JPS6091979A - Flow feed control of substrate and its device - Google Patents

Abstract

PURPOSE:To improve production efficiency of yeast, by regulating properly a feed of a substrate during cultivation. CONSTITUTION:A seed mold is put in the culture tank 1, a substrate is fed from the substrate tank 7 by the pump M to the tank, datum from the measuring device 5 for oxygen partial pressure at the inlet, the measuring device 6 for an amount of gas at the inlet, the measuring device 11 for oxygen partial pressure of gas at the outlet, the measuring device 12 for partial pressure of carbonic acid gas, and the measuring device for an amount of exhaust gas are treated to calculate RQ, and a flow feed velocity of substrate (alpha value) is changed. Formation of by-product is detected, and when substrate flow is minimum or zero, the signal of dissolved oxygen sensor 9 is detected by the dissolved oxygen meter 10, alpha value is changed depending upon the change of it, to regulate the flow feed velocity of substrate.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a method for aerobic tl'f cultivation of microorganisms, and particularly to a method and apparatus for controlling substrate fed JIt in yeast culture. It is.

[Background of the invention] For yeast cells such as food/fed yeast and baker's yeast): 1. In production, add a small amount of the substrate.
The fed-batch culture method that supplies it is E1! I'm there. In order to carry out this culture efficiently, it is essential that the fed substrate be completely consumed by the yeast and that by-products such as ethanol be small.

Conventionally, since there is no means to quickly measure the bacterial cell concentration and bacterial activity in Jiff culture, a method has been used in which the cellulose is added to one Jff culture tank according to a predetermined program. In this method, it was impossible to feed the substrate in accordance with the bacterial cell activity in the tank, and the productivity was not high.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned current situation, and its purpose is to provide a method and apparatus for improving yeast cell production efficiency by appropriately controlling the amount of substrate fed during culture. This is what we provide.

[Summary of the invention]

The substrate fed-batch method for achieving the purpose of the present invention detects the production of by-products such as ethanol by increasing RQ, reduces or eliminates the amount of substrate fed, and then the generated by-products are transferred to yeast. This method is characterized by detecting the assimilation by the increase in dissolved oxygen concentration and increasing the amount of substrate fed.

Next, the method of the present invention will be explained in detail. To implement this control method, it is necessary to quickly know the production and consumption of ethanol, but at present there is no effective means to directly and quickly measure the ethanol concentration in the culture solution. Therefore, the present inventors detected the production of ethanol using RQ, and
The present invention was based on the discovery that the dissolved oxygen concentration rapidly rises to - due to the consumption of ethanol by yeast.

In yeast culture using sugar as a substrate, RQ = 1.0 indicates good cell growth, and RQ > 1.0 indicates ethanol production since a large amount of carbon dioxide gas is produced. Therefore, if RQ>1.0, it is assumed that ethanol has been produced, and the substrate feeding is reduced or stopped. On the other hand, RQ
>1. In the case of O, either the substrate is insufficient or the yeast is assimilating the produced ethanol, and it cannot be determined whether the yeast has completely consumed the ethanol. However, when the ethanol in the culture solution is completely assimilated by the yeast while substrate feeding is reduced or stopped, the amount of oxygen quenched by the yeast decreases, resulting in a rapid increase in the dissolved oxygen concentration. By detecting this rapid increase in dissolved oxygen concentration, complete consumption of ethanol is predicted and the substrate feeding is increased.

An experimental example is shown in FIG. 2.5 hours after the start of culture, RQ exceeded 1.0 and ethanol production was detected. At this time, the ethanol concentration had reached 9 g/Q or more, and the acanthose yield tended to decrease.

Therefore, the substrate feeding was stopped by setting the 11i4 mass flow acceleration (referred to as α value) per bacterial cell amount to zero from the 3111 frontage, and the produced ethanol was assimilated by the yeast. 5 from the start of culture
At the time, the O concentration, which had been controlled in the range of approximately 4 to 5 m3/Q, rose rapidly and assimilation of ethanol was detected, so substrate feeding was restarted. During the suspension time of substrate feeding, the analytical f yield tended to increase and reached a maximum value of 0.53 when substrate feeding was restarted.

As a general substrate used in the present invention, glucose, flag 1 to
-sugar, sucrose, and industrial raw material molasses. In addition, ammonium sulfate, urea, and
Examples include ammonia water, potassium phosphate, yeast extract, magnesium sulfate, ferrous sulfate, and various vitamins and minerals.

