Continuous Real-time Detection of Microbial Contamination in Water using Intrinsic Fluorescence

Abstract

With the rapid increase in global population, geographically changing drought conditions and the ensuing potential water shortage, water quality has become a major concern. In some extreme cases, such as Arizona, the population may have to switch and use recycled toilet water for potable use in the near future. However, our current monitoring methods for drinking water do not provide fast and reliable results to deal with these challenges. By using intrinsic fluorescence, microbial contamination in water can be monitored in real-time, continuously, without sample collection or contact and at very low concentration. The detection limit of the instrument designed specifically for this purpose and reported here is ~50 bacterial cells/L. By monitoring the fluorescence of cellular components of microorganisms, their concentrations and metabolic states (live, dead, spores) can be determined. These fluorophores include reduced pyridine nucleotides (RPNs), flavins, and cytochromes to distinguish live cells; cytochromes for dead cells; and calcium dipicolinic acid (DPA) for spores. By using this method, a wide range of microorganisms such as bacteria, protozoa, amoebae, fungi and other microorganisms can be detected