WO2002089599A1

WO2002089599A1 - Keratin feed additive and process for making same

Info

Publication number: WO2002089599A1
Application number: PCT/AU2002/000586
Authority: WO
Inventors: Michael Gocher
Original assignee: Michael Gocher
Priority date: 2001-05-10
Filing date: 2002-05-10
Publication date: 2002-11-14
Also published as: AUPR490401A0

Abstract

A process for producing a high protein feed additive for animals comprising the steps: (i) hydrolysed a high keratin containing material, such as wool, by treatment with an alkali salt in aqueous solution until the material breaks down and forms a suspension (ii) neutralising the suspension from step (i) by adding an acid to form a floc suspended in a liquor (iii) separating the floc from the liquor where the floc is the feed additive.

Description

Keratin feed additive and process for making same

TECHNICAL FIELD

The present invention relates to a high protein feed additive derived from a keratin containing natural material, especially from wool obtained from sheep, goats and the like. A process for the production of a high protein feed additive is also disclosed. A by-product from the process for producing the feed additive, which is a fertiliser for agricultural use, is also disclosed.

BACKGROUND ART

Raising livestock is a major industry, which produces animals that have a multitude of uses; for meat, fibres, and hides, for example. It is important to feed the stock animals a proper balanced diet, to ensure optimum growth, and health for the stock animals. Frequently, it is helpful to add protein supplements to the animal's feed.

In nature, animals, particularly herbivores, obtain their protein needs from vegetable matter. However, plants that contain high levels of protein are often in demand for use as food directly for humans, and so are often expensive to give to stock animals. In recent times, manufactured protein supplements have been used to boost the amount of protein in the animal's diets. These protein supplement additives tend to have been made from inexpensive materials such as from animal protein, .commonly offal. This is an easily obtained by-product from slaughter-houses. Offal from slaughtered pigs, sheep, cattle and' poultry, is ground up, processed, and added to the . stock animal ' s feed.

Recently, the ethics and medical risks of this form of protein supplement have been called into question, and even banned in some countries. Many people feel it is unnatural to feed animal protein, even if heavily processed, to herbivores. Also, serious human and animal diseases have been transmitted, or suspected of being transmitted, by this farming practice, such as for instance; Creutzfeldt- 5 Jakob disease in humans, or commonly "mad cow" disease in cattle, scrapie in sheep and goats, and "foot and mouth" disease in cattle, swine and sheep.

Therefore, if a high protein feed supplement could be found that avoided or ameliorated these problems, then 0 there would be a market for it, particularly if it avoided the use of offal.

DISCLOSURE OF INVENTION

There is now disclosed a high protein feed additive for animals comprising a keratin containing material that has s been hydrolysed by treatment with an alkali salt in aqueous solution, followed by neutralisation with an acid.

Preferably, the keratin containing material is wool. It is also preferred that the alkali salt is selected from any one or more of potassium hydroxide or calcium hydroxide. It o is also preferred that the acid is selected from any one or more of sulfuric acid, nitric acid, or phosphoric acid. Preferably, the cation of the alkali salt and the anion of the acid are agriculturally beneficent. It is highly preferred that the alkali salt is potassium hydroxide, and 5 the acid is sulphuric acid. In a preferred embodiment, the keratin containing material is cleaned before treatment with the alkali salt.

In another form, the invention also- comprises.;^"a! ^"prό^'ce^'sεi- for producing a high protein feed additive for animals, o comprising the steps of:

(a) treating a keratin containing material with an alkali salt in aqueous solution until said material breaks down and forms a suspension,

(b) neutralising the suspension from step (a) by adding an acid to form a floe suspended in a liquor, (c) separating said floe from said liquor, whereby said floe comprises said feed additive.

Preferably in this process, the keratin containing material is wool .

It is further preferred that the alkali salt is selected from any one or more of potassium hydroxide or calcium hydroxide, and/or that che acid is selected from any one or more of sulfuric acid, nitric acid, or phosphoric acid. Ideally, the cation of said alkali salt and the anion of said acid are agriculturally beneficent, For instance, the alkali salt is potassium hydroxide, and said acid is sulphuric acid.

