FI95725B - Process for preparing a growth substrate or growth substrate component for lactic acid bacteria, a product which is obtained in this way, and its use - Google Patents

Abstract

The invention relates to a process for preparing a growth substrate or a growth substrate component for lactic acid bacteria, with the process being characterised in that a) a press liquid which is derived from producing silage is recovered fresh and stored, where appropriate using a preservative, and, if desirable, the press liquid is converted into grass molasses in a manner known per se, b) the pH of a fresh press liquid, which contains preservative, where appropriate, or of grass molasses which have been produced from a press liquid whose dry substance content has been diluted to less than 25% by weight, is raised to a value greater than 7.7, c) the solution obtained in step b) is heated to a temperature which exceeds 35 degree C, d) the precipitate which has formed is removed from the solution obtained in step c), which solution has a pH greater than 7.7 and a temperature greater than 35 degree C, e) the solution obtained in step d) is cooled and its pH is lowered to a value less than 7.7, and f) if necessary, other growth substrate materials are added to the solution obtained in step e), and g) if desirable, the solution obtained in step e) or f) is concentrated by evaporation to a dry substance content of at least 40% by weight, and to a product which is obtained in this way and to its use as a growth substrate or growth substrate component for lactic acid bacteria.

Description

95725

The invention relates to a process for the preparation of a lactic acid bacterial medium or a medium component, the product thus obtained and its use. The product obtained is clarified grass molasses suitable as a growing medium or growing medium component in the industrial production of lactic acid bacteria.

During the production of AIV feed, pressed liquid leaks from the feed. The pressed liquid drains from the damaged plant cells during harvesting and, on the other hand, the acidification of the feed causes plasmolysis, i.e. the general release of cellular fluids. Most of the fluid is formed within about a week of the feed being made. Depending on the circumstances, the pressurized liquid losses in the production of feed are 5 to 20% by weight of the fresh weight of the feed, and an average of 1200 kg of pressed liquid is formed per annual feed requirement of one cow.

The dry matter content of the pressed liquid typically varies between 3 and 10% by weight. The liquid contains carbohydrates, amino acids and growth factors from grass in rapid growth, so it is prone to spoilage. When released into the environment, pressurized liquid contaminates surface and groundwater and clogs ditches. On the other hand, the liquid is acidic, typically having a pH of about four. Acidic compression fluid damages the crop and corrodes structures. Pressed liquid is therefore an environmental problem in livestock farming.

On farms, the pressed liquid can be utilized with a solder-30 racket for animals or by applying it to the fields as fertilizer. Watering is difficult to arrange due to the poor shelf life of the liquid and application as a fertilizer is limited by the acidity of the liquid. In both cases, dosing is hampered by large variations in the dry matter content of the liquid.

95725 2

The problems caused by the poor preservation of the pressed liquid and the variation of the dry matter content have been solved in Finnish patent publication 87 881, which discloses a method for recovering the pressed liquid in good quality and concentrating it into grass molasses that remains at a constant dry matter content. Grass molasses has proven to be a tasty sugar feed for cows (Miettinen, Maito and Me 4/1991 p.19).

The poor shelf life of the pressed liquid is a sign that it is rich in microbial nutrients. Efforts have been made to reduce the high oxygen consumption of the pressed liquid by growing Torulopsis alabrate (Olsen and Pedersen, Acta Agricultura Scandinavica 24 (1974) 160-168) or by producing methane from it in a bioreak-15 market (Barry and Colleran, Agricultural wastes 4 (1982) 231-239). ). It can also be concluded from the composition data that the pressed liquid and suitably diluted grass molasses are suitable as growth media for microbes (Poutanen, Pellervo 10 (1983) 46-47 and Finnish patent publication 87,881).

20 Lactic acid bacteria are very demanding on their growth media. In addition to fermentable sugars, the medium must contain free amino acids or short peptides, as the proteolytic activity of lactic acid bacteria is weak. In addition, lactic acid bacteria need various vitamins and other growth factors from their growth medium.

