A feed additive and a method for preparing a feed additive

Abstract

According to an example aspect of the present invention, there is provided a feed additive obtainable by a method comprising the steps of: providing a soluble lignin-containing organic solution; providing an aqueous precipitant solution comprising about wt-% to about 40 wt-% of acid(s); adding the aqueous precipitant solution to the soluble lignin-containing organic solution to provide a mixture having a temperature in the range of about 40°C to about 90°C; cooling the mixture containing a precipitated lignin product for about 2 sec to about 2 hours; separating and recovering the precipitated lignin product from the mixture; collecting the resulting mixture as a feed additive.

Description

A FEED ADDITIVE AND A METHOD FOR PREPARING A FEED ADDITIVEFIELD

[0001] The present invention belongs to the technical field of animal nutrition. More specifically, the present invention belongs to the field of feed additive compositions for improving storability and microbial quality of feed.BACKGROUND

[0002] Microbial toxins are common in silage feed when no preservative is used. Improving the storability of silage feed is typically based on the activity of beneficial lactic acid bacteria, naturally present in silage in anaerobic conditions. The presence of lactic acid reduces pH, which inhibits the growth of aerobic microbes, such as yeasts, enterobacteria and molds, which causes spoilage in silage.

[0003] Quality of animal feed has impact on animal health, as pathogens cause illness, in particular in monogastric animals (pigs, poultry). The excessive use of antibiotics is causing globally antibiotic resistance, which is why the use of antibiotics is heavily regulated. In addition, EU is in the near future going to ban to use of zinc due to its harmful effect to the environment. Thus, new feed ingredients with antimicrobial qualities are needed to help reducing usage of antibiotics, while also having beneficial (probiotic or prebiotic) effects on animal metabolism.

[0004] Current strategies to reduce antibiotics in animal feed include addition of probiotics or prebiotics to feed (Anadon, 2019). Such additives include for example different types of probiotics, prebiotics, organic acids, plant extracts, fatty acids and immunostimulants. An effect has however been shown only for some of these strategies.

[0005] Other additives that are used in maintaining growth of lactic acid bacteria in animal feed include added lactic acid bacteria, enzymes, sodium nitrite, sodium benzoate and potassium sorbate. Some of these additives can further be used to slow or inhibit the growth of pathogens. Current strategies for improving aerobic stability of the feed include adding lactic acid bacteria, propionic acid salts, sodium benzoate, potassium sorbate orsodium nitrite into feed. The mode of action of these strategies is to inhibit growth of yeasts and moulds.

[0006] As is obvious from above, a variety of strategies are in use for improving storability and microbial quality of feed. Yet, there is a high demand for new, efficient methods. Especially methods that can provide simultaneous effects on aerobic stability and microbial quality of feed are of high importance.SUMMARY OF THE INVENTION

[0007] The invention is defined by the features of the independent claims. Some specific embodiments are defined in the dependent claims. The present invention is meant to mitigate / minimize the problems of the solutions described in the prior art and / or to improve storability and microbial quality of the feed

[0008] According to a first aspect of the present disclosure, there is provided a feed additive obtainable by the method comprising the steps of:- providing a soluble lignin-containing organic solution,- providing an aqueous precipitant solution comprising about 5 wt-% to about 40 wt-% of acid(s),- adding the aqueous precipitant solution to the soluble lignin-containing organic solution to provide a mixture having a temperature in the range of about 40°C to about 90°C,- cooling the mixture containing a precipitated lignin product for about 2 sec to about 2 hours,- separating and recovering the precipitated lignin product from the mixture,- collecting the resulting mixture as a feed additive.

[0009] According to a second aspect of the present disclosure, there is provided a feed additive comprising spent cooking liquor from an organosolv pulping process of a lignocellulosic material from which lignin has been precipitated by addition of 5 to 40 wt- % of at least one acid.

[0010] According to a third as aspect of the present disclosure, there is provided use of the feed additive according to the first or the second aspect of the disclosure for preserving feed.

[0011] According to a fourth aspect of the present disclosure, there is provided there is provided use of the feed additive according to the first or the second aspect of the disclosure as a feed supplement.

[0012] According to a fifth aspect of the present disclosure, there is provided a method for producing a feed additive, comprising the steps of:- providing a soluble lignin-containing organic solution,- providing an aqueous precipitant solution comprising about 5 wt-% to about 40 wt-% of acid(s),- adding the aqueous precipitant solution to the soluble lignin-containing organic solution to provide a mixture having a temperature in the range of about 40°C to about 90°C,- cooling the mixture containing a precipitated lignin product for about 2 sec to about 2 hours,- separating and recovering the precipitated lignin product from the mixture,- collecting the resulting mixture as a feed additive.

[0013] The present invention is thus based on separating lignocellulosic raw material into an acidic fraction comprising lignin-derived compounds and saccharides and into an insoluble fraction. The acidic fraction has been found to increase storability and microbial quality of feed. Further, such fraction may serve as a prebiotic for modulating animal gut microbiota.

[0014] Advantages of the invention

[0015] An advantage of the present invention is that it provides a new feed additive which can be used as a preservative.

[0016] Another advantage of the invention is that it provides a new feed additive which has prebiotic activities.

[0017] Another advantage of the present inventions is that it may reduce the cost of feed by providing a less expensive alternative for preserving feed.

[0018] Another advantage of the present inventions is that the feed additive is non- corrosive at temperatures in which it is used.

[0019] Another advantage of the present invention is that the feed additive may be used for modulating rumen fermentation.

[0020] Another advantage of the present inventions is that the feed additive may comprise less acids, for example formic acid, than other comparable commercial compositions, such as AIV solution used for producing AIV fodder.

[0021] Considerable advantages are obtained by the means of the invention. The inventors have found that the feed additive (which may be referred to also with the term “acidic sugar liquor” in the present context) as disclosed herein, is able to maintain anaerobic stability of opened silage containers. This effect can be achieved despite the fact that the feed additive may contain less formic acid than the conventional AIV silage additive. Formic acid is typically used for preserving feed because it is able to quickly reduce the pH of the feed and thus inhibits growth of at least some microbes. It appears that the components present in the feed additive of the present disclosure have additional and / or a synergistic effects with formic acid that allow reducing the total amount of formic acid while still being effective in preserving food. Without wishing to be bound by theory, we hypothesize that one possible source for the observed additional / synergistic impacts is the presence of lignin-derived phenolic compounds and / or hemicellulosic sugars in the feed additive.

[0022] The feed additive of the present disclosure thus may provide a combination of improved aerobic stability, selective bactericidal effect and probiotic effect that improves simultaneously both the storability of the feed and the microbial quality of the feed.

[0023] Further, the feed additive of the present disclosure has been observed at least in some embodiments to be beneficial to animal gut microbiome composition. For example, the amount of harmful microbes may be reduced.BRIEF DESCRIPTION OF THE DRAWINGS

[0024] FIGURE 1 present the number of lactic acid bacteria in broth feed samples (y-axis = cfu / g).

[0025] FIGURE 2 presents the number of yeasts in broth feed samples (y-axis = cfu / g).

[0026] FIGURE 3 presents the number of molds in broth feed samples (y-axis = cfu / g).

[0027] FIGURE 4 presents the pH of broth feed samples.

[0028] FIGURE 5 presents cumulative gas production in crop samples during 6 hours. Grade A, 0.1 % of DM is ASLI of table 11, Grade A, 0.5 % of DM is ASL2 of table 11, Grade A, 1.0 % of DM is ASL3 of table 11, Grade A, 5.0 % of DM is ASL4 of table 11. BMD = bacitracin methylene disalicylate which is used as positive control. The error bars indicate standard deviation between the replicate simulation vessels and asterisks the statistical difference to the unamended Negative control by Student’s t-test.

[0029] FIGURE 6 presents the pH of crop samples after six-hour fermentation. Grade A, 0.1 % of DM is ASLI of table 11, Grade A, 0.5 % of DM is ASL2 of table 11, Grade A, 1.0 % of DM is ASL3 of table 11, Grade A, 5.0 % of DM is ASL4 of table 11. BMD = bacitracin methylene disalicylate which is used as positive control. The error bars indicate standard deviation between the replicate simulation vessels and asterisks the statistical difference to the unamended Negative control by Student’s t-test.

[0030] FIGURE 7 presents acid concentrations in crop samples after six-hour fermentation. A presents concentration of lactic acid, B presents concentration of acetic acid and C presents concentration of short-chain fatty acids. Grade A, 0.1 % of DM is ASLI of table 11, Grade A, 0.5 % of DM is ASL2 of table 11, Grade A, 1.0 % of DM is ASL3 of table 11, Grade A, 5.0 % of DM is ASL4 of table 11. BMD = bacitracin methylene disalicylate which is used as positive control. The error bars indicate standarddeviation between the replicate simulation vessels and asterisks the statistical difference to the unamended Negative control by Student’s t-test.

[0031] FIGURE 8 presents cumulative gas production in ileum samples. Grade A, 0.5 mg / mL is ASLI of table 11, Grade A, 2.5 mg / mL is ASL2 of table 11, Grade A, 5.0 mg / mL is ASL3 of table 11, Grade A, 10 mg / mL is ASL4 of table 11. BMD = bacitracin methylene disalicylate which is used as positive control. The error bars indicate standard deviation between the replicate simulation vessels and asterisks the statistical difference to the unamended Negative control by Student’s t-test.

[0032] EIGURE 9 presents the pH of ileum samples after six-hour fermentation. Grade A, 0.5 mg / mL is ASLI of table 11, Grade A, 2.5 mg / mL is ASL2 of table 11, Grade A, 5.0 mg / mL is ASL3 of table 11, Grade A, 10 mg / mL is ASL4 of table 11. BMD = bacitracin methylene disalicylate which is used as positive control. The error bars indicate standard deviation between the replicate simulation vessels and asterisks the statistical difference to the unamended Negative control by Student’s t-test.

