However much coffee or Red Bull you gulp down in a given day, you’re a lightweight compared to Pseudomonas putida CBB5, a recently discovered strain of soil bacteria that is capable of living on pure caffeine.
When humans consume caffeine, it circulates through the bloodstream, is broken down into metabolites by the liver, and is then excreted in urine, all without being used for caloric energy; this is why the calorie count of a cup of black coffee is essentially nil. But caffeine is, after all, comprised of carbon, hydrogen, oxygen, and nitrogen (its chemical formula is C8H10N4O2), the four most important building blocks of life. Pseudomonas putida CBB5 uses special enzymes to break that caffeine down into carbon dioxide and ammonia, generating energy in the process.
Within the caffeine molecule are three structures, known as methyl groups, composed of 1 carbon and 3 hydrogens atoms. This bacterium is able to effectively remove these methyl groups (a process known as N-demethylization) and essentially live on caffeine.
Summers and his colleagues have identified the three enzymes responsible for the N-demethylization and the genes that code for these enzymes.
If scientists are able to cheaply synthesize the enzymes responsible, they could potentially be used as building blocks for structurally similar drugs used to treat asthma and blood arhythmias, and, more straightforwardly, to decaffeinate coffee and tea without using the chemical solvents currently used to do so.
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