Whey is used as the main raw material in the substrates used in the industrial production of lactic acid bacteria and the substrate has to be supplemented with expensive supplements such as yeast extract and casein hydrolyzate. This is due to the inability of lactic acid bacteria to synthesize the growth factors they need. The substrates used in production are quite expensive, the cost of the substrate is up to half of the total cost of production. In the microbiological laboratory work, 11 95725 3 commercial MRS and M17 media, the composition of which is given in Table 1, are used as microbial growth media. These media are very expensive to use, so it is desirable in the art to provide more cost-effective growth media.

5

Table 1. Compositions of commercial media (MRS and M-17) for growing lactic acid bacteria MRS M-17 10 Peptone 10.0 g Polypeptide 5.0 g

Meat extract 10.0 g Phytonipeptone 5.0 g

Yeast extract 5.0 g Yeast extract 2.5 g

Glucose 20.0 g Meat extract 5.0 g

Tween 80 * 1.0 ml Disodium glycol 15 Dipotassium hydrogen serophosphate 19.0 g phosphate 2.0 g Magnesium sulphate 0.25 g

Sodium acetate 5.0 g Ascorbic acid 0.5 g

Diammonium citrate 5.0 g

Magnesium sulphate 0.2 g 20 Water 1000 ml Water 1000 ml Polyethylene oxide sorbitan monooleate

Compressed liquid and suitably diluted grass molasses have been found to be suitable as such as a growth medium for certain lactic acid bacteria used in feed and feed preservatives (J. Sahlstein, Diploma Thesis, Helsinki University of Technology, 1992). In the same context, it is stated that grass mold is also suitable as a component of the microbial culture medium. Grass molasses apparently contains all the nutrients needed by lactic acid bacteria in a suitable ratio, and a substrate based on grass molasses is inexpensive compared to substrates currently used industrially.

In addition to a suitable nutrient composition, a substrate suitable for the industrial production of lactic acid bacteria is required not to cause problems in the production process itself. Most of the medium can cause problems concentrating cells from the growth solution after growth has stopped. 5 microfiltration or ultrafiltration is used to concentrate lactic acid bacteria on an industrial scale, making even a small precipitate in the medium difficult.

As previously mentioned, the natural pH of the pressed liquid is about four. Then the liquid contains mainly cells, plant residues and possibly sand from the field 10 as solids. In the production of lactic acid bacteria, the optimal pH conditions are generally in the range of pH 5.5 to 7.5. When the pH of the pressed liquid or grass molasses is adjusted to this range, the divalent cations and phosphate naturally present in the liquid precipitate. The precipitate is very fine and, even at low concentrations, it quickly forms a dense secondary layer on the filter surface which impedes flow, i.e. the filter becomes clogged and the concentration has to be stopped (cf. Example 1). Thus, pressed liquid or suitably diluted grass molasses 20 as such are not suitable as a growth medium for the industrial production of lactic acid bacteria.

It has now surprisingly been found that pressed liquid or suitably diluted grass molasses are suitable as substrates for the industrial scale production of lactic acid bacteria when the solids contained therein and the phosphate precipitate formed during pH adjustment are removed according to the invention.

The method according to the invention is therefore characterized in that a) the pressed liquid from the manufacture of silage is recovered fresh and preserved, possibly by means of a preservative, and if desired the pressed liquid is converted into grass molasses in a manner known per se, b) fresh, optionally preserved-containing pressed liquid or dry. the pH of the grass molasses made from pressed liquid diluted to a content of less than 25% by weight is raised to more than 7.7, it 95725 5 c) the solution obtained in step b) is heated to a temperature above 35 ° C, d) the solution obtained in step c), a pH of more than 7,7 and a temperature of more than 35 ° C, the precipitate formed is removed, (e) the solution obtained in step (d) is cooled and its pH is reduced to less than 7,5 and (f) other media are added to the solution obtained in and 10 g) the solution obtained in step e) or f) is, if desired, evaporated to a dry matter content of at least 40% by weight.

