US-20260125724-A1 - METHOD FOR MANUFACTURING FERMENTATION PRODUCTS WITH A SENSOR DEVICE

Abstract

The present invention is a manufacturing method for producing fermentation products using a fermentation vessel, including steps of: preparing a fermentation vessel and a sensor, introducing liquid into the fermentation vessel, and operating the fermentation vessel in which properties of liquid in the fermentation vessel are measured to adjust operating conditions; wherein the sensor device has a sensor for measuring liquid properties and a sensor cover body; a bottom permeable portion for passing liquid and crystals in the liquid is disposed on the bottom surface of the cover body, and a top permeable portion for passing liquid and crystals in the liquid is disposed on the top surface of the cover body; micropores are respectively formed in the bottom permeable portion and the top permeable portion; and micropores disposed in the top permeable portion are the same or larger than micropores disposed in the top permeable portion.

Inventors

• Motohiro Takenaka
• Masaaki Fujie
• Yohei KODAMA

Assignees

• AJINOMOTO CO., INC.

Dates

Publication Date

20260507

Application Date

20251218

Priority Date

20191225

Claims (12)

1. 1 . A method for manufacturing an amino acid by operation of a fermentation vessel bubbles are mixed and crystals with an average particle size of 5 μm or greater are formed in a liquid, comprising: preparing a fermentation vessel and a sensor device for measuring properties of liquid inside the fermentation vessel; introducing liquid to be fermented into the fermentation vessel; and operating the fermentation vessel for fermentation, wherein properties of liquid in the fermentation vessel are measured by the sensor device, and conditions of fermentation operation are adjusted based on results of the measurement; wherein the sensor device has a sensor for measuring liquid properties and a cover body for the sensor disposed to surround the sensor; wherein the cover body has a bottom side permeable portion for passing at least a portion of the liquid and crystals in the liquid disposed on at least a portion of the bottom surface of the cover body and a top side permeable portion for passing at least a portion of the liquid and crystals in the liquid disposed on at least a portion of the top surface of the cover body; and wherein the bottom side permeable portion and the top side permeable portion have numerous micropores for passing liquid respectively, and the micropores disposed on the top side permeable portion are sized to be the same as or larger than the micropores disposed on the bottom side permeable portion.
2. 2 . The method for manufacturing the amino acid of claim 1 , wherein the average diameter of bubbles mixed into the liquid in the fermentation vessel is 50 μm or greater.
3. 3 . The method for manufacturing the amino acid of claim 1 , wherein the fermentation vessel comprises a ventilation tube for feeding gas into the fermentation vessel, and the hole diameter at an outlet of the ventilation tube is 1 μm or larger.
4. 4 . The method for manufacturing the amino acid of claim 1 , wherein the fermentation vessel comprises a ventilation tube for feeding gas into the fermentation vessel, and the volume of gas fed into the fermentation vessel per hour is less than or equal to twice the culture medium volume at a start of fermentation in the fermentation vessel.
5. 5 . The method for manufacturing the amino acid of claim 1 , wherein the cover body is formed in a cylindrical shape, and the sensor extends into interior thereof in an axial direction.
6. 6 . The method for manufacturing the amino acid of claim 5 , wherein the bottom permeable portion is disposed over the entire surface of a lower semicircular portion of the approximately cylindrical cover body, and the top permeable portion is disposed over the entire surface of an upper semicircular portion of the cover body.
7. 7 . The method for manufacturing the amino acid of claim 1 , wherein the cover body is formed from a thin metal sheet, and the micropores disposed in the bottom permeable portion and top permeable portion are approximately circular holes formed in the thin metal sheet.
8. 8 . The method for manufacturing the amino acid of claim 1 , wherein the diameter of micropores disposed in the top permeable portion is 1 to 5 times larger than the diameter of micropores disposed in the bottom permeable portion.
9. 9 . The method for manufacturing the amino acid of claim 1 , wherein the diameter of micropores disposed in the bottom permeable portion is between 540 μm and 750 μm.
10. 10 . The method for manufacturing the amino acid of claim 1 , wherein the amino acid produced by the fermentation operation of the fermentation vessel is cysteine, and oxidation of at least part of the cysteine results in the accumulation of cystine in the fermentation vessel.
11. 11 . The method for manufacturing the amino acid of claim 1 , wherein the cover body is disposed to project diagonally downward from the sidewall surface of the fermentation vessel containing liquid, and a measurement portion of the sensor is positioned near a tip portion of the cover body.
