Sense and sensitivity in bioprocessing—detecting cellular metabolites with biosensors

•Recent developments in metabolite biosensors important for bioprocessing are reviewed.•Industry still mainly employs electrochemical biosensor analyzers.•Advances in electrochemical and biological biosensors provide new opportunities.•Examples of trends in synthetic biology that can be integrated into biosensors for bioprocessing are described.•Future perspectives on how to translate new biosensors into industry are discussed. Biosensors use biological elements to detect or quantify an analyte of interest. In bioprocessing, biosensors are employed to monitor key metabolites. There are two main types: fully biological systems or biological recognition coupled with physical/chemical detection. New developments in chemical biosensors include multiplexed detection using microfluidics. Synthetic biology can be used to engineer new biological biosensors with improved characteristics. Although there have been few biosensors developed for bioprocessing thus far, emerging trends can be applied in the future. A range of new platform technologies will enable rapid engineering of new biosensors based on transcriptional activation, riboswitches, and Förster Resonance Energy Transfer. However, translation to industry remains a challenge and more research into the robustness biosensors at scale is needed.