Fundamentals of Biosensor Application in Environmental Pollutant Monitoring Vinay Patel, Rishi Pramod, Namita Khanna, Prajakta Pawar, Abhilasha Singh Mathuriya, and Soumya Pandit Abstract Population explosion and rapid industrialization have led to increase in concen- tration of pollutants posing threat to the environment. Therefore, it is essential to detect and reduce the level of pollutants, to conserve our natural habitat and protect the environment from further degradation. Biosensors offer a solution as analytical devices that can be customized to detect a variety of pollutants. It comprises of three essential parts—bioreceptor, transducer, and data transfer and processing. The biosensing devices have a biological component: the bioreceptor, which is biological in origin and may comprise of whole cells, cell-based receptors, enzymes, antibodies, or nucleic acids. These biological components provide advantages like detection of pollutant in low amounts, high specificity, and precision. This chapter focuses on biosensors, their types, and principles as well as recent advancements in the field. Keywords Biosensors · Pollutant · PAH · Endocrine disruptive chemicals · Electrochemical sensors · Receptors V. Patel School of Biomedical Engineering, McMaster University, Hamilton, ON, Canada R. Pramod · P. Pawar Amity Institute of Biotechnology, Amity University, Mumbai, India N. Khanna Department of Biotechnology, Birla Institute of Technology and Science, Dubai, United Arab Emirates A. S. Mathuriya · S. Pandit (*) Department of Life Sciences, School of Basic Sciences and Research, Sharda University, Greater Noida, India # Springer Nature Singapore Pte Ltd. 2021 M. P. Shah (ed.), Removal of Emerging Contaminants Through Microbial Processes, https://doi.org/10.1007/978-981-15-5901-3_15 311