This paper briefly describes the research and application of biosensors, especially microbial sensors, in the fermentation industry and environmental monitoring in recent years, and predicts and looks forward to their development prospects and marketization. Bioelectrodes are sensitive materials that use immobilized biological components as molecular recognition elements. Together with oxygen electrodes, membrane electrodes, and fuel electrodes, they constitute biosensors, which are widely used in fermentation industries, environmental monitoring, food monitoring, and clinical medicine. Biosensors offer high specificity, ease of operation, simple equipment, rapid and accurate measurements, and a wide range of applications. With the development of immobilization technology, biosensors have a strong competitive edge in the market.
It has been 40 years since Clark and Lyons first proposed the concept of biosensors in 1962. Biosensors have received significant attention and widespread application in fermentation processes, environmental monitoring, food engineering, clinical medicine, and military and military medicine. In the first 15 years, biosensors were mainly based on the development of enzyme electrodes. However, due to the high cost and instability of enzymes, the application of sensors using enzymes as sensing materials was somewhat limited.
In recent years, the continuous development of microbial immobilization technology has led to the emergence of microbial electrodes. Microbial electrodes use living microorganisms as molecular recognition elements, offering unique advantages over enzyme electrodes. They overcome weaknesses such as high cost, difficult extraction, and instability. Furthermore, they can simultaneously utilize coenzymes within the microorganisms to handle complex reactions. Currently, fiber optic biosensors are also being used more and more widely. Moreover, with the development of polymerase chain reaction (PCR) technology, the application of PCR in DNA biosensors is increasing.
Among various biosensors, microbial sensors are best suited for measurements in the fermentation industry. This is because interfering substances often exist during fermentation, and the fermentation broth is usually not clear and transparent, making it unsuitable for methods such as spectroscopic analysis. Microbial sensors, however, are highly likely to eliminate these interferences and are not limited by the turbidity of the fermentation broth. Furthermore, due to the large-scale production in the fermentation industry, the low cost and simple equipment of microbial sensors give them a significant advantage.
Microbial sensors can be used to determine raw materials such as molasses and acetic acid, and metabolites such as cephalosporins, glutamic acid, formic acid, methane, alcohols, penicillin, and lactic acid. The basic principle of measurement involves using a suitable microbial electrode and an oxygen electrode. Microorganisms consume oxygen through assimilation, and the amount of oxygen loss is measured by measuring the change in current at the oxygen electrode, thus achieving the purpose of measuring substrate concentration.