Preferably, the keratin containing material is cleaned prior to step (a) . Also, preferably, step (a) also includes the presence of a dispersing agent. It is preferred that the dispersing agent is sodium hexametaphosphate .

In the process the aqueous mixtures in steps (a) and/or (b) may preferably be agitated.

In another form, the invention also comprises an agriculturally useful by-product, which comprises said liquor separated in step (c) of the process described above .

Preferably, the agricultural-ly-. useful- by-product _i;S a liquid fertilizer for plants. BRIEF DESCRIPTION OF DRAWINGS

The invention is discussed with reference to drawings, where :

Figure 1 shows a flow chart of one process according to a preferred embodiment of the invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

The invention is now described in more detail.

A high protein feed additive or supplement has been discovered, that can comprise a significant proportion of essential amino acids, which are used to boost the growth and health of animals. The term "high protein" indicates that the additive contains^' a significant proportion of proteinaceous materials, such as protein fragments, peptide fragments, and amino acids, and their derivatives, which are used by animals to produce muscle tissue when eaten.

The animals with which the supplement can be used, include cattle, sheep, horses, poultry, pets, fish, and the like. The additive may be used with herbivores, as well as with omnivores and carnivores. Normally the feed additive will be added in a suitable amount to the normal feed of the animal, such as to hay or other fodder, or manufactured foods, for cattle, for example. However, the feed additive may also be fed on its own to the animals. In addition, other feed additives common in the industry may be included. Furthermore, suitable food flavourings, food aromas, food colourings or. the . like , substances and materials may. be included, to make the final product more desirable to be eaten. In addition, the animal may include human beings, after appropriate regulatory testing is carried out and the necessary approvals are obtained.

The feed additive is produced from a keratin containing substance. Preferably the keratin containing substance is wool from a sheep or goat. However, other sources of keratin may also be utilised. For instance, the hair, wool, horn, nails claws, beaks, scales and feathers of most animals with these features generally consist of a major portion of keratin. Some of the time, these features are waste products from the processing of animals, particularly from the butchering of animals in the meat industry, and so these materials may be inexpensive to obtain, and so may ideally be used in this invention. Sheep's wool, chicken feathers, and hair removed from hides are an example of such materials.

The keratinous material may be further processed before using it to create the high protein additive, such as with physical treatment such as by chopping up or grinding the material, or chemically, or by using normal cleaning methods. Ideally, the material is used as it is obtained, to minimize its' costs.

Nevertheless, it is generally preferred to utilise only keratin containing materials from animals that do not give rise to ethical or health concerns. With this in mind, a particularly preferred keratin containing material is wool. Wool from sheep is especially preferred, but the wool of other animals (eg goats, etc) may als^'o be utilised.

Wool generally is the fibrous hair of fleecy animals such as lambs, sheep and goats, and although the present invention is hereafter discussed mostly in regard to this material, note should be taken that other keratin containing materials will also fall within the scope of the invention. Wool grows on the body of a sheep, and in this natural state is made up mainly of keratin, as well as 5 containing a coating of a natural grease, which is chiefly lanolin.

Keratin is a complex fibrous protein, composed of the important amino acids that make up the proteins used by all living creatures. It is distinguished by being in the form 0 of fibres and by having a high cystine content. More precisely, keratin fibres are composed of bundles of fibrils, and each fibril is composed of three polypeptide chains, each a right handed c-helix, twisted in a left- handed helix. These fibres are embedded in a matrix made s from polypeptide chains rich in cysteine. These fibres moves towards the skin surface, and the chains link together by disulfide bridges, and form a dense interlocking structure that fills the cell, and eventually becomes the strand of hair, once it reaches the surface, o and grows out from the skin.