An example of a Jt'f culturing device according to the method of the present invention is shown in FIG.
Inoculum is placed in a tank 1, and a substrate is supplied from a substrate tank 7 using a substrate supply pump 8. At this time, the person 1-1 oxygen partial pressure measuring device 5, the human log gas measuring device 6. Output log gas oxygen partial pressure measuring device 11. The data from the carbon dioxide gas partial pressure measuring device 12 and the exhaust gas amount measuring device 13 are input into the control electronic side calculator 4 and RQt
& is calculated, and from this point the α value is changed to control the substrate flow acceleration, and the substrate supply pump 8 is operated according to the speed. When the production of by-products is detected and the substrate feeding is very small or zero, the signal from the dissolved oxygen sensor 9 is detected by the dissolved oxygen meter 10 and sent to the electronic N1W machine 4, and the change is detected. The substrate flow acceleration is controlled by changing the α value from . Also, during culturing, 2 mg of
/Q': However, this is determined from the dissolved oxygen concentration data sent to the electronic computer 4, which determines the rotation speed of the stirrer 2 and the flow rate of the oxygen into the oxygen separator 3 (-1 gas oxygen 'a degree). Person 1”
By controlling the gas kite rl) Maintaining the existing oxygen concentration at a constant value 7 [Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be explained in detail, but the present invention does not have any effect on this. Not limited to A 16 Bacterial body; 'Saccharomyces cerev, 1
Sjae (yeast) medium; glucose T1-su 500g
, urine A 53 , 75 g, Na211P(1,-21
1,025g, MgSO4・7tl, 0 0.5g,
KCρ5.5g, sodium citrate 62.5g,
Add 12.2 g of yeast extract, 25 mQ of vitamin liquid, and 25 mQ of mineral liquid to tap water IQ, dissolve, and adjust to pH 5.0.
Adjusted to.

However, the vitamin liquid contains 0.04g of biotin, vitamin B,
Distilled 0.08 g, vitamin B 62.0 g, bread 1 to calcium thenate A+, Og and boar 1-- 20 g
<Made by dissolving in tQ, mineral liquid is CuSO4.5
+1200.05, Zr+SO4・7412(] O
08g and FeSO4, (N114) 2 ・611
It was prepared by dissolving 200.3 g in distilled water IQ.

j9 Cultivation conditions: using a 50Q melting jar fermenter, temperature 30℃, Pt (5, O2 dissolved oxygen concentration depending on stirrer rotation speed, oxygen partial pressure of aeration gas and aeration amount)
/Q. Note that the oxygen partial pressure of the ventilation gas was changed using an air compressor and an oxygen cylinder.

The tank internal pressure was controlled at 0.5 Kg/c...2[; and the exhaust gas carbon dioxide concentration was controlled within 20%. The initial liquid volume is 15Q,
The initial bacterial cell concentration was 50 g/Q (per bacterial cell), and the mass flow acceleration was 0.3 g/7 g/11.

Results: At point #r of the 6-hour culture, the ethanol concentration was set to 0/Q, and the final sugar yield was 0.44. At this time, 99.8% of the fed crucose was consumed and the bacterial cell concentration reached 6G, 3HC/Q.

〔Effect of the invention〕

The present invention has the effect of achieving microbial cell tit cultivation that improves the maximum sugar yield by finally reducing the amount of by-products. The productivity of the f1 tank can be improved.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an experimental example of the present invention, and FIG. 2 is a schematic diagram of an example of a culture apparatus of the present invention. 1...Culture tank, 2...Agitator, 3...Oxygen separator, 4...Electronic control computer, 5...Oxygen partial pressure measuring device, G...Incoming log gas star measurement vessel, 7...substrate tank, 8.
... Substrate supply pump, -9 ... Dissolved oxygen sensor, 10
...Dissolved oxygen n1, ■1...Oxygen partial pressure measuring device, 12.
・・Carbon dioxide gas partial pressure measuring device, 13...4Jli gas i
atII gauge, 14, 15, 16° 17... conduit.

Claims (1)

[Claims] J. When aerobically cultivating yeast, if by-products are generated when feeding substrates into the culture tank, reduce the amount of substrate feeding and prevent the by-products from sticking to the yeast. In the case of assimilation, increase the amount of substrate fed.
-) O) A substrate feeding control method characterized by detecting an increase in concentration. 2. Measuring the flow rate of inlet gas and outlet gas, and measuring the oxygen and carbon dioxide concentration in the inlet and outlet gases. Oxygen and carbon dioxide analyzer with functions to measure pressure and transmit output; dissolved oxygen analyzer with functions to measure dissolved oxygen concentration in culture solution and transmit output
1+11 constant device, person [1 and outlet gas flow rate measurement equipment,
9. Calculate using input signals from the oxygen and carbon dioxide gas analyzer and dissolved oxygen concentration measuring device in the inlet and outlet gases.
A substrate fed-batch control device comprising a control device having a function of outputting the result as an output signal to a substrate supply device.