EP1991687A2

EP1991687A2 - Extraction of fermentation-inhibiting substances from a fluid

Info

Publication number: EP1991687A2
Application number: EP07722009A
Authority: EP
Inventors: Christian Uphoff
Original assignee: Georg Fritzmeier GmbH and Co KG
Current assignee: Georg Fritzmeier GmbH and Co KG
Priority date: 2006-03-09
Filing date: 2007-03-09
Publication date: 2008-11-19
Also published as: EP2322639A1; WO2007101434A3; WO2007101434B1; US20090130256A1; WO2007101434A2

Abstract

Disclosed is a method for decomposing fermentation-inhibiting substances in a fluid that comprises saccharin-containing matter. According to said method, a microbiotic solution, especially a mixture of photosynthetic microorganisms and light emitting microorganisms, which is designed to decompose the fermentation-inhibiting substances, is introduced into the fluid.

Description

description

Degradation of gärhemmender substances from a fluid

The present invention relates to a process for the degradation of gärhemmender substances from a fluid, a process for the production of ethanol, in particular from whey, and an array of bioreactors for carrying out the process for producing ethanol from whey.

It is known from the prior art that ethanol can be obtained from saccharide-containing substances, in particular sugar or glucose. It cereals, sugar beet, potatoes and whey are known as glucose suppliers, which are suitable for ethanol production. But other saccharide-containing foods and food residues can be fermented.

The problem is, however, that on the one hand just in food residues due to incipient decomposition, caused for example by mold or the like, are gärhemmende substances that impede ethanol production from these products and therefore make unprofitable. On the other hand, the production of ethanol from whey is currently not economical, since the ethanol yield obtained from the whey is insufficient for a commercial evaluation.

Object of the present invention is therefore to provide a method by which gärhemmende substances can be easily removed and thereby a simple and inexpensive ethanol production, especially from the whey, guaranteed.

This object is achieved by a process for the degradation of fermentation-inhibiting substances from fluids according to claim 1, a process for producing ethanol according to claim 13, a process for producing ethanol from whey according to claim 14, and an arrangement of bioreactors for producing ethanol from whey according to Claim 29 solved.

The present invention is based on the finding that the low ethanol yield in the ethanol production from saccharide-containing foods or food residues, such as whey, is due to two problems: For one thing, when using whey as a food residue, ie. There were inhibitors in the whey as a waste product from cheese dairies, which severely restricted the production of ethanol. These inhibitors include, in particular, copper, which makes the fermentation of whey into ethanol almost impossible, as well as mold fungi which settle by non-immediate further processing of the whey. Such inhibitors are also present in other saccharide-containing fermentable foods, such as grapes or barley, and must be removed from the fluid to be fermented for ethanol production.

For this purpose, the fluid to be fermented with a microbiotic mixture of photosynthetic microorganisms and light-emitting microorganisms is applied, which is designed to degrade the gärhemmenden Stofffe. If the whey is not yet heavily loaded, adding hops can also provide sufficient bacteriostatic effects.

However, in another preferred embodiment, the microbiotic mixture is not added directly to the fluid, but the materials from which the fluid is made are pretreated with the microbiotic mixture. This is particularly advantageous in the production of wine or beer, in which the grapes or apples or malting barley are treated before applying must or mash with the microbiotic mixture. This allows fermentation-inhibiting substances, such as mildew, to be removed before the fermentation process and can not contaminate must or mash.

Experiments have shown that in addition to the addition of the microbiotic mixture to must, but especially in the pretreatment of grapes with the microbiotic mixture, the subsequent fermentation process can be significantly accelerated, in addition, a rapid sugar degradation and a rapid increase in temperature during fermentation was observed. In addition, the addition of the microbiotic mixture prevented the fermentation product from smelling musty or bad.

