Photocatalytic Disinfection

System neutralizes pathogens in contaminated water.

01 January 2017

Two US scientists have engineered an environmentally friendly optical technology to kill outbreak-causing viruses and bacteria from public drinking water.

David Wendell, an associate professor in University of Cincinnati’s College of Engineering and Applied Science, and a former graduate student, Elizabeth Wurtzler, developed a protein-based photocatalyst that uses light to generate hydrogen peroxide to eliminate E. coli, Listeria, giardia, and cryptosporidium.

If mass produced, this protein, called StrepMiniSog, could be used to safely “spike” the public water supply in the event of an outbreak, he predicts.

“We designed this protein to attach to pathogens of interest using antibodies, so that when the attached photocatalyst is exposed to light, it generates hydrogen peroxide and kills the pathogen,” Wendell said.

Wendell notes that this technology neutralizes viruses and bacteria in water without adding troublesome contaminants, such as antibiotics or disinfection byproducts, to the environment.

“In the environment or engineered water treatment systems, there are many bacteria that you want to preserve,” he said. “We need a disinfectant that can ignore helpful bacteria while neutralizing pathogens responsible for sporadic outbreaks.”

Wendell said the it is essentially a seek-and-destroy technology where it will attach only to the organisms of interest. By using a selective approach, we can preserve existing microbiomes, which makes them more resistant to opportunistic pathogens.”

Wendell said current methodologies for treating outbreaks involve increasing chlorine concentrations at water treatment plants, but too much chlorine can produce other types of water contamination, commonly referred to as disinfection byproducts (which are regulated by the US Environmental Protection Agency). And certain bacteria — Legionella for example — are gaining resistance to chlorine.

Wendell received a $500,000 grant in 2016 as part of an award from the National Science Foundation to develop a mass-production system for his protein-based photocatalyst.

“I think it is feasible to have a mass-production technology in less than five years,” Wendell said.

Beyond the potential use in water treatment, Wendell adds that the StrepMiniSog photodisinfection system could also be used as a personal disinfectant product. And unlike antibacterial products (which kill all types of bacteria, including helpful types) his would target only harmful pathogens.

“The technology is also very useful for any sort of surface disinfection, including treating human skin,” Wendell said.


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