DD155287A3 - METHOD FOR PRODUCING DRY LEAD WITH IMPROVED APPLICATION PROPERTIES - Google Patents

Abstract

The method relates to an improvement in the use of dry yeast as feed. The aim of the invention is the production of a dry yeast whose content of ash formers, in particular in the form of inorganic Zellinhaltsstoffen, is substantially reduced, without the content of water-soluble organic valuable materials, such as proteins and carbohydrates, is reduced to the same extent. Before a thermolytic treatment, which takes place above 328 K, the crude protein component content in the suspension is adjusted so that the content of organically bound nitrogen is at least 2% of the nitrogen bound in the yeast cells of the suspension. The mechanical separation of the aqueous phase is carried out to a yeast dry matter content of the drying suspension of at least 10%.

Description

Process for the production of dry yeast with improved application properties

IPK: C 12 D

Field of application of the invention

The present invention relates to a process for improving the use of dry yeast as feed or for processes in which dry yeast is to be freed by solvent extraction of hydrocarbons and lipids and then fed to animal nutrition or other use. It can be used in plants where dry yeast with a low ash content and non-organic content as well as a high protein content is to be produced. These include in particular large-scale plants for feed yeast extraction from carbohydrates and hydrocarbons.

Characteristic of the known technical solutions

In industrial plants for the production of forage yeast, dry yeast is usually produced as an intermediate or end product. This dry yeast contains about 7-9 wt .-% inorganic components, known as ash formers, which are partly naturally present as cell constituents of the yeast or by drying of inorganic components from the Restnährmedien the yeast cell suspension to be dried in the dry product.

The proportion of organic non-protein substances is between 3 and 50% by weight. The proportion of nitrogenous compounds ^; in the following called crude protein, moves in the Gr OZ ^ - order of 40 - 55 wt .-%

High-quality products are characterized by a low content of ash formers and a high crude protein content. Dry yeasts, which are based on the growth of yeasts on hydrocarbons, contain from 0.5 to about 10 wt .-% hydrocarbons, which must be removed in the Hegel by extraction with organic solvents. Suitable extractants are u.a. According to patent DD 124 057 mixtures of gasoline and alcohols, economically favorable extraction processes operate on the countercurrent principle. The extraction with countercurrent guidance of the extractant requires a good wetting and Absinkverhalten, since the dry yeast particles are moved alone by the Erdschwerkraft in countercurrent to the extractant. Throughput and extraction efficiency are thus directly related to the wettability and Absinkverhalten of the solid to be extracted. In particular, the discharge of unextracted yeast with the extractant must be prevented. This problem of yeast release with the extractant is a general problem in countercurrent extraction. ..... ...-

According to the method according to DD 110 644, a device is used in which the coagulation of the discharged unextracted solid is aimed at by adding a liquid which is immiscible with the extractant, 2.B · water. This coagulated solid now has a better Absinkverhalten so that it can be reduced in the extractor. Thus, the part of the yeast dry product, in the poor wetting and Absinkverhalten is directly visible in gasoline alcohol mixtures, by wetting and coagulation with a second substance in

converted a better adapted to the method form. However, the majority of the yeast dry product is naturally in terms of its wetting and Absinkverhaltens in the vicinity of the product with the poor properties, since the suspension prior to drying is a homogeneous mixture and prevail in the drying process substantially uniform conditions for the drying of Trcfcenproduktanteile. The inorganic components which are dried on the yeast during the drying process - both the residual components of the nutrient solution and the inorganic constituents of the cell, which enter the surrounding water of the yeast cell during the drying process by bursting of the yeast cells and also on the outer layer of the dry particles as crystalline Dried layer are an essential interference factor for the wetting and diffusion processes in the extraction process by means of organic solvents,

Extensive removal of the inorganic components, both the cell contents and the dried with the residual nutrient solution, would therefore be desirable.

The separation of the residual nutrient solution can be carried out by washing with water and separation, for example by centrifugation. The removal of inorganic cell ingredients can be achieved by partially tubermolysing the yeast cells, converting the inorganic cell ingredients into the aqueous phase of the suspension, and mechanically separating the aqueous phase by centrifugation. At the same time, depending on the degree of thermolysis, 50 % of the proteins are transferred to the aqueous phase.

The separation of inorganic Zellinhaltsstoffe after previous Thermo Iy se and mechanical separation of the aqueous phase thus leads to the simultaneous removal of nitrogen-containing organic water-soluble compounds, such as amino acids and peptides, from the drying to be supplied suspension, so that there is a noticeable reduction in the content of these compounds in the Dry product and thus may lead to undesirable losses.

