Research Harnesses Solar-Powered Proteins to Filter Harmful Antibiotics from Water

University of Cincinnati researchers have developed and tested a solar-powered nano filter that is able to remove harmful carcinogens and antibiotics from water sources -- lakes and rivers -- at a significantly higher rate than the currently used filtering technology made of activated carbon. 

In the journal Nano Letters, Vikram Kapoor, environmental engineering doctoral student, and David Wendell, assistant professor of environmental engineering, report on their development and testing of the new filter made of two bacterial proteins that was able to absorb 64 percent of antibiotics in surface waters vs. about 40 percent absorbed by the currently used filtering technology made of activated carbon. One of the more exciting aspects of their filter is the ability to reuse the antibiotics that are captured.

The presence of antibiotics in surface waters is harmful in that it breeds resistant bacteria and kills helpful microorganisms, which can degrade aquatic environments and food chains. In other words, infectious agents like viruses and illness-causing bacteria become more numerous while the health of streams and lakes degrades.

Surprisingly, this filter employs one of the very elements that enable drug-resistant bacteria to be so harmful, a protein pump called AcrB. Wendell explained, "These pumps are an amazing product of evolution. They are essentially selective garbage disposals for the bacteria. Our innovation was turning the disposal system around. So, instead of pumping out, we pump the compounds into the proteovesicles." One other important innovation was the power source, a light-driven bacterial protein called Delta-rhodopsin which supplies AcrB with the pumping power to move the antibiotics.