It is particularly advantageous if the photosynthetic microorganisms contained in the microbiotic mixture are prochlorophytes, cyanobacteria, green sulfur bacteria, purple bacteria, chloroflexus-like forms, heliobacteria and heliobacillus-like forms, and mixtures of two or more thereof and the light-emitting microorganisms contained in the microbiotic mixture Photobacterium phosphoreum, Vibrio fischeri Vibrio harveyi, Pseudomonas lucifera or Beneckea or mixtures of two or more there are more of them. Furthermore, it may be advantageous if the microbiotic mixture additionally contains plant extracts, enzymes, trace elements, polysaccharides, alginine derivatives and / or other microorganisms individually or in combination.

The other problem, especially with ethanol production from whey, is that the glucose contained in the whey is not freely available. So you can not just add whey to the whey for a fermentation process, but the glucose must first be extracted from the lactose. Lactose is usually only in a percentage of 30 - 40% contained in the whey and is also not 100% of glucose, but also from galactose. Although galactose is also a monosaccharide, it can not be fermented to ethanol, which further reduces the ethanol yield.

According to the invention, therefore, a method is proposed in which, in a first step, such inhibitors, such as copper, are removed from the whey. In a subsequent step, the lactose present in the whey is broken down into glucose and galactose, whereby the galactose is not treated as a waste product, but, as another particularly preferred embodiment shows, with the aid of a certain yeast strain, the so-called Kluyveromyces. converted to glucose.

Only then, in a third step, is a fermentation agent, in particular yeast or bacteria, added in order to convert the now comparatively high concentration of glucose into ethanol.

Since, as described above, in particular copper was identified as an ethanol production inhibitor, in a particularly preferred embodiment copper is removed from the whey by means of electrolysis.

Another limitation is that the percentage of ethanol in the fermentation solution must be taken into account when fermenting to ethanol, since an excessively high alcohol content adversely affects the fermentation process. Therefore, as another advantageous embodiment shows, the alcohol content is maintained at a certain level, preferably below 12%. For this purpose, excess ethanol can preferably be removed from the fermentation solution by means of membrane filtration.

It is particularly advantageous if the method according to the invention takes place in a bioreactor. The three main steps of the procedure can be be carried out in the same bioreactor. For this, however, the bioreactor must be prepared for the next step between the individual steps.

Since this is cumbersome, as another preferred exemplary embodiment shows, the method can also take place in preferably three bioreactors arranged one behind the other, wherein a conversion of the individual bioreactors due to the method steps assigned to them permanently is dispensed with.

In this case, a first bioreactor is preferably equipped with an electrolysis device, so that a removal of copper from the whey is made possible. For this purpose, a special equipment of the bioreactor can be used. Namely, a particularly preferred bioreactor consists of a coated container and a coated filling body, wherein the coatings are chosen such that upon application of an electric field the bioreactor itself acts as an electrolysis device. A photocatalytic coating of the bioreactor and an activated carbon coating of the filling body have proved to be particularly advantageous. When the electric field is applied, the filler body then serves as the anode and the copper ions are deposited on the activated carbon layer.

In this first bioreactor, for example, whey is introduced from a cheese factory and removed the interfering copper from it. If the whey is heavily loaded, for example because it was already stored, the whey may also be added to the microbial mixture here. If the whey is only slightly loaded or fresh, the whey may also be added to hops before it is introduced into the first bioreactor, preferably 100 g of hops per hectolitre of whey, so that on the one hand an already existing load is reduced or at least slowed down, on the other hand it can be ensured that such a burden does not occur at all.

The whey prepared in this way is then transferred to a second bioreactor in which the lactose contained in the whey is broken down into glucose and galactose by means of lactase. For this purpose, further Kluyveromyces - yeasts may be provided in the second bioreactor, which on the one hand also cause a breakdown of lactose into glucose and galactose, on the other hand, but are also able to convert galactose into glucose. In a third bioreactor into which the glucose mixture is introduced, there are microorganisms, in particular yeasts or fermenting bacteria, which bring about a conversion of glucose by means of alcoholic fermentation into ethanol. The ethanol thus produced is then preferably separated from the glucose mixture by means of a membrane. Particularly preferred is a bioreactor arrangement in which the individual bioreactors are coated with a photocatalytically active layer, and have one or more recesses for the passage of the whey into the interior of the bioreactor. In addition, it is advantageous if in the bioreactor, a filler with activated carbon is present, which increases the reaction surface, wherein deposited on the filler preferably copper or settle microorganisms for ethanol production and enzymes can be immobilized. Especially advantageous is an embodiment of the bioreactors in which a longitudinal strip-shaped photocatalytic coating alternates with a longitudinal strip-shaped diamond coating.

