Microbial Sensors for Process and Environmental Control

Abstract

Many organic and inorganic compounds are present in fermentation process and waste waters. Rapid and sensitive on-line monitoring of these compounds is required. Microbial sensors composed of immobilized microorganisms and an electrochemical device are suitable for the determination of these compounds. A microbial sensor for glucose consisted of immobilized whole cells which utilize mainly glucose and an oxygen electrode. The steady state current obtained depended on the concentration of glucose. The microbial sensor could be used for the determination of glucose in fermentation media. Furthermore, alcohols, acetic acid, ammonia, and methane were determined by microbial sensors based on the same principle. On the other hand, potentiometric microbial sensors have been developed for fermentation process. A microbial sensor for glutamic acid consisted of immobilized Escherichiacoli having glutamate decarboxylase activity and a carbon dioxide gas-sensing electrode. The concentration of glutamic acid in some fermentation broths were determined by the sensor. Cephalosporines were also measured by a microbial sensor system. Furthermore, microbial sensors were applied to the determination of organic pollution. A microbial sensor for BOD consisted of Trichosporoncutanium and an oxygen electrode. The sensor could be used for a long time for the estimation of BOD. Nitrite and mutagens were also determined by microbial sensor systems.