[0033] EIGURE 10 presents acid concentrations in ileum samples after six-hour fermentation. A presents concentration of lactic acid, B presents concentration of acetic acid and C presents concentration of short-chain fatty acids. Grade A, 0.5 mg / mL is ASLI of table 11, Grade A, 2.5 mg / mL is ASL2 of table 11, Grade A, 5.0 mg / mL is ASL3 of table 11, Grade A, 10 mg / mL is ASL4 of table 11. BMD = bacitracin methylene disalicylate which is used as positive control. The error bars indicate standard deviation between the replicate simulation vessels and asterisks the statistical difference to the unamended Negative control by Student’s t-test.EMBODIMENTS

[0034] In the present context, the term “lignocellulosic” comprises materials containing both cellulose and lignin. Lignin is generally understood as a heterogenous macromolecule of plant origin. Lignin may be generally defined as an amorphous three- dimensional polymer, which is mainly and naturally composed of phenolic building blocks. The exact chemical composition of lignin varies from species to species. Traditionally lignin is considered to be formed from oxidative coupling of p-coumaryl alcohol, conifer alcohol and sinapyl alcohol.

[0035] As used herein, the term “lignin-derived compounds” may refer to any compound of smaller molecular weight than the natural lignin polymer, including small molecules, i.e. low molecular weight compounds, and that has been obtained from lignin through breakage of chemical bonds. These compounds may be produced through lignin degradation. In the context of the present application, lignin degradation to lignin-derived compounds is obtained through degradation of lignin by organic acids, such as formic acid and / or acetic acid. Lignin-derived compound may be a (macro-)molecule, which corresponds to or is derived from a (monomeric) building block of natural lignin or is a homo- or heterodimers of such (monomeric) building blocks. Such compounds are derived from natural lignin via its modification by the method disclosed in the present claims. Examples of lignin-derived compounds include aromatic compounds, such as phenols, small molecular weight fragments and oligomeric and monomeric lignin moieties, such as p-coumaryl alcohol, conifer alcohol, sinapyl alcohol, vanillin, syringaldehyde, coniferyl aldehyde, vanillic acid, and / or syringic acid. The monomeric lignin moieties may form dimeric or oligomeric compounds of varied lengths. Typically, lignin derived compounds are a highly heterogeneous assembly of monomeric and oligomeric phenolic structures. The structures may contain functional groups such as carboxylic, aldehyde, ketone, ester, ether, and hydroxyl and methoxy groups. Furthermore, lignin derived compounds also react with other components such as furans and sugars, creating a heterogeneous group of so-called pseudolignins (i.e. humins). The term “lignin-derived compounds” includes also such pseudolignins. Typically, humins have a polymeric furanic-type structure, with hydroxyl, aldehyde and ketone functionalities.

[0036] The term “hemicellulosic sugars” as used herein refers to sugars that may be obtained from hemicellulose by cleavage of chemical bonds. Hemicellulose is typically present in lignocellulosic materials. Hemicelluloses are polysaccharides that may be branched, are shorter in length than cellulose (typically 500 to 3000 sugar units), and also show a propensity to crystallize. Hemicelluloses are composed of diverse sugars, and can include the five-carbon sugars xylose and arabinose, the six-carbon sugars glucose, mannose and galactose, and / or the six-carbon deoxy sugar rhamnose. Hemicellulosic sugars may be polysaccharides, disaccharides or monomeric sugars. Hemicellulosic sugars include for example glucose, galactose, mannose, xylose, arabinose, rhamnose, 4-O-methyl glucuronic acid, and galacturonic acid; and disaccharides and / or polysaccharides comprising one or more of these monomers.

[0037] In the present context, the term “organosolv pulping process” refers to a pulping technique that uses an organic solvent to solubilise lignin and hemicellulose. In a typical process, lignocellulosic raw material is contacted with an aqueous organic solvent at temperatures ranging from 140 to 220 °C for a period of time. This step is called cooking and it causes lignin to break into fragments that are soluble in the aqueous organic solution. In addition to lignin, also other components such as hemicellulose and different chemicals, such as phenols, fats, proteins, saccharides, waxes, terpenes and / or terpenoids, are dissolved in the organic solvent. After the cooking phase, cellulose is removed from the mixture and directed to further processing steps for example to produce bioethanol. In the present context, the term “organosov pulping methods” includes the steps from providing a lignocellulosic material to separation of cellulose from the mixture after cooking.

[0038] In the present context, the term “spent cooking liquor” refers a solution that is obtained from organosolv pulping process after the cooking step by removal of insoluble fraction, which includes cellulose. In some embodiments, the organosolv pulping process of lignocellulosic material may be performed in aqueous solution comprising organic acids, such as formic acid, acetic acid or combinations thereof. After cooking of the lignocellulosic material (i.e. delignification), cellulosic fiber and other insoluble matter is separated from the solution and directed to additional processing. The remaining mixture, from which cellulose has been removed, is referred herein as “a spent cooking liquor”. Such spent cooking liquor may comprise for example lignin and different degradation products of lignin, hemicellulose, proteins, sugars, and phenolic compounds.

[0039] The term “feed” refers to animal feed comprising any agricultural foodstuff used specifically to feed domesticated livestock, such as cattle, pigs, chickens, horses, sheep and goats. In particular, the term feed refers to fodder, which refers to food given to animals (including plant cuts and carried to them) rather than that which they forage for themselves. Feed may comprise for example grass, grass mixes, hay, compressed and pelleted feeds, oils, sprouted grains, grass crops, legumes, whole crop cereals, cereal grains, crimped grains or liquid / broth feed. Examples of feed include com, barley, oats, rye, sorghums, wheat, alfalfa, clovers, timothy, flaxseed, soybean, sugar beet and straw. The terms “feed” and “animal feed” are used interchangeably.

[0040] As used herein, the terms “broth feed” and “wet feed” or “liquid feed” are used interchangeably and refer to liquid feed that may comprise different components,such as grains, side-streams from food industry, such as whey, and / or molasses, vegetable oils, minerals, and vitamins.

[0041] As used herein, the terms “aqueous organic solvent” and “aqueous organic solution” may refer to an aqueous solution comprising at least one organic acid. The at least one organic acid may be formic acid, acetic acid or combinations thereof. For example the term “aqueous organic solution” may refer to an aqueous solution comprising formic acid, acetic acid or combinations thereof. The term “aqueous organic solvent” may refer to an aqueous solution comprising formic acid, acetic acid or combinations thereof.

[0042] As used herein, the term “silage” refers to feed preserved by an anaerobic fermentation, e.g. hay silage and com silage. Silage making relies on the conversion of plant sugars to acid. The acid decreases the pH and preserves the feed. There are a variety of naturally occurring bacteria that can be present in silage. They produce a range of fermentation acids. A lactic fermentation is the most desirable because minimal energy is lost during the fermentation process and lactic acid produces palatable, high feed value silage.

[0043] As used herein, the term “feed additive” refers to a composition added to feed. Feed additives may be used for example to increase stability during storage and / or to enhance overall health of animals.

[0044] As used herein, the term “soluble lignin-containing organic solution” refers to a solution comprising dissolved lignin and organic components. Such organic components may comprise for example acetic acid, formic acid, furfural, proteins, hemicellulose, polysaccharides, degradation products of lignin, or combinations thereof.

[0045] Unless otherwise stated, properties that have been experimentally measured or determined herein have been measured or determined at room temperature. Unless otherwise indicated, room temperature is 25 °C. Unless otherwise stated, properties that have been experimentally measured or determined herein have been measured or determined at atmospheric pressure.

[0046] As used herein, the term “about” refers to the actual given value, and also to an approximation to such given value that would reasonably be inferred to one of ordinary skill in the art, including approximations due to the experimental and / or measurement conditions for such given value.

[0047] The present disclosure describes a new feed additive that may be used for improving the stability of feed and / or providing prebiotic effects to animals consuming the feed. It has been observed, that degradation of components of lignocellulosic material provides a mixture that may improve stability and lifetime of feed and further provide prebiotic effects. Especially, degradation of lignocellulosic materials during organosolv pulping process in acidic conditions appears to be beneficial for formation of such mixture of degradation products. Without wishing to be bound by the theory, it is thought that acid catalyzed degradation of lignocellulosic material may be important so that the effective composition for feed additive is formed. The different compounds within such mixture provide synergistic effects that result in the herein described effects.

[0048] In the present disclosure a feed additive is provided and its use as feed supplement is described. The feed additve is obtainable by a method comprising the steps of: providing a soluble lignin-containing organic solution; providing an aqueous precipitant solution comprising about 5 wt-% to about 40 wt-% of acid(s); adding the aqueous precipitant solution to the soluble lignin-containing organic solution to provide a mixture having a temperature in the range of about 40°C to about 90°C; cooling the mixture containing a precipitated lignin product for about 2 sec to about 2 hours; separating the precipitated lignin product from the mixture; and collecting the resulting mixture as a feed additive. It has been found that such feed additive may be used as a preservative for feed. Further, the feed additive may have probiotic effects on animals.

[0049] The method may be based on an organosolv pulping of a lignocellulosic material in which cellulose, lignin and hemicellulose present in the lignocellulosic material are separated in two main streams, i.e., cellulosic pulp and a solution of soluble lignin and hemicellulosic sugars, by using an aqueous organic solvent as a cooking liquor. The cooking liquor as disclosed herein may be acidic and may include for example formic acid and acetic acid, water and furfural. During cooking, hemicellulosic sugars and a portion of lignin are dissolved in the cooking liquor. Cooking herein refers to a process step during the organosolv pulping process.

[0050] In the context or the present disclosure, the term “organosolv pulping” means that delignification of the lignocellulosic material is performed with organic acids in an aqueous solution constituting a cooking liquor. The organic acids may include formic acid and acetic acid. In the present disclosure, the organosolv pulping of a lignocellulosicmaterial may thus be performed in acidic conditions. In some embodiments, the total content of organic acids in the cooking liquor may be about 65% wt.% to about 90% wt.%. Typically, the cooking liquor does not comprise any non-polar solvents.

