Abstract
Express assessment of the biochemical activity of microorganisms is important in both applied and fundamental research. A laboratory model of a microbial electrochemical sensor formed on the basis of the culture of interest is a device that provides rapidly information about the culture and is cost effective, simple to fabricate and easy to use. This paper describes the application of laboratory models of microbial sensors in which the Clark-type oxygen electrode was used as a transducer. The formation of the models of the reactor microbial sensor (RMS) and the membrane microbial sensor (MMS) and the formation of the response of biosensors are compared. RMS and MMS are based on intact or immobilized microbial cells, respectively. For MMS, the response of biosensor is caused both by the process of transport of substrate into microbial cells and by the process of the initial metabolism of substrate; and only initial substrate metabolism triggers the RMS response. The details of the application of biosensors for the study of allosteric enzymes and inhibition by substrate are discussed. For inducible enzymes, special attention is paid to the induction of microbial cells. This article addresses current problems related to implementation of the biosensor approach and discusses the ways how to overcome these problems.