The potential of application of microbial biosensors

The increasing levels of environmental pollution and its hazardous mutagenic and carcinogenic effects on living organisms. including human health requires specific, sensitive, rapid and effective tests for monitoring the presence of cytotoxic and genotoxic agents in surface, subsurface water, soil, sediments, sewage, air and in food products. Recently, microbial (or bacterial) biosensors use reporter lux, luc or gip genes with genetic fusion of selected promoters have been developed to detect a variety of chemicals, genotoxic agents and factors, which are responsible for DNA damage, oxidative damage or cell growth inhibition. Nowadays, the most popular microbial biosensors are based on analysis of the intensity of reporter gene expression, typically by creating transcriptional fusion between SOS promoter region and reporter gene in genetically engineered microorganisms (GEMS), usually in Escherichia coli strains. Living bacterial-based biosensors can perform functional sensing and provide measurement, such as bioavailability, cytotoxicity and genotoxicity or general toxicity. Microbial biosensors are being characterized of high level of specificity, fast response time, low cost, portability, ease of use and giving a continuous in situ and real time signal, so are famous for dynamic development and represent of the advantages compared with traditional methods, for example chromatography. For living cells biosensors, bacteria are suitable due to their easy and rapid growth rate, very often on standard medias and low cost of their culturability. Current trends in biosensors technology have been directing to creation more sensitive and flexible genetic constructs for simultaneous biomonitoring cytotoxic and genotoxic action of analyzed samples. The presented review focuses on characterization of general definition and classification of biosensors. Nowadays trends for creation of more robust genetic constructs for bacterial biosensors are also discussed. 1. Introduction. 2. The general definition of biosensor. 3. The classification and properties of whole-cells microbial biosensors. 4. The stress response mechanisms and its application in bacterial biosensors. 5. The characterization of biosensor's activity with recA promoter. 6. The nowadays trends in biosensors technology. 7. Summary