12. 12 . The method for manufacturing the amino acid of claim 1 , wherein said amino acid is at least one member selected from the group consisting of glutamic acid (Glu), tryptophan (Trp), phenylalanine (Phe), threonine (Thr), tyrosine (Tyr), cysteine (Cys), cystine (Cys2), glutamine (Gln), aspartic acid (Asp), leucine (Leu), isoleucine (Ile), valine (Val), inosine, guanosine, and adenine.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS The present application is a divisional of U.S. application Ser. No. 17/807,998, filed on Jun. 21, 2022, which is a continuation of International Patent Application PCT/JP2020/044859, filed Dec. 2, 2020, which is based on and claims the benefit of priority to Japanese Application No. 2019-233846, filed Dec. 25, 2019. The entire contents of all the above applications are incorporated herein by reference. TECHNICAL FIELD The present invention pertains to a method for producing fermentation products, and in particular to a fermentation product manufacturing method and sensor device for producing fermentation products by the fermenting operation of a fermentation vessel into which bubbles are mixed, and in which crystals of an average particle size of 5 μm or larger are produced in a liquid. BACKGROUND ART The production of various fermentation products requires measurement of various properties such as the electrical conductivity and turbidity of liquid in a fermentation vessel, and the concentration of specific components in the liquid. Japanese Patent No. 3074781 (Patent Document 1) describes a method for manufacturing L-lysine. In this production method, a carbon source is added to maintain a carbon source concentration at 5 g/L or less in the culture liquid. I.e., in this method, carbon source concentration is measured by sampling the culture liquid in a timely manner and directly analyzing carbon source concentration, or by measuring pH and dissolved oxygen concentration to sense a carbon source deficiency from changes therein, so as to control feeding of the medium. Although it is relatively easy to extract a portion of liquid to be measured from the manufacturing process and measure properties of the liquid, as in the invention described in Patent Document 1, inline measurement without extracting liquid from the manufacturing process is preferable from a manufacturing efficiency standpoint. However, it can be difficult to measure liquid properties inline, particularly if bubbles are present in the liquid to be measured, or crystals are formed in the liquid. For example, bubbles of supplied oxygen or air, or bubbles of the carbon dioxide gas metabolic product of microorganisms themselves in culture may be mixed into the culture liquid during aerated culture, introducing noise into the readings, or increasing measurement errors. Japanese Patent No. 4420168 (Patent Document 2) describes a turbidity sensor. The turbidity sensor has a hollow semicylindrical member made of stainless steel, with a test solution inlet and an automatically opening and closing swing valve at the bottom, and a hole at the top for venting bubbles. In addition, a wetted photometric portion of a laser turbidimeter is disposed at the tip position on the inside of the hollow semicylinder. When measuring with this turbidity sensor, a swing valve is first opened to replace the test solution inside the hollow semicylinder. The swing valve is then closed, bubbles in the hollow semicylinder are discharged through bubble vent holes and, after the detected turbidity is allowed to stabilize, turbidity is measured. In the Patent Document 2 invention, the effect of bubbles in a liquid being tested is thus reduced. PRIOR ART DOCUMENTS Patent Documents [Patent Document 1] Japanese Patent No. 3,074,781 [Patent Document 2] Japanese Patent No. 4,420,168 SUMMARY OF INVENTION Problem to Be Solved However, the turbidity sensor of Patent Document 2 requires waiting for the detection value to stabilize after the swing valve is closed, making it difficult to perform real-time detection. If the turbidity sensor is applied to a liquid in which crystals form in the liquid, there is a risk that crystals may accumulate on moving parts such as the swing valve, causing failures. In addition, the requirement in the Patent Document 2 turbidity sensor for a swing valve which is opened and closed by remote control complicates the structure, leading to the problem of time-consuming maintenance to achieve stable operation over long durations. On the other hand, when a sensor is applied to a liquid in which crystals are produced, there is a need not only to suppress the effect of the crystals, but also to analyze, simultaneously with the liquid phase, the amount of solids precipitated when the concentration of the fermentation product in the liquid phase exceeds its solubility. Here, when a sensor cover is provided on the sensor to suppress the effect of bubbles, crystals are deposited near the sensor and inside the sensor cover, making it difficult to accurately measure the concentration of products. Measures such as discharging crystals precipitated inside the sensor cover as needed are therefore required to keep the crystal concentration in the fermentation vessel and the crystal concentration around the sensor at the same levels, so as to prevent such deposition. The present invention therefore has the object of providing a fe