DD239607A1 - METHOD FOR THE CONTINUOUS CULTIVATION OF HEEDS - Google Patents

Abstract

The invention relates to a process for the cultivation of yeasts on hydrocarbons for the production of biomass. The aim of the invention to reduce the consumption of raw materials during cultivation is achieved by regulating the culturing conditions by influencing the carbon and energy source. The current hydrocarbon concentration is after the n-alkanes in the limits of 0.6-2.2%, the difference between initial and current concentration in the limits of 0.8-1.6% and the degree of n-alkanutilization in regulated the limits of 40-70%.

Description

Field of application of the invention. , -

The invention relates to a process for the cultivation of yeasts on hydrocarbons for the production of biomass. The invention can be applied in technical microbiology.

Characteristics of the known technical solutions' ι

The cultivation of yeasts on hydrocarbons yields biomass as a source of protein, lipids and other biologically active substances.

Hydrocarbon as a starting point has the advantages over a traditional carbon source that the cultivation of the yeasts does not have to be carried out under sterile conditions and that the starting product does not require any special pretreatment.

However, the raw material requirements for the production of biomass are very high.

For the formation of 1 kg protein biomass 1.2 kg and more hydrocarbons are consumed. According to the literature, the consumption of raw materials is reduced in intensive processes in which the carbon source is consumed primarily for the formation of biomass (build-up metabolism).

(Gololobov, A.P., 1968, Microbiological Industry, 3rd Edition, pp. 14-22). , '

According to SU copyright No. 507625, there is known a method of cultivating microorganisms, the purpose of which is to save raw material. At certain intervals, the economic coefficient, biomass yield per spent carbon source, is determined. Depending on the level of the economic coefficient, the raw material concentration in the nutrient medium is corrected. The raw material efficiency can be increased by this measure by 5-10%, that is, it can

5-10% raw material savings, which is still not enough. _:

There is also known a method according to SU Patent No. 426373, in which, for the cultivation of microorganisms, the carbon source is metered as a function of the consumption of the nitrogen source used to alkalinize the culture medium

serves. ι

A Mehrmehrverbrauchverbrauch can not be avoided with this method, since the supplied in the form of ammonium hydroxide nitrogen is consumed for alkalizing the culture medium for biomass formation and for the neutralization of the acidic metabolic products, which are introduced by microorganisms in the culture medium. As the culturing conditions worsen, the concentration of acidic metabolites increases, as does the

Consumption of ammonium hydroxide and consequently the consumption of carbon source. ,

According to SU Patent No. 4,338,386 a process for the cultivation of microorganisms is known in which the supply of raw material and nutrient medium is carried out as a function of the degree of mismatch between the optimum and current concentration values of the raw material in the culture medium. For this purpose, the current raw material concentration is determined periodically and, knowing the optimum concentration, the raw material supply is regulated so that the two concentration values are almost identical.

Although the method allows an increase in the biomass yield, but not a reduction in the consumption of raw materials.

According to FR Patent No. 1554423, a process for the continuous cultivation of yeasts on a hydrocarbon mixture containing not less than 90% of n-alkanes is known. To increase the degree of alkanutilization and the biomass yield, the raw material concentration in the culture medium is regulated at a level of at least 0.5 g / l.

The process achieves an alkanutilization from the hydrocarbon mixture of 90-95% and a biomass yield of 80-90% with the n-alkanes introduced into the process. In the process, there is the disadvantage that the specific consumption of raw materials is very high, at least 1.1-1.2 kg per 1 kg of biomass.

The aim of the invention · -

The aim of the invention is to reduce the consumption of raw materials in the cultivation of yeasts.

Explanation of the essence of the invention

The technical problem underlying the invention is to regulate the culturing conditions by influencing the carbon and energy source in order to reduce the specific consumption of raw materials. The technical object of the invention is achieved by regulating the current hydrocarbon concentration according to the n-alkanes in the culture medium within the limits of 0.6-2.2%, the difference between the initial and the current concentration of n-alkanes in the limits of 0.8-2.2%. 1.6% and the degree of n-alkanutilization within the limits of 40-70%.

Yeasts of the genus Candida, Torulopsis, Endomyces Hansenula and others are utilized in a continuous process with aeration on a hydrocarbon mixture containing 5-95% n-alkanes. The aqueous nutrient medium contains nitrogen, phosphorus, potassium and magnesium compounds as well as the trace elements iron, zinc, manganese and copper.

The cultivation of the yeasts takes place in stirred fermentors under the following process parameters:

Temperature of the medium: 29-42 ⁰ C

pH of the medium: 3.0-5.5

Intensity of ventilation: 80-120 Nm ³ rrV ¹

Flow rate of the medium: 0.15-0.35rT ¹

The degree of n-alkanutilization is calculated according to the formula

•. s. , '

certainly. Mean

π = degree of n-alkanutilization,

S ₀ = initial concentration of hydrocarbons S = current n-alkane concentration The initial concentration S ₀ is controlled so that the difference S ₀ -S in the limits of 0.8-1.6% and the degree of n-alkanutilization in the limits 40th -70%. Under these conditions, the specific paraffin consumption is 0.6-0.8 kg / kg of yeast dry matter, which means that it is 1.5 to 2 times lower than in known methods.

Sample Execution Examples: "

The process is explained in more detail by 6 examples.

example 1

Yeasts of the genus Candida guilliermondii were cultured in a fermentor with a working load of 20 kg with stirring and aerating on a hydrocarbon mixture containing 12% n-alkanes.

