Reagentless real-time microbial monitoring using deep UV auto-fluorescence

Overview

A reagentless, non-destructive microbial monitoring technology provides real-time detection and quantification of water-borne pathogens, including bacteria such as E. coli and Legionella, as well as yeast, mold, and fungi. The system exploits the unique auto-fluorescence signature of each microorganism, enabling differentiation from other fluorescing materials present in water. Beyond total cell counts, the technology has demonstrated greater than 90 percent accuracy compared to flow cytometry when quantifying intact viable cell counts across diverse water matrices, from raw source water to finished tap water.

The solution addresses a need for continuous, cost-effective microbial surveillance without the delays, reagents, and laboratory infrastructure required by traditional culture-based or cytometry-based methods. Compact inline probes can be installed across water assets and monitored remotely, enabling operators to detect contamination events as they occur.

Technical specifications

Core technology:

• Deep UV (DUV) intrinsic auto-fluorescence of aromatic biomolecules combined with advanced spectral component analysis
• Each microbial species produces a unique auto-fluorescence signature that can be distinguished from background fluorescing materials in water

Key hardware innovations:

• Recent advances in DUV light-emitting diode (LED) sources enable compact, inexpensive spectrometer designs
• Ultra-sensitive avalanche photodiode (APD) detectors match or exceed the performance of research-grade spectrometers
• Modular optical architecture allows customization for specific applications and deployment environments

Performance characteristics:

• Greater than 90 percent correlation with flow cytometry for intact viable cell counts
• Independently validated against flow cytometry and cell culture in three customer-commissioned studies
• Demonstrated correlation with a UK water utility's most sensitive laboratory microbiology tool in 2020
• Non-invasive, reagentless operation suitable for continuous inline monitoring

Deployment options:

• Compact inline probes designed for easy installation across water assets
• Remote monitoring via an intelligence platform
• Current installations include water treatment works, pre- and post-contact tanks, service reservoirs, and a beverage company clean-in-place process

Technology readiness level

The technology has progressed beyond laboratory validation into active field deployment. Prototypes have been independently validated against flow cytometry and cell culture through three customer-commissioned studies, including a 2020 demonstration at a UK water utility where the system correlated with the utility's most sensitive laboratory microbiology tool.

Current field deployments include monitoring at a water treatment works, pre- and post-contact tanks, service reservoirs, and an upcoming installation at a beverage company to monitor clean-in-place processes. Ongoing validation work is focused on determining the key optical parameters required for a compact inline system capable of continuously quantifying viable and non-viable target bacteria, yeast, mold, and fungi species in a specified matrix, generating fluorescence landscape profiles, and producing a preliminary optical layout or prototype for inline installation.