[0051] In the present disclosure, the cooking liquor used in the organosolv pulping may comprise a low amount of at least one alcohol, such as methanol and / or ethanol. However, the organosolv pulping in at least some embodiments of the present disclosure does not correspond to organosolv delignification with alcohols. Thus, in some examples, the cooking liquor may contain for example less than 8 wt.% of at least one alcohol. In some embodiments, the soluble lignin-containing organic solution contains less than 8 wt.% of at least one alcohol, such as methanol and / or ethanol.

[0052] In some embodiments, the organosolv pulping process of a lignocellulosic material may be performed by using an aqueous solution comprising at least one organic acids as a cooking liquor. Preferably, the organic acid is selected from formic acid, acetic acid or combinations thereof.In context of some embodiments of the present disclosure, a soluble lignin-containing organic solution may be obtained from cooking of a lignocellulosic material with an aqueous organic solvent. Such soluble lignin-containing organic solution may be in these embodiments be described as “a spent cooking liquor”. Thus in some embodiments, the soluble lignin-containing organic solution may be a spent cooking liquor from an organosolv pulping process of a lignocellulosic material. The spent cooking liquor thus contains, e.g.., soluble lignin, hemicellulosic sugars, inorganics, proteins and extractives, and also components of original cooking liquor. Such components may include for example organic acids, such as formic acid and / or acetic acid. As used herein, the terms “soluble lignin-containing organic solution” and “spent cooking liquor” are interchangeable in such embodiments. In some examples, the spent cooking liquor may be concentrated to obtain the soluble lignin-containing organic solution.

[0053] In some embodiments, the lignocellulosic material may be selected from a group comprising straw materials, wood materials, grass materials and combination thereof. Straw material refers to an agriculture byproduct comprising dry stalks of cereal plants after the grain and chaff have been removed. Straw material may include for example wheat, barley, oat, rice and rye. Straw materials may further refer to bagasse. In preferred embodiments, the straw material is wheat or bagasse. Wood material may comprise any wood derived materials, for example wood particles, wood chips or sawdust.The source of the wood material may be for example birch, pine, spruce or eucalyptus. In preferred embodiments, the wood material may be eucalyptus. Grass materials may refer to any plants in the family of monocotyledonous flowering plants. Grass materials comprise for example cereal grasses, bamboos, mischantus, napier grass and the grasses of natural grassland. In preferred embodiments, the grass material may be bamboo or napier grass.

[0054] In the method of the disclosure, soluble lignin may be precipitated from the spent cooking liquor using an aqueous solution which comprises organic acids. Soluble lignin as disclosed herein refers to lignin that has been dissolved in the spent cooking liquor. Dissolving is preferably achieved via organosolv process as explained above. It was surprisingly found, firstly, that a lignin precipitate of high purity was obtained using specific precipitation conditions involving employing an aqueous organic solution comprising acids as a precipitant solution, and secondly, using a dynamic mixer in mixing the spent cooking liquor and an aqueous organic solution in a continuous manner affected the precipitated lignin product yield and properties, and thirdly, quick cooling of the lignin precipitate provided beneficial filterability of the lignin precipitate. In particular, use of an aqueous solution comprising organic acids for lignin precipitation, and quick cooling of the lignin precipitate have a favorable effect on quality of the lignin precipitate. Acidic precipitant solution obtainable from the organosolv pulping process provides a lignin precipitate of high purity and diminishes need of fresh water.

[0055] In the context of the present disclosure, the term “lignin precipitate of high purity” means a precipitated lignin product which contains a decreased amount of sugars, inorganics and proteins when compared to lignin that has been precipitated by conventional methods. The term "beneficial filterability" means a precipitated lignin product which filtrates with an increased rate compared to filtering lignin that has been precipitated by conventional methods.

[0056] Generally, it is challenging to achieve a lignin product with high purity without compromising process effectiveness and savings in energy and in use of fresh water. “High purity” refers herein to a lignin product comprising more than 70 %, such as more than 80 wt%, or more than 90 wt%, or more than 95 wt% of lignin. The method of the disclosure employs specific precipitation conditions whereby lignin filterability of a lignin precipitate is improved. Significant energy savings may be achieved with method of the disclosure by utilizing acidic process streams, and a spent cooking liquor of high dry matter content in the precipitation, while a high quality lignin product is achieved.

[0057] The present disclosure provides in some embodiments an efficient and economic method for producing and recovering a pure precipitated lignin product having minor amounts of impurities, such as protein, by filtration using an acidic precipitant solution and quick cooling after the precipitation. The lignin precipitate of high purity ensures efficient recovery of the lignin product by filtration whereby clogging of the filter is avoided. The method of the disclosure efficiently employs in some embodiments acidic process streams avoiding need for fresh water thus providing savings in energy costs.

[0058] The method further produces a liquid fraction, which is the fraction obtained after removal of the precipitated lignin as disclosed herein. The term “acidic sugar liquor” or “ASL” is used in the present context to describe this fraction as it comprises at least one acid and saccharides. The liquid fraction, i.e. the acidic sugar liquor, is the feed additive obtainable with the herein disclosed method.

[0059] The present disclosure provides a feed additive obtainable by a method, that can be also used for producing a lignin product, comprising the steps of:- providing a soluble lignin-containing organic solution,- providing an aqueous precipitant solution comprising about 5 wt% to about 40 wt% of acid(s),- adding the aqueous precipitant solution to the soluble lignin-containing organic solution to provide a mixture having a temperature in the range of about 40°C to about 90°C,- cooling the mixture containing a precipitated lignin product about 2 sec to about 2 hours,- separating and recovering the precipitated lignin product from the mixture, collecting the resulting mixture as the feed additive.

[0060] The percentages of the various constituents used in the method of the present invention are given on weight basis, i.e. wt.%.

[0061] The term “soluble lignin-containing organic solution” refers to solution comprising solubilized lignin, e.g. dissolved lignin. The solution may further comprise for example organic components, such as organic acids, saccharides, proteins and / or polyphenols, and inorganic components, such as minerals. Soluble lignin-containing organic solution may be originated from an organosolv pulping method of a lignocellulosicmaterial. In the method disclosed herein for obtaining the feed additive, the soluble lignincontaining organic solution may contain a low amount of at least one alcohol, such as methanol and / or ethanol. In an embodiment, the amount of ethanol may be at most 5 wt.%. In an embodiment, the amount of methanol may be at most 6 wt.%. For example, the soluble lignin-containing organic solution may comprise less than 8 wt.% of at least one alcohol, such as methanol and / or ethanol.

[0062] In an embodiment, the soluble lignin-containing organic solution may comprise formic acid, acetic acid, and water. In some embodiments, the soluble lignincontaining organic solution may further comprise furfural. In another embodiment, the soluble lignin-containing organic solution may comprise formic acid, acetic acid, water and furfural. In some examples, the soluble lignin-containing solution may comprise formic acid, acetic acid, water, furfural or combinations thereof.

[0063] In an embodiment, the soluble lignin-containing organic solution may comprise about 65 wt.% to about 90 wt.% of organic acids in total based on the liquid part (i.e., volatile components including formic acid, acetic acid, furfural, alcohol(s), water) of the soluble lignin-containing organic solution. In an embodiment, the organic acids may be formic acid and acetic acid. For example, the soluble lignin-containing organic solution may comprise about 65 wt.% to about 90 wt.% of formic acid, acetic acid or combinations thereof calculated from the total amount of compounds evaporated from the soluble lignincontaining organic solution at 105 °C under atmospheric pressure.

[0064] In an embodiment, the dry matter content of the soluble lignin-containing organic solution may be in the range of about 50% to about 90%. In another embodiment, the dry matter may be from about 60% to about 85%. In a further embodiment, the dry matter may be from about 70% to about 80%. Thus, the dry matter content of the soluble lignin-containing organic solution may range from about 60 wt-% to about 85 wt-%, or from about 70 wt-% to about 80 wt-%. For example, the dry matter content of spent cooking liquor may range from 50 wt-% to 90 wt-%, such as from 70 wt-% to 80 wt-%.

[0065] The aqueous precipitant solution comprises about 5% to about 40% of acid(s). In another embodiment, the aqueous precipitant solution may comprise about 20% to about 30% of acid(s). The acid(s) may be organic acid(s). In an embodiment, the acid may be selected from formic acid, acetic acid and a mixture thereof. In some embodiments, the acid(s) may comprise at least one of formic acid and acetic acid.

[0066] In an embodiment, the aqueous precipitant solution may comprise an acidic process stream from organosolv pulping process of the lignocellulosic material. In an embodiment, the aqueous precipitant solution may consist of an acidic process side stream from organosolv pulping process of the lignocellulosic material. Such acidic process side stream may be formed for example when the cellulose fibers, that are separated from the cooking liquor, are directed to additional processing steps. The term “acidic process side stream” as used herein may thus refer to an acidic side stream formed in processing of cellulose fibers. Using at least partly acidic process side streams originated from organosolv pulping process in the lignin precipitation, savings in fresh water and in energy costs are achieved.

[0067] The aqueous precipitant solution may be added to the soluble lignincontaining organic solution in a weight ratio of about 0.7:1 to about 2.5:1. In an embodiment, the aqueous precipitant solution is added in a weight ratio of about 1 :1 to about 2:1.