In the present invention "keratin" refers to the "hard" (or "a;-") keratin found in hair and wool, and not the "soft" keratin (or "pseudokeratin" or "keratohyalin" ) found in the epidermis. Keratin, in the form in which it 5 naturally occurs, is not especially suitable as a food for animals, as in most animals, it cannot be digested in the animals' gut to release the amino acids that comprise its complex protein chain structure. It is believed that when the structure -of the keratin ^"protein^" chain is broken down, o then the constituent amino^' acids are released and consequently become digestible by animals, particularly herbivores . Ideally the wool is obtained in lots from wool scourers, after most of the grease, dirt and vegetable matter has been removed. The low cost wool is preferred, made up of pieces, belly and short length wool from the shearing and scouring processes, which is the wool that has low commercial demand anyway.

Once source of such low-cost wool is from sheep or goats that have wool not normally used for fibre production, such as sheep or goats bred for meat production, or for milking (eg "Awassi" breed of sheep) , for example. Pigmented wool is often of low commercial value and this may also be a source of low cost wool for the present process. Sheep or goats being exported for slaughter in other countries are often shorn prior to their export, and this wool is often available at low cost.

This clean dry wool may be used directly in the process, or else it may be further processed, to separate the fibres, or to chop the fibres into smaller lengths.

Preferably batches of this wool are added to a large mixing vessel, containing water in which a strong alkaline has been dissolved. The water is preferably at ambient or room temperature or may be heated if desired. The wool is preferably agitated in the vessel until the alkaline breaks down the fibres and the keratin structure. A complex mixture of amino acids and peptide and protein fragments is produced. These go into suspension and some dissolve in the alkaline mixture. If desired a wetting or dispersing agent may be added to this mixture- _ o assist.-, in--.dispe-r-s.ing ..the components .

The agitation of this mixture continues until the wool fibres are no longer apparent in the mixture. This occurs normally after a time on the order of approximately 2 hours. However, the actual time required will depend on a number of factors; including the temperature of the mixture, the shear of the mixer, the concentration of the alkali present, the physical attributes of the wool, and so on. Therefore the actual time taken will vary according to all of these factors, and will need to be determined anew by inspection on each occasion that any of the conditions changes .

At the end of this stage, the mixture may be sieved to remove the vegetable matter and other materials that do not react to the alkaline conditions. ^'For example, the mixture may be sieved with a mesh of about 1 mm pore size to achieve this.

Then the mixture is adjusted, to a neutral pH. This requires the addition of an acid. The aqueous mixture is tested, using pH paper or a ph meter for instance, and acid is added, or more alkaline salt added until the isoelectric point is reached at pH 7. At this point the hydrolysed protein material precipitates out as a semi-solid agglomeration (or "floe"), with the solid material coagulating together. This material will be the protein supplement, and it can be removed from the waste liquor by coarse filtration.

The proteinaceous material is then preferably treated to lower its moisture content, for example by filter pressing into blocks, air drying them, and sieving and screening the dry material to a -suitable..particle size. _;for its use. A small particle size is advantageous, because the smaller the particle size then the larger the surface area that is available for digestion. Preferably, the material is adjusted to be a powder with an average particle size of 1 mm or less . The material is a light brown coloured powder, with a slight odour. Other treatments may be used, and alternatively, the material may be left in blocks, or else it may be finely ground.

It is preferred that the alkali used in this process is a salt of a hydroxide, such a potassium or calcium hydroxide, although other alkaline substances may also be used.

It is preferred that the acid used is a strong mineral acid, such as sulfuric acid, nitric acid, or phosphoric acid, although other acids may also be used.

It is further preferred that the cation of the alkali salt and the anion of the acid should be agriculturally beneficial. In other words, these ions should be suitable for use in an agricultural fertiliser. This allows the liquor waste from the process, which will include these ions in solution as well as any organic protein derivatives still soluble in the neutral pH of the solution, can then be used as an agricultural fertilizer. The waste liquor may be packaged as it results from the process as a liquid fertilizer, or some or all of the water may be removed. The extra value of this fertilizer by-product helps to make this process economic.

For example, potassium hydroxide and sulfuric acid are an ideal combination to utilise in the process, as potassium sulfate results, which is a useful fertiliser.

