DD243296A1 - METHOD FOR THE AUTOMATIC CONTROL OF BIOTECHNICAL FABRICATION PROCESSES - Google Patents

Abstract

The invention relates to a method for the automatic control of biotechnical material conversion processes in which microorganisms are involved. The aim of the invention is the increase of the efficiency of the processes, the improvement of the stability, the achievement of disturbance, and the saving of labor. The object of the invention is to filter such information from measured values which enable an optimal determination of the switching time for dynamic process executions. According to the invention, the object is achieved in such a way that an optimizing control is used which is based on situation recognition methods whose main component is a prognosis filter.

Description

8 <R <15 2 <H <5 2 <Z <5 2 <V <9.

4. The method according to item 1,2 and 3, characterized in that preferably the reference variables nutrient supply (supply of C and energy source, O ₂ -, Nährsalz- and trace element supply) and / or temperature, pH in the fermentation medium, energy input, residence time , Use amount of fermentation medium in the reactor.

Field of application of the invention

The invention relates to a method for automatically controlling biotechnical material conversion processes in which microorganisms, which may also be genetically modified, are involved in pure or mixed culture. These processes can be used for the extraction of biomass, the extraction of products, the disposal of waste or the extraction of energy sources.

Characteristic of the known technical solutions

There are known methods of biotechnical conversion in which by an alternating gradual change in the carbon substrate concentration in the fermentation system, wherein the duration of the periods of the length of the phases of the cell cycle is adjusted, an improvement in the efficiency of the process, especially a reduction in the use of raw materials is achieved.

(DD-PS 140150, DD-PS 219036). , '

This schedule control of a partially synchronized microorganism population works with fixed periods, that is, this control principle does not take into account the input disturbances of the fermentation system such. B.

Changes in temperature, input material concentrations, inflow and raw material quality on the metabolic activity of microorganisms in the fermentor.

In addition, the variability of biological properties, such as the duration of the phases of the cell cycle, can not be taken into account.

However, these disturbances and variability require different optimal periods for a favorable process control.

This requirement can not meet the previously known solutions or with an off-line control only with greatly increased effort.

Object of the invention

The aim of the invention is to increase the material and energy efficiency of the process, improving the stability, the achievement of susceptibility to interference, and the saving of labor for process control.

Essence of the invention

The invention has for its object to filter on-line such information from the process characterizing measured values, which allow an optimal determination of the switching time for dynamic process control. According to the invention the object is achieved so that an optimizing control is used, which is based on situation detection method, whose main component is a prognosis filter. The structure of the corresponding filter can be done both hardware-wise and software-moderately. A multi-dimensional feature vector (important measured variables) is cyclically detected by the controller, checked for reliability according to a special reasonability test on the basis of limit value change rate test of the process variables and a time series test, and fed to the prognosis filter.

The filter carries out the determination of the prognosis values for all measured variables of the feature vector and makes a decision about the change of the control regime by means of a triggering mechanism, e.g. B. a change in the delivery parameters of the substrate pump.

Compared to other filters, a Gauss filter has proven particularly useful. Forecast values are the values of the measured variables of the feature vector at a future sampling time. As essential parameters of the filter, the prognosis width and the minimum number of past measured values have to be adapted for each special process application. The triggering mechanism of the filter responds to a change in the trend of the individual process sizes. It is based on the constant determination of the prediction and actual standard deviation of all features of the vector as well as the comparison of the quotient of these two quantities with respect to the entire feature vector with a limit value corresponding to the Fisher distribution.

While the forecast standard deviation describes the scatter of the forecast values by the actual values of the measured quantities, the current standard deviation characterizes the fluctuation range of the measured values by the respective moving average of the measured quantities.

The essential characteristics of the method according to the invention are therefore:

H: necessary forecast value number for the forecast location deviation R: minimum number of smoothed measured values for a forecast

V: Filter parameters for GAUSS filters

Z: prognosis range.

They are in the following areas:

8 <R <15 2 <H <5 2 <Z <5 2 <V <9.

The invention is illustrated by the following examples: Example 1

The yeast strain LodderomyceselongisporusEH 15 ZIMET H 128 was grown on glucose in a 101 fermenter aerobically and continuously. The glucose was fed to the fermentor in aqueous 5% solution. The aqueous nutrient brine contained per liter

8,000mg N as NH ₄ Cl 800mg KaIs K ₂ CO ₃ 800mg P as H ₃ PO ₄ (85%) 160mg Mg as MgSO ₄ .7H ₂ O

and Spurensalzverbindungen in sufficient quantities.

The glucose fermentation was carried out to obtain high-protein feed yeast at a ventilation of 50 l / kg h, a mass of the fermentation medium of 32 ⁰ C. The pH was controlled with 5% sodium hydroxide solution. The glucose, nutrient saline, and water were added to the fermentor periodically for a period of 24 hours.

per period glucose solution setpoint nutrient solution setpointWater setpoint

0.5 h 0 5.2 ml / min γ 5.2 ml / min

2.5 hours 12.5 ml / min. 5.2 ml / min. J 5.2 ml / min

The period of change of the glucose dosage was 3 h. The residence time was varied periodically with the addition of the glucose solution and was 3.6 h during the O, 5h phase and during the 2.5 h phase, on average 4 h.