Further preferred embodiments and advantages are defined in the subclaims.

In the following, particularly preferred embodiments of the invention will be explained in more detail with reference to figures. The figures are purely exemplary and should not be used to limit the scope of the claims to the embodiments shown.

Show it:

Figure 1 is a schematic drawing of a preferred embodiment of the present invention, in which three bioreactors are connected in series in series to carry out the process according to the invention for producing ethanol from whey; and

Figure 2: a schematic drawing of a preferred embodiment of a bioreactor for the inventive method.

FIG. 3 shows a schematic drawing of a further exemplary embodiment of the present invention in order to carry out the process according to the invention for producing ethanol from whey.

Figure 1 shows a preferred embodiment of an arrangement 1 of bioreactors 2a-c for carrying out the method according to the invention. In order to produce ethanol from whey, whey, which is otherwise produced as a waste product by cheese dairies, is treated further. For this purpose, the whey is transferred from a storage or delivery tank 4 via a first line 6 in the arrangement 1 of bioreactors 2a-c. But it is also possible to provide directly to the cheese factory itself such a system or at least a bioreactor for ethanol production. Then the whey could be passed directly through the line 6 from the cheese factory in the arrangement 1, without a tank 4 would be required.

In order to prevent or reduce a bacteriological load on the whey, the whey in the tank can be added to 4 hops, preferably 100 g hops / hl whey. Hops are mycotically selective and suppress the gram-positive bacteria, which means that foreign germs contained in the whey can no longer multiply. This also means that especially the Zuckerverstoffwechselden bacteria that reduce the ethanol yield due to Zuckergehaltreduzierung be prevented in their multiplication. It is possible to add hops as total substance, but it is also possible to add only the ß - acids of the hops necessary for the bacteriostatic effect of the hops as a hop extract of the whey.

If the whey is already heavily contaminated with foreign germs, it is also advantageous for the whey to add a microbiotic mixture of photosynthetically active microorganisms and light-emitting microorganisms. This microbiotic mixture is also suitable for removing mold in the whey.

In a first bioreactor 2a, the whey is separated from inhibitors for ethanol production. This can be done via electrolysis, especially in the presence of copper. In addition, additions of the microbiotic mixture can take place in the bioreactor 2a. For the electrolysis, an electrolysis device 8 is provided, at which the copper ions are deposited at the anode. The electrolysis apparatus can also be designed as a coated bioreactor with filler body, in which an electric field is formed by an alternating coating of diamond and, for example, titanium dioxide and an activated carbon coating of the filler body. The filler may have the form of a spindle, which in turn has the coating of activated carbon. A schematic representation of such a bioreactor with packing is described in detail in FIG. However, since this electric field is quite weak, an external power source for the electrolysis should be used for a good result. For this purpose, a weak current between 400 and 600 mA, or 0.3 to 2.6 V, preferably 1, 9 V, applied, and the filler used as the anode.

Since the copper ions are not freely present in the whey, but are bound to the already contained in the whey for the breakdown of lactose in glucose and galactose responsible lactase enzymes, it makes sense to recover these enzymes back to not unnecessarily many enzymes in it To have to use the following process step of Laktoseaufspaltung. For this purpose, the applied current is turned off and initialized a voltage reversal, whereupon the enzymes dissolve from the packing, while the copper ions remain on the packing. If, at the same time, the whey thus treated is removed from the first bioreactor 2a via a further line 10, the lactase enzymes are present in the whey, but no or vanishingly few copper ions.

The whey comes directly from the cheese factory, it usually has a temperature of 45 ⁰ C - 55 ⁰ C. For the electrolysis, the temperature does not matter, so that the bioreactor 2a does not need to be equipped with a temperature control unit.