On the other hand, sodium - hydroxide -and- hydrochloric- acid are to be avoided, if a useful ^'fertiliser by-product is desired from the process, as in this case, the liquor will contain sodium chloride, which is of little, or no, use in agriculture. As mentioned previously, in the treatment step with alkaline, a wetting/dispersing agent such as sodium hexametaphosphate (also know as "SHMP" or "sodium polymetaphosphate" (NaP0₃)_x) may be used. Other wetting agents or surfactants may also be used, especially those that do not react or break down under strong alkaline conditions. For example, orthoxylated nonyl-phenols, or orthoxylated fatty acid alcohols, -type wetting agent, or their like may be used. Mixtures of different wetting agents may also be used.

The amount of alkali added will depend to some extent on the type and quality of the keratinous starting material. Too high an alkali concentration will result in the keratinous material "burning" , and in excessive damage to the sulfur bonds in the keratin, and to the product. Too little alkali causes the keratin to react too slowly, if at all.

The amount of alkaline added can vary between 2% and 50%, more preferably from 4% to 15%, and most preferably about 6% by weight, based on the amount of water present. These ranges are calculated in respect of KOH, and therefore should be scaled accordingly for other alkaline substances. The pH in the resulting mixture will normally be between 10 and 14, and more preferably about pH 13.

The amount of wetting agent is preferably present in an amount of from 0% to 10%, more preferably from 0.5% to 2% and most preferably about 0.6%, by weight, based the water present, calculated using SHMP,-. with ithe .amounts, .adjusted accordingly if another wetting agent is- used instead.

The product in its final, dry powdered form has been found to have a protein content as high as 100%, and to contain the amino acids of particular interest as feed additives for animals.

The liquor by-product has also been found to act as a valuable and effective fertilizer for plants.

The production process can be a batch process, where separate batches of wool are treated by the method described above, or alternatively, the process may be a continuous one. As a further option, the production process may be integrated into an existing wool scouring process, to utilise the wool waste that otherwise would be of little value in the scouring operation.

The process may preferably be conducted at ambient temperatures. However, increasing the temperature will speed up the process, and cooling the mixture in the reaction vessel will slow it down. Therefore, the temperature may be adjusted to provide ideal conditions for the reactions.

EXAMPLE 1 - PROCESS FOR PRODUCTION

A quantity of sheep's wool was obtained from commercial' wool scourers, where most of the wool grease (lanolin) and most of the contaminating dirt and vegetable matter (mostly burrs, seeds and such) , have been removed. Ideally, the less valuable fleece is used; particularly off-cuts and locks of wool; such as wool taken from the sheep's bellies and from lambs, for example. The scourers remove the bulk of the grease and vegetable matter, and this is then used in the following process. -Qiιa-ntities__. of; such scoured' -wool . can be obtained at a relatively- low cost .

An example of a suitable reaction vessel is one having a capacity of holding 4,000 litres (about 4 tonne) of water, and fitted with an agitator having an impeller speed of around 10 to 20 rpm.

The reaction vessel was filled with about 3000 litres of clean water, at room temperature. The agitator was s started.

Firstly, 180 kg of 89-90% potassium hydroxide {KOH) was slowly added to the agitated water. Then, 10 kg of a dispersing agent, such as sodium hexametaphosphate (also know as "SHMP" or sodium polymetaphosphate (NaP0₃)_x) was o added to the KOH aqueous solution. The solution was stirred until all the solids dissolved.

About 700 kg of the clean dry wool was slowly added to the vessel. The mixing impeller was allowed to run at a faster speed until all the wool had gone into suspension, s free from any obvious wool filaments. This took about 2 hours. Some vegetable matter, not removed from the wool in the prior scouring process, remained in the mixture. A filter screen with about a 1 mm mesh size was lowered into the stirred suspension, allowing the residue of solid o matter to be collected and removed from the vessel.

Then 400 kg of 35% sulphuric acid (H₂S0₄) was slowly added with continued stirring. The pH of the mixture was then adjusted to pH 7 using pH filter paper or a pH meter, by adding additional KOH or H₂S0₄ as needed, to either 5 increase or decrease the resulting pH, respectively.

An off-white coloured flocculate appeared, and the mixture formed a slurry. This flurry was pumped to a filter press, to recover the protein -^"material on the filter screen, and the water removed was also collected. The o recovered protein containing solids were tumble-dried and sieved to a 1 mm maximum particle size. The product appeared as an off-white powder, with a slight odour.

