DD269164A1 - PROCESS FOR OBTAINING BIOMASS WITH IMPROVED EXTRAILABILITY - Google Patents

Abstract

Process for the production of biomass with improved extractability by culturing microorganisms, in particular yeasts, on liquid n-alkane-containing hydrocarbon mixtures. The invention can be used in biotechnology, mainly in the feed yeast industry. According to the invention, the growth of the microorganisms to obtain a biomass which has been improved in its extractability is carried out by controlling the amount of the organic constituents in the separated process waters of the processing stages during the return to the fermentation process. As a characteristic for the extractability of the chemical oxygen consumption (CSV value) of the process water is suitable. With its help, a targeted Prozessfuehrung the total water content of the fermentation process to ensure high quality requirements for the extractively purified biomass end product is possible.

Description

Ar ¹ ·. Field of the invention

The invention relates to a method for Povvinnung of biomass, which is obtained by culturing microorganisms on n-alkane-containing hydrocarbon mixtures, in particular petroleum distillates and raffinates in the non-sterile Prozoß and by processing and purification processes. The invention can be applied in the microbiological industry.

Characteristic of the known technical solutions

Processes for the production of biomass, which are obtained by conversion of n-alkr> ;; containing hydrocarbons and by concentration of the biomass suspension obtained, are known (WP 105825). These processes are distinguished from processes which work when using conventional substrates, such as For example, carbohydrates, molasses, sulfite liquor that remaining residual hydrocarbons and also species tiogene Zeilinhaltsstoffe organoleptic, physiological and toxicological reasons before their use as feed, littelkomponenten in animal production from the Biorrasse must be removed (WP 139650, WP 139651, WP 142439, WP 153494, WP 219039). When pure n-alkane mixtures are used as the substrate base, industrial processes use methods for doing so by culturing the microorganisms in such a way that the n-alkane mixtures used are almost completely utilized or removed by washing processes during the primary workup of the biomass suspension, with the exception of traces , When n-alkane-containing petroleum distillates or raffinates are used, however, fractions of nicitutilizable hydrocarbons remain on and in the biomass and must be removed as far as possible by a subsequent purification process. This process "is based on methods for FesWflüssig extraction with organic solvents or mixtures (WP 139650, WP 139651).

These methods place very high demands on the technology to be used and cause great economic effort. In addition, it is essential that the dry product used for the extraction to ensure optimal diffusion of the extractant to the grain certain requirements must be made in terms of its physico-chemical properties, for example, the size, the water content and the material composition in the ratio of crude protein, Lipid and carbohydrate content.

It is also known that microbial material conversion processes are based on high productivity in the fermentation process. Prerequisites for this are the use of a high-performance production strain, a high-performance fermentor and the application of optimal Milicubedingungen in the breeding process. The latter cause the stability of Fermentorbiozönose in unsterile process and thus the achievement of high growth rates with low substance-specific consumption figures.

In the processes for large scale microwave production of feed whites, it is known that the recycling of separated process waters is of great importance in biomass concentration as an intensification measure. Thus, the enriched with raw materials, excipients and metabolic products process water from a fermentation process downstream Aufrahmungsstufe using petroleum distillates or raffinates as the substrate basis is also attributed to the fermentation process as well as the Separatorenfiltrat from the suspension concentration, which additionally contains thermolysis (WP 160231, FROMMHOLZ, G., SCHNEIDER, J. and ANNEMUELLER, W., Chem. Techn. 30, 4 (1978), pp. 180-185, ASH, SG and TOPIWALA, HH, 5th International Fermentation Symposium Berlin 1976, Session 3, Abstracts 3.16).

Likewise, it is gebräuchli ^rK that process waters from the overall process connected refining stages of Erdöldestillatbzw. Raffinate regeneration be additionally attributed to the breeding process. All of these measures to increase the circulation in the process seeks above all economic advantages in terms of reducing the fresh water requirement, the rational use of carbon sources and inorganic nutrients, trace and auxiliary substances, reducing losses in biomass concentration and reducing the wastewater environmental impact. In practice, it has been shown that parallel to the increase in the recycle level of process waters in the fermentation process an accumulation effect on the entrained in the process water ingredients up to a stationary granules occurs. This stationary state is dependent on, especially ötr applied residence time, different lengths and 'jedarf usually a longer application phase of the biological system.

It is also known daf. .Ίη unsterile process under non-optimal fermentation conditions and the conditions of a high rate of recirculation of process waters it to microbiological Prozosstörungen, z. B. the occurrence of increased Begleithefeanteile, an additional proportion of bacteria, to decreasing productivity of the process, the tendency of the multiphase mixture to emulsification or to change the Biomassezuscmmensetzung may come (WP 155700, WP 218777, WP 241086).

