DD201147A1 - METHOD FOR OBTAINING EGYPTIC NUCLEAR SAFE AROMATIC BIOMASSES - Google Patents

Abstract

The invention relates to the field of biotechnology, in particular the cultivation of microorganisms suitable as feed. The aim of the invention is a method which allows the cost-saving and without increased technological effort durchfuehrbare production of suitable as feed biomass. The object of the invention is to develop a method which allows the production of a biomass with a high crude protein and low nucleic acid content. According to the invention, the object is achieved in such a way that the residence time of the culture medium in the fermentation process is 3.5 to 5 hours, the fermentation temperature is 31 to 34 ° C. and the specific consumption value for phosphorus is 12 to 18 g P / kg HTS.

Description

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title

Process for obtaining protein-rich, low-nucleic acid biomass

Field of application of the invention

The invention relates to a method for obtaining protein-rich nukIeinsäurearmeη biomass obtained by a microbial conversion of hydrocarbon mixtures, in particular petroleum distillates or raffinates with an n-carbon chain length range of Cq to C, q with yeasts · It can be used in the micro-. be classified in the IPK C 12 N ·

Characteristic of the known technical solutions

Microbial biomass produced by cultivating micro-organisms, eg. are known to be produced in the fermentation process * Corresponding processes are described in DE-OS 1 417 560, DE-OS 1 470 484, DE-OS 1 470 490, DE-OS 1 470 517 and DD-WP 105 825 described in the above methods, the space-time <-Aferbase dea fermentation process of the growth rate of the microorganisms used as production strains, the type of fermenter used and the fermentation conditions applied «

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The quality of the biomass obtained is influenced by the specific characteristics of the production strain, as well as by the fermentation and processing conditions for the production of biomass. The key quality indicators of microbial biomass, the crude protein and nucleic acid content, are determined by the regime of the fermentation process used. It is also known that fermentations with yeasts or bacteria lead to biomasses that differ significantly in crude protein and nucleic acid content. Thus, the crude protein content in bacteria is usually greater than in yeasts, but at the same time, the nucleic acid content of the biomass obtained is also higher. Increased nucleic acid levels in microbial biomass are undesirable for nutritional reasons. Therefore, a large number of methods are known from the literature for the recovery of microbial biomass and protein concentrates, which have the goal of removing the nucleic acids. These methods for removing or lowering the nucleic acid content from biomass represent an additional] technical-economic effort for the biomass extraction process. (Lovland, J., Horper, J.M., and Frey, A.L. Lebensm.-Wiss., & Technology 9, 131-142 (1976)). In addition to the processes which require additional technological and thus economic effort to remove or reduce the nucleic acid content in biomass, there is also a process for reducing the nucleic acid content of microorganisms after the growth phase microorganisms with oxygen and an aqueous nutrient medium be brought into contact, wherein in the latter an inhibitor is included. Such inhibitors are antibiotics, analogues of amino acids, analogues of purine or pyrimidine bases or carbon dioxide. A reduction of the nucleic acid concentration by a maximum of 60% of the initial value is possible.

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In this method results from the addition of an excipient in the fermentation process, an increased technological and economic effort, and this addition can also lead to other adverse effects on the process flow.

Object of the invention

The aim of the invention is a method which allows the cost-saving and without increased technological effort to be carried out producing a suitable as feed ge-TO biomass,

Explanation of the essence of the invention

The invention has for its object to develop a method that allows the production of a biomass with high Rohprotein- and low nucleic acid content.

According to the invention the object is achieved so that in the fermentation process a favorable residence time of the culture medium in the fermentor at an equally favorable fermentation temperature and a certain phosphate content in the nutrient medium is applied.

On the basis of the fact that the growth rate or residence time of microorganisms in the fermentation process has a decisive influence on the level of Rohprotein- and nucleic acid content, it has been found in yeasts and hydrocarbon mixtures, especially petroleum distillates or raffinates as substrate, that for obtaining a high productivity and a high crude protein content in the feed yeast with a low nucleic acid content in the order of 4.0 to 8.0 % residence times of 3 »5 to 5 hours, preferably 4 hours, at a fermentation temperature of 31 ° to 34 ° C, preferably 33 ° C, must be applied.

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At the same time, it was found that the nucleic acid content of yeasts can be influenced by the phosphorus offered in the nutrient medium. Thus, in order to obtain low nucleic acid values in combination with the abovementioned measures, it has been found that a phosphorus content in the feed yeast of 1.1 to 1 , 7 %, preferably 1.3 is favorable. This corresponds to a specific consumption value in the fermentation of 12 to 18 g / kg yeast dry matter, wherein in aqueous culture medium, a phosphate concentration of <20 mg P / l should be sought.

The combination of the above-mentioned process conditions in the fermentation results in a biomass having a high crude protein value and a reduced nucleic acid value which is suitable as a feed component.

embodiment

The invention is explained in more detail in the following example.

example 1

C are cultured for 3 in a Rührfermentor with a total volume of 250 m and a working volume of 90 t in a continuous process, yeasts of the strain Lodderomyces elongisporus on a petroleum distillate fraction having a boiling range of 240 to 36O ^0th The n-alkane content in the petroleum distillate used is 16.3 % * The fermentation temperature is 33 ° C, the pH is 4.2. The 'specific fumigation intensity is 6400 m / h, the energy consumption 26O kW. The residence time is 4.5 hours. The Mhr and trace salts are introduced in the form of two nutrient salt solutions in the fermentation process, a 15% aqueous potassium chloride solution and an acidic salt solution consisting of magnesium sulfate, copper sulfate, zinc sulfate, manganese sulfate, ferric chloride, phosphoric acid and water.

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The specific consumption indicators are:

Element Spez.Elementbedarf used

g E / kg HTS raw material

P 17.5-18 phosphoric acid, 74.5% pure

K 20 potassium chloride

Mg 0.94 magnesium sulfate

Pe 0.02 ferric chloride

Cu 0.02-0.03 copper sulfate

Mn 0.16 manganese sulfate

Zn 0.22 zinc sulfate

An auxiliary combination of the structural product propylene oxide ethylene oxide adduct / polyethylene glycol in a concentration of 600 mg / l of aqueous culture medium is added to the aqueous culture medium to intensify the process of the permentation process.

The productivity of the fermentation process is 3.6 kg / HTS / t · h.

By creaming takes place from the four-phase mixture of petroleum distillate / biomass / process water / air, a separation of 60 % of the process water · To Erdöldestillat / biomass / Pr-ozeßwasser suspension is added about 0.8 g of said excipient combination and heated the suspension to 80 to 85 ° C. By means of two industrial separators the dewaxed petroleum distillate is largely and further process water separated.

The concentrated biomass suspension is further enriched by vacuum evaporation and then dried in a spray-drying process. The process waters from the creaming and about 40% of the separated aqueous phase in the separation are returned to the fermentation process.

By extractive cleaning of the dry biomass in a continuous rotary disk extraction system at 40 ° C with an extractant mixture gasoline Ä'thanol-water (80-

3.5 19-1 vol.%), The remaining hydrocarbons and the majority of the lipids are removed from the biomass. The extractant is then extracted from the

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Biomass removed by a two-stage thermal drying. The end product obtained is characterized by a high crude protein content, a reduced nucleic acid content and a high protein digestibility.

Characteristics of the biomass, based on dry product:

Appearance: beige to light brown Crude protein content: 62.3%

Stocking: without lysine content: 7.6%

Structure: not lumpy Methionine content: 1.4%

Odor: typical nucleic acid content: 7 »1 %

Phosphorus content: 1.2%

Example 2

In comparison with Example 1, a further experiment is carried out under the described working conditions. In contrast, the residence time of the culture medium in the per-mentor is 3.3 hours, the fermentation temperature is 28 ° C., and the specific phosphorus consumption value is 21.0 g / kg yeast substance.

The productivity of the fermentation process is 2.9 kg HTS / t.h.

The extracted biomass obtained under said process conditions has the following characteristics:

Characteristics of the biomass, based on dry product:

Appearance: beige to light brown Crude protein content: 60.8 %

Stocking: without lysine content 6.5 %

Structure: not lumpy Methionine content 1.3 %

Odor: species-specific nucleic acid content 8.4%

Phosphorus content: 1.8%

Claims (1)

- * - 23 3 861 2 invention claim 1. A process for obtaining protein-rich low-nucleic acid biomass obtained by culturing yeasts on hydrocarbon mixtures, in particular petroleum distillates or raffinates having a carbon chain length range Cq to CUq, characterized in that the residence times of the culture medium in the fermentation process 3.5 to 5, 0 hours, preferably 4.0 hours, at a fermentation temperature of 31 to 34 C, preferably 33 ° C, and that the specific consumption value for phosphorus in the fermentation process 12 to 18 g P / kg yeast dry matter, preferably 15 to 17 g P / kg Yeast dry substance.