This process is summarised in the flowchart shown as Figure 1.

EXAMPLE 2 - PROTEIN ANALYSIS

The protein material obtained from the process described in Example 1 was analysed to determine its protein and amino acid content .

It was found that the product contained about 100% of proteinaceous material, on a dry basis. It contained significant amounts of important amino acids such as aspartic acid, glutamic acid, arginine, lysine, leucine and others, which indicates the material is a valuable stock feed supplement and protein booster.

A more detailed analysis, based on the average of a number of samples, using sheep fleece wool, is given in the table below

TABLE 1 - Protein content/ sheep fleece wool

Also, the raw materials used on the production process were all Technical Grade Active Concentrates, and so are excluded from any National Register (NRA) approvals.

EXAMPLE 3 - PROCESS BY-PRODUCT

The by-product water suspension / solution obtained from the process in Example 1 was also analysed, and found to contain potassium ions at a concentration of 9.7_ gram/dm³, and sulfate ions at a concentration of 13.4 gram/dm³, making this by-product suitable as a liquid agricultural fertilizer. It will be apparent that obvious variations and modifications of the invention in accordance with its spirit can be made without departing from the scope of the invention, and these are intended to be part of the invention.

Claims

The Claims :

1. A high protein feed additive for animals comprising a keratin containing material that has been hydrolysed by treatment with an alkali salt in aqueous solution, followed by neutralisation with an acid.

2. The additive of claim 1, wherein said keratin containing material is wool .

3. The additive of claim 1 or claim 2, wherein said alkali salt is selected from any one or more of potassium hydroxide or calcium hydroxide.

4. The additive of any one of claims 1 to 3 , wherein said acid is selected from any one or more of sulfuric acid, nitric acid, or phosphoric acid.

5. The additive of any one of claims 1 to 4 , wherein the cation of said alkali salt and the anion of said acid are agriculturally beneficent.

6. The additive of any one of claims. 1 to 5 , wherein said alkali salt is potassium hydroxide, and said acid is sulphuric acid.

7. The additive of any one of claims 1 to 6 , wherein said keratin- containing material is cleaned before treatment with said alkali salt.

8. A process for producing a high protein feed additive for animals, comprising the steps of:

(b) neutralising the suspension from step (a) by adding an acid to form a floe suspended in a liquor, (c) separating said floe, from said liquor, whereby said floe comprises said feed additive.

9. The process of claim 8, wherein said keratin containing material is wool.

10. The process of claim 8 or claim 9, wherein said alkali salt is selected from any one or more of potassium hydroxide or calcium hydroxide.

11. The process of any one of claims 8 to 10, wherein said acid is selected from any one or more of sulfuric acid, nitric acid, or phosphoric acid.

12. The process of any one of claims 8 to 11, wherein the cation of said alkali salt and the anion of said acid are agriculturally beneficent .

13. The process of any one of claims 8 to 12 , wherein said alkali salt is potassium hydroxide, and said acid is sulphuric acid.

14. The process of any one of claims 8 to 12 , wherein the keratin containing material is cleaned prior to step (a) .

15. The process of any one of claims 8 to 14, wherein step (a) also includes the presence of a dispersing agent .

16. The process of claim 15, wherein said dispersing agent is sodium hexametaphosphate.

17. The process of any one of claims 8 to 16, wherein the aqueous mixtures in steps (a) and/or (b) are agitated.

18. An agriculturally useful by-product, which comprises said liquor separated in step (c) of the process defined in any one of claim 8 to 17.

19. The agriculturally useful by-product of claim 18, which is a liquid fertilizer for plants.

20. A high protein feed additive for animals substantially as herein described with reference to any one or more of the examples and / or the drawing.

21. A process for preparing a high protein feed additive for animals substantially as herein described with reference to any one or more of the examples and / or the drawing.

22. An agriculturally useful by-product, which comprises the liquor removed from the high protein feed additive, substantially as herein described with reference to any one or more of the examples and / or the drawing.

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