JPH08211021A - Bacterial cell amount measuring device - Google Patents

Abstract

PURPOSE: To accurately measure the bacterial cell density (dielectric constant) of a suspension over the total process of fermentation by attaching a means removing the measuring error caused by bonded and deposited yeast fungi to a probe. CONSTITUTION: Mechanical vibration is applied to an electromagnetic induction type probe 3 by a vibrator 6 to remove yeast fungi deposited on the probe 3. The vibrator 6 is provided with a motor 8, a crank 9, a bearing 10 and a bushing 11 in a housing 7. The rotary shaft of the motor 8 is fixed with one end of the crank 9 and the other end of the crank 9 is loosely inserted in the bearing 10 and the bearing 10 is fixed with the probe 3 in the vicinity of the cable connection end of the handle part thereof. The cable connection end of the probe 3 is subjected to circular motion by the rotation of the motor 8. Therefore, the probe 3 is subjected to vibration of circular motion centering around the bushing 11 to remove deposited bacterial cells.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to an impedance measuring device, and more particularly to a bacterial mass measuring device used in the field of electrically monitoring a yeast growth process, that is, a fermentation process.

[0002]

BACKGROUND OF THE INVENTION Colloids and suspensions are dispersion systems consisting of a particulate dispersoid and a continuous phase dispersion medium. As a method for evaluating the appearance of such a heterogeneous structure, there is a measurement of electrical characteristics such as conductivity and permittivity. Particularly in recent years, methods for measuring the dielectric constant using impedance measurement have been studied. The present applicant describes in Japanese Patent Application No. 6-172023 a dielectric constant meter capable of monitoring the fermentation process by utilizing the fact that the electric impedance of the yeast suspension liquid is slightly larger than that of pure water. It was Therefore, we proposed a means for realizing a probe for an electromagnetic induction type conductivity / permittivity meter that solves the problem of error due to interface polarization.

It will be described in detail below that the on-line monitoring of the fermentation process can be performed by the dielectric constant measurement. Since the microbial cell density is proportional to the dielectric constant, the microbial cell density can be measured by measuring the dielectric constant as described above. The dielectric constant is obtained from the measured capacitance value. FIG. 3 shows the appearance and part names of a specific example of the electromagnetic induction probe for measuring the dielectric constant. In the first half of the fermentation process, carbon dioxide bubbles generated by the active fermentation action cause convection in the suspension. Therefore, even if the fermenter is stationary or the suspension is not mechanically stirred, the suspension is naturally stirred and the yeast is uniformly dispersed in the suspension. . However, in the latter half of fermentation when the sugar content in the suspension is low, the convection is weakened as the carbon dioxide generation is reduced, and unless the suspension is stirred, yeast cells having a slightly higher specific gravity than the suspension settle.

A typical change in the cell density (dielectric constant of the liquid phase) in the suspension due to the fermentation process as described above becomes a curve as shown in FIG. In the first half of fermentation, the cell density increases and the dielectric constant increases as the fermentation progresses. In the latter half of the fermentation, as the cells settle down, the cell density in the suspension decreases and the dielectric constant decreases. Therefore, the fermentation process can be known from the rise and fall of the cell density (dielectric constant). However, when the dielectric constant is actually measured with a probe, a curve as shown in FIG. In this curve, the moving average value shows a tendency to increase even in the latter half of fermentation because bacterial cells having a high dielectric constant adhere to and accumulate on the probe, and the dielectric constant continues to increase only in the vicinity of the probe. Further, the minute changes are due to the deposited bacterial cells that have adhered and grown randomly peeling off. Since the conventional technique exhibits such a curve, it is impossible to monitor the fermentation process practically.

[0005]

It is an object of the present invention to equip a probe with means for removing a measurement error due to yeast that adheres and deposits, and to accurately measure the cell density (dielectric constant) of a suspension throughout the fermentation process. It is intended to provide.

[0006]

SUMMARY OF THE INVENTION A method of devising the shape and material of the probe can be used to reduce the deposition and deposition of the sedimenting yeast on the probe. The present invention positively eliminates the deposited and deposited bacterial cells. .

[0007]

An embodiment of the present invention is shown in FIG. The fermenter 2 is filled with the yeast suspension 1. The electromagnetic induction probe 3 inserted in the suspension is connected to the capacitance measuring device 4. The control computer 5 controls the measurement of the capacitance measuring device 4 and records the measurement result. In the present invention, the microbial cell removing means 6 applies mechanical vibration to the electromagnetic induction type probe 3 to remove the microbial cell. The control computer also controls the operation of removing the cells. It has been confirmed that a sufficient effect can be obtained only by performing the cell removal operation immediately before the capacitance measurement.

