Caffeine-addicted bacteria to eat up pollutants

How do you decaffeinate water that's polluted by our widespread use of caffeine? Engineer some bacteria who literally live off caffeine. They'll eat it.

Okay, many of us joke about our dependence on caffeine. (I’m on my second imperial pint of coffee today.) Now, scientists have genetically engineered E. coli bacteria who literally live off caffeine.

Caffeine and related chemical compounds are becoming major water pollutants due to their widespread use in coffee and tea, soda and energy drinks, chocolate, and even certain prescription drugs for asthma. In fact, caffeine levels in wastewater and surface waters around population centers are used as a marker of human impact.

In 2011, scientists discovered a naturally-occurring soil bacterium, Pseudomonas putida CBB5, that feeds solely on caffeine, and can be used to clean up environmental contamination.

So a team led by Jeffrey Barrick from the University of Texas at Austin decided to transfer genetic material for metabolizing caffeine from P. putida into that of E. coli -- the workhorse of biotechnology because it’s easy to handle and grow.

When engineered into E. coli, the result was bacteria literally addicted to caffeine. The team also developed a synthetic packet of genes for breaking down caffeine that can be moved easily to other microbes.

Some potential applications:

  • Decaffeination and decontamination of wastewater
  • As a biosensor to measure the caffeine content of common beverages
  • Environmental remediation. Caffeine pollution alters natural bacterial flora and inhibit the growth of certain plants.
  • Help with the recovery of nutrient-rich byproducts of coffee bean processing. Toxic levels of caffeine in the carbohydrates, proteins, and other nutrients make those byproducts unsuitable as agricultural or biofuel feedstocks.
  • And possibly even cost-effective research and bioproduction of medication for asthma and other lung diseases.

Their report was published in ACS Synthetic Biology.

[Via American Chemical Society]

Image: J. Fang

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