A method for recovering and converting pressed liquid into grass melons is described in Applicant's F1 Patent Publication No. 87,881.

In the process according to the invention for preparing the lactic acid bacteria medium or the medium component, it is essential that the pH of the precipitate in step d) is above 7.7 and preferably pH 8-10 and that the temperature is above 35 ° C and preferably 50-60 ° C, since the precipitate The formation is dependent on pH and temperature. The solution obtained in step d) is removed from the solution obtained in step c), for example by filtration or centrifugation. The product obtained is used as a suitably diluted medium for lactic acid bacteria and the media are heat-treated. : 25 before adding pure culture. If values lower than the above-mentioned pH and temperature values are used to remove the precipitate, the precipitate is re-formed during the heat treatment of the medium (Examples 3 and 4).

The solution obtained in step e) in step d) is cooled to a pH of less than 7.5, preferably less than 5, in order to promote the preservation of the medium properties of the product (Example 13).

If necessary, other media are added to the solution obtained in step f) in step e) to ensure the secrecy of the medium. Such optional additives may include, for example, sugars and glucose, as well as yeast extract and casein hydrolyzate.

The solution already obtained in step d) or e) can be used as a medium for lactic acid bacteria as such or supplemented as necessary. The solution obtained in step e) or f) can, if desired, be evaporated to a dry matter content of at least 40% by weight.

Example 2 provides a practical description of the clarification process according to the invention, in which the product according to FI patent publication 87 881 is used as a starting material, and Table 2 shows the changes in the composition of the product during the process.

15 Table 2. Compositions of the product according to FI patent publication 87 881 and the product according to the invention Product according to FI patent publication 87 881

Protein 127 g / kg 125 g / kg

Glucose + fructose 187 g / kg 198 g / kg

Organic acids 110 g / kg 110 g / kg 25 Ash 155 g / kg 190 g / kg phosphorus 5.4 g / kg 0.6 g / kg potassium 3.9 g / kg 59.9 g / kg calcium 8.1 g / kg 0.9 g / kg chloride 27.4 g / kg 36.4 g / kg 30 -magnesium 5.1 g / kg 2.7 g / kg: sodium 2.0 g / kg 33.0 g / kg

The product prepared according to steps a) to g) described above is suitably diluted with a variety of lactic acid bacteria, such as the lactic acid bacterium Enterococcus

II

7

QR79R

faecium, Lactobacillus plantarum, Lactobacillus fermentum and Streptococcus thermophilus, as a culture medium either as such or supplemented with specific needs such as glucose or yeast extract (Examples 5 and 6).

From the product prepared according to steps a) to g), the medium prepared by suitable dilution gives better cell yields than expensive commercial optimum media or industrial whey-based media (Examples 7 and 8).

10 It has now surprisingly been found that the product prepared according to steps a) to g) described above is suitably diluted for the production of lactic acid bacteria on an industrial scale and it is possible to concentrate the cells produced with it in industrial production equipment (Example 9).

According to the Finnish patent publication 87,881, the growing medium properties of grass molasses vary depending on the feed harvest and the year. It has now surprisingly also been found that the cell yields of the medium produced by the method described in a) to g) above are better and more stable than the suitably diluted grass molasses prepared according to Finnish Patent Publication 87,881 (Example 10).

The product of the invention can also be used. 25 as a medium for other industrially interesting lactic acid bacteria, if for some reason it cannot be used as a major component of the medium (Example 11).

The treatment according to the invention also improves the microbiological quality of the product. Although the growth media are heat-treated to kill the bacteria and spores involved in the substrate components, spores in particular can withstand this heat treatment. Therefore, in industrial production, attention is already paid to the microbiological quality of raw materials. Example 12 shows that the treatment improves the microbiological quality of the 35 products.

