Kombucha cultures make excellent sustainable water filters, study finds

The culture ofbacteria and yeast is used in kombucha.

According to a recent paper published in the American Chemical Society journal, the key to affordable, sustainable living for water filters might be found in the refreshing tea that's all the rage these days among certain global demographic. The researchers at Montana Technological University and Arizona State University found that the growth of a new type of culture, called a kombucha culture, could prevent the formation of biofilms, a significant challenge in water purification.

You need three basic ingredients to make kombucha. Combine tea and sugar with a SCOBY culture. The culture is also known as tea mushroom or Manchurian mushroom. Kombucha tea is believed to have originated in China or Russia.

It's basically like a sourdough starter. The perfect breeding ground for yeast andbacteria can be found in a SCOBY of a firm, gel-like collection of cellulose fiber. After dissolving the sugar in non-chlorinated boiling water, steep some tea leaves in the hot sugar-water and discard them.

Once the tea cools, add the SCOBY and pour the whole thing into a jar. If you want to keep out insects, cover the beaker or jar with a paper towel and let it sit for two to three weeks. You own your own brew. A new "daughter" SCOBY will be floating at the top of the liquid.

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Beyond its popularity as a beverage, kombucha holds promise as a useful biomaterial. Last year, scientists at MIT and Imperial College London created new kinds of tough "living materials" out of SCOBYs that could one day be used as biosensors. These materials can help purify water or detect damage to packing materials. The yeasts used in kombucha are difficult to modify, so the scientists couldn't use them. The researchers used a strain of yeast called Saccharomyces cerevisiae. SCOBY was created by combining the yeast from the brewer's yeast with a bacterium called Komagataeibacter rhaeticus.

Water filters made from a kombucha culture with livingbacteria and yeast are more resistant to clogging than traditional filters.

The team was able to engineer the cells in the yeast to produce glow-in-the-dark enzymes that could sense pollutants and then break them down after detection. One of their prototype materials can detect estradiol, while the other can detect a bioluminescentProtein.

There is a chance of SCOBY-based water filters. According to the authors of this latest paper, there are over 2,000 deaths of children each day due to contaminated drinking water. Commercial filters can strain off many dangerous contaminants, includingbacteria, parasites, and even some viruses. The amount of clays, oils, minerals, andbacteria that accumulate in the filters eventually causes them to become clogged, decreasing the rate of water flow. They are difficult to remove once they form. Scientists are working on ways to fight the growth of biofilms on the filters. A more promising strategy would be to focus on developing materials that block the growth ofbacteria. That's where the SCOBYs come in.