Researchers from the University of Texas at Austin and the University of Iowa have created a strain of E. coli that is so addicted to caffeine that it dies when given decaf. And although the premise sounds sadistic, there’s no need to start picketing. The findings show promise for a variety of wonderfully beneficial applications.

Caffeine and methylxanthine come to us by way of chocolate, sodas, energy drinks, tea and coffee — and many of us are undeniably grateful for that. But as a result of their popularity, these compounds have become a common pollutant in wastewater and surface waters. Caffeine is toxic to a variety of organisms and can wreak havoc on ecosystems; it alters natural bacterial flora and inhibits the germination and growth of some plants.

Several years ago scientists discovered a soil bacterium, Pseudomonas putida, that eats nothing but caffeine. Working from that discovery, the Texas and Iowa teams led by Jeffrey Barrick tried transferring genetic material for metabolizing caffeine to E. coli from P. putida. E. coli is the darling of bacteria researchers because it behaves so well in the lab.

The result was a bacterium that depends on caffeine for its survival; when the growth medium was switched to caffeine-free Coca Cola, the E. coli died.

The discovery offers a host of potential uses. The most obvious is that of decontaminating caffeine-polluted water. It may also be employed as a simple biosensor to measure the caffeine content of common beverages.

Another potential use could be to help purify coffee waste. Byproducts from processing and brewing coffee beans are often rich in carbohydrates, proteins, and other nutrients, and could be used for agricultural feedstock or biofuels – but toxic levels of caffeine prohibit this. The ability to decaffeinate coffee industry byproducts could transform waste into a viable resource.

The team also notes that the discovery could lead to cost-effective research and bioproduction of medication for asthma and other lung diseases.

The study was published in the American Chemical Society journal, Synthetic Biology.

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Scientists have engineered a strain of caffeine-dependent Escherichia coli that could be used in tackling water pollution.