8 95725

The invention is further illustrated by the following examples. In the examples, reference is made to the accompanying drawings, in which Figure 1 is a graphical representation of the results of the 5 experiments described in Example 1 showing precipitated grass molasses-based (- □ -) and whey-based (- · -) medium as a function of concentration of lactic acid bacteria in industrial scale production .

10 Figure 2 shows the years of clarified grass molasses-based (- □ -) and whey permeate-based (- · -) media as a function of concentration of lactic acid bacteria with a microfilter used in industrial scale production.

Example 1 Enterococcus faecium is an intestinal lactic acid bacterium used in ready-to-eat and silage preservatives, especially for young animals.

Figure 1 shows permeate flows as a function of time 20 when concentrating E. faecium cells from two different growth solutions with a microfilter used in the industrial production of lactic acid bacteria (Alfa-Laval type MFS 1X38, pore size 1.4 μm). Curve 1 (- · -) depicts the permeate flow when concentrating E. faecium grown on a conventional whey-based medium. Curve 2 (- □ -) depicts the flow of permeate when concentrating E. faecium cells in a medium which is an 11% by weight aqueous solution of grass molasses prepared according to FI patent publication 87 881. Part of the precipitate had been removed from the medium and about 30 of the original, i.e. 6 g / l, remained.

! It can be seen from Figure 1 that the precipitated medium clogged the filter and the run had to be stopped after 15 minutes of filtration. On a traditional whey medium, the concentration could be completed in one go.

li 9 95725

Example 2

286 g of a product prepared according to FI patent publication 87 881 with a dry matter content of about 70% by weight were weighed into the vessel. The product was dissolved in 800 g of water to give a solution with a dry matter content of about 20% by weight. The pH of the solution was raised to 9.5 with sodium hydroxide and the temperature was raised to 55 ° C. The precipitate formed was separated by centrifugation in a laboratory centrifuge (3000 g, 10 min), the clear portion was collected and the pH was lowered to five with hydrochloric acid, after which it was evaporated on a vacuum evaporator to a dry matter content of 60% by weight.

143 g of the product prepared as described above were weighed into the vessel, dissolved in 900 g of water, and the pH of the mixture was adjusted to seven with sodium hydroxide, which is the optimum pH for the growth of some lactic acid bacteria. When the mixture was heat treated as commonly used in biotechnology (15 minutes at 121 ° C), no precipitate formed.

20 Example 3

143 g of a product prepared according to FI patent publication 87 881 with a dry matter content of about 70% by weight were weighed into the vessel. The product was dissolved in 900 g of water to give a solution with a dry matter content. 2 5 was about 10% by weight. The pH of the solution was raised to 9.5 with sodium hydroxide and the temperature was raised to 22 ° C. The precipitate formed was separated by suction filtration and Whatman GF / A filter paper. The clear portion was collected and the pH was lowered to five with hydrochloric acid, after which it was evaporated on a vacuum evaporator to a dry matter content of 60% by weight.

143 g of the product prepared as described above were weighed into the vessel, dissolved in 900 g of water, and the pH of the mixture was adjusted with sodium hydroxide to seven, which is the optimum pH for the growth of some lactic acid bacteria. When the 95725 10 mixture was heat treated as commonly used in biotechnology (15 minutes at 121 ° C), a precipitate formed.

Example 4 143 g of a product prepared according to FI patent publication 87 881 with a dry matter content of about 70% by weight were weighed into a container. The product was dissolved in 900 g of water to give a solution with a dry matter content of about 10% by weight. The pH of the solution was raised to 7.5 with sodium hydroxide and the temperature was raised to 55 ° C. The precipitate formed was separated by suction filtration and Whatman GF / A filter paper. The clear portion was collected and the pH was lowered to five with hydrochloric acid, after which it was evaporated on a vacuum evaporator to a dry matter content of 60% by weight.