After 24 hours of dynamic process control in the time regime, the process was controlled automatically. As measuring signals for the filter CO ₂ and O ₂ content of the exhaust air and the current length consumption were used. The main filter parameters were

R = 15; V = 5.6; H = 3; Z = 4.

Conventional \ Invention

Procedure procedure

Biomass concentration [g / kg] Productivity [g / kgh] Specific carbon substrate consumption [g / g] Specific oxygen consumption [g / g] Pure protein content [%]

Example 2

The yeast strain Saccharomyces cerevisiae was grown on crude cane sugar in a 0.51 reactor continuously aerobically to obtain a yeast population with approximately 70% budding cells. The pH was 4.0, the temperature was 30 ⁰ C and the stirrer speed was 1000 U / min. The fermenter effluent was passed in an ethanol production fermentor and the yeast cells were used anaerobically and continuously for ethanol production. The pH at this stage was 3.5, the

13.6 13.6 3.4 3.4 1.9 1.8 0.7 0.6 48 48

Temperature was 33 ° C and the stirrer speed was 500 rpm. A residence time of 2 h was set and the biomass was recycled after separation of the fermenter effluent. The old cells with lower density were removed with the separated aqueous medium and replaced in the reactor by aerobically pre-cultured budding yeast cells. The nutrient medium contained per liter:

500 mg N as NH ₄ Cl 100 mg P as H ₃ PO ₄ 50 mg KaIsK ₂ CO ₃ 10 mg Mg as MgSO ₄ .7H ₂ O 0.1% yeast extract 150 g raw cane sugar.

The nutrient medium was fed periodically in the production fermentor (period 15-30 min) on a 24 hour schedule.

Subsequently, the nutrient media supply was started to be controlled automatically.

The measurement signals for the filter were the ethanol concentration and an NADH signal.

The filter parameters were R = 12; V = 5.6; H = 3; Z = By applying the method according to the invention, the following process parameters were achieved:

Cell mass concentration 50 g / kg Ethanol formation rate 40 g / kgh

Yield 0.53 g / g.

Example 3

The genetically engineered bacterial strain E. coli pLCR 665-58 was grown aerobically and continuously at a residence time of 2h, a pH of 7.0 and a temperature of 38 ° C. The nutrient medium contained per liter

2 200 mg N as NH ₄ Cl 200 mg P as H ₃ PO ₄ 200 mg K as K ₂ CO ₃ 100 mg Mg as MgSO ₄ -7H ₂ O. , ' ^!

0.2% yeast extract

Trace elements. The glucose concentration was changed periodically at a nutrient solution delivery rate of 6.6 l / h:

period glucose concentration 30 min 13.3 g / l 40 min 26.7 g / l

Subsequently, the process was automatically controlled using the cytochrome C content, a redox signal and the nitrogen content of the medium as readings.

The filter parameters were: R = 10; H = 5; Z = 4; V = 7.1.

The following process codes were reached:

specific glucose consumption 1.7 g / g

Productivity 13 g / l

Crude protein content of the cell mass 60%.

Example 4

The yeast strain Candida lipolytica was cultured in a laboratory fermentor of 121 gross volume in 51 of a medium of the following composition (calculated for 20 g of organism growth):

6g / l NH ₄ CI 1.4g / l KH ₂ PO ₄ C, 7g / l MgSO ₄ -7H ₂ O 0.1g / l CuSO ₄ -5H ₂ O 0.04g / l ZnCl ₂ 0.01g / l CoSO ₄ -7H ₂ O 0.08 g / l MnSO ₄ .4H ₂ O 0.11 g / l H ₃ BO ₃ 0.09 g / l CaCl ₂ -6H ₂ O 0.01 g / l FeCl ₂ 2, 5 g / l CaCO ₃ 5 g / l yeast extract ₁₀ g / l paraffin (range C ₁₀ to C ₂₀ ).

The pH is 4.2, the temperature 31 ⁰ C, the stirrer speed 2000 U / min and the air flow rate 1001 / kgh.

After a process time of 16 h, the growth process is terminated at 20 g HTS / I due to nitrogen imitation.

Periodically, paraffin is now fed automatically controlled (period 5 to 30 min). The measured values for the filter were NAOH signal and the CO ₂ content of the exhaust air.

The filter parameters were: R = 15; V = 4.2; H = 3; Z = After 48h, 50% of the nutrient medium containing nutrients for a doubling of the cell substance is exchanged. The exchange can be repeated as often as you like.

The following process codes were achieved:

Specific Paraffin Consumption 0.7g Paraffin / g Acid Productivity 2.5g Acid / kg · h

Claims (3)

Invention claim: 1. A method for automatic control of processes of biotechnical material conversion continuous or partial continuous breeding of naturally occurring or genetically manipulated cells on all usable C and energy sources, characterized in that the reference variables of the process are controlled periodically and thereby the optimal period by a prognosis filter Trigger mechanism is determined. 2. The method according to item 1, characterized in that a Gaussian filter is used as a prediction filter whose characteristic values H (minimum number of prediction values for the forecast location deviation), R (minimum number of smoothed measured values for a prognosis), V (filter parameters for GAUSS filter) and Z (Prognosis size) are tuned to the respective process and which has a triggering mechanism on the basis of the quotient of forecast and current location deviation of the individual process variables (characteristics), wherein the limit for the detection of state changes must be tracked according to the values of the Fisher distribution. 3. Method according to item 1 and 2, characterized in that the characteristic values lie in the following range: