This paper briefly reviews the recent research and applications of biosensors—particularly microbial sensors—in the fermentation industry and environmental monitoring, while also forecasting their future development and commercialization prospects. Bioelectrodes utilize immobilized biological entities as molecular recognition elements; when combined with components such as oxygen electrodes, membrane electrodes, or fuel electrodes, they form biosensors that are widely applied in fields including fermentation, environmental monitoring, food analysis, and clinical medicine. Biosensors offer high specificity, ease of operation, simple equipment requirements, rapid and accurate measurement capabilities, and a broad scope of application. Driven by advancements in immobilization technology, biosensors possess strong market competitiveness.

  It has been 40 years since Clark and Lyons first proposed the concept of the biosensor in 1962. Biosensors have since garnered significant attention and found widespread application in fields such as fermentation processes, environmental monitoring, food engineering, clinical medicine, and military and military medical sectors. During the initial 15 years, development focused primarily on enzyme-based electrodes; however, the high cost and insufficient stability of enzymes imposed certain limitations on the application of sensors utilizing them as sensing materials.

  In recent years, the continuous development of microbial immobilization technology has led to the creation of microbial electrodes. These electrodes utilize living microorganisms as molecular recognition elements, offering distinct advantages over enzyme electrodes; specifically, they overcome issues such as high costs, extraction difficulties, and instability. Furthermore, they can leverage intracellular coenzymes to facilitate complex reactions. Meanwhile, fiber-optic biosensors are finding increasingly widespread application. Additionally, the advancement of polymerase chain reaction (PCR) technology has driven the growing use of DNA biosensors based on PCR.

  Among the various types of biosensors, microbial sensors are best suited for measurements in the fermentation industry. Fermentation processes often involve substances that interfere with enzyme-based sensors, and fermentation broths are frequently turbid rather than clear, rendering spectroscopic methods unsuitable. In contrast, microbial sensors can effectively eliminate interference and are unaffected by the turbidity of the broth. Furthermore, given the large-scale nature of fermentation production, the low cost and simple equipment requirements of microbial sensors offer significant advantages.Microbial sensors can be used to determine raw materials such as molasses and acetic acid, as well as metabolites such as cephalosporin, glutamic acid, formic acid, methane, alcohols, penicillin, and lactic acid. The measurement principle generally involves a system composed of a suitable microbial electrode and an oxygen electrode; the assimilation process of the microorganisms consumes oxygen, and the reduction in oxygen—measured by the change in the oxygen electrode's current—is used to determine the substrate concentration.