Pickles Picked for Azo Dye Pollution Solution

September 18th, 2010 by Tina Casey

Move over, Peter Piper, because a new pickle-picker has picked up on the potential for pickles to provide a solution to the pollution problem posed by azo dyes from industrial wastewater. Scientists at the U.S. Department of Agriculture have identified a bacteria in pickle juice that could turn azo dyes into harmless substances.

The Problem with Azo Dyes

Azo dyes are commonly used in the textile industry, mainly to produce bright, warm colors in the yellow to red range. They are also used in many paints. Most are apparently non-toxic, but recent studies have suggested a link between some azo pigments and cancer.

Azo Dyes and Wastewater

The possible cancer connection is a double whammy, first because of the potential for health impacts when treated wastewater is disposed in the environment, and second because it could throw a monkey wrench into efforts to reclaim industrial wastewater for other purposes. Municipal wastewater is being reclaimed for bioplastics, irrigation and even biofuel, and if industrial wastewater can be sufficiently cleansed of toxins it could provide an additional resource.

Pickles and Azo Dyes

The USDA discovery came about when researchers were trying to find out what kind of bacteria was causing some dill pickles to turn red and spoil during the commercial fermentation process. They pinpointed a species of microorganisms called Lactobacilli, and they found that some Lactobacilli were transforming azo dyes into non-mutagenic substances. The finding is significant in the green chemistry movement because, although the search for a means of treating azo dyes in wastewater is not new, this is the first time that a food grade bacteria has been identified with that capability.

Image (altered): Pickles by Vilseskogen on flickr.com.

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Tags: azo dyes, bioplastic, green chemistry, pickles, usda, Wastewater

About the Author

Tina Casey Tina Casey specializes in military and corporate sustainability, advanced technology, emerging materials, biofuels, and water and wastewater issues. Tina’s articles are reposted frequently on Reuters, Scientific American, and many other sites. Views expressed are her own. Follow her on Twitter @TinaMCasey and Google+.