CS263298B1 - Process for producing yeast extract and ergosterol - Google Patents

Abstract

It is a method of processing microorganisms, especially yeast, to obtain ergosterol and yeast extract. The advantage of the process is to achieve a higher yield of ergosterol (over 85%) without the need to saponify the lipid fraction while producing yeast extract. Neutral or acidic microorganism cells are heated vigorously from 0-25 ° C to 55-85 ° C and then cooled rapidly to 0-25 ° C after 5-20 seconds. Cooling must take place within one second before autolysis occurs after heating to 45 to 58 ° C. After separating off the solid particles from which ergosterol is extracted after disintegration, a yeast extract is obtained. The advantage of the process is that substantially less ergosterol losses occur in the process than in the prior art, and the other components of the cell are utilized so that especially the nitrogenous substances of the microbial cell are not impaired. The process is relatively simple, thus easy to implement. Waste is not difficult to dispose of.

Description

The invention relates to a method for producing yeast extract and ergosterol.

The economics of ergosterol production from microorganisms depends on its concentration in the starting material. For this reason, efforts are made to achieve the highest possible concentration of ergosterol already at the fermentation stage. Attempts to influence the sterol content by cultivation conditions have led to the fact that the total sterol content has increased, but mainly due to the presence of the residual 24 (28) dehydroerosterol. The method of selecting a strain with a constitutively high ergosterol content has proven to be much more advantageous. This strain contains up to 1.6% ergosterol. Further increase in the ergosterol content by biological means is very difficult.

Methods of treating raw materials (e.g. yeast) by biochemical means aimed to use some other parts of the cell before extracting ergosterol so that they are not degraded and at the same time ergosterol is concentrated. A method of obtaining cell walls of microorganisms for the production of ergosterol is described (no. AO 189 440) based on the activation of lithium enzymes of the cell, disintegration and subsequent 10-hour autolysis. Separated cell walls then serve as the starting material for obtaining ergosterol. Similarly, AO 223 007 addresses the concentration of ergosterol in a small volume of ballast lipids in connection with the technological process according to AO 161 299. In both cases, it concerns the concentration of part of ergosterol into a certain fraction during the processing of yeast (microbial) cells. The disadvantage of the described and known methods is the concentration of only part of ergosterol. Although its losses are balanced by the acquisition of other products, the loss of 30% or more of ergosterol is still quite large.

This disadvantage is eliminated by a method for producing yeast extract and ergosterol, the essence of which is that a suspension of cells of microorganisms, preferably yeast-like, with a neutral or acidic pH is subjected to heat shock, by heating from a temperature of 0 to 36 °C to a temperature of 55 to 85 °C and after 5 to 20 s cooling to a temperature of 0 to 25 °C within a time of less than one second, after which the suspension is heated to a temperature of 45 to 58 °C, subjected to autolysis for a period of 0.5 to 4 h and the yeast extract is separated from solid particles.

To extract ergosterol from separated and optionally washed solid particles, a mixture of a non-polar solvent, toluene, petroleum ether, hexane or heptane with the addition of 5 to 20% by volume of aliphatic alcohol is preferably used.

The proposed procedure hydrolyzes nucleic acids and proteins, while lipids, especially sterols, remain unchanged. Separation of the resulting low-molecular substances results in a decrease in the dry mass of cells, obtaining a yeast extract and, consequently, a relative concentration of ergosterol in the cells. The mass loss ranges from 20 to 30% of the original mass. Low-molecular substances separated from the cell suspension can be used as a high-quality extract with suitable organoleptic properties after concentration and drying. The procedure according to the invention is very suitable for continuous production and therefore for automation of the entire procedure. In addition, it is possible to disintegrate the cells after concentrating ergosterol and extract it with a mixture of, for example, petroleum ether-ethanol (9:1) without hydrolysis (saponification) of the lipid components of the biomass. This simplifies the entire procedure considerably.

The following examples are provided to illustrate, but not to limit, the invention.

Example 1% by weight suspension of Saccharomyces oerevisiae yeast in water with pH 4.5 and temperature 21 °C was pumped at a rate of 1,300 ml/h through a copper exchanger, the design of which ensured heating of the suspension to 75 °C in about 0.6 s and a delay at this temperature of 13 s, including a connecting pipe to a cooler, which cooled the suspension to a temperature of 20 °C in 0.8 s. The suspension then entered a flow-through temperature-controlled vessel, where it reached a temperature of 53 °C. The volume of this stirred thermostated vessel was 3,000 ml, so that the average residence time was 2.3 h. After each accumulation of 1 liter of suspension (in the storage vessel, after flow through the thermostated vessel, the solid particles (treated cells) were separated by centrifugation (10 min) at 3,500 g and washed with the same amount of water. The supernatant was separated and dried after concentration. The sediment (treated cells containing all ergosterol) was resuspended to a suspension of 6% by weight of dry matter, disintegrated and extracted in a ratio of 1 part of the suspension, 2 parts of ethanol and 18 parts of petroleum ether (b.p. 30 to 50 °C) for 1 hour under intensive shaking. Ergosterol was isolated from the organic phase. The ergosterol content in the individual fractions during the procedure according to Example 1 is shown in Table 1.

Table 1

Material Amount of dry matter g Sterols g 24/28 dehydro -ergo- sterol G Ergo· ster< g suspension before extraction 130.0 2.10 0.40 1.70 total suspension after extraction 130.0 2.10 0.40 1.70 extracted cells (processed) 93.6 2.06 0.37 1.69 extract-supernatant after separation of solid particles 37.1 0.01 0 0.01 organic phase after extraction of disintegrated processed cells 1.85 0.40 1.45

The total gain of ergosterol is more than 85% of the original amount.

Example 2

A 10% by weight suspension of Candida utilis yeast grown on sulphite leachates was processed using the same procedure as in Example 1. Hexane was used for extraction instead of petroleum ether. The sterol content in the individual fractions is given in Table 2

Table 2

Material Dry weight Δ5,7- sterols 24/28 dehydro- ergosterol Ergosterol g g g g

original suspension 130.0 0.60 0.13 0.47 suspension after extraction 130.0 0.58 0.11 0.47 extracted cells processed 98.5 0.58 0.11 0.47 extract (supernatant after separation of solid particles) 31.5 0 0 0 organic phase (hexane) after extraction of disintegrated treated yeast 0.51 0.10 0.41 The total gain of ergosterol is 87 % of the original amount.

The losses of ergosterol in the treatment method according to the invention range up to 20%, thus achieving more advantageous parameters than, for example, in the method according to AO 189 440. In addition, it is possible to extract the homogenate directly after disintegration, since the release of ergosterol from the cell extract occurs during the heat shock and saponification is not necessary.

Claims (2)

Process for the production of yeast extract and ergosterol, characterized in that a suspension of cells of preferably micro-organisms, preferably yeast, of neutral or acidic pH is subjected to heat shock, heating from 0 to 36 ° C to 55 to 85 ° C and after 5 to 20 with cooling to 0 to 25 ° C in less than one second, after which the suspension is heated to 45 to 58 ° C, subjected to autolysis for 0.5 to 4 h and the yeast extract is separated from the solid particles which are extracted. 2. Process according to claim 1, characterized in that a mixture of a non-polar solvent, toluene, petroleum ether, hexane or heptane with an addition of 5 to 20% by volume of aliphatic alcohol is preferably used for extracting ergosterol from the separated and after optionally washing the disintegrated solid particles.