[0068] Addition of the aqueous precipitant solution to the soluble lignin-containing organic solution provides a mixture. In an embodiment, the content of organic acids in total based on the liquid part (i.e., volatile components including formic acid, acetic acid, furfural, alcohol(s), water) of the mixture is at most 60 wt.%. In an embodiment, the total organic acid content is in the range of about 5 wt.% to about 60 wt.% based on the liquid part. “Liquid part” herein refers to the part of the mixture that can be evaporated at 105 °C under atmospheric pressure. In other words, when the mixture is subjected to evaporation at 105 °C under atmospheric pressure, the evaporated compounds form the liquid part of the mixture. The liquid part may comprise for example water, alcohols, short-chain fatty acids, such as formic acid and acetic acid, furfural and other compounds that are volatile at 105 °C under atmospheric pressure. The part of the solution not belonging to the liquid part is typically referred to as the dry matter of the solution. Such distinction herein is made because in some embodiments the dry matter content of the soluble lignin-containing organic solution may be high and thus the acid concentration may seem low if calculated from total volume of the soluble lignin-containing organic solution. However, one feature that is important for the technical effect observed in the present disclosure is the change in acid concentration within the liquid part of the solution and not the acid amount of the whole soluble lignin-containing organic solution. Typically, the acid content of the solublelignin-containing organic solution, or at least of the liquid part, decreases when the aqueous precipitation solution is added. This may be for example achieved by using an aqueous precipitant solution that comprises less acids, such as organic acids, than the soluble lignin-containing organic solution. In some examples, the liquid part of an aqueous precipitant solution may have a lower concentration of acids than the liquid part of the soluble lignin-containing organic solution.

[0069] After adding the aqueous precipitant solution to the soluble lignin-containing organic solution to provide a mixture, the temperature of the mixture is in the range of about 40 °C to about 90 °C. This is typically achieved by one or both of the aqueous precipitant solution and the soluble lignin-containing organic solution having a temperature in the range of 40 °C to about 100 °C before the adding step. In some examples, one of the aqueous precipitant solution and the soluble lignin-containing organic solution may have a temperature below 40 °C, such as for example at least 20 °C. The temperature of the mixture of the soluble lignin-containing organic solution and the aqueous precipitant solution before cooling is in an embodiment in the range of about 50°C to about 90°C. In an embodiment, the temperature is about 60°C to about 85°C. In another embodiment, the temperature of the mixture is in the range of about 65°C to about 80°C. It is not necessary that the temperature of the soluble lignin-containing organic solution and the aqueous precipitant solution are initially the same. The temperature of the precipitant solution may be lower than that of the soluble lignin-containing organic solution. For example, the precipitant solution and the soluble lignin-containing organic solution may have a temperature of about 60°C and about 95°C, respectively.

[0070] After the aqueous precipitant solution has been added, cooling of the mixture is started. The mixture containing precipitated lignin may be cooled to about 20°C to about 50°C. Specifically, the mixture may be cooled to about 25°C to about 40°C. In an embodiment, cooling of the mixture is performed for about 2 sec to about 2 hours. According to the precent disclosure, the mixture containing a precipitated lignin product is cooled for about 2 sec to about 2 hours. In another embodiment, cooling of the mixture is performed within 60 minutes. Duration of cooling is dependent on the efficiency of a heat exchanger employed in the method. Shorter cooling time is achieved with a more efficient heat exchanger. Fast cooling ensures that uniform particle size of a lignin is achieved providing, in turn, enhanced filterability of the precipitated lignin product. In someembodiments, the cooling of the mixture during the cooling step is performed within 60 minutes, specifically from about 10 minutes to about 60 minutes. In other embodiments, the mixture is cooled during the cooling step to about 20°C to about 50°C, specifically from about 25°C to about 40°C. For example, the cooling of the mixture containing precipitated lignin product may be performed within 60 minutes to cool the mixture to a temperature ranging from about 20°C to about 50°C, or from 25°C to about 40°C.

[0071] The precipitated lignin product is separated and recovered. In an embodiment, the separation is carried out by filtration. In other embodiments, the separation may be carried out by a solid-liquid separation method, such as filtration and centrifugal means. For example, the separating step may be performed by a solid-liquid separation method, such as filtration and / or by centrifugal means. After removal of lignin, the residual mixture is collected as the feed additive.

[0072] If desired, the precipitated lignin product may be washed, e.g., with water to remove any residual impurities in the product. The liquid obtained from such washing may be in some embodiments combined with the feed additive obtainable by the method disclosed herein.. The solution used for washing may comprise organic acid, preferably the same organic acid(s) that is(are) used in other steps of the method. For example, the precipitated lignin product may be washed with water comprising formic acid and / or acetic acid.

[0073] The feed additive may be in some embodiments concentrated after the collecting step. Concentration may be performed with any suitable methos, for example by evaporation. In some embodiments, the composition of the feed additive may be adjusted after the evaporation step by addition of compounds that were lost during the concentration step. For example, if the feed additive has been concentrated by evaporation, at least some of the formic acid and / or acetic acid in the feed additive may also be evaporated. Thus, formic acid and / or acetic acid may be added to the feed additive after the concentration step to restore the original acid content of the feed additive.

[0074] In a further aspect, the disclosure provides a precipitated lignin product comprising at least 50% of acid insoluble lignin determined with NREL TP-510-42618 method (August 2012). Lignin determined by this method is also known “Klason lignin”. The feed additive obtainable by the method disclosed herein may comprise acids, such asorganic acids, hemicellulose and hemicellulosic sugars, proteins, polysaccharides, inorganic compounds, solubilized lignin, lignin degradation products, lignin-derived compounds, such as phenols and polyphenols, or combinations thereof.

[0075] In some embodiments, the feed additive may comprise less than 60 wt-% of at least one acid, preferably at least 4 wt-% of at least one acid calculated from the total mass of the feed additive. The at least one acid may be an organic acid, such as formic acid, acetic acid or combinations thereof.

[0076] In some embodiments, the feed additive may comprise less than 20 wt-% of formic acid, preferably 5-20 wt-%, such as 6-13 wt-%, calculated from the total mass of the feed additive. In some preferred embodiments, the feed additive may comprise less than 9 wt-% of formic acid, preferably 5-8 wt-% of formic acid, calculated from the total mass of the feed additive.

[0077] The feed additive may in some embodiments comprise both formic acid and acetic acid. In some embodiments, the ratio of formic acid and acetic acid may range from 10:1 to 1 :10, for example from 1 :5 to 5:1.

[0078] The pH of the feed additive is acidic. In some embodiments, the pH may be below 4. In other embodiments, the pH of the feed additive may be below 3, for example below 2.5, below 2.3 or below 2.1.

[0079] The feed additive may comprise furfural and / or 5-(hydroxymethyl)furfural. Furfural may be formed during the organosolv process in which hemicellulose may react to form furfural. Typically, the feed additive comprises less than 5 wt-% of furfural and / or 5- (hydroxymethyl)furfural, such as less than 3 wt-%, or about 1 wt-%. In some examples, furfural may be added to the feed additive as an additive.

[0080] In some embodiments, the feed additive may comprise dissolved lignin, lignin-derived compounds, hemicellulose, hemicellulosic sugars, furfural or combinations thereof.

[0081] Typically, the feed additive comprises large amounts of hemicellulosic monomeric, dimeric and / or oligomeric sugars and polysaccharides. Hemicellulosic sugars may include for example glucose, galactose, mannose, xylose, arabinose, rhamnose, 4-O- methyl glucuronic acid, galacturonic acid or combinations thereof; or disaccharides and / orpolysaccharides comprising one or more of these monomers. For example, the feed additive may comprise 30 to 80 wt-% of saccharides, such as at least 30 wt-%, or in the range of 40 to 60 wt-%, from the dry weight of the feed additive. In some examples, at least 50 % or at least 70 % of the saccharides in the feed additive are monomeric sugars, such as xylose, arabinose, glucose, galactose, mannose and / or rhamnose. In some examples, 5 to 15 wt-% of the dry weight of the feed additive may comprise oligosaccharides and / or polysaccharides. Typically, these oligosaccharides and / or polysaccharides are hemicellulosic sugars having 2 to 6 monomeric units. Monomeric sugars are typically pentoses and / or hexoses. For example, the feed additive may comprise 20 to 80 wt-%, such as 30 to 70 wt-%, or more than 40 wt-%, of monomeric sugars calculated from the dry weight of the feed additive.

[0082] For example, wheat straw may be used in the organosolv pulping process to produce a spent cooking liquor as explained above. At least in these cases, when the feed additive is produced from such spent cooking liquor, the main saccharide in the produced feed additive is xylose. The feed additive may comprise for example 30 to 50 wt-% of xylose calculated from the dry matter of the feed additive. The feed additive in these embodiments may further comprise 4-8 wt-% of arabinose, 4-8 wt-% of glucose, and 2-6 wt-% of other hexose sugars, such as galactose, mannose, and / or rhamnose, from the dry weight of the feed additive.

[0083] In some embodiments, the feed additive may comprise lignin-derived compounds. These compounds may include fragments produced from lignin through acid catalysis. Such fragments may have molar masses below 500 g / mol, such as below 300 g / mol. Lignin fragments may include for example monomeric and oligomeric phenolic structures, such as monomers and / or oligomers comprising p-coumaryl alcohol, conifer alcohol, sinapyl alcohol, vanillin, syringaldehyde, coniferyl aldehyde, vanillic acid, and / or syringic acid. In some examples, lignin-derived compounds may include reaction product of lignin fragments, such as humins. Lignin-derived compounds, such as phenols, polyphenols and / or humins, may form 2 to 30 wt-%, such as 5 to 20 wt- %, of the dry-mass of the feed additive. These may include both acid soluble phenols and acid-insoluble phenols, such as Klason lignin. The term “acid soluble lignin“ refers to a fraction of lignin that is soluble in 72 % sulfuric acid.

[0084] In some embodiments, the feed additive may comprise different small molecule extractives. For example, the feed additive may comprise 1-6 wt-% of extractives from the dry weight of the feed additive. In some embodiments, the additive may comprise acidic sugars, such as uronic acids. The feed additive may comprise for example 1 - 5 wt- % or acidic sugars from the dry weight of the feed additive.

[0085] In some embodiments, the feed additive may comprise proteins, protein fragments and / or amino acids that originate from the lignocellulosic biomass. Typically, the protein and amino acid content of the feed additive may be less than 10 wt-%, such as 2 to 6 wt-%, calculated from the dry matter of the feed additive.