In addition, the whey in the bioreactor 2a can still be concentrated. That is, excess water is removed from the whey, so that a high lactose concentration is achieved.

Once the whey has been processed, it is passed via the second line 10 into another bioreactor 2b. There is a splitting of lactose into its two components glucose and galactose instead. Preferably, this is done at a temperature of 30 ⁰ C to 35 ⁰ C. If the whey is not already cooled to this temperature, because it comes, for example, directly from the cheese factory, or too cold, the bioreactor 2b a cooling or heating unit ( not shown here) or integrated into the bioreactor, which brings the whey to the desired temperature before the breakdown of the lactose. Furthermore, a temperature sensor (not shown here) can also be arranged in the bioreactor itself, which constantly monitors the reaction temperature.

For the Laktoseaufspaltung itself are enzymes - the so-called lactase - responsible, which are advantageously immobilized in a contained in the bioreactor contained in a container 12 filler. An exact structure of the organic Reactor is described in Figure 2. The Füilkörper increases on the one hand the reaction surface and on the other hand it provides a simple way, even with the use of a single bioreactor by simply replacing the packing from the bioreactor for step B - ie the splitting of lactose - to a bioreactor for step C. - Ethanol production - retrofit.

The enzyme used is lactase, which is advantageously produced by Kluyveromyces

- Yeasts is provided. The big advantage of using Kluyveromyces

- Yeasts is that the lactase they provide not only a breakdown of lactose in glucose and galactose is achieved, but also a conversion of galactose into glucose is possible. This is of decisive advantage for the production of ethanol since it increases the glucose content and thus the amount of ethanol.

Advantageously, less than 10 mg / l of enzymes, optimally 1 mg / l enzymes of whey are added. During an advantageous period of 8 to 10 hours, the enzymes then break down lactose into glucose and galactose. During another 14 - 16 hours, the conversion of galactose into glucose takes place.

As a result, a relatively highly concentrated glucose mixture is obtained which, for further processing in the embodiment shown here, is transferred via a third line 14 into a further bioreactor 2c. As already mentioned, the bioreactors 2b and 2c can also be integrally formed. This would now be a replacement of the filler be made to retrofit the bioreactor to the fermentation process.

The bioreactor 2c is equipped with a packing 16 which may contain yeast or bacteria as microorganisms used for fermentation. Since both fermentation processes do not take place at the same temperatures, a simultaneous presence of the two types of microorganisms in the packing is possible, but only the microorganisms for which the corresponding temperature is applied are active. Thus, an alcoholic fermentation by means of yeasts at a temperature of less than 25 ⁰ C _1, preferably between 8 ⁰ C and 10 ⁰ C, instead, while the fermentation with the aid of bacteria, especially Thermoanaerobacter ethanolicus, takes place at 60 ⁰ C to 65 ° C. , To precisely control the temperature, the bioreactor 2c may be preceded or integrated with a cooling or heating unit (not shown). Likewise, a temperature measuring device may be present, which controls whether the temperature meets the requirements.

The microorganisms are immobilized by the packing 14 in the bioreactor 2c, which simultaneously provides an increased reaction area.

Since the fermentation process is inhibited by an excessively high alcohol concentration, the already produced ethanol must be removed from the bioreactor 2c. This can advantageously be done via a diffusion membrane, not shown here. But it is also conceivable to use a special distillation membrane, which is relatively expensive. Ideally, the alcohol concentration should not exceed 12%.

The ethanol produced can then be fed via a further line 18 to a storage tank 20.

Figure 2 shows a schematic diagram of a preferred embodiment of the bioreactor consisting of a container 22 and a packing 24. In this embodiment, the container 22 is cylindrical, but it may also have any other shapes. The side walls of the container 22 are made of stainless steel in the illustrated embodiment and partially be provided with a photocatalytic coating 26. This coating 26 may be formed on the inner peripheral wall of the container 22 and / or - as shown in Figure 2 - on the outer wall 28. In the illustrated embodiment, the container 22 is made of V4A steel and provided with a titanium dioxide coating. Instead of this titanium dioxide, indium tin oxide or the like can also be used. The outer wall 28 of the container 22 is provided with a plurality of apertures 30, so that the whey to be converted can reach the interior of the container 22. These breakthroughs 30 may be stamped, for example, and it is advantageous if then the burrs protrude inwards. The lower end face 32 of the container may be closed, so that the inflow of the whey into the container 22 takes place substantially in the radial direction. The upper end face can also be closed. In the case where the upper surface is above the liquid level, sealing may be dispensed with.

