DD213946A1 - METHOD OF CULTURING MICROORGANISMS ON SUBSTRATE MIXTURES - Google Patents

Abstract

The invention relates to a process for the production of microbial biomass. The object of the invention is to convert the carbon of heterotrophic substrates for the growth of microorganisms by using a further substrate, which can only act as an energy supplier, to a maximum, determined only by the C metabolism, into cell substance. For glucose as a growth substrate, e.g. for Hansenula polymorpha, in combination with formic acid in a mixing ratio of 1: 1 to 1.6 (in g, glucosa: formate), the yield of 0.5 g / g with glucose alone to 0.7 g of dry matter per g of glucose increased.

Description

A -

Title of the invention

Process for the cultivation of microorganisms on substrate mixtures

Field of application of the invention

The invention relates to a biotechnical method for the cultivation of microorganisms using an additional energy source. The invention is incorporated into the field of microbiological protein and product recovery and can be used in plants for the production of biomass as feed and for food. The invention is classified in the IPK C 12 N.

Characteristic of the known technical solutions

The cultivation of microorganisms on a heterotrophic substrate, e.g. B, sugars, alcohols or hydrocarbons (Is Biotechnology (Ed., By H. Rehm and G. Reed) Vol. 3: Microbial Products, Biomass and Primary Products, Verlag Chemie-Weinheim-Deerfield Beach, Florida-Basle 1983} but also on mixtures -O from heterotrophic substrates (see M. Rychtera: SCP Production from Sulphite Waste Liquors and Ethanol, in Dechema monographs "Microbiology applied to Biotechnology, Vol. 83, No. 1704-1723, Verlag Chemie-Weinheim New York, 1979, pp. 53-82; Th. Egii 1980

Diss. ETH No. 6538; L. Eggeling u. H.-Sahm 19 81, Arch. Microbiol. 130. 362; B. Heinritz ot al. 1982, Z. AlIg. Microbiol. 22 535; DD-WP 139 870 j DD-WP 246 335.2) for the production of biomass is known.

The simultaneous use of two or more substrates has the advantage of better utilization of substrates _(v Ertragskoef f iciently) and higher productivity. In the case of the production of "single cell protein", only substrate mixtures have been used in which each substrate is the carbon and energy source at the same time. The resulting yield increases range between 10 and a maximum of 25 % {s, R. Müller et al. 1983, Z. Alig Microbiol. 23, M :. 3)). However, the highest possible yield coefficients (, g of dry matter per g of substrate carbon) due to carbon metabolism for each substrate were not achieved.

Object of the invention

^Since s aim of the invention is to achieve the related to the carbon heterotrophic substrates maximum yield at aer cellular substance synthesis,

Explanation of the essence of the invention

The invention has for its object to supplement heterotrophic substrates for the cultivation of microorganisms for the purpose of generating cell substance energetically

 According to the invention, the object is achieved in such a way that substrates which can be used individually as a source of carbon and energy, with another

Substrate that only supplies energy. In the case of the use of glucose or other sugary substrates (molasses) and Hansenula polymorpha MH20, the yield of cell substance is increased when z. B, formic acid, which can only act as an energy supplier, is added. At a mixing ratio of 1: 1 to 1.6 (in g of glucose to formate), the yield becomes maximum. It is 0.7 gg ", which equates to an increase in yield of about 40 % .

Example 1:

Hansenula polymorpha MH20 is grown in a stirred fermentor suitable for aerobic cultivation. The temperature is 37 C, the pH of 4.8 is controlled by the addition of 0.5 N NaOH or 1 H HCl. The dissolved oxygen concentration ranges between 60 and 80%. The nutrient solution, which was initially weighed for 15 g / l, has the following composition (data in g / l):

NH ₄ Cl 7H ₂ O 7.63 KH ₂ PO ₄ 2H ₂ O 2.81 MgSO _4. 7H ₂ O 0.59 CaCl ₂ ♦ 3H ₂ O 0,055 FeSO ₄ . 7H ₂ O 0.0375 MnSO ₄ · 5H ₂ O 0,017 ZnSO ₄ · 4H ₂ O 0,022 CuSO ₄ · • 2H ₂ O 0,004 CoCl ₂ · 0.0028 Na ₂ MoO ₄ 0.0026

H ₃ BO ₄ 0.004

KJ 0.0026

Biotin 0.00005

Thiamine 0.005

EDTA 0.45

The starting culture was Hansenula polymorpha MH20, which was cultured continuously (Olimitiert)) to 0.75 g / 1 glucose and 0.25 g / 1 methanol at a dilution rate of 0.16 h ~. The initial concentration of yeast dry matter

* Substance was 0.6 g / 1. This culture medium is continuously added (dilution rate is 0.16 h "}, which contains 1.27 g / 1 glucose and an increasing concentration of Na-formate. As a result of this rising formate there is an increase in biomass yield _unc j 5 _e j_ At a formate concentration of 1.4 g / l, a new steady-state biomass concentration is reached which is 0.89 g / l of yeast dry matter and corresponds to a yield coefficient of 0.70 g / g glucose at a formate / glucose mixing ratio of 1.1.

Glucose is fully utilized under these conditions and the residual formate concentration in the fermentor is 50 mg / l at a concentration increase of 0.21 g formate / l.h.

Example 2;

Hansenula polymorpha MH20 is cultured as under the conditions described in Example 1. with the exception that the pH was adjusted to 5.2. The starting culture was again pre-cultured to 0.75 g / l glucose and 0.25 g / l methanol at a dilution rate of 0.16 h. The initial biomass concentration was 0.57 g / l. This culture is added continuously at a rate of dilution of 0.16 h ^{-1 of} medium containing 1.18 g / l glucose and an increasing concentration

Contains Na formate. The formate concentration at which new steady state biomass value is reached is 1.9 g / l. The yield coefficient for glucose is 0.71 g / l with a mixing ratio of formate / glucose of 1.6.

Claims (2)

Erfindunqsanspruch 1. A process for the cultivation of microorganisms on substrate mixtures, characterized in that the carbon of substrates which are also carbon and energy source for the growth of microorganisms, by adding organic or inorganic electron or hydrogen donors in a certain mixing ratio maximum , determined solely by the carbon metabolism, is converted into cell substance. 2 * Method according to item 1, characterized in that with growth on glucose in the presence of formic acid in a mixing ratio of 1: 1 ... 1.6 (in g)> Hansenula polymorpha MH20 yields 0.7 g of yeast dry matter per g glucose is reached.