DD276103A1 - METHOD FOR OBTAINING NUCLEIC ACID BIOMASS - Google Patents

Abstract

The invention relates to a process for the extraction of low-nucleic acid biomass by cultivating known selected yeast strains on carbohydrate-containing substances, in particular whey, with the aim of a comprehensive and advantageous application in animal nutrition from a nutritional physiological point of view. The invention has for its object to develop a method which can be realized without any additional effort and without reducing the utility of the biomass. According to the invention, the object is achieved by continuously fermenting the yeast compounds Debaryomyces hansenii LH 306 and Kluyveromyces marxianus LH 35 in a ratio of 2: 1 to 7: 1, preferably 3: 1, to the said substances. Nucleic acid levels up to 26 g NS / kg dry matter are achieved.

Description

Field of application of the invention

The invention relates to a process for the extraction of low-nucleic acid biomass obtained by cultivating selected yeast strains on carbohydrate-containing substances, in particular whey. It can be used in biotchnological production.

Characteristic of the known technical solutions

The use of microbially produced biomass in animal nutrition is substantially limited by the content of nucleic acids for nutritional reasons. A number of methods have become known which include the goal of providing a nucleic acid-reduced biomass. These methods can be broken down into the following groups:

- Method for reducing the nucleic acid content after cultivation

These include methods for mechanical or thermal digestion of the culture medium and its extraction with auxiliaries, for. For example, DE PS 2 503868 and DD PS 211921, or * enzvmatischen splitting by nucleic acids, eg. For example, DE OS 3500912 and DD PS 161243 described. These include methods for heat shock treatment and subsequent incubation for up to 180 min for hunted saltpans (Kie'er Milchwirtschaftliche Forschungsberichte 31 (4) 1979, pp. 297-361). All procedures of the listed classification is the high energy, material or equipment expense, coupled with quality degradations of biomass, eigin.

- Process for the control of fermentation;

In DD PS 201147 a method with Phosptarlimitation based on hydrocarbons is presented. After a subsequent cultivation of the necessary concentration and extraction of the biomass, a content of nucleic acids of 7.1% to 8.4% is achieved in the dry product.

The content of nucleic acids obtained by the genannton method suggests that. Changes in the content of certain cell-derived ingredients are only possible in the smallest areas by controlling the fermentation regime (see also SCHULZ, OSLAGE: Prote In quality and utilization of SCP as e ff ected by the fermentation process of post-fermentation treatment.) AS Symposium, Sorock 1981).

- Method of growing a low-nucleic acid biomass

According to a semi-continuous process ("Kieler Dairy Research Reports" 31 [4] 1979, p.346ff.) Based on whey, the following parameters are set:

fermentation time RNS RP inn % DHTS % d.HTS 0 4.07 49.3

21.4 2.37 40.6

The shown high temporal and thus economic expenditure is connected with a deterioration in biomass quality. The disadvantage of high breeding times with a fungus of Ar; Penicillium notatum is also disclosed in SU PS 597362. DD A23K / 297745.6 describes a "process for obtaining high quality feed whey from whey" in which a suicic acid content of 3.5% is achieved in T. In this process, which is oriented towards high protease yield, the strains used cause Pichia norwegensis H73 and Aciculocunidium aculeatum H308 6in relative increase of nucleic acid content in the biomass.

Object of the invention

The aim of the invention is a method for the extraction of low-nuclear biomass, which can find a comprehensive and advantageous application in animal nutrition from a nutritional point of view.

-2- 276103 Presentation of the Essence of the Invention

The invention has for its object to develop a method for breeding low-nucleic acid biomass, which without any additional effort and without loss of utility for the biomass, z. B. loss of amino-protein and drugs can be realized. The object is achieved according to the invention by the fact that the yeast strains Debaryomyces hansenii LH306 (ZIMET43788) and Kluyveromyces marxianus LH35 (ZIMET 43786) in ratios of 2: Ί bio 7: 1, preferably 3, on carbohydrate-rich substances, in particular whey, in a CLG high-performance fermentor. 1, at a pH of 1.8 to 2.5, preferably 1.9 to 2.1 and a residence time of 3 to 5h, preferably 4 h, are continuously fermented. Surprisingly, it has been found that, both in single-component fermentation and two-component fermentation of said yeast strains and only in said ratio biomass is produced with a very low content of nucleic acid. Thus, nucleic acid contents could be achieved by culturing on glucose or whey to 2.6% in dry matter.

Ausführungsbelspiei

In a milk processing plant, rennet whey in a total amount of 30 tons is discontinued on a daily basis. This substrate is continuously fermented for 24 hours in a 10m ³ C-LG jet fermentor at a rate of 1240 L / hr. The raw (lab) whey used for fermentation has the following average contents over the entire daily rhythm (analysis density: 2 h):

Dry substance (TS): 6Cg / kg original substance

Lactose 050 g / kg TS

Crude protein 1C0 g / kg TS

Nucleic acid 15 g / kg TS phosphorus 9.93 g / kg TS

Already in the starting process, a seed yeast in the 2001 batch with the following proportions is added to the whey substrate:

- Debaryomyces hansenii LH 306 - 3 parts

- Kluyveromyces marxianus LH 35 -1 part

The continuous fermentation process proceeds with additions of ammonium sulfate adequately to the respective content of lactose dos Fermentorzu hoof of the raw whey, on average of the day of 13kg / t raw whey. Furthermore, on average, trace salt additions of:

Cu: 0.75 ppm Zn: 5 ppm Mn: 3 ppm

The fermentation process is above the daily rhythm with a residence time between 4 and 4.5 hours, a pH between 1.8 to 2.2 and a fermentation temperature between 35 ⁰ C and 36 ° C without interference. The continuously harvested biomass is subjected to a short-term heating at 90 ° C and a heat holding time of 120 see according to veterinary regulations and fed to the sales tank. The salable biomass has the following average daily values:

Dry substance (TS): 44 g / kg of original substance

Residual lactose content: 15 g / kg DM

Crude protein: 460 g / kg TS

Nucleic acid content: 26 g / kg TS

Phosphorus: 13.9 g / kg TS

Furthermore, the cultivation conditions were changed as follows:

- When using LH 306 Sirr ultan in the fermenter, a content of NS of 38g / kg TS was achieved.

- The use of LH 35 sim jltan in the fermentor yielded a biomass with a content of NS of 35 g / kg DM.

The use of the mixed population according to DD A23 K / 297745.6 with LH306, LH35 and the yeast strains Pichia norregensis H73, Aciculoconidium sculcatum H303 and Hansenula iodine H307 yielded a nucleic acid content of 35 g / kg DM at a crude protein content of 470 g / kg OS.

Claims (1)

A process for obtaining low-nucleic acid biomass by cultivating known selected yeast strains on carbohydrate-containing substances, in particular whey, in a CLG high-performance jet fermentor, characterized in that the yeast strains Debaryomyces hansenii LH 306 (ZIMET 43788) and
Kluyveromyces marxianus LH 35 (ZIMET 43786) in a ratio of 2: 1 to 7: 1, preferably 3: 1 and the specific cultivation conditions pH of 1.8-2.5, preferably 1.9-2.1 and a residence time of 3-5 h, preferably 4 h, be continuously fermented.