As means for removing the accumulated bacterial cells, (1) a method of applying ultrasonic vibration to the probe (2) a method of applying mechanical vibration (oscillation) or impact to the probe (3) convection in the vicinity of the probe Method of generating (4) A method of injecting a suspension flow onto the probe is considered. The embodiment shown in FIG. 1 specifically illustrates the method (2). This method is simple and highly effective. The fungus body removing means is realized by the vibrating device 6 that applies circular motion vibration to the transformer portion of the probe. FIG. 1A is a view showing the inside of the vibration device. The vibrating device 6 includes a motor 8, a crank 9, a bearing 10 and a bushing 11 in a housing 7.
Have. The handle portion of the probe 3 is fitted into the elastic bushing 11, and this bushing is fitted in the opening portion of the housing 7. The housing 7 is fixed to the fermenter 2 and the probe 3 is held in the suspension 1. The rotation shaft of the motor 8 and one end of the crank 9 are fixed to each other, and the other end of the crank is the bearing 1
It is inserted in 0. The bearing 10 is fixed near the end of the handle portion of the probe 3 on the side of the cable portion. The rotation of the motor 8 causes the bearing end of the crank 9 to move circularly, which causes the bearing 10 to move circularly. Due to this circular movement, the transformer portion of the probe 3 makes a substantially circular movement with the bushing 11 as a fulcrum.
As a result, the friction with the suspension removes the accumulation of bacterial cells. In this embodiment, the vibration of circular motion is applied to the probe, but the vibration is not limited to circular motion, and the direction of vibration is not limited. The motor 8 includes an appropriate speed reducer. Bushing 1
Reference numeral 1 denotes an elastic body, which is in close contact with the handle portion of the probe and the housing 7 and serves as a fulcrum for the circular movement of the probe and prevents the suspension from entering the housing 7. Although the embodiments of the present invention have been described above, the exemplary forms, partial shapes, arrangements, etc. are not limited, and modifications of the configuration are allowed as necessary without losing the gist of the present invention.

[0009]

EFFECTS OF THE INVENTION According to the present invention, since the bacteria accumulated on the probe are removed and the measurement is carried out, the change in the dielectric constant of the suspension can be measured with high accuracy, and the fermentation process can be practically used. It is beneficial to use.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a microbial cell removing means of the present invention.

FIG. 1A is a diagram showing the inside of an embodiment of a microbial cell removing means of the present invention.

FIG. 2 is a diagram showing an embodiment of a fermentation process measuring device of the present invention.

FIG. 3 is a diagram showing an example of the appearance of an electromagnetic induction probe.

FIG. 4 is a diagram showing an example of measuring the capacitance of a suspension in fermentation.

[Explanation of symbols]

 1: Suspension 2: Fermenter 3: Probe 4: Capacitance measuring device 5: Control computer 6: Vibration device 7: Vibration device housing 8: Motor 9: Crank 10: Bearing 11: Bushing

Claims (5)

[Claims] 1. An apparatus for measuring the amount of bacterial cells in a suspension using an electromagnetic induction probe, wherein the electromagnetic cells are deposited on the electromagnetic induction probe by applying mechanical vibration to the electromagnetic induction probe. A microbial cell amount measuring device having a microbial cell removing means for removing the microbial cell. 2. The fungus body removing means has means for applying mechanical vibration near the cable connection end of the handle portion of the electromagnetic induction type probe, and the fulcrum means of the probe is provided near substantially the center of the handle portion. 2. The bacterial cell amount measuring device according to claim 1, wherein the transformer portion of the probe vibrates mechanically. 3. The fungus body removing means has means for imparting circular motion near the cable connection end of the handle portion of the electromagnetic induction type probe, and fulcrum means for the probe is provided near substantially the center of the handle portion. However, the transformer unit of the probe makes a substantially circular motion, and the bacterial cell amount measuring apparatus according to claim 1. 4. The means for imparting the circular movement includes a motor, a crank and a bearing, a rotary shaft of the motor and one end of the crank are fixed, and the other end of the crank is loosely inserted in the bearing, Is fixed near the cable connecting end of the handle portion of the electromagnetic induction probe, the fulcrum means has an elastic bushing and a housing, the handle portion is fitted into the bushing, and the bushing is an opening of the housing. The fungus body amount measuring device according to claim 3, wherein the device is fitted to a portion and the housing is fixed to the fermenter. 5. The cell mass measuring apparatus according to claim 1, wherein the means for removing the accumulated bacterial cells is operated only immediately before the sampling measurement of the bacterial cell quantity by computer control.