[0086] The feed additive may in some embodiments comprise inorganic compounds, such as minerals. Inorganic compounds are sometimes also referred to with the term ash. Minerals includes for example as kalium, natrium, magnesium, and calcium, phosphoric compounds. In some examples, the feed additive may comprise 5-20 wt-%, such as 8-15 wt-%, of inorganic compounds from the dry weight of the feed additive.

[0087] In some embodiments, the feed additive may comprise less than 8 wt-% of alcohol, such as ethanol or methanol.

[0088] Another aspect of the present disclosure is a feed additive comprising spent cooking liquor from an organosolv pulping process of a lignocellulosic material from which lignin has been precipitated by addition of 5 to 40 wt-% of at least one acid. The at least one acid may be selected in embodiments from formic acid, acetic acid and combinations thereof.

[0089] In some embodiments, the organosolv pulping process of lignocellulosic material is performed in aqueous solution comprising formic acid, acetic acid or combinations thereof. In embodiments, the spent cooking liquor is formed by removal of cellulosic fibers from the aqueous solution after the organosolv pulping process.

[0090] In some embodiments, the spent cooking liquor may comprise about 65 wt.% to about 90 wt.% of formic acid, acetic acid or combinations thereof calculated from the total amount of compounds evaporated from the spent cooking liquor at 105 °C under atmospheric pressure. In some embodiments, the spent cooking liquor may comprise about50 wt.% to about 90 wt.%, specifically about 60 wt.% to about 85 wt.%, more specifically about 70 wt.% to about 80 wt.%, of dry matter.

[0091] In some embodiments, the feed additive may comprise at least one organic acid in the range of 4 to 60 wt-.%. In other embodiments, the feed additive may comprise less than 20 wt% or formic acid, such as between 5 to 20 wt-% of formic acid. In some embodiments, the pH of the feed additive may be below 4.0, such as below 3.0.

[0092] It is preferred that the feed additive comprises less than 8 wt-% of alcohol, such as ethanol and / or methanol.

[0093] The feed additive may comprise any of the compounds mentioned above. In some embodiments, the feed additive comprises dissolved lignin, lignin-derived compounds, hemicellulose, hemicellulosic sugars, furfural or combinations thereof.

[0094] In some embodiments, the lignocellulosic material may be selected from a group comprising straw materials, such as wheat or bagasse, wood materials, such as eucalyptus, grass materials, such as bamboo, napier grass or mischantus, and combination thereof.

[0095] The inventors have found that the feed additive obtainable by the disclosed method is able to maintain anaerobic stability of feed that has been brought in contact with air, such as in opened silage containers. This effect is achieved even if the feed additive comprises less formic acid than the conventional AIV silage feed additive. This indicates that the components that are present in the feed additve have additional and / or a synergistic impacts with formic acid on anaerobic stability of feed, such as silage or liquid feed. Without wishing to be bound by theory, it is hypothesized that one possible source for the observed additional / synergistic impacts is the presence of lignin-derived phenolic compounds in the feed additive.

[0096] Further, the feed additive has been found to have a strong bactericidal impact on yeasts, already at low concentrations, while no bactericidal impact on the beneficial lactic acid bacteria has been observed. Such beneficial selective impact on the bacterial composition is desirable not only for storability of the feed but also for animal digestion. Again wishing not to be bound by a specific theory, we hypothesise that phenolic compounds present in the feed additive may possess antimicrobial activities that mayprovide the observed selective bactericidal effect. Such compounds may be for example lignin-derived phenolic compounds. The inventors have further found that the feed additive may inhibit growth of pathogenic bacteria, which may provide significant advantages over merely inhibiting the growth of yeasts and moulds.

[0097] The feed additive may in some embodiments be used in the range of 1-40 L per ton of feed, preferably in the range of 5-30 kg / t of feed.

[0098] The feed additive according to some embodiments may comprise less than 20 wt-% of formic acid, preferably 5-20 wt-%, such as 6-13 %, calculated from the total mass of the feed additive. In preferred embodiments, the feed additive comprises less than 9 wt-% of formic acid, preferably 5-8 wt-%, calculated from the total mass of the feed additive. In some embodiments, the feed additive may comprise both formic acid ad acetic acid. The ratio of acetic acid and formic acid may range for example from 1 :10 to 10:1, such as from 1 :5 to 5 : 1.

[0099] In another aspect of the present invention, use of the feed additive according as disclosed herein for preserving feed is provided. In some embodiments the feed additive is used for preserving silage, legumes, whole crop cereals, cereal grains or crimped grains. In other embodiments, the feed additive may be used for preserving grass, such as timothy and meadow fescue.

[0100] Another aspect of the present invention, is use of the feed additive as a feed supplement. In some embodiments, the feed supplement may be a probiotic feed supplement. Prebiotics are non-digestible feed ingredients that stimulate the growth or activity of bacteria in the digestive system. Prebiotics may provide beneficial effects to health.

[0101] In some examples, the feed additive may be diluted with a dilution solution, for example with an aqueous solution such as water, before using it as a feed additive, for preserving food or as a feed supplement. Typically, feed additive and a dilution solution are mixed in a ratio below 1 :1, such as in the range of 50: 1 to 1 : 1.

[0102] In some examples, at least one additive may be added to the feed additive. Typically, the total amount of the at least one additive may be less than 50 wt-%, such as less than 30 wt-%, of the total weight of feed additive. In some examples, the compositionof the feed additive does not substantially change when the at least one additive is added. Suitable additives include those typically utilized in preparing feed, for example sugars, amino acids, fatty acids, or fungal products. For example, saccharides, such as sugars with five carbon atoms, may be added to the feed additive. Typically, the amount of added saccharide is 15 wt-% or less, such as less than 10 wt-%. Other example of a suitable additives includes silicates, such as aluminosilicates. In some examples, side streams produced in biorefineries may be used as additives. Such side streams may include silicate ash, silicate containing white waters from processing of cellulose and / or stillage cake obtained from ethanol production. Such stillage cake may be formed in the fermentation of cellulosic materials into ethanol, wherein the stillage cake is the side stream comprising residual solid matter, such as yeast and starch.

[0103] Another aspect of the present invention is a method for producing a feed additive. The method comprises the steps of:- providing a soluble lignin-containing organic solution,- providing an aqueous precipitant solution comprising about 5 wt-% to about 40 wt-% of acid(s),- adding the aqueous precipitant solution to the soluble lignin-containing organic solution to provide a mixture having a temperature in the range of about 40°C to about 90°C,- cooling the mixture containing a precipitated lignin product for about 2 sec to about 2 hours,- separating and recovering the precipitated lignin product from the mixture,- collecting the resulting mixture as a feed additive.

[0104] Embodiments of the method have been described above.Experimental section

[0105] The following examples are presented for further illustration of the invention without limiting the invention thereto.

[0106] The content of acid soluble lignin was measured according to technical report of NREL TP-510-42618 (August 2012).

[0107] The content of pentosans was determined according to standard “TAPPI T223 cm-10 Pentosans in wood and pulp”, wherein furfural is analysed with HPLC.Example 1 :

[0108] Wheat straw lignocellulosic material was delignified with a cooking liquor containing water, formic acid and acetic acid to provide a soluble lignin-containing spent cooking liquor. The soluble lignin-containing spent cooking liquor was concentrated to a dry matter content of 57%. The content of formic acid and acetic acid in total based on the liquid part of the soluble lignin-containing spent cooking liquor was 77%. The liquid part of the soluble lignin-containing spent cooking liquor was determined as everything except the dry matter of the liquor. For example, if the weight is 100 kg and dry matter content is 57 %, the liquid part of the soluble lignin-containing spent cooking liquor is 100 *(1-0.57) =43 kg.Two acidic aqueous solutions containing 20% and 35% of formic acid and acetic acid in total were used as precipitant solutions to precipitate lignin in the concentrated spent cooking liquor. These acidic aqueous solutions both contain formic acid and acetic acid. Water was used as a reference precipitant solution (0% acid). The precipitant solutions were added to the concentrated spent cooking liquor in a ratio of 1 : 1 (w / w) to provide a mixture.Addition of water (0% acid) gave a mixture containing 23% of formic acid and acetic acid in total based on the liquid part of the mixture, which was determined as explained above. Addition of 20% acidic solution gave a mixture containing 37% of formic acid and acetic acid in total based on the liquid part of the mixture. Addition of 35% acidic solution gave a mixture containing 48% of formic acid and acetic acid in total based on the liquid part of the mixture.The resultant mixtures had a temperature of 40°C. After precipitation, the mixture was cooled for about 15 min to reach the temperature of about 35°C. Precipitated lignin was separated using a filter paper having a retention capacity of 0.6 pm.Table 1 shows the effect of the precipitant solutions on the purity of the precipitated lignin products. The percentages are based on weight and on dry matter of the precipitated lignin.Table 1The results show that less protein, acids and pentosan hemicellulose impurities are bound to precipitated lignin, and thus the purity of the lignin product is increased when the acid content of the precipitant solution increased.Reference example 2

[0109] The example illustrates an effect of different cooling times on filterability of lignin precipitates.Two soluble lignin-containing spent cooking liquors were tested having a different dry matter content. Pure water was used as a precipitant solution. The precipitant solution was added to the spent cooking liquors with vigorous stirring to provide mixtures. The temperature of the mixtures was 80°C. The spent cooking liquors containing precipitated lignin were cooled to a room temperature of about 22°C before filtering.Precipitated lignin was filtered using a filter paper having a retention capacity of 0.6 pm.Total filtration time describes the minimum time required to stop dropping of a filtrate.The results of Table 2 relate to a lignin precipitation from a soluble lignin-containing spent cooking liquor having a dry matter content of 35% before lignin precipitation. The precipitant solution (water) was added to the spent cooking liquor in a ratio of 1 : 1.The results of Table 3 relate to a lignin precipitation from a soluble lignin-containing spent cooking liquor having a dry matter content of 79% before lignin precipitation. The precipitant solution was added to the spent cooking liquor in a ratio of 1 : 1 and 2:1.Table 2. DM 35% of the lignin-containing spent cooking liquor concentrate* cooling time to lower the temperature from 80°C to 22°CTable 3. DM 79% of the lignin-containing spent cooking liquor concen-trate* cooling time to lower the temperature from 80°C to 22°C The results of Tables 2 and 3 show that filtration of the precipitated lignin product became faster when the cooling time was shortened after the precipitation of the lignin product. This indicates that the precipitated lignin product desirably has a beneficial particle size distribution allowing fast filtration of the precipitated product.The results show that the combination of the hot lignin-containing spent cooking liquors and the hot precipitant solution, and quick cooling after precipitation produce a lignin precipitate exhibiting good filterability.Example 3

