Microbe Discovered That Lives on Caffeine

Posted on May 28, 2011

A new bacterium that uses caffeine for food was found in a flower bed at the University of Iowa. A research report by Ryan Summers, a doctoral student at the University of Iowa, says the bacterium, Pseudomonas putida CBB5, uses four newly discovered digestive proteins to break down caffeine, which allows it to live and grow.
Due to the extensive presence of caffeine in the environment, it is not surprising that there are bacteria that can "eat" this molecule for growth and reproduction. The caffeine molecule itself is composed of carbon, nitrogen, hydrogen, and oxygen, all of which are necessary for cell growth. We have isolated a new caffeine-degrading bacterium, P. putida CBB5, which breaks caffeine down into carbon dioxide and ammonia.

The three methyl groups in caffeine, each composed of one carbon and three hydrogen atoms, are effectively removed by this bacterium from the main part of the molecule. Thus, the bacterium is able to "live" on caffeine. Caffeine utilization by bacteria via removal of the three methyl groups (a process known as N-demethylation) has been reported previously; however, the exact mechanism for N-demethylation has been a mystery for many years. This work, for the first time, demonstrates the enzymes and genes utilized by bacteria to live on caffeine. Also for the first time, this work reports the degradation of theophylline, a natural product related to caffeine which is used to treat asthma. Theophylline contains only two methyl groups, as opposed to three in the caffeine molecule.
The discovery could potentially lead to