High risks for process dia- logue and additional technological and thus economic expenses are the consequence in order to meet the required performance indicators of the process and the required high quality features of the biomass.

Object of the invention

The aim of the invention is to reduce the expenses for the extraction process of the dried biomass in the process of microbial protein synthesis on the B «is liquid n-alkane hydrocarbon mixtures in recycling of process water phases and to minimize the risks for the control of the extraction process in deviations from predetermined process parameters ,

Presentation of the essence of the invention

The invention has for its object to create conditions for a good extraction behavior of the biomass obtained already by a specific influence on the process control in the breeding and processing process.

According to the invention, the object is achieved by using the chemical oxygen demand of the process water obtained after the cultivation process as a parameter for controlling the extractability of the biomass end product.

It has been found that the CSV value of said process waters has a direct correlation to the extractability of the biomass. High CSV words normally signal poor extractability that can be detected in the course of the process only at a much later time. H. high levels of residual hydrocarbons and crude fats of the extracted biomass.

It has been found that the CSV value of the Aufrahmwassers not higher than 8000mg O ₂ / l, that of the separation water may not be nich 'higher than 23000mg O ₂ / l, when the spray-dried biomass by means of an extraction agent mixture, bes'ehend of hexane / Ethanol / water in the ratio 80/19/1 is extracted in the continuous rotary disk extraction process and then a residual content of hydrocarbons of <0.5Ma .-% and a crude fat content of <5Ma .-% should have. Preferably, the upper limits for the CSV value of the Aufrahmwassers should 6500mg O ₂ / l, the amount of water separation 21000mg O ₂ / I.

The use of the CSV value of said process water phases thus represents a preliminary information for the expected end product quality and makes it possible to carry out measures already in the fermentation and work-up process which result in a reduction in the CSV values.

Accordingly, all possible measures are to be understood as meaning those which have a direct or indirect influence on the type and concentration of organic process water constituents. These can be both organic metabolic and thermolysis products. These are, in particular, polysaccharides, organic N compounds and fatty acids which can accumulate in the fermentation step on the biomass end product in the event of repeated recycling of the process water streams. In particular, the polysaccharide compounds have proven to be very disadvantageous for a subsequent extraction.

Exceeding the CSV values can occur in particular due to deviations from the predetermined parameters of the microbial growth process and the time and temperature regime of the workup steps. The CSV control can be used to infer non-predefined process parameters and localize and correct the deviation.

However, in order to ensure directly the desired extractability properties of the biomass end product, the ratio of process water recycling fresh water dosage in the cultivation process is to be changed so that the specified upper limits of the CSV values are achieved. By this simple feasible measure, the stability of the overall process in terms of achieving a high biomass yield in the process and the assurance of high quality standards of the end product forage yeast with respect to the residual hydrocarbon and crude fat content is achieved.

In addition, technological and thus economic burdens due to measures for the extractive purification of the biomass are eliminated, and additional losses of end product were avoided. At the same time, the wastewater-side load in the case of an operating management according to the invention is reduced for the handling of the overall process. The invention will be explained with reference to subsequent embodiments.

example 1

In a 2200m ³ Tauchstrahlfermentor with a working volume of 1 225m ³ yeasts of the genus Candida maltosa are bred on a petroleum distillate fraction boiling in the range 513 to 633 K in a continuous process. The n-alkane content in the petroleum distillate is 14.1%, the amount of petroleum distillate used 15.2% by mass. The residence time in the reactor is 4.2 h, the pH of the fermentation medium is 4.1. The fermentation temperature is 305K.

The nutrient and trace salts are introduced in the form of two nutrient salt solutions in the fermentation process, namely an approximately 15% potassium chloride solution and a nutrient salt solution consisting of l ^Λ η salts manganese carbonate, magnesium sulfate, copper sulfate, zinc sulfate, ferric chloride, sulfuric acid and water ,

To intensify the fermentation process, a polypropylenepolyethylene copolymer in an amount of up to 200 mg / l is added to the water;

The amount of drinking water supplied is 45m ³ / h.

The power input to the fermentor is adjusted under the above performance parameters to achieve a productivity of the fermentation process of 3.0 g / kg.h and a fermentor throughput of 250 t / h.

The concentration of the Fermentorablaufes carried by eina creaming of the four-phase mixture petroleum distillate / biomass / process water / air, the degree of separation is 0.75 and the recirculation level of Aufrahmwasser is 0.50.