Object of the invention

The aim of the present invention is the production of a dry yeast whose content of ash formers, ins-. particular in the form of inorganic Zellinhaltsstoffen, is significantly reduced, without the content of water-soluble, organic recyclables, such as proteins and carbohydrates, is reduced to the same extent. In particular, a significant reduction in the potassium content in the dry product should be achieved. The dry yeast produced should have a largely amorphous surface and have a good wetting and sinking behavior in organic solvents.

Explanation of reading the invention

It has been found that a largely selective delivery of predominantly inorganic components from the yeast cell to the aqueous environment medium with sufficient

thermal treatment of the yeast suspension is achieved if in the aqueous yeast suspension before the thermal treatment of water-soluble crude protein components or in the chemical composition of the. Crude protein similar substance group complex is present.

Under this condition, the delivery of water-soluble proteins from the cell to the aqueous circulation medium can be reduced to about 10% by weight of the value otherwise customary under these thermal conditions. At the same time, the release of up to 95% by weight of potassium and 20% by weight of the phosphorus to the aqueous phase of the suspension is achieved.

In order to obtain a sufficient effect, it is necessary to adjust the amount of lysate so that the organically bound nitrogen of the lysate is at least 2% by weight of the organic nitrogen of the suspension bound in the yeast cell. The suspension thus prepared is then heated to 333-353 K is heated and concentrated by separating the aqueous medium at least 16 wt .-%, preferably 18 - 28 wt -% yeast dry matter for the substantial mechanical removal of the aqueous medium. This suspension can now be processed as desired into dry products.

If the dry product is subsequently to be fed to a continuous countercurrent extraction, it is advantageous to use a spray drying method to produce a suitable grain spectrum *

The aqueous phase obtained during the centrifugation or separation, the potassium and magnesium separated off from the cell, the phosphorus and the predominant fraction

of the previously added lysate may be advantageously used in the same plant for nutrient solution preparation or added to the nutrient solution. In fermentation processes in which the lysate is not or only partially utilized by the microorganisms, the required additional amount of lysate may be reduced if necessary.

The water-soluble crude protein component can be produced by partial or complete thermolysis or hydrolysis from the yeast suspension or also from ITeben- or waste products of the microbiological industry. It usually has the following average composition based on dry matter

Amino acid 10-30% by weight Proteins 40-60% by weight Nucleic acid 10-30% by weight

The advantage of the method manifests itself in the fact that the dry product produced, despite thermolytic treatment of the suspension to be dried and mechanical separation of a water phase from this suspension, is increased in protein content in favor of a reduction in the ash content.

During the drying of this suspension under the usual technical conditions, a product is thus obtained which assumes a largely amorphous surface structure of the dry yeast particles due to the greatly increased ratio of water-soluble organic components to water-soluble inorganic components in the final phase of the drying. This amorphous structure creates better conditions

for the wettability and for the diffusion processes in an optionally required extraction of the dry yeast with organic solvents.

Ausführun ^ sbeispiele

The invention will be explained in more detail with reference to the following examples:

example 1

In a pilot plant for the production of feed petroleum distillate based on a 5% yeast suspension, based on dry matter, to. This suspension was heated to 353 K for about 2700 s for the recovery of lysate and then separated continuously. The Elar phase contained 1400 mg / l organically bound nitrogen which was bound in the following main groups:

24 % in amino acids

48% in proteins

28 % in nucleic acids and nucleotides.

In a small-scale fermenter with a capacity of about 5OO 1 yeast of the genus Lodderomyces elongisporus was grown on n-paraffins under normal conditions simultaneously · The fermenter was continuously 40 l / h fermentation mixture removed. This fermentation mixture provided a yeast suspension with the following

Characteristics:

Temperature 326 K

pH 4.0 - 4.2

Yeast content 1.9% yeast dry substance

Potassium content 90 - 110 mg / 1

Phosphorus content 20 - 60 mg / 1

organic _{? 0} _ ^ _{50 mg / 1 #}

nitrogen

This suspension was continuously added as much of the o.g. Clear phase added that the level of organic nitrogen in the mixture around I50, 250 and 350 mg / 1 was.

This mixture was heated to 353 K for 2100 s and a yeast concentrate with a dry matter content of 22.5% by weight was separated with a jet separator. The resulting clear phase was analyzed for organic nitrogen and potassium and calculated from the yeast cell potassium and organic nitrogen amount in mg / 1 yeast dry matter calculated.

The values are summarized in the following table. The individual columns contain:

1. Organically bound nitrogen in the water phase of the separation mixture before heating in mg / l.

2. Organically bound nitrogen in the clear phase after heating and separation in mg / l.

3 · Release of yeast organic nitrogen in mg / g yeast dry matter.

4. Potassium in the separation mixture before heating in mg / l.

5 · Potassium in the clear phase after heating and separation in mg / l.

6. Specific release of potassium in mg / g yeast, 7 · Specific release of phosphorus in mg / g yeast.

153 365 11 6 120 540 18 5 4 4 252 371 6 260 690 18 3, 1 354 382 1" 350 770 17 "ι

From column 3 it can be seen that as the amount of water-soluble crude protein components increases, the thermo-lytic release of organic nitrogen compounds from the yeast cell is virtually suppressed. From column 6, the independent, high, selective potassium release of 18 mg / g = about 90% by weight is clearly recognizable.

The separated potassium and lysate-containing clear phase was used completely for nutrient solution preparation for the fermentation process.

The experimental fermentor was operated continuously under the conditions of test point 3.

Using the complete amount of clear phase for nutrient solution preparation, after one day in the fermentor, a level of about 150 mg / 1 of unconsumed organically bound nitrogen was introduced.

To test point 3 under the specified conditions, i. Concentration of organic nitrogen before heating and separation continue to operate, the fresh amount of crude protein components used could be reduced to about 30 wt .-% ·

From the individual test sections, dry product samples were generated and analyzed for crude protein and ash content.

The following values were obtained:

crude protein 2 ash in % 1. 53.2 4.2 Second 54.7 3.9 з. 57.1 3.5 example

An almost analogous experiment was conducted using n-paraffinic petroleum distillate as a carbon source.

Approximately the same ratios were obtained with regard to the biomass concentration and the resulting concentrations of organic nitrogen and potassium.

The thermionic treatment was carried out at 353 K after setting a level of 35.0 mg / L of organically bound nitrogen over 2100 seconds.

To prepare the yeast concentrate, the unused petroleum distillate and then the aqueous clear phase were first separated with the addition of 1.2 g / kg of a nonionic surfactant from ethylene oxide and propylene oxide.

The concentrated yeast suspension with 23 wt .-% yeast dry matter was dried in a jet spray dryer at 368 K vapor outlet. There was obtained a yeast powder of the following characteristics.

crude protein 57 ,1 Wt .-% hydrocarbons , 5 Wt .-% lipids 8th , 5 36 parts by weight ash 2 2 Wt .-% water 9 Weight JS Kornspoktrum 97 in the area

From this product, 5 samples were extracted discontinuously in four stages with a mixture of gasoline, boiling point 338-378 K and ethyl alcohol. The extraction temperature was 298 K pesticide / solvent ratio 1: 5 ·

The mixture was stirred vigorously in a 2 1 vessel for 500 s and then allowed to settle. In the first extraction stage, the proportion of floating, non-wettable dry product and the average settling time were determined. "After the 4th stage, the dry product was filtered, sucked air dry through a suction filter and the residual solvent was driven off at 383 K. Subsequently, a total hydrolysis were carried out and the unextracted residual hydrocarbons were determined.

In the 6th column a comparative dry product with an ash content of 7% by weight and a crude protein content of 52.9% by weight is indicated.

Product samples Comparative product 1, 2, 3, 4 ,, 5, 6

On se hw <imraendes in the

1st stage © in 0.3 0.1 0.2 0.2 0.1 7.4% by weight

Settling side in seconds 14 I3 16 15 I3

Residual hydrocarbon content after

4. the extraction ° ^'1 0.08 0.12 0.1 0.05 0.21 tion in wt .-%

Claims (2)

- ль invention claim Process for the preparation of dry yeast with low ash and high crude protein content by selectively © thermionic transfer of potassium and phosphorus from the yeast to the aqueous phase of the yeast suspension to be dried and subsequent extensive mechanical separation of this aqueous phase, characterized in that before the thermolytic treatment and mechanical separation in the suspension, a content of natural water-soluble crude protein components is adjusted in such an amount that the content of organically bound nitrogen of this water-soluble crude protein component at least 2% by weight of the nitrogen bound in the yeast cells of the suspension is that the thermolytic treatment takes place above 328 K and the mechanical separation of the aqueous phase takes place so far that the suspension drying below contains at least 10% by weight of yeast dry substance.