In the interior of the container 22, a replaceable filling body 24 is received, which, as shown in the elevational view, a spiral-shaped structure on has. In the illustrated embodiment, this filling body 24 consists of a support 34, which may be, for example, a spirally turned stainless steel sheet. On this helical spiral support 34 made of stainless steel shown here, a foam material, for example a PU foam, is applied to both sides, which is coated or mixed with activated carbon and, if necessary, nano-composite material. The PU foam forms a pore system, the walls of which are coated with activated carbon, so that a large mass transfer area is provided.

Specifically, in the illustrated embodiment, the carrier 34 consists of a two to three millimeters thick VA grid body, wherein the helical structure is formed by two grid surfaces, between which a semi-hard, open-cell PU foam is introduced with activated carbon coating. The arranged on the downward side of the helix bars 36 are provided with a photocatalytic surface, the mesh size is at these down facing large areas about 10 - 12 mm. At the the upwardly facing large area of the spiral forming bars is no coating provided. The mesh size here is about 25 to 30 mm.

The microorganisms and enzymes mentioned above can be introduced centrally via a dosing hose into the center of the spiral-shaped filling body 24. However, it is also possible to introduce these microorganisms and enzymes with nanocomposite materials already in the production of the filler 24 in the pore system. Very promising have been experiments in which the microorganisms or enzymes and nanocomposite materials are dissolved in chitosan and this mixture added with the nano-composite materials is then applied to the filler, for example by impregnation, so that continuous feeding of microorganisms or enzymes deleted and only at regular intervals replacement of the filler 24 is required.

The PU foam is coated in the embodiment shown here on the downwardly facing side of the helix with a gel-like material of chitosan. In this chitosan, the nano-composite materials are embedded, each of which is a piezoelectric ceramic system of PZT Kr cfasern with photocatalytic lytic coatings. Furthermore, microorganisms or lactase-producing Kluyveromyces yeasts are also embedded in the fermentation. The container 22 is coated both on its inner surface and on its outer surface with the photocatalytically active layer 26 - so for example, the titanium dioxide. This layer is completely applied to the inner surface, that is to say on the side facing the filler body 34, while on the outer surface the titanium dioxide is applied in the form of strips 26, between which regions which are provided with a diamond coating 38 remain.

Such a diamond coating 38 can be produced synthetically by heating methane and hydrogen and a suitable carrier substance, for example niobium, silicon or ceramic, in a vacuum chamber to temperatures of up to approximately 2000 °. It then comes to a reaction in which a diamond lattice is formed on the carrier. This coating 38 is then applied to the outer wall 28 of the container 22, so that with a photocatalytically active 26 and provided with a diamond layer 38 areas adjacent to each other. These areas 26, 38 extend in the longitudinal direction of the container 22. In the illustrated embodiment, the width of the strips 26 corresponds approximately to the distance of four hole-shaped openings 30, while the width of the areas 38 is substantially smaller and approximately equal to the distance between two adjacent openings 30 ,

In cooperation with the catalytic coating of the container 22 and the above-described coating and the activated carbon therein of the helical filling body 24, a comparatively strong electromagnetic field arises. The resulting potential difference is applied to the regions provided with the diamond coating 38, which then act as diamond electrodes. This voltage can be used to deposit the copper ions contained in the whey at the anode acting as an electrode. In addition, an external power source can be present, which actively supports the electrolysis of copper. Details about the electromagnetic field resulting from the coating are disclosed in the earlier application DE 103 30 959.4, so that further explanations in this respect are unnecessary.