The nutrient medium had the following composition in%: *

Hydrocarbon mixture converted to

n-alkanes 3,6 (S ₀ )

Ammonium hydroxide (25%) 1.7

Phosphoric acid (70%) 0.22

Magnesium sulfate 0.07

Iron chloride 0.0022

Zinc sulfate 0.002

Manganese sulfate 0.008

Copper sulfate 0.0014

Water up to 100 kg

Ammonium hydroxide was used simultaneously to alkalinize the medium.

The cultivation process was conducted with the following parameters:

pH 4.0-4.2

Media temperature 32-34 ⁰ C

Intensity of ventilation lOONI-rT ^ kg " ¹

Flow rate 0.2 h " ¹ -

The current n-alkane concentration in the culture medium was cheating

S - 2,15 % So - S · 3 ₉ 6 - 2, Ί5 «1s45%

^ »^ X ^; _# 100 β 40.5 %

The productivity of the process was 5kg h ~ '-t " ¹ biomass and the specific n-alkane consumption 0.58kg / kg yeast dry matter.

Example 2 'a

Yeasts of the genus Candida guilliermondii were cultured in a fermentor with a feedstock of 751 with stirring and aeration on a hydrocarbon mixture containing 21% n-alkanes.

The nutrient medium had the following composition in%:

Hydrocarbon mixture converted to

n-alkanes 2,6 <S _O )

Ammonium hydroxide (25%) 1.21

Phosphoric acid (74%) 0.15

Potassium chloride 0.096

Magnesium sulfate 0.056

Iron sulfate, 0.0035

Zinc sulfate 0.0062

Manganese sulfate 0.0014

Water up to 100 kg

The cultivation process was conducted with the following parameters:

pH value 4.0-4.2 '

Media temperature 32-34 ° C

Intensity of aeration 87Nm ³ -t ~ ¹ -h ~ ¹

Flow rate 0.2h " ¹

The current n-alkane concentration in the culture medium was

So - S «2 ₉ 6 - 1.05 - 1 * 55 %

.100 β 60 ,%.

The productivity of the process was 4.0kg-t ~ ¹ -h ~ ¹ biomass and the specific paraffin consumption was 0.78kg / kg yeast dry matter. ^;

example

Yeasts of the genus Candida guilliermondii were cultured analogously to Example 2.

The difference was that the concentration of the hydrocarbon mixture in the nutrient medium calculated on n-alkanes S ₀ = 2.1%.

There were ^ __-,

S «Ο, 63 % So - S .- 1 ₉ 47 ^V %

_m loo β 70 %

The productivity of the process was 4.0kg-t ~ ¹ -h ~ ¹ biomass and the specific paraffin consumption was 0.73kg / kg yeast dry matter. , -.

Example 4

Yeasts of the genus Candida Salmonicola were cultured analogously to Example 1.

The difference was that a hydrocarbon mixture containing 42% n-alkanes was used for the cultivation

contained. »

Further process parameters were:

Initial concentration S ₀ = 2.6%

pH 3.8-4.0

Media Temp 34-36 ° C '

Intensity of ventilation 1-20Nlkg " ¹ -h" ¹ . . '

Flow rate 0.25 h ~ ¹

These were: ----- "~ -

So - S .1,3%.   "; ... ..."

^ m | a | _β 100 β 50 %

The productivity of the process was " ¹ ^" ¹ biomass and the specific paraffin consumption 0.65 kg / kg yeast dry matter. '

Example 5

Yeasts Torulopsis utilis were cultured analogously to Example 1. .

The difference was that the n-alkane concentration in nutrient medium S ₀ = 4.5% and the flow rate

0.25h " ^1. ,

Here goods:

So - S 4 ₀ 5 - 2 * 8 1 _S T $

, 100 38 %

The productivity of the process was 3,3kgt '-h ¹ biomass and the specific paraffin consumption 1,29kg / kg yeast dry matter.

Example 6.

Yeasts of the genus Candida guilliermondii were cultured analogously to Example 2. The difference was that the flow rate of the medium was 0.17 h ^-1 . The goods were: _j ---___ ^

"" S. «O ₉ 55 %: -,. T ^ -. , So - S 2 _? 6 .. «0 ₉ 55 2» 05 %

^iU ^. 100 "<s 79

The productivity of the process was 2.2kg-t ~ ^1- h " ¹ biomass and the specific paraffin consumption 1.59kg / kg yeast dry matter.

In this way, in the regulation of the current n-alkane concentration in the culture medium (S) in the limits of 0.6-2.2%, the difference of the initial and the current n-alkane concentration (S ₀ -S) in the limits of 0.8-1.6% and the degree of n-alkanutilization in the limits of 40-70% of the specific n-alkane consumption 0.6-0.8 kg / kg yeast dry matter; ie, the n-alkane consumption is 1.5 to 2 times lower than in known processes.

Claims (1)

  , ν; :. '·. .,. ... , 1-1 239 607 Invention claim: A process for the continuous cultivation of yeasts under aerobic conditions in the presence of the necessary nutrient sources on a hydrocarbon mixture containing n-alkanes, characterized in that the current hydrocarbon concentration in the limits of 0.6-2.2% after the n-alkanes, the Difference between initial and current concentration in the limits of 0.8-1.6% and the degree of n-alkanutilization from the hydrocarbon mixture is regulated in the limits of 40-70%. , '.