Ajinomoto Co., Ltd.

Motohiko Hikuma

Shuichi Suzuki

Isao Karube

Takeo Yasuda

Haruo Obana

Tadashi Shirakawa

Takashi Nakamura

Takahiro Kuratani

Yasutsugu Morita

Tatsuru Kubo

The method of the present invention which relates to the measurement of the turbidity of a liquid media, is characterized by the following steps.

Method and apparatus for measuring the turbidity of liquid media

Electrochemical method for determining the concentration of a carbon source and L-amino acid in a fermentation medium or cultured broth by contacting a microbial electrode consisting of an oxygen-sensitive electrode or a carbon dioxide gas-sensitive electrode combined with fixed microbial cells of a microorganism capable of assimilating said carbon source or decarboxylating said L-amino acid with a sample solution and sensing electrically the rate of current decrease which is caused by the consumed oxygen in the solution in proportion to the concentration of carbon source; or the electric motive force which is caused by the liberation of carbon dioxide in the sample solution in proportion to the concentration of L-amino acid. Microbial electrodes and systems useful in carrying out the aforementioned method are disclosed.

System for determining the concentration of an L-amino acid in

Electrochemical method for determining the concentration of a carbon source and L-amino acid in a fermentation medium or cultured broth by contacting a microbial electrode consisting of an oxygen-sensitive electrode or a carbon dioxide gas-sensitive electrode combined with fixed microbial cells of a micro-organism capable of assimilating said carbon source or decarboxylating said L-amino acid with a sample solution and sensing electrically the rate of current decrease which is caused by the consumed oxygen in the solution in proportion to the concentration of carbon source; or the electric motive force which is caused by the liberation of carbon dioxide in the sample solution in proportion to the concentration of L-amino acid. Microbial electrodes and systems useful in carrying out the aforementioned method.

Method for determining the concentration of an L-amino acid in

The concentration of ammonia in an aqueous liquid is determined by contacting a sample of the liquid with dissolved oxygen and with a microbial electrode comprising an oxygen-sensitive electrode, a porous membrane, and nitrifying bacteria confined or immobilised by the membrane which are in direct or close contact with the diaphragm of the electrode. The rate of oxygen consumption under otherwise uniform conditions is as precise a measure of concentration of ammonia as a conventional colorimetric method and distillation-titration method.

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Yokohama, Japan

Motohiko Hikuma