143 g of the product prepared as described above were weighed into the vessel, dissolved in 900 g of water, and the pH of the mixture was adjusted to seven with sodium hydroxide, which is the optimum pH for the growth of some lactic acid bacteria. When the mixture was heat treated as commonly used in biotechnology (15 minutes at 121 ° C), a precipitate formed.

Example 5

To grow Enterococcus faecium, 143 g of the product of the invention were dissolved in 900 g of water, the pH of the mixture was adjusted to 7.0 with sodium hydroxide, and the mixture was heat-treated at 121 ° C for 15 minutes. After inoculation of the pure culture, the cell concentration was 5.4-109 colonies / ml and after 20 hours of growth, the cell concentration in up to -30 was 12.0-109 colonies / ml. During the growth period, the temperature was »· 35 ° C and the pH was maintained at 7.0 with a regulator and 20% by weight of sodium hydroxide.

To grow Lactobacillus plantarum, 250 g of the product of the invention was dissolved in 820 g of water, the pH of the mixture was adjusted to 6.0 with sodium hydroxide and the mixture was heat-treated for 15 minutes at 121 ° C. After inoculation of pure culture (inoculation 1% by volume of medium volume) and growth for 22 hours, the cell concentration in the dish was 9.7-109 colonies / ml. During the growth period, the temperature was 32 ° C and the pH was maintained at 6.0 with a regulator and 20% by weight sodium hydroxide.

Example 6

To grow Lactobacillus plantarum, 250 g of the product according to the invention and 5 g of yeast extract were dissolved in 820 g of water. The pH of the mixture was adjusted to 6.0 with sodium hydroxide and the mixture was heat treated at 121 ° C for 15 minutes. After inoculation of pure culture (inoculum 1% by volume of medium volume) and growth for 22 hours, the cell concentration in the dish was 11.1-109 colonies / ml.

During the growth period, the temperature was 32 ° C and the pH was maintained at 6.0 with a regulator and 20% by weight sodium hydroxide.

To grow Lactobacillus fermentum, 143 g of the product of the invention and 15 g of glucose were dissolved in 900 g of water. The pH of the mixture was adjusted to 6.0 with sodium hydroxide-20a and the mixture was heat treated at 121 ° C for 15 minutes. After inoculation of the pure culture and growth for 12 hours, the cell concentration in the dish was 3.4109 colonies / ml. During the growth period, the temperature was 37 ° C and the pH was maintained at 6.0 with a regulator and 20% by weight sodium hydroxide.

: 25 Example 7

To grow Lactobacillus plantarum, 250 g of the product of the invention was dissolved in 820 g of water, the pH of the mixture was adjusted to 6.0 with sodium hydroxide, and the mixture was heat-treated at 121 ° C for 15 minutes. After inoculation of pure culture (inoculum 1% by volume of medium volume) and growth for 22 hours, the cell concentration in the vessel was 9.7-109 colonies / ml. During the growth period, the temperature was 32 ° C and the pH was maintained at 6.0 with a regulator and 20% by weight sodium hydroxide.

95725 12

Lactobacillus plantarum was grown in commercial MRS medium, the composition of which is shown in Table 1 above. After inoculation of pure culture (inoculum 1% by volume of medium volume) and growth for 22 hours, the cell concentration in the vessel was 2.5-109 colonies / ml. During the growth period, the temperature was 32 ° C and the pH was maintained at 6.0 with a regulator and 20% by weight sodium hydroxide.

To grow Lactobacillus fermentum, 143 g of the product of the invention and 15 g of glucose were dissolved in 10,900 g of water. The pH of the mixture was adjusted to 6.0 with sodium hydroxide and the mixture was heat treated at 121 ° C for 15 minutes. After inoculation of pure culture (inoculum 1% v / v of the volume of medium) and growth for 12 hours, the cell concentration in the dish was 3.4,109 colonies / ml. During the growth period, the temperature was 37 ° C and the pH was maintained at 6.0 with a regulator and 20% by weight sodium hydroxide.