FIG. 3 schematically shows a further embodiment of the present invention in which ethanol is obtained from whey. From a tank 31 of raw whey added to hops in a ratio of preferably 100 g / hl, the whey is introduced into an aerobic loop reactor 32 of the type already described above. If the whey is heavily loaded, the microbial mixture 33 described above can be added to the aerobic loop reactor of the whey. Furthermore, demineralization of the whey can take place in the loop reactor. In particular, potassium, but also salts, such as NaCl affect the fermentation and can sometimes hinder this strong.

The whey thus treated is then transferred to a buffer tank 34 in which whey is collected from the loop reactor to be available for further processing. In this case, whey can be brought together from a wide variety of dairies, so that advantageously also a stabilization of the whey takes place. It is particularly advantageous if a whey with a certain lactose content is present in the buffer container. For this purpose, the introduced whey can either be diluted or concentrated.

In a further container 35, the pH of the whey is raised to the value necessary for the subsequent enzyme treatment, between pH 5 - 7, 5, in particular pH = 5.8 - 6.3. The enzyme treatment and the breakdown of lactose and galactose into glucose has already been described above.

Subsequently, in a membrane filtration system 36, some tiny particles are removed from the whey in order to achieve a particularly good fermentation result.

The thus pretreated whey - actually now the glucose-containing fluid - is now transferred to a fermentation tank 37, in the fermentation yeast, which was preferably pretreated in a yeast fermenter 38, is added. After fermentation is carried out in another container 39, the yeast deposition in order to obtain ethanol in the purest possible form. Thereafter, the ethanol thus obtained is transferred to another container 40 in which the last residues of yeast and sugar are fermented to ethanol.

Disclosed is a method for degrading gärhemmender substances in a fluid containing saccharide-containing substances, wherein in the fluid, a microbiotic mixture, in particular a mixture of photosynthetic microorganisms and light-emitting microorganisms, introduced, which is designed to degrade the gärhemmenden substances.

Claims

claims:

1. A method for degrading gärhemmender substances in a fluid containing saccharide-containing substances, characterized in that in the fluid a microbiotic mixture, in particular a mixture of photosynthetic microorganisms and light-emitting microorganisms, is introduced, which is adapted to degrade the gärhemmenden substances ,

2. The method of claim 1, wherein the microbiotic mixture is added to the fluid.

3. The method of claim 1, pretreating the saccharide-containing materials contained in the fluid with the microbiotic mixture to be introduced into the fluid.

4. The method of claim 1, 2 or 3, wherein the fluid consists of food, and / or food residues.

5. The method of claim 4, wherein the fluid is whey.

6. The method of claim 4, wherein the fluid is must, in particular from grapes or fruit, or mash, in particular from barley.

7. The method of claim 6, wherein the must and / or the barley underlying substances are pretreated with the microbiotic mixture.

A method according to any preceding claim, wherein the photosynthetic microorganisms contained in the microbiotic mixture are prochlorophytes, cyanobacteria, green sulfur bacteria, purple bacteria, chloroflexus-like forms, heliobacteria and heliobacillus-like forms, and mixtures of two or more thereof.

9. The method according to any one of the preceding claims, wherein the light-emitting microorganisms contained in the microbiotic mixture are Photobacterium phosphoreum, Vibrio fischeri Vibrio harveyi, Pseudomonas lucifera or Beneckea or mixtures of two or more thereof.

10. The method according to any one of the preceding claims, wherein the microbial mixture of the further plant extracts, enzymes, trace elements, polysaccharides, alginates and / or other microorganisms contains individually or in combination.

11. The method according to any one of the preceding claims, wherein the fluid hops and / or hop extracts are added.

12. The method according to any one of the preceding claims, wherein the method is used in the production of ethanol for the degradation of gärhemmenden substances.

13. A process for the production of ethanol, characterized in that for the degradation of fermentation inhibiting substances, a method according to any one of claims 1 to 12 is performed.