[0110] Soluble lignin-containing spent cooking liquor having a dry matter content of 79% before lignin precipitation was provided. The organic acid content of the liquid part of the soluble lignin-containing spent cooking liquor was 76 wt.%. The liquid part wasdetermined as in example 1. An aqueous solution containing formic acid and acetic acid in total of 20% was used as a precipitant solution. The precipitant solution was added to the spent cooking liquor in a ratio of 2: 1 (w / w) to provide a mixture. The mixture had a formic acid and acetic content in total of 25 wt.% based on the liquid part of the mixture. The liquid part was determined as in example 1.The temperature of the mixture was 80°C. Cooling and filtration were carried out as described in reference example 2.The results are shown in Table 4.Table 4. DM 79% of the lignin-containing spent cooking liquor concentrate* cooling time to lower the temperature from 80°C to 22°CThe results show that filtration of the precipitated lignin product became faster when the cooling time was shortened after the precipitation of the lignin product.Example 4

[0111] The following Table 5 shows fresh water and energy savings obtained by using an acidic precipitant solution in accordance with the method of the invention instead of pure water.The spent cooking liquor containing soluble lignin solution used for precipitation had a dry matter content of 70% (w / w). Flow rate of the spent cooking liquor was 30.5 t / h.The effect of three different precipitant solutions on fresh water and energy savings were tested. Pure water was used as a reference. Precipitant solution B was an acidic process stream containing at least 5% of acids and consisting of a condensate of hemicellulosefiltrate produced in an organosolv pulping of a cellulosic material. Precipitant solution A contained 50% (w / w) of pure water and 50% (w / w) of the acidic process stream.Each precipitant solution was added to the spent cooking liquor in the ratio of 2:1. Flow rate of the precipitant solution was 61 t / h.Resultant lignin precipitate was washed with water. Water used for precipitation and washing was led to a distillation. Energy consumption needed in distillation is given in Table 5.Table 5The results show that use an acidic precipitant solution reduces fresh water consumption and energy consumption compared with the case when pure water is used for lignin precipitation.Example 5

[0112] Production of the feed additiveIn the example 5-7, the feed additive as disclosed herein is referred to with the terms “acidic sugar liquor” or “ASL”.Wheat straw lignocellulosic material was delignified with a cooking liquor containing water, formic acid and acetic acid to provide a soluble lignin-containing spent cooking liquor. The soluble lignin-containing spent cooking liquor was concentrated to a dry matter content of 51%. The content of formic acid and acetic acid in total based on the liquid partof the soluble lignin-containing spent cooking liquor was 77%. The liquid part of the soluble lignin-containing spent cooking liquor was determined as everything except the dry matter of the liquor. For example, if the volume is 100 kg and dry matter content is 51 %, the liquid part of the soluble lignin-containing spent cooking liquor is 100*( 1-0.51) =49 kg-Water (0% acid) was used as precipitant solutions to precipitate lignin in the concentrated spent cooking liquor. The precipitant solution was added to the concentrated spent cooking liquor in a ratio of 1,9:1 (w / w) to provide a mixture. Mixing of water and the concentrated spent cooking liquor was performed by combining two pipeline to one pipeline with y- branch arrangement. After combining, mixture was directed to container having gentle agitation to prevent settling.Addition of water (0% acid) gave a mixture containing 16% of formic acid and acetic acid in total based on the liquid part of the mixture, which was determined as explained above.The resultant mixture had a temperature of 37°C. After precipitation, the mixture was led to cool to the room temperature (about 20°C) without external cooling. Precipitated lignin was separated using a filtering machinery and the resulting liquid (called acidic sugar liquor or ASL) was used in the experiments disclosed below.

[0113] Mixed timothy and meadow fescue grass was mixed with produced acidic sugar liquor as indicated in table 6. In the ASL samples acidic sugar liquor was used as the preservative. AIV Assa Na was used for the AIV fodder control as the preservative. Water was added to decrease the dry matter content as indicated in table 6. Samples were stored at room temperature for 52 days after treatment.Table 6. Sample preparation. All additions shown as L / t.Sample Added preservative Added water Total added volumeControl 0 30 30AIV fodder 5 25 30ASL 1 5 25 30ASL 2 15 15 30ASL 3 30 0 30

[0114] Composition of acidic sugar liquor that was used in the present experiment is shown in table 7.Table 7. Composition of acidic sugar liquor used in the present study.Parameter Content in acidic sugar liquorOven dry matter (DM) excluding volatiles 89.9 g / kgAsh 124.1 g / kg DMWater soluble carbohydrates 43.1 g / kg DM pH 2.06Formic acid 70.3 g / kgAcetic acid 89.4 g / kgAll other volatile fatty acids 0

[0115] Based on the measurements shown in table 7, the real application doses of formic acid, acetic acid and propionic acid to the prepared samples were calculated. These are shown in table 8. The total amount of formic acid was reduced in all samples comprising acidic sugar liquor when compared to the commercial AlV-product. This may be advantageous, because it may make to feed tastier for the animals. In addition, the amount of acetic acid, which is a good nutrient and provides shelf life, was increased.Acidic sugar liquor did not comprise any propionic acid, which may be problematic in fermentation.Table 8.Real application dose, kg / tonSamprle Formic acid A * ce xti-c acid Propionic acid To xta ilAIV fodder 2.90 - 1.00 3.90ASL 1 0.35 0.45 - 0.80ASL 2 1.05 1.34 - 2.40ASL 3 2.11 2.68 - 4.79

[0116] The following parameters were determined from the samples: dry matter content, pH, ammoniacal nitrogen content, concentration of lactic acid, concentration of volatile fatty acids (acetic acid, propionic acid, butyric acid), ethanol concentration, aerobic stability and ensiling losses (Table 9).Ensiling losses were estimated by using weight loss of silage during ensiling as an estimate of CO2 production. For each mole of produced CO2 during ensiling, 1 mole of H2O is also produced. Thus, each gram of weight decrease because of CO2 losses means that 0.44 g of dry matter was also lost as water. It is counted as an ensiling loss even if water is still in a silo. Total dry matter losses (g / kg initial dry matter) were then estimated to be decrease in weight of the silo multiplied by 1.44 (Knicky and Spomdly, 2015). Laboratory analyses were conducted using standard analytical methods (for details, see Seppala et al., 2016).

[0117] Aerobic stability test was conducted using routine method. Silages were packed into plastic bags and inserted into polystyrene boxes so that air ingress into the feed material is guaranteed. MicroLite thermometers were inserted into the sample material and the temperature from each sample was automatically recorded at 10- minute intervals for 12 days. Aerobic stability is defined as the time taken to increase the temperature of sample for 2 °C above the ambient temperature. The samples were weighed before and after the aerobic incubation. Table 9.TreatmentsCtrl ASLI ASL2 ASL3AIVfodderDry matter (DM), g / kg 289 289 289 295 290 pH 3.68 3.80 3.86 3.94 3.82Ammonia N, g / kg N 46 46 39 27 24Ethanol, g / kg DM 4.6 5.3 6.6 14.6 14.8Acids, g / kg DMLactic acid (LA) 127 122 112 85 81Acetic acid (AA) 18.7 23.1 26.2 28.1 19.1Acetic acid corrected 18.7 22.6 24.8 25.4 19.1Propionic acid 0.24 0.19 0.19 0.16 2.37Butyric acid 0.01 0 0 0 0Caproic acid 0.01 0 0 0 0Tot volatile fatty acids 18.9 23.3 26.4 28.2 21.5Tot fermentation acids 146 145 138 113 102Tot fermentation products 151 150 145 127 117LA / AA ratio 6.8 5.3 4.3 3.0 4.2Aerobic Stability (2 °C), hours 102 288 288 288 288Aerobic Stability (3 °C), hours 116 288 288 288 288Ensiling losses, g / kg of initial DM 25.6 25.5 26.5 27.2 27.9Aerobic stability losses, g / kg fresh matter 30.6 13.9 15.3 13.9 13.5Ctrl=control; LA / AA ratio= lactic acid / acetic acid ratio; total fermentation products= ethanol and total fermentation acids;

[0118] The results show that the acidic sugar liquor provides a good acid balance without overly reducing the pH. Lactic acid was produced in all samples indicating that acidic sugar liquor does not inhibit lactic acid bacteria. Further, the ratio lactic acid and acetic acid was in a good level in all samples. No fermentation leading to formation of butyric acid was observed. Aerobic stability was good and thus acidic sugar liquor can be used for improving storage time of feed. No fermentation by yeasts could be observed. It is notable, that these results could be obtained already with a much smaller amount of acidic sugar liquor than what is needed when the commercial AlV-fodder is used. This might be due to synergistic effects that is obtained by the combination of different components in the acidic sugar liquor.Importantly, aerobic stability of all samples with acidic sugar liquor was as good as for the commercial control even though the amount of formic acid is much lower. Thus, the acidic sugar liquor provides surprising synergistic effects that significantly improve aerobic stability, for example by specifically inhibiting growth of yeasts.From these results, it is clear that acidic sugar liquor is effective in preserving silage.Example 6

[0119] Wet feed was obtained from a Finnish farm. Four samples were prepared as shown in table 10. Acidic sugar liquor was prepared as explained in example 5.Table 10.Sample name Wet feed Acidic sugar liquor (L)Samples were taken from each preparation at time points 0 h, 2 h, 4 h, and 6 h from begin of the study. Microbial growth for the following microbes were analyzed from each sample: lactic acid bacterium, enterobacterium, Clostridium, yeasts and molds using standard methods in five replicants. In addition, pH was determined from each sample.The results are shown in figures 1-5. These results further show that acidic sugar liquor does not reduce the number of lactic acid bacteria but it does reduce growth of molds and especially the amount of yeasts.Example 7

[0120] Acidic sugar liquor was prepared as explained in example 5. Acidic sugar liquor was tested for its effect on bacterial fermentation in two intestinal segments of the broiler chicken intestine, crop and ileum. The same products were used both in crop and ileum model, but the dosing principles were different. The bacterial substrate in the crop fermentation model is actual feed. Therefore, test product dosing was calculated against feed dry matter. In ileum fermentation model the substrate is extract from small intestinal contents. Therefore, doses are expressed as product dry matter per m of fermentation medium. A growth promoting antibiotic, bacitracin methylene disalicylate (BMD), was used as a positive control. Treatments are shown in table 11.Table 11.

[0121] In the crop fermentation model, the products were added as such with no pH neutralisation. Therefore, also the potential pH effect mimics well the real-life situation. In the ileum model, the test products were pH neutralised before they were introduced into the fermentation medium. This is because also in real-life situation pancreatin and other endogenous buffers would neutralise the feed digest before it enters the ileum. All treatments with test products were fermented in five replicates and the negative control in ten replicates.

[0122] In the ex vivo crop fermentation model the fermentation vessels mimic the conditions in the chicken crop. The diet used was commercial wheat-soya based feed. The pellets were ground and the test products added at the doses indicated in table 11. Feed wasmixed in water using the ratio 1 part feed (5g) + 1.8 parts water (9.0 mL), to make a slurry in the fermentation vessels. Inoculum for the fermentation was fresh crop digesta collected from broiler chickens on a commercial farm. The digesta used for inoculation was spiked with fresh cultures of Salmonella enterica, Escherichia coli and Campylobacter jejuni to be able to follow potential suppression / stimulation of the pathogens by the test products. The fermentation was started by mixing 0.2 parts of fresh crop digesta (1 g) in the feed slurry. The exact time of inoculation was recorded for each fermentation vessel. Inoculation order was random to ensure that potential effect of the order (inoculum ageing) did not bias the results. The incubation was continued for 6 hours at 38°C, and 2 mL of water was added in vials after 8 h fermentation. After incubation, samples were vigorously shaken for 1 min and subjected to low-speed centrifugation at lOOxg for 1 min. 0.4 mL of supernatant was transferred to microbial analysis and the rest of the vial content was extracted and subjected to short-chain fatty acid analysis.

[0123] In the ex vivo ileum fermentation model, fermentation vessels mimic the conditions in the chicken ileum (distal small intestine). For the model, the growth medium was prepared from the intestinal digesta recovered from proximal ileum (proximal half of intestine between Meckel’s diverticulum and ileocaecal junction) of animals grown on wheat-based control diet. Digesta used for substrate preparation was extracted with anoxic buffer (1 part of digesta + 3 parts of buffer) and clarified by high-speed centrifugation to get rid of the solid material and the bulk of bacteria. Inoculum for the fermentation was fresh ileal digesta collected from broiler chickens on a commercial farm. Also in this model, the digesta used for inoculation was spiked with fresh cultures of S. enterica, E. coli and C. jejuni to be able to follow potential suppression / stimulation of the pathogens by the test products. As in crop fermentation, the fermentation onset occurred at the very moment when ileal digesta (10%) was mixed with the intestinal substrate. Inoculation order was again randomised to ensure that a potential effect of inoculation order did not bias the results. Fermentation proceeded at 38 °C for 8 hours.

[0124] Following parameter were analysed from the samples:Gas production: Bacterial gas production was measured at 2-hour intervals to express the overall activity of fermentation.Short-chain fatty acids: At the end of the fermentation, the vials were analysed for shortchain fatty acids (SCFAs) by gas chromatography. The method followed the previouslypublished protocol (Apajalahti et al.). The individual SCFAs quantified were acetic, propionic, butyric, isobutyric, 2-methyl-butyric, valeric, iso-valeric, and lactic acid.Bacteria: In the end of the fermentation, the vessels were analysed for the total bacteria and the three pathogens the vessels were spiked with. Briefly, bacteria in the samples were washed, bacterial cell walls disrupted, and the chromosomal DNA quantitatively purified with the method optimised for the upper GI tract contents of broiler chickens. Consequently, all individual DNA samples were subjected to quantitative real-time PCR analysis of total eubacteria, S. enterica, E. coli and C. jejuni.Data analysis: Statistical analysis consisted of two-tailed t-tests for all measured parameters. The tests were performed against the Negative CTRL treatment (no test product). Significance according to Student’s t-test: p-value < 0.1 ~, p-value < 0.05 *, p- value < 0.01 **, p-value < 0.001 ***ResultsCrop fermentation models

[0125] Gas production: During the 6-hour fermentation crop bacteria produced approximately 20 mL of gas when no amendments were made. During the first 4 hours BMD slightly inhibited fermentation but during the last 2 hours bacterial growth accelerated and, eventually, at 6 hours there was no effect on cumulative gas production (Figure 5). The tested product was clearly inhibitory, and the effect was dose dependent. For an unknown reason, the treatment with the highest dose of acidic sugar liquor rapidly released gas during the first 2 hours. This may have been an abiotic phenomenon leading to CO2 release if there was a significant amount of carbonate present since this high dose of product most likely dropped pH of the medium. It is also possible that the gas came from abiotic or bacterial decarboxylation of formic acid in the product.

[0126] pH: Crop bacteria produce predominantly lactic acid which is the strongest acid commonly produced by intestinal bacteria. Therefore, active fermentation causes typically a significant pH drop. Therefore, active fermentation causes typically a significant pH drop. The pH results after the crop fermentation are shown in Figure 6. In the current ex vivo study pH dropped from the starting pH of 6.8 to 4.7 when no fermentation inhibiting additives were introduced. When BMD was present the final pH was slightly higher, ~4.8. This indicates small inhibition of fermentation. In the presenceof the acidic sugar liquor was in the same range as for the control sample except for the sample having the highest amount of acidic sugar liquor for which the pH dropped to 4.15. This was due to significant acid addition when the product was added rather than effect of fermentation.

[0127] Short chain fatty acids (SCFA): Total acid concentration indicates the overall fermentation activity, and the relative abundance of individual acids indicates the respective activity of different fermentation pathways. In the broiler chicken crop, lactic acid bacterial fermentation which produces lactic and acetic acids at different ratios is expected to dominate. Lactic acid bacteria may be classified as homofermentative or heterofermentative based on their end-products of sugar fermentation. Residual concentration of the main SCFAs after the fermentation are shown in Figure 7.

[0128] Lactic acid was the most abundant individual SCFA produced by crop microorganisms, indicating that the fermentation was dominated by homofermentative lactic acid bacteria. The final concentration after the 6-hour fermentation was 185 mM, which indicates highly active fermentation. BMD caused an 8% reduction in the lactic acid concentration which suggests that the antibiotic caused a moderate inhibition of fermentation.

[0129] Addition of acidic sugar liquor induced a significant suppression of fermentation also when measured as the yield of the major metabolic product, lactic acid. The reduction of residual lactic acid concentration by acidic sugar liquor was dose dependent. With the highest product dose, no lactic acid was produced; the measured 8 mM concentration corresponds to the amount that was added at 0 hours with the crop digesta inoculum.

[0130] The changes in the concentration of acetic acid were dominated by the effect of the acidic sugar liquor. It was obvious that the significant product dose-dependent increase in the concentration of acetic acid was due to the acid present in the product itself. When the acetic acid concentration present in the vessels of the control treatment was subtracted from the treatments with the product, the remaining acetic acid corresponds well to that added with the product (assuming that fresh product contained 8.2% acetic acid).

[0131] Growth of bacteria: The crop microbiota provides the first barrier against enteric pathogens through competitive exclusion by commensal bacteria. Most of thebacteria inhabiting the crop are assigned to the genus Lactobacillus. Acidic sugar liquor significantly inhibited the growth on total eubacteria. At the highest product dose, the density of bacteria was two orders of magnitude lower than in the absence of the test product. This confirmed the findings observed from the analysis of gas and acid production. The inhibition profile of E. coll and S. enterica at different doses of acidic sugar liquor was nearly identical. The lowest dose inhibited the growth of E. coli by 50%, while the highest dose caused a 75% inhibition. With S. enterica the growth suppressive effect was nearly identical. None of the treatments affected the growth of C. jejuni.Ileum fermentation model

[0132] Gas production: Although the small intestinal microbiota in broiler chickens is also dominated by lactic acid bacteria, the microbiota is more diverse and adapted to degradation of more complex substrates than the lactic acid bacteria in the crop. It is also worth noting that feed provided to crop bacteria is rich in nutrients while bacteria in ileum utilise substrate leftovers remaining when the host animal has absorbed most monomeric sugars and amino acids. Figure 8 shows the production of gas by ileal microbes and the response to addition of the test products.

[0133] Gas production in the absence of test products was relatively linear during the 8-hour fermentation. BMD had a small suppressing effect, mainly at the end of the fermentation period. Acidic sugar liquor showed a significant stimulation of gas production. The dose response curve was quadratic the lower doses showing significant stimulation during the entire fermentation period while the highest dose was inhibiting gas production strongly. It is likely that the substrates present in the product can be readily utilised by the ileal bacteria, thus causing a stimulatory effect. At the highest dose, the acids present exceeded the concentration tolerated by the bacteria and their growth was inhibited or ceased.

[0134] pH: Normally, when intense lactic acid fermentation proceeds in a moderately buffered medium pH is significantly reduced due to production of lactic acid. When acid-producing bacteria are inhibited, pH remains unchanged. It is worth noting that in our ileal fermentation model the test products were neutralised before introducing in the test vessels. Figure 9 shows the pH after the differently amended ileal fermentations. The inhibitory effect of acidic sugar liquor clearly reflects to pH, which is significantly higher at the higher doses of the product.

[0135] Shor chain fatty acids: Residual concentration of the main SCFAs (lactic acid and acetic acid) after the fermentation are shown in Figure 10.

[0136] Due to the low substrate content, the concentration of lactic acid in the ileal model is modest when compared to the concentration in the crop. BMD caused a statistically significant, 18% reduction in the concentration of lactic acid, indicating clear inhibition of fermentation. Acidic sugar liquor significantly stimulated lactic acid fermentation, the magnitude of stimulation being as much as 79% at the 5 mg / mL dose. The suppression of fermentation was obvious at the highest product dose. This is in line with the gas production data.

[0137] The test products significantly affected the residual concentration of acetic acid when measured after the 8-hour fermentation. BMD slightly inhibited acetate production while the other treatments significantly and dose-dependently increased it. It was again obvious that the effect of acidic sugar liquor was due to the acetate in the product itself. The concentration analysed at the highest product dose was consistent with the addition of the product at 10 mg / mL.

[0138] Bacterial growth: Acidic sugar liquor clearly inhibited the growth of the total ileal bacteria at all doses. At the highest product dose, the reduction was over 90%. With this product also all the pathogens were inhibited to the same extent. Interestingly, acidic sugar liquor did not inhibit the growth of C. jejuni in the crop model, but in the ileal habitat the inhibition was clear.

[0139] In conclusion, the acidic sugar liquor has a positive impact on the microbiome of both crop and ileum.

[0140] It is to be understood that the embodiments of the invention disclosed are not limited to the particular structures, process steps, or materials disclosed herein, but are extended to equivalents thereof as would be recognized by those ordinarily skilled in the relevant arts. It should also be understood that terminology employed herein is used for the purpose of describing particular embodiments only and is not intended to be limiting.

[0141] Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment” or “in an embodiment”in various places throughout this specification are not necessarily all referring to the same embodiment.

[0142] As used herein, a plurality of items, structural elements, compositional elements, and / or materials may be presented in a common list for convenience. However, these lists should be construed as though each member of the list is individually identified as a separate and unique member. Thus, no individual member of such list should be construed as a de facto equivalent of any other member of the same list solely based on their presentation in a common group without indications to the contrary. In addition, various embodiments and example of the present invention may be referred to herein along with alternatives for the various components thereof. It is understood that such embodiments, examples, and alternatives are not to be construed as de facto equivalents of one another, but are to be considered as separate and autonomous representations of the present invention.

[0143] Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided, such as examples of lengths, widths, shapes, etc., to provide a thorough understanding of embodiments of the invention. One skilled in the relevant art will recognize, however, that the invention can be practiced without one or more of the specific details, or with other methods, components, materials, etc. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the invention.

[0144] While the forgoing examples are illustrative of the principles of the present invention in one or more particular applications, it will be apparent to those of ordinary skill in the art that numerous modifications in form, usage and details of implementation can be made without the exercise of inventive faculty, and without departing from the principles and concepts of the invention. Accordingly, it is not intended that the invention be limited, except as by the claims set forth below.

[0145] The verbs “to comprise” and “to include” are used in this document as open limitations that neither exclude nor require the existence of also un-recited features. The features recited in depending claims are mutually freely combinable unless otherwiseexplicitly stated. Furthermore, it is to be understood that the use of "a" or "an", i.e. a singular form, throughout this document does not exclude a plurality.CITATION LISTNon Patent LiteratureAnadon, A., Ares, L, Martinez-Larranaga, M.R., Martinez, M.A. (2019). Prebiotics and Probiotics in Feed and Animal Health. In: Gupta, R., Srivastava, A., Lail, R. (eds) Nutraceuticals in Veterinary Medicine. Springer, Cham, https: / / doi.org / 10.1007 / 978-3- 030-04624-8 19Apajalahti et al. 2019; Frontiers in Veterinary Science, 6:311

Claims

CLAIMS:

1. A feed additive obtainable by the method comprising the steps of:- providing a soluble lignin-containing organic solution,- providing an aqueous precipitant solution comprising about 5 wt-% to about 40 wt-% of acid(s),- adding the aqueous precipitant solution to the soluble lignin-containing organic solution to provide a mixture having a temperature in the range of about 40°C to about 90°C,- cooling the mixture containing a precipitated lignin product for about 2 sec to about 2 hours,- separating the precipitated lignin product from the mixture,- collecting the resulting mixture as a feed additive.

2. The feed additive according to claim 1, wherein the soluble lignin-containing organic solution is a spent cooking liquor from an organosolv pulping process of a lignocellulosic material.

3. The feed additive according to claim 2, wherein the organosolv pulping process of a lignocellulosic material is performed using an aqueous solution comprising at least one organic acid as a cooking liquor.

4. The feed additive according to claim 3, wherein the organic acid is selected from formic acid, acetic acid or combinations thereof.

5. The feed additive according to claim 3 or 4, wherein the aqueous solvent comprises furfural.

6. The feed additive according to any of the claims 2-5, wherein the lignocellulosic material is selected from a group comprising straw materials, such as wheat or bagasse, wood materials, such as eucalyptus, grass materials, such as bamboo, napier grass or mischantus, and combination thereof.

7. The feed additive according to any one of the preceding claims, wherein the soluble lignin-containing organic solution comprises formic acid, acetic acid, and water.

8. The feed additive according to claim 7, wherein the soluble lignin-containing organic solution further comprises furfural.

9. The feed additive according to any of the preceding claims, wherein the soluble lignincontaining organic solution comprises about 65 wt.% to about 90 wt.% of formic acid, acetic acid or combinations thereof calculated from the total amount of compounds evaporated from the soluble lignin-containing organic solution at 105 °C under atmospheric pressure.

10. The feed additive according to any of the preceding claims, wherein the soluble lignincontaining organic solution comprises less than 8 wt.% of at least one alcohol, such as methanol and / or ethanol.

11. The feed additive according to any one of the preceding claims, wherein the dry matter of the soluble lignin-containing organic solution is in the range of about 50 wt.% to about 90 wt.%, specifically about 60 wt.% to about 85 wt.%, more specifically about 70 wt.% to about 80 wt.%.

12. The feed additive according to any one of the preceding claims, wherein the aqueous precipitant solution comprises about 20 wt.% to about 30 wt.% of acid(s).

13. The feed additive according to any of the preceding claims, wherein the acid(s) in the aqueous precipitant solution are organic acid(s).

14. The feed additive according to claim 12, wherein the acid(s) are selected from formic acid, acetic acid or combinations thereof.

15. The feed additive according to any one of the preceding claims, wherein the aqueous precipitant solution comprises an acidic process side stream from organosolv pulping process of the lignocellulosic material.

16. The feed additive according to any one of the preceding claims, wherein the aqueous precipitant solution is added to the soluble lignin-containing organic solution in a weight ratio of about 0.7:1 to about 2.5:1, specifically about 1 :1 to about 2:1.

17. The feed additive according to any one of the preceding claims, wherein the mixture has a temperature of about 50°C to about 90°C, specifically 60°C to about 85°C, more specifically about 65°C to about 80°C.

18. The feed additive according to any of the preceding claims, wherein the mixture after the adding step comprises at most 60 wt.%, specifically in the range of about 5 wt.% to about 60 wt.%, of at least one organic acid calculated from the total weight of compounds evaporated from the soluble lignin-containing organic solution at 105 °C under atmospheric pressure.

19. The feed additive according to any one of the preceding claims, wherein the mixture is cooled to about 20°C to about 50°C, specifically about 25°C to about 40°C.

20. The feed additive according to any one of the preceding claims, wherein the cooling of the mixture is performed within 60 minutes.

21. The feed additive according to any of the preceding claims, wherein the cooling of the mixture during the cooling step is performed from about 10 minutes to about 60 minutes.

22. The feed additive according to any one of the preceding claims, wherein the separation is carried out by solid-liquid separation method, such as filtration and centrifugal means.

23. The feed additive according to any of the preceding claims, wherein the feed additive is concentrated after the collecting step.

24. The feed additive according to any of the preceding claims comprising less than 20 wt- % of formic acid, preferably 5-20 wt-%, more preferably 6-13 wt-% of formic acid.

25. The feed additive according to any of the preceding claims comprising less than 60 wt- % of at least one acid, preferably at least 4 wt-% of at least one acid.

26. The feed additive according to any of the preceding claims, wherein the pH of the feed additive is below 4.0, such as below 3.0.

27. The feed additive according to any of the preceding claims, wherein the feed additive comprises dissolved lignin, lignin-derived compounds, hemicellulose, hemicellulosic sugars, furfural or combinations thereof.

28. The feed additive, wherein the feed additive comprises less than 8 wt-% of alcohol, such as ethanol or methanol.

29. A feed additive comprising spent cooking liquor from an organosolv pulping process of a lignocellulosic material from which lignin has been precipitated by addition of 5 to 40 wt-% of at least one acid.

30. Use of the feed additive according to any of the claims 1 to 29 for preserving feed.

31. Use according to claim 30, wherein the feed is silage, legumes, whole crop cereals, cereal grains, crimped grains or combinations thereof.

32. Use of the feed additive according to any of the claims 1-29 as a feed supplement.

33. Use according to claim 32, wherein the feed supplement is a prebiotic feed supplement.

34. A method for producing a feed additive, comprising the steps of:- providing a soluble lignin-containing organic solution,- providing an aqueous precipitant solution comprising about 5 wt-% to about 40 wt-% of acid(s),- adding the aqueous precipitant solution to the soluble lignin-containing organic solution to provide a mixture having a temperature in the range of about 40°C to about 90°C,- cooling the mixture containing a precipitated lignin product for about 2 sec to about 2 hours,- separating and recovering the precipitated lignin product from the mixture,- collecting the resulting mixture as a feed additive.

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