Lactobacillus fermentum was grown in a commercial MRS medium, the composition of which is shown in Table 1 above. After inoculation of pure culture (inoculum 1 ti-20% by volume of medium volume) and growth for 12 hours, the cell concentration in the vessel was 5.7-10® colonies / ml. During the growth period, the temperature was 37 ° C and the pH was maintained at 6.0 with a regulator and 20% by weight sodium hydroxide.

Example 8 To grow Enterococcus faecium, 143 g of the product of the invention were dissolved in 900 g of water, the pH of the mixture was adjusted to 7.0 with sodium hydroxide and the mixture was heat-treated at 121 ° C for 15 minutes. Cell content after inoculation of pure culture (inoculum 1% by volume of 30 volumes of medium) and growth for 20 hours «. the vessel had 12.0 109 colonies / ml. During the growth period, the temperature was 35 ° C and the pH was maintained at 7.0 with a regulator and 20% by weight sodium hydroxide.

In the medium used to grow Enterococcus faecium, 60 g of whey permeate, 10 g of casein 95725 13 hydrolyzate, 4 g of yeast extract and 1 ml of Tween 80 were dissolved in 930 g of water and the mixture was heat-treated for 15 minutes at 121 ° C. After inoculation of pure culture (inoculum 1% by volume of medium volume) and growth for 20 hours 5, the cell concentration in the vessel was 5.5 · 109 colonies / ml. During the growth period, the temperature was 35 ° C and the pH was maintained at 7.0 with a regulator and 20% by weight sodium hydroxide.

Example 9

Figure 2 shows the permeate flows when concentrating E. faecium cells with a microfilter used in the industrial production of lactic acid bacteria (Alfa-Laval nitrogen MFS 1X38, pore size 1.4 μιη). Curve 1 (- · -) depicts the permeate flow when concentrating E. faeci-15 uma grown on a traditional whey-based medium. Curve 2 (- □ -) depicts the flow of permeate when concentrating a culture in which the product of the invention has a dry matter content of 10% by weight.

It can be seen from Figure 2 that there are no significant differences in permeate flows. Thus, lactic acid bacteria can be concentrated with filters used in industrial production when the product of the invention is used in the medium.

Example 10

Table 2 shows the number of colonies from experiments in which the cell yields of E. faecium in the medium prepared from the product according to FI patent publication 87 881 and the product prepared according to the invention have been compared in different years. The medium made of grass molasses according to FI patent publication 87 881 has been prepared by dissolving 158 g of the a cane-30 mold made according to the patent publication to 890 g of water and by adjusting the pH of the solution to 7.0 with sodium hydroxide. The medium made from the product according to the invention has been prepared by dissolving 143 g of the product according to the invention in 900 g of water and adjusting the pH of the solution to 7.0 with sodium hydroxide. In all cases, the inoculum was 1% by volume of the medium volume and the growth time was 20 h.

95725 14

Table 3. Colony counts of E. faecium when grown in growing media from different years, on the one hand according to FI patent publication 87 881 and on the other hand made from products according to the invention 5

Colony count 109 CFU / ml

Product of the 1991 harvest according to FI patent publication 87,881 10.1 10 Product of the invention of the 1991 harvest 12.4

Product of the 1992 harvest according to FI patent publication 87 881 8.1 15 Product of the invention of the 1992 harvest 12.0

Product of the 1993 harvest according to FI patent publication 87 881 8.0 20 Product of the invention of the 1993 harvest 12.3

Example 11

The lactic acid bacterium Strepto- · 25 coccus thermophilus used in cheese and yoghurt patties is produced on a whey-based medium supplemented with casein hydrolyzate. The concentration of casein hydrolyzate in the medium is 0.5%. When the casein hydrolyzate was replaced by the corresponding amount of grass molasses calculated as dry matter, no differences were observed in the growth rate of the cells or in the final cell concentration. During the growth, the pH was kept above six.

Example 12 From the grass molasses produced according to FI patent publication 87 881 and the product according to the invention, the amounts and total bacterial concentrations of aerobic bacterial spores and clostridial spores 95725 15 were determined. The results of the assays are shown in Table 4. The table shows that the treatment improves the microbiological quality of the product.

5 Table 4. Results of microbiological analyzes of grass molasses and the product according to the invention According to FI patent publication

Aerobic bacterial spores 10,000 pcs / g <100 pcs / g

Clostridial spores 30 MPN / g <3 MPN / g 15 Bacterial colony counts 15,000 / g <100 / g

Example 13

To investigate the shelf life of the product according to the invention, two 500 g batches of the product according to the invention were weighed. The pH of the product after preparation was 7.0. The pH of the second batch was lowered to 5.0 with 25% by weight hydrochloric acid, but the pH of the second batch was not changed. Cell yields of both batches with Entrococcus faecium were determined at the beginning of the experiment and after six months of storage.

To grow Entrococcus faecium, 143 g of the test portion was dissolved in 900 g of water, the pH of the mixture was adjusted to 7.0 with sodium hydroxide, and the mixture was heat-treated at 121 ° C for 15 minutes. After inoculation of pure culture (inoculum 1% by volume of medium volume) and growth for 20 hours, cell yield was determined by separating the cells from 100 ml of medium in a laboratory centrifuge, washing them twice with deionized water, drying the washed cell mass at 102 ° C. hours and weighing the dry cell mass.

16 95725

Table 5 shows the cell yields of the two products of the invention stored at different pH before and after six months of storage. It can be seen from the table that at pH 7 the product has completely lost its medium properties in six months, but the medium properties of the product stored at pH 5 are still partially preserved.

Table 5. Effect of storage pH on the preservation of medium properties of the product of the invention

Storage pH Cell yield Cell yield at the beginning of 6 months of storage 15 5 3.9 g / l 2.7 g / 1 7 4.0 g / 10 g / l • · a »·

Claims (7)

A process for preparing a growth substrate or a growth substrate component for lactic acid bacteria, characterized in that a) a fresh preparation of silage-derived press liquid is freshly collected and stored, possibly with the aid of a preservative and if desired, in the case of pressurized water. b) the pH of a fresh, possibly preservative containing pressurized liquid or in a turf, prepared from a pressurized liquid and whose dry matter content is diluted to less than 25% by weight; is raised to a value above 7.7, c) the solution obtained in step b) is heated to a temperature exceeding 35 ° C, d) the precipitate formed is removed from the solution obtained in step c), which has a pH above 7 , 7 and a temperature above 35 ° C, e) the solution obtained in step d) is cooled and its pH is lowered to a value below 7.5 and f) in the step e) the poured solution is added to other growth substrate materials as needed; and. G) if desired, the solution obtained in step e) or f) is evaporated to a dry matter content of at least 40% by weight. Process according to claim 1, characterized in that in step b) the pH of the solution is raised to a value 8-10, to which it is poured in step d). 3. Process according to claim 1 or 2, characterized in that in step e) the pH of the solution is lowered to a value below 5. 4. A process according to any one of claims 1-3, characterized in that in step c) the solution is heated to a temperature of 50 - 60 eC at which it is poured in step d). Process according to any of claims 1-4, characterized in that in step d) the precipitate is removed by filtration or centrifugation. 6. Growth substrate or a growth substrate component for lactic acid bacteria, characterized in that it is prepared according to a process according to any of claims 1-5. Use of a product prepared according to any one of claims 1-5 as a growth substrate or growth substrate component for lactic acid bacteria. • I · 1