Tired of replacing expensive water filters? Researchers, finally, present a water filter with a life span. No really, it’s alive. In a recent study published in “American Chemical Society EST Water,” filtration membranes made from bacterial biofilms withstood longer durations with less buildup than artificial filters. Biofilms are a community of microorganisms that grow together on a surface. The data suggests that living filtration devices could be crucial in increasing durability, specificity and accessibility of safe water.
Current water filter membranes are formed using long polymer chains, which physically trap contaminants in small pores. As a result, bacteria, viruses and parasites build up on the membranes. Because the captured microorganisms can still grow and form strong aggregates known as biofilms, the very function of capturing microbes eventually decreases filter efficiency.
The living filtration membranes were derived from the same bacteria and yeast used in the fermentation of kombucha tea. The bacteria and yeast were grown together using inexpensive culture techniques that included growth in sugar, black tea, vinegar and water. A fine membrane of yeast and bacteria formed where the culture came into contact with air. The living membrane formed smaller pore sizes than those found in artificial membranes. Furthermore, the bacteria within the membrane produced acetic acid, which kills other bacteria. This provides an active defense against captured microorganism communities.
Living and synthetic membranes were tested on three municipal drinking sources in Montana. In all water samples, the living membrane filters outperformed the commercial nonliving membranes in maintenance of water flow quality. Although both membranes accumulated microorganisms, the living membrane filter showed greater resistance to biofilm formation. In addition to filtration superiority, the living culture membranes were also inexpensive and sustainable.