In Aufrahmwasser inferred ingredients were determined:

Organic nitrogen (mg / l): 65

Total steam-volatile

Fatty acids (mg / l): 130

Carbohydrates (mg / l): 420

Chemical oxygen consumption

(K ₂ Cr ₂ O ₇ ) (mgO ₂ / l): 6500

The biomass suspension is treated with the above surfactant and concentrated in two stages at a temperature of 353-358 K of most of the expensive paraffinic petroleum ether and of further process water to a yeast solids concentration of 22%. In the heat treatment TherrrHyseerscheinungen of the protein occur, with cell ingredients from the cell in the oily and aqueous media occur. The polysaccharides are almost completely released to the aqueous medium. Separation process water 45m ³ is separated, with about 30m ^{3 are} recycled back into the fermentation process. The separation water has the following characteristics:

Organic nitrogen (mg / l): 500 Inorganic. Nitrogen (mg / l): 170 Total steam-volatile Fatty acid (mg / l): 385 Carbohydrates (mg / l): 1050 Phosphorus (mg / I): 142 Potassium (mg / l): 1010 /; Ü value: 6.0 Chemical oxygen consumption (K ₂ Cr ₂ O ₇ ) (mgO ₂ / l): 21000

The separated distillate is re-processed in a multistage refining process for use as a mineral oil component. Fatty acid ammonia washing waters and organically loaded phosphoric acid are obtained, which are recycled to the fermentation process in the order of 20 or 10 m ³ / h. The Biomassesuspensic η is dried in a spray dryer. The resulting dry product having an average grain diameter of 180 microns and a Wassf content of 7 to 10Ma .-% is extracted in a continuous rotary disk extraction process using an extract, '' middle mixture of a hexane / ethanol / water composition 80/19/1, removing residual hydrocarbons and lipids. The solvent-moist solid is dried in two stages in a Horizonte / irbelight dryer. The composition of the erfinrlungsgemi '> final product obtained determined is:

Hydrocarbon content (wt.%): 0.25

Crude fat content (% by mass): 3.80

Crude protein content (% by mass): 67.1

Example 2

Compared to Example 1, another production trial is carried out under the described working conditions.

In contrast, instead of a petroleum distillate a hydrotreated in medium pressure petroleum distillate used in the analog boiling range.

The final product produced has the following characteristic values:

Hydrocarbon content (wt.%): 0.23

Crude fat content (% by mass): 4.0

Crude protein content (% by mass): 66.7

Example 3

According to Example 1, a final product was obtained, but the degree of recycling of the separated process water in the separation was increased compared to the introduced in dsn fermentation process drinking water content. Thus, 50 m ³ / h of separation water were introduced into the fermentation process and the amount of drinking water reduced to 20 m ³ / h.

In the process water after creaming, an increase in organic content is detected as follows:

Organic Nitrogen Flmo / l): 190

Sum waoäerdampfflüc.itiiier

Fatty acids (mg / l): 345

Carbohydrate "(mg / l): 890

Chemical oxygen consumption

(K ₂ Cr ₂ O ₇ ) (mgO ₂ / l): 9900

The separation water separated in the continuous process has a chemical oxygen consumption of 29950 mg O ₂ / l.

The biomass end product has the following composition:

Hydrocarbon content (wt.%): 0.85

Crude fines content (% by mass): 5.1

Crude protein content 'Ma .-%): 65.3

Example 4

According to Example 3, the recirculation of process waters from the refining stages of the regeneration of the petroleum distillate in the fermentation process was simultaneously increased with 26m ³ / h ammonia washing water and 12m ³ / h organically loaded phosphoric acid.

The chemical oxygen consumption in Aufrahmwasser sets with 9800, in the separation water with 30800mg O ₂ / l. The generated biomass has the following key figures:

Carbon fiber content (% by mass): 0.91

Crude gel (% by weight): 4.9

Crude protein content (% by mass: 64.9

At the same time in the process in the multiphase systems of fermentation, Aufrahmun.j and separation, an increase in the emulsifiability of the substances can be visually determined, which can cause technological disadvantages in Beiriebsführung especially for separation processes.

Claims (3)

1. A process for the production of biomass with improved extractability by culturing microorganisms, in particular yeasts, on liquid hydrocarbon mixtures as a substrate, in particular n-alkane-containing petroleum distillates or raffinates, concentration of the biomass suspension and extractive purification of the dry product, characterized in that as a parameter for the control of the extractability of the biomass product, the chemical oxygen consumption (CSV value) of the incurred after the cultivation process creaming and separation process waters ν ^ is used. 2. Process according to claim 1, characterized by the upper limits of the CSV value for the creaming water phase of 8000 (mg O ₂ / l), preferably of 6500 (mg O ₂ / l) and for the separation process water phase of 23000 (mg O ₂ / l ), preferably 21000 (mg O ₂ / l). 3. The method according to claim 2, characterized in that the upper limits of the CSV values are set by changing the volume ratios of recycled into the fermenter process water phases for metered fresh water and not exceeded.