14. A process for the production of ethanol from whey characterized by the following steps

A. removing inhibitors, in particular copper, from the whey;

B. converting lactose contained in the whey into glucose;

C. Adding microorganisms, in particular yeast and / or bacteria, for the production of ethanol from glucose.

The method of claim 14, wherein the step of converting lactose into glucose comprises breaking down lactose into glucose and galactose, and converting galactose into glucose by means of Kluyveromyces yeasts or similar acting organisms.

16. The method of claim 14 or 15, wherein the inhibitors are removed from the whey by electrolysis.

17. The method according to any one of claims 14 to 16, wherein the whey before step B hops and / or hop extracts and / or a microbiotic mixture of photosynthetic microorganisms and light-emitting microorganisms is added.

18. The method according to any one of claims 14 to 17, wherein prior to step C, a method for degrading gärhemmenden substances according to one of claims 1 to 12 is performed.

19. The method according to any one of claims 14 to 18, wherein at step C, the ethanol content is maintained by diffusion through an ethanol-permeable membrane at a certain percentage, in particular less than 12%.

20. The method according to any one of claims 14 to 19, wherein the step A at a temperature between 2O ⁰ C and 70 ⁰ C, preferably at a temperature between 48 ⁰ C and 50 ⁰ C is performed.

21. The method according to any one of claims 14 to 20, wherein the step B at a temperature between 1O ⁰ C and 60 ⁰ C, preferably at a temperature below 36 ° C, in particular at a temperature between 28 ° C and 35 ° C, carried out becomes.

22. The method according to any one of claims 14 to 21, wherein the step C in the use of bacteria at a temperature between 30 ⁰ C and 80 ° C, preferably at a temperature between 58 ⁰ C and 68 ° C is performed.

23. The method according to any one of claims 14 to 21, wherein the step C in the use of yeasts at a temperature between 0 ⁰ C and 40 ⁰ C, preferably at a temperature below 25 ° C, in particular at a temperature between 5 ° C and 12 ° C, is performed.

24. The method according to any one of claims 14 to 23, wherein the steps A, B, and / or C in succession in at least one, preferably in three series-connected bioreactors (2a-c) are performed.

25. The method of claim 24, wherein the at least one bioreactor (2a-c) comprises a container (22) having at least one recess for the passage of the whey, and a filling body (12, 16, 24) inside the container (22). is arranged, wherein the container outer walls are partially coated with a photocatalytically active layer (26), and the filler body (24) has a coating of activated carbon.

26. The method of claim 25, wherein in the bioreactor used between the sectionally photocatalytically active coating (26) a diamond coating (38) is applied.

27. The method according to claim 25 or 26, wherein the photocatalytically active layer (26) of the bioreactor used is in particular titanium dioxide or indium tin oxide.

28. The method of claim 25, 26 or 27, wherein the photocatalytic active layer (26) and the diamond layer (38) are strip-shaped applied in the longitudinal direction of the container.

29. Arrangement (1) of bioreactors (2a-c) for carrying out a method according to one of claims 14 to 28, wherein at least two, preferably three, bioreactors are arranged in series one behind the other and at least one of the bioreactors a container (22) with at least a recess (30) for the passage of the whey, and a filling body (12, 16, 24) which is arranged in the interior of the container (22), wherein the container outer walls are partially coated with a photocatalytically active layer (26) and the Packing (24) has a coating of activated carbon.

30. Arrangement of bioreactors according to claim 29, wherein in the at least one bioreactor (2a-c) between the sectionally photocatalytically active coating (26) a diamond coating (38) is applied.

31. Arrangement of bioreactors according to claim 29 or 30, wherein the photocatalytically active layer (26) of the bioreactor used is in particular titanium dioxide or indium tin oxide.

32. Arrangement of bioreactors according to claim 29, 30 or 31, wherein the photocatalytic active layer (26) and the diamond layer (38) are applied in strips in the longitudinal direction of the container.

Use of a bioreactor for carrying out the method characterized in claims 14 to 28 with a container having at least one recess for the passage of the whey, and a filling body which is arranged in the interior of the container, wherein the container outer walls are partially coated with a photocatalytically active layer and the filler (24) has a coating of activated carbon.