Grantee Research Project Results
Final Report: Laser-based In-situ Testing of Microbes with Ultraviolet Spectroscopy (LITMUS)
EPA Contract Number: 68HERC21C0010Title: Laser-based In-situ Testing of Microbes with Ultraviolet Spectroscopy (LITMUS)
Investigators: Bhartia, Rohit
Small Business: Photon Systems, Inc.
EPA Contact: Richards, April
Phase: I
Project Period: March 1, 2021 through August 31, 2021
Project Amount: $99,985
RFA: Small Business Innovation Research (SBIR) - Phase I (2021) RFA Text | Recipients Lists
Research Category: Small Business Innovation Research (SBIR) , SBIR - Water , SBIR - Clean and Safe Water
Description:
LITUMS addresses the need for continuous microbial monitoring in water reuse treatment systems. The efforts under the phase 1 SBIR lead to demonstration of a near-real-time, in-situ, reagentless sensor in potable and non-potable water systems. LITMUS (Laser-based In-situ Testing of Microbes with Ultraviolet Spectroscopy) uses deep UV laser excitation to directly detect microbes from the autofluorescence of protein-bound aromatic amino acids. LITMUS mitigates the challenges of current microbial detection methods being used by enabling an in-line/continuous flow, autonomous, low consumable method, with a detection range from >1x106 cells/ml, down to <10 microbial cells/ml.
Summary/Accomplishments (Outputs/Outcomes):
The efforts under this program focused on bringing LITMUS from concept to demonstration of microbial detection, differentiability, and quantitation in an implementable solution for reuse water on-line monitoring. The detection task met this goal by demonstrating deep UV fluorescence based single cell detection within a laser pulse for bacterial cells, bacterial spores, as well as protozoa.
In addition, the LITMUS system has met the primary purpose differentiating of bacteria vs. protozoa vs bacterial spores. Furthermore, we tested the ability to detect specific microbes, i.e. E.coli, in the presence of a background of other microbes inherent to the tap water. In doing so we demonstrated the ability to differentiate key marker microbes within the total bioload.
For quantitation, we developed a detection and analysis methodology that demonstrated quantification for number of total cells in the water and an ability to detect and quantify the number of E. coli cells in a background of microbes.
As per the proposed effort, we also have designed the LITMUS instrument such that it can incorporate these critical capabilities to analyze 50 ml of fluid/day and with an add-on capability to provide genera/species level specificity.
Conclusions:
Over the course of the LITMUS effort, we were able to demonstrate detection, differentiability, and quantitation of microbes in water. The results show a path to incorporating a deep UV laser induced aufluorescence detection instrument for on-line microbial monitoring with high sensitivity, minimal maintenance cost and minimal consumables.
Current method for microbial detection in water are intermittent and require laboratory efforts that delay results. As discussed with the potential user community, as water reuse becomes more prominent, the community will need to replace intermittent observation and the long delays for analysis. The need for on-line microbial monitoring systems that “bring-the-lab-capabilities-to-the-field” will increase and the LITMUS instrument, with deep UV laser induced fluorescence, provides a critical solution.
The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.