DD269862A1 - METHOD FOR CULTIVATING MICRO-ORGANISMS FROM EXTREME ENVIRONMENTS FOR OBTAINING BIOMASS - Google Patents

Abstract

The invention relates to a method for the cultivation of microorganisms from extreme environments for the production of biomass. The object of the invention is to remove from the culture medium the extracellular hydrophobic, growth-inhibiting substances released by the microorganisms into the culture medium during the cultivation of the microorganisms. The goal is achieved by the addition of water-insoluble solid hydrophobic substances, such as the decated and dealuminated NaY zeolites US Ex.

Description

Characteristic of the bang-ann technical solutions

In the cultivation of microorganisms from extreme environments for the production of biomass, extracellular substances are released into the culture medium by the microorganisms. These extrazelhiven substances act when they are present in higher concentrations in the culture medium inhibiting the growth of microorganisms. This greatly affects the specific growth rate of the microorganisms and the biomass yield. Methods are known which aim to remove these extracellular substances from the culture medium. In DD-PS 211579, ionogenic metabolites, such as citric acid, are removed from the culture medium by means of an ion exchange band. This method has the disadvantage that only the hydrophilic substances are removed, the hydrophobic substances remain in the culture medium.

In another method (DE-OS 3246189), the use of Adsorbentier. such as activated carbon, described for the efficient production of soluble metabolites. The use die'.er adsorbents but has the disadvantage that this one? Variety of nutrient solution components including the essential for the formation of biomass vitamins binds. This method thus requires a necessary pretreatment of the adsorbents with vitamins until their saturation. This in turn increases the economic outlay for the extraction of biomass.

Object of the invention

The object of the invention is to develop a method for reducing the concentration of extracellular, hydrophobic substances in the culture medium.

Essence of the invention

The object of the invention is to select and use those adsorbents which have the ability to preferentially adsorb extracellular hydrophobic substances.

According to the invention the object is achieved in that the culture medium water-insoluble hydrophobic solid substances, such as the dekantionierte and dealuminated NaY zeolite US Ex, in a concentration of 0.01 to lOOg / Γ ^{1 are} added.

These adsorbents are characterized by the ability to preferentially bind hydrophobic substances with very specific molecular diameters. The selectivity of these adsorbents with a secondary structure superimposed on the primary structure of the surface allows the binding of hydrophobic extracellular biomass-inhibiting substances without removal of finely biomass-forming essential substances such as water-soluble vitamins.

With the use of the method according to the invention, the growth rate of the microorganisms is increased by a maximum of four times and the yield increase of the microbial biomass by about 30% compared to the known methods.

This method according to the invention is applicable to the cultivation of microorganisms from extreme environments, such as thermo, halo, alkalo, acido and / or psychrophilic microorganisms, preferably microorganisms of the genus Bacillus.

In the following examples, the invention is explained in more detail.

example 1

The thermophilic strain Bacillus stearothermophilus TP5 was cultured intermittently in a 101 stirred reactor at 70 ° C and a pH of 6.8 on a glucose / nutrient medium with yeast extract addition.

The nutrient medium contained ₄ .7H ₂ 0,0,59g KH ₂ PO _4, 0,26ml H ₃ PO ₄ (85%), 15 g of glucose, 1 g of yeast extract and trace element compounds in sufficient quantities. 0.3 g per liter MgSO The pH was controlled with aqueous ammonia solution (2.5%).

In three approaches became the nutrient medium

1. US Ex

2. Silicalite

3. NaY

(Conzentration in culture medium 1 g Γ ¹ ) Compared to the discontinuous process with Nährmediuni without addition of Adsorbfintien was increased in all three series of experiments, the specific rate of recovery of microbial biomass:

1. by US ex fourfold

2. By silicalite to three and a half times

3. threefold by NaY.

The maximum specific speed achieved was 4 hours " ^1. At the same time, the yield of biomass formation was increased from 30% to a maximum of 45%.

Example 2 The thermophilic strain Bacillus stearothermnphilus TP 32 was grown in an 11 reactor at 0 ° C and a pH of 6.8

continuously aerobically cultivated on an I. lactose / Nährsalzmedium with yeast extract additive.

The nutrient medium contained per liter

0.3 g MgSO ₄ .7H ₂ .0.59 g KH ₂ PO ₄ , 0.26 ml H ₃ PO ₄ (85%), 6 g lactose, 1 g yeast extract and trace element compounds in sufficient quantities. The pH of the culture medium was controlled with 2, ii% aqueous ammonia solution.

The residence time was 3 h. The following results were achieved without the use of adsorbents:

specific growth rate 0.7 g Γ ¹ · h ^-1 spicy lactose consumption ³ g lactose · g BTS

B'omasse concentration 2g BTS · l ~ \ By dosing 0.2 g US Ex h "'the biomass concentration was increased by about 30% and the specific Accordingly, lactose consumption also increased by 30% at a constant specific growth rate.

Claims (1)

Process for the cultivation of microorganisms from extreme Umwelton for the production of biomass, characterized in that the culture medium water-insoluble hydrophobic solid substances, such as the decationized and dealuminated NaY zeolite US Ex, in a concentration of 0.01 to 100g / r ^{1 are} added. Field of application of the invention The invention relates to the cultivation of microorganisms from extreme environments for the production of microbial biomass. The invention can be used in the biotechnology industry.