DD211241A3 - PROCESS FOR AEROBIC CULTIVATION OF HEEDS - Google Patents

Abstract

The invention relates to a method for the aerobic cultivation of yeasts by influencing the metabolism and the activity of the microorganisms used during the fermentation process, which is carried out on the basis of hydrocarbons, in particular petroleum distillation. The aim of the invention is to obtain a qualitatively improved feed protein with an increased content of essential amino acids such as lysine, methionine, valine and histidine. According to the invention, as a function of O below 2 and CO 2 content of the exhaust air, the oxygen transfer rate from the gas to the liquid phase in the limits 7,0-13,0g O below 2 / kg.h and the respiratory coefficient in the limits 0 , 45-0,65, whereby the ratio between the oxygen of the incoming air and the carbon of the nutrient medium is regulated within the limits 2.0-15.0: 1.

Description

Title of the invention, Process for the aerobic cultivation of yeasts

IPK: C 12'.N

To whom the invention dung area

The invention relates to a method for the aerobic cultivation of yeasts by influencing the metabolism and the activity of the microorganisms used during the fermentation process, which is carried out on the / basis of hydrocarbons, in particular petroleum distillates. \,: ·

The invention belongs to the field of technical microbiology and is classified in the IPK in the class C 12 Έ . The invention can be applied to all aerobic breeding processes based on liquid hydrocarbons.

Characteristic of the known technical solutions

It is known that proteins which have been microbiologically based on hydrocarbons as a carbon source, contain all essential amino acids such as lysine, methionine, tryptophan, valine, histidine, leucine, isoleucine, tyrosine, treonin and phenylalanine.

Purely the wholeness of a putty whites is not only the presence of all essential amino acids of crucial importance, but from their respective content in the feed.

Several methods are known for intensifying and controlling cultivation processes.

According to SU Patent No. 424 875, a method of controlling a culture process via the amount of heat released by the microorganisms is known. According to SU Patent No. 444 375, the cultivation of the microorganisms is regulated by the ratio of the acid and carbon dissolved in the culture medium. Furthermore, a method according to SU patent no. 502015 is known in which the control of the breeding process according to the rate of change of the redox potential and taking into account the partial pressure of the dissolved oxygen in the medium. According to SU Patent No. 413 183, the rate of mixing of the culture medium is controlled by the COp concentration in the exhaust air. With the known methods mentioned, only the goal of intensifying the cultivation process and increasing the biomass yield is pursued.

The patent SU 534340 it can be seen that the control of the aerobic cultivation process takes place in that the intensity of the ventilation is regulated with the aim of reducing the air consumption as a function of the CO "concentration in the exhaust air, which falls below a certain value of the delivered C0 _? In the exhaust air, the intensity of the ventilation is cocultivated depending on the concentration of dissolved oxygen in the medium. "A disadvantage of all methods is that there is no possibility to produce a protein with a specific composition and a certain content of essential amino acids.

Object of the invention

The aim of the invention is to obtain a quality improved putty whiteness with an increased content of essential amino acids such as lysine, methionine, valine and histidine.

Explanation of the essence of the invention

The object of the invention is, by influencing the metabolism and the activity of the microorganisms used in the aerobic cultivation, in particular yeast, to produce a quality-enhanced putty protein with an increased content of essential amino acids such as lysine, methionine, valine and histidine.

The object is achieved in that the aerobic cultivation process of yeasts based on hydrocarbons is controlled by the COP and Op content in the exhaust air.

After the Op and COp content in the exhaust air, the oxygen transfer rate from the gas to the liquid phase in the limits of 7.0 to 13.0 g O "/ kg.h and the respiratory coefficient in the limits of 0.45 to 0 , 65 regulated. The ratio between the oxygen of the supplied air and the carbon in the nutrient medium is set within the limits 2 to 15: 1.

According to the invention yeast strains of the genera Candida, Torulopsis u.a. under conditions of continuous aeration at a flow rate of

- 1

Cultured for 0.1 to 0.4 h on a nutrient medium containing as carbon source petroleum distillates and the necessary trace elements for the supply of minerals.

The temperature of the Kährmediums is maintained at 30 to 42 ⁰ C and the pH at 2.5 to 6.0 »For the cultivation of yeasts is used as a carbon source a Erdöldestillatfraktion which boils within the limits of 200 to 400 ⁰ C and 10 to 50 Ma. - contains% n-alkanes. The concentration of n-alkanes in Uährmedium is 1 to 5 wt .-%. The intensity of the ventilation of the nutrient medium is between 60 and 200 U l / kg. H.

The oxygen and carbon dioxide concentration of the fermentor exhaust air are determined continuously with measuring instruments

 The oxygen transfer rate; is calculated according to the formula:.

1.13. V _g . C ₀

0.3V _g -1ÖÖ - C _n - C _rn

r_ = ^υ 2 ^υυ 2

where:

r _n oxygen transfer rate (g 0 _o / kg.h) υ ₂ ά

C _n 0 _Q concentration (

C0 ₂ concentration (Vol _o -%)

V registered air volume (U l / h)

M Filling volume of the fermentor (kg) 0.3 and 1.13 conversion coefficients.

The rate of COp formation is calculated according to the formula:

_r s

^C0 2 'TT

V ¹ · ⁵⁶ -

where:

- 5

Speed of formation of ² CO ₂ (gC0 ₂ /kg.h) 1.56 conversion coefficient

The respiratory coefficient is calculated according to the following formula:

RQ =

>:

The ratio of the oxygen introduced via the aeration in the cultivation process to the carbon present in the nutrient medium is calculated according to the following formula:

° 2 = 0.3 ^V °: 0.85. So. D

:. , - ;; C ~ " : ''" ~

where:

0.85 carbon content of the hydrocarbons used (n-alkanes)

Thus concentration of hydrocarbons utilized by the yeasts in the nutrient medium, g / kg

- 1 D flow rate h

The yeast suspension produced in the fermentor according to the invention is purified and dried by known methods.

An analysis of the protein content and the amino acid composition of yeast dry matter showed the following result:

13 % lysine, 3 % methionine, 7.5% valine and 5 % histidine.

compared to the prior art (7.5 - 11.0 % lysine, 0.7 - 1.7 % methionine, 3.7 - 5.5 % valine and

2.1 - 3) 3% histidine) results in a 1.5 to 2 times higher content of essential amino acids.

EXAMPLES

The invention will be explained in more detail by the following examples, without limiting it.

example 1

A yeast strain of the species Candida guilliermondii was in a stirred fermentor with a volume of 2001 on a distillate boiling range 240 - 360 ⁰ C with a content of 21 Ma. -% n-alkanes aerobically cultivated.

The nutrient medium had the following composition concentration in the aqueous phase (mg / l)

nitrogen 3 000.0 Pho sphor 365.0 potassium 620.0 magnesium 38.0 iron 3.5 zinc 8 * 3 manganese 5.9 copper 2.1

The n-alkanes were introduced into the nutrient medium in the form of a hydrocarbon mixture of a petroleum distillate. The nitrogen source was a 12% ammonium hydroxide solution used to alkalize the medium. Phosphorus source was 70% phosphoric acid, potassium source was potassium chloride. Sources of magnesium, iron, zinc, manganese and copper were the corresponding sulfates. The pH of the medium was 3.5; the temperature 35 ⁰ C.

Parameters of continuous cultivation:

- Operating filling of Ferraentor (M) 80 kg

Concentration of the n-alkanes in the

Nutrient medium (S ") 36 g / kg

- Flow rate (D) 0.25 h

- Air volume (V) 7000 Nl / hi

The yeast suspension passed from the per-mentor to a separator where it was separated into two phases; in an aqueous and a 4-component system (yeast-water-dewaxed distillate-air). The aqueous phase was recirculated to the per-mentor.

The 4-component system was processed and separated with a surfactant (sulfoureide or Ferman). In this case, three phases were separated:

an aqueous phase

a hydrocarbon phase

- A concentrated yeast suspension with a dry matter content of 10 - 12 %.

The suspension was further concentrated by evaporation and dried.

In the dry biomass, the protein content and the content of amino acids were determined on an amino acid analyzer. The perfume exhaust air was analyzed for the Op and COp contents by means of continuously operating devices (Permolyt, Infralyt). On the basis of the analytical data, the oxygen transfer rate (r _n ) was calculated.

² The content of:

C _n 13.4 vol. 56 ²

3.6 vol.-56

The transition speed of the Op can then be calculated as follows:

1.13 "13s4 .7000 ^r n * 7000 .0,3" 100-13.4 - 3, T "= 10.3 gO ^ / kg per hour

^U 2 - öO ^ά

Speed of COp formation:

_rn *, * 7000, 1.56 .3.6 = 5.9 g COp / kg. h. ^U 2 80 (100-13.4-3.61 ^

Respiratory quotient:

ΪΛ- = ° »57 10,

Ratio 0 ₂ / C:

0.3. - §§: 0,85 .36. 0.25 = 3.4:

In the biomass the following content of essential amino acids was obtained (calculated on the sum of the amino acids of the protein), (%):

- Lysine 1 2.5 - Methionine 2.8 - Valin 6.5 - histidine 4.5 Example 2:

The yeast Candida salmonicola was cultured analogously to Example 1. The difference was that the concentration of n-alkanes in the nutrient medium was S = 25 g / kg. In the exhaust air was the content, in Vol .-%:

^C 0 = 13.7 ⁰ CO ₂ = 3.8

1.13. 13,7. 7000 = ,

_ 7000 .1,56 .3,8 _ r - _pn y ,. , _b

^r C0 ₂ - 80 (1ÖÖ - 13,7 - 3,0) - ö, 3 g C0 ₂ /kg.n

RQ = ^ lg = 0.63

O JO = 0.3. - ⁷ ^: 0.85 ... 25. 0.25 = 4.9

In the biomass the following content of essential amino acids was obtained (calculated on the sum of the amino acids of the protein), (%):

Lysine 11,8

Methionine 2.5

Valine 6.1

Histidine 4.3

Example 3:

The yeast Candida guilliermondii was cultured analogously to Example 2. The difference was that the intensity of the aeration of the medium was increased and the speed of the air supply

V _g = 12000 N l / h.

In the exhaust air was the content, in Vol .-%:

O ₂

= 2.0

1.13. 17. 12000 - 12000. 0.3 - 100 - 17 - 2 ~

- 10 -

12,000. 1.56. 2 ς ο ¹ CO ₂ "80 UOO - 17 - Z) ~ ³⁾

RQ _β 2a§ _B 0.-62

0 ₂ / C = 0.3. ^^ §§: 0.85. 25. 0.25 = 8.5:

In the biomass, the following content of essential amino acids was obtained (calculated on the sum of the amino acids of the protein), (%) z

lysine 12.8

Methionine 2.7

Valine 6.2

Histidine 4.1

Example 4

The yeast Candida salmonicola was cultured analogously to Example. The difference was that the intensity of the aeration was V = 20000 li / h

and the concentration of n-alkanes S _Q = 152 kg. In the exhaust air were, in Vol .-%: C ₀ = 17.5

⁰ CO ₂ = ¹ » ³

1.13. 17,5. 20000

= 14.1

r _n = 20,000. 0.3 "100 - 17.5 - 1.3 = 14.1 gO ₉ /, J ₂ gß, ^

- 20000 - 1.56. 1,3 _ r '. _{ro / k} ,

- _öö ^ J ^ j ₅ 'J ι'3) - ^b ' ² ^ S GO ₂ /kg.h

-

tttt

0 ₂ / G = 0.3 £££ §§: 0.85. 15 .0.25 = 23.5: 1

In the biomass the following content of essential amino acids was obtained (calculated on the sum of the amino acids of the protein) ( % ):

Lysine 9,8

Methionine 1.7

Valine 3.9

Histidine 2.5

Example 5

The yeast Candida guilliermondii was cultured analogously to Example 1. The difference was that the intensity of the aeration V = 4000 I l / h, the concentration of the n-alkanes S _n 5 % and the flow rate

- 1 speed D = 0.2 h "amounted.

In the exhaust air were, in Vol _e -%:

1.13 c 12.5. 4000 _{= 64g} o / _kgh

_C.

₂ = ^{5 '7} 8 V

RQ = | x | , 0.88

0 ₂ / C = 0.3. - ^ g: 0.85. 50. 0.2 = 1.8: 1

In the biomass the following content of essential amino acids was obtained (calculated on the sum of the amino acids of the protein) ( % ):

- 12 -

lysine 9.3 methionine 1.6 valine 4.2 histidine 2.2

In this way, in the regulation of the cultivation process of yeasts on petroleum distillates according to the proposed method in the biomass produced, the content of essential amino acids was increased by 1.5-2.0 times. This in turn increases the nutritional value of the microbial protein.

Claims (1)

He-making ^ san demanding Process for the aerobic cultivation of yeasts by influencing the metabolism and the activity of the microorganisms used characterized in that, depending on the O ₂ - and CCL content of the exhaust air, the oxygen transfer rate from the gas to the liquid phase in the limits 7.0 - 13, 0 g Op / kgoh and the respiratory coefficient are set in the limits 0.45 - 0.65, whereby the relationship between the oxygen of the incoming air and the carbon of the Eährmediums within the limits 2.0 - 15.0: 1 is set.