrate composition fraction, i.e. the wood-derived carbohydrate composition to be obtained, was produced with the following sub-step durations: A = 183 s; B = 274 s; C = 183 s; D = 654 s. Thus, the total cycle time of the ISMB process was 86 min 16 s. The formed wood-derived carbohydrate composition (indicated as "product" in Fig. 1) was collected in sub-steps A and C while a by-product was collected in sub-step B. The results are presented in the below table 1. The wood-derived carbohydrate composition was evaporated to a dry matter content of 65.7 weight-%.

[0076] Table 1. Composition of the liquid carbohydrate fraction (indicated as "feed" in Fig. 1) and the wood-derived carbohydrate composition (indicated as "product" in Fig. 1)

[0077]

[0078] From the above results one can see that a carbohydrate composition with a high amount of oligosaccharides and protein may be obtained, while simultaneously exhibiting properties such as a soluble lignin content that beneficially affects the use of the carbohydrate composition as an animal feed additive .

[0079] Example 2 - Testing the effects of the wood-derived carbohydrate composition as an animal feed additive

[0080] In this example the performance of the wood- derived carbohydrate composition produced in example 1 as an animal feed additive was tested with weaning piglets in an in vitro study .

[0081] The effect of the wood-derived carbohydrate composition was compared to a positive control ( inulin) and to a negative control (glucose ) in a piglet faecal ecosystem around weaning . For the in vitro trial , 135 bottles were prepared under anaerobic conditions . Eight treatments were tested in triplicate , and three bottles of each treatment were opened at 5 different times : 0 h (before incubation) , 6 h, 12 h, 24 h, and 48 h after incubation . Each bottle contained :

[0082] 40 ml of dilution medium, - 10 ml of faecal inoculum (i.e. 0.014 g fresh feces per ml in the bottle) ,

[0083] - 0 or 1.00 g of substrate,

[0084] - no additive to be tested or one of the three products to be tested: wood-derived carbohydrate composition (marked as "GOS" in Fig. 2 and Fig. 3) , inulin (positive control) , and glucose (negative control) .

[0085] Alfalfa was used as the substrate as its biochemical composition is close to that of the piglet large intestine content in terms of fibre and protein.

[0086] The three products to be tested were diluted in deionised water to facilitate their addition to the bottles. 50 mg of the wood-derived carbohydrate composition and inulin were added to each bottle. This amount corresponded to 5 % of the substrate. The amount of glucose added (14.4 mg) in the control bottles was calculated on the basis of the monomeric glucose content of the wood-derived carbohydrate composition.

[0087] After the addition of inoculum, substrate, and products to be tested, all bottles were immediately placed in a shaking water bath at 38°C for 48 hours.

[0088] Gas production was recorded in the headspace of all bottles using a pressure transducer according to the method described by Theodorou, M. K. , Williams, B. A., Dhanoa, M. S., McAllan, A. B., & France, J. (1994) . A simple gas production method using a pressure transducer to determine the fermentation kinetics of ruminant feeds. Animal feed science and technology, 48 (3-4) , 185- 197.

[0089] The concentrations of volatile fatty acids (VFAs) were measured on the liquid fraction from each opened bottle by gas chromatography.

[0090] Without substrate addition, fermentation continued over the first 18 h after which the gas production practically stopped (see Fig. 2) . Higher fermentation efficiency was observed in the bottles containing the wood-derived carbohydrate composition compared to the glucose control . This was expected as the 50 mg of wood- derived carbohydrate composition added to the bottles contained not only 14 . 4 mg of glucose , but also other fermentable compounds ( carbohydrates and proteins ) . On the contrary, less gas was produced with the wood-derived carbohydrate composition than with inulin . This indicated that the 50 mg of inulin was more fermentable than the 50 mg of the wood-derived carbohydrate composition which also contained non-f ermentable compounds ( ash, soluble lignin, etc . ) . The higher fermentations with inulin were consistent with the higher VFA concentrations measured, which support a more important fermentation of carbohydrates .

[0091] Same trends were observed with the Alfalfa substrate in the fermentation mixture as without the substrate ( see Fig . 2 ) . I . e . a higher gas production with inulin than with the wood-derived carbohydrate composition and then than with glucose . However, with the substrate , the gas formation was notably stronger than without the substrate .

[0092] Acetate , propionate and butyrate were the most abundant VFAs measured in the supernatant , accounting for an average of 99 . 7 ± 0 . 3% of the total VFAs ( see Fig . 3 ) . I so-butyrate , valerate and iso-valerate were consistently close to the detection limit . Very few significant differences in VFA concentrations in the bottles were observed throughout the fermentation process . Acetate and total VFA concentrations were never significantly different between treatments during the 48 hours follow-up . After 12 hours of fermentation, propionate and butyrate concentrations were higher in bottles with inulin than in bottles without product , and after 48 hours of fermentation, butyrate concentrations were higher in bottles with inulin than in controls . The fermentation trials showed clearly that the wood-derived carbohydrate composition is well fermented by the faecal microbiota of the piglet at weaning . The wood-derived carbohydrate composition resulted in less fermentation and therefore lower amount of VFAs than inulin ( see Fig . 3 ) . This may be more favorable for the colonic microbial ecosystem, as too much fermentation can generate acidity, which is detrimental to the functioning of the ecosystem .

[0093] It is obvious to a person skil led in the art that with the advancement of technology, the basic idea may be implemented in various ways . The embodiments are thus not limited to the examples described above ; instead they may vary within the scope of the claims .

[0094] The embodiments described hereinbefore may be used in any combination with each other . Several of the embodiments may be combined together to form a further embodiment . A wood-derived carbohydrate composition, a use , or an animal feed additive may comprise at least one of the embodiments described hereinbefore . It will be understood that the benefits and advantages described above may relate to one embodiment or may relate to several embodiments . The embodiments are not limited to those that solve any or all of the stated problems or those that have any or all of the stated benefits and advantages . It will further be understood that reference to ' an ' item refers to one or more of those items . The term "comprising" is used in this specification to mean including the feature ( s ) or act ( s ) followed thereafter, without excluding the presence of one or more additional features or acts .

Claims

CLAIMS1. A wood-derived carbohydrate composition, wherein :- the carbohydrate composition comprises at least 30 weight-% of carbohydrates based on the total dry matter content of the carbohydrate composition, and wherein 5 - 80 weight-% of the carbohydrates are oligosaccharides; and the carbohydrate composition comprises protein in a total amount of 2 - 15 weight-% based on the total dry matter content of the carbohydrate composition .

2. The wood-derived carbohydrate composition of claim 1, wherein the carbohydrate composition comprises 30 - 90 weight-%, or 35 - 80 weight-%, or 40 - 70 weight-%, of carbohydrates based on the total dry matter content of the carbohydrate composition.

3. The wood-derived carbohydrate composition of any one of the preceding claims, wherein 7.5 - 70 weight-%, or 10 - 60 weight-%, or 15 - 50 weight-%, of the carbohydrates are oligosaccharides.

4. The wood-derived carbohydrate composition of any one of the preceding claims, wherein at least 60 weight-%, or at least 70 weight-%, or at least 80 weight- % , or at least 90 weight-%, of the carbohydrates are C6 sugars .

5. The wood-derived carbohydrate composition of claim 4, wherein at least 80 weight-%, or at least 85 weight-%, or at least 90 weight-%, of the C6 sugars are glucose.

6. The wood-derived carbohydrate composition of any one of the preceding claims, wherein at least 85 weight-%, or at least 90 weight-%, or at least 95 weight- % , of the oligosaccharides are C6 oligosaccharides.

7. The wood-derived carbohydrate composition of any one of the preceding claims, wherein the carbohydrate composition comprises protein in a totalamount of 3 - 12 weight-%, or 4 - 10 weight-%, or 5 - 8 weight-%, based on the total dry matter content of the carbohydrate composition.

8. The wood-derived carbohydrate composition of any one of the preceding claims, wherein the carbohydrate composition comprises soluble lignin in a total amount of 6 - 20 weight-%, or 8 - 18 weight-%, or 10 - 16 weight-%, based on the total dry matter content of the carbohydrate composition.

9. The wood-derived carbohydrate composition of any one of the preceding claims, wherein the carbohydrate composition comprises sulphur in a total amount of 0.05 - 1.0 weight-%, or 0.1 - 0.6 weight-%, or 0.2 - 0.4 weight-%, based on the total dry matter content of the carbohydrate composition.

10. The wood-derived carbohydrate composition of any one of the preceding claims, wherein the conductivity of a 30 % aqueous solution of the carbohydrate composition is 1 - 5 mS / cm, or 2 - 3.5 mS / cm, when determined according to SFS-EN 27888.

11. The wood-derived carbohydrate composition of any one of the preceding claims, wherein the ICUMSA color value of an aqueous solution of the carbohydrate composition is 100000 - 300000 IU, or 125000 - 250000 IU, or 150000 - 200000 IU.

12. The wood-derived carbohydrate composition of any one of the preceding claims, wherein the pH of the carbohydrate composition is 4 - 7, or 4.5 - 6.5, or 5 - 6.

13. The use of the wood-derived carbohydrate composition of any one of claims 1 - 12 for the production of ethanol, biogas, or animal feed additive.

14. Animal feed additive comprising or consisting of the wood-derived carbohydrate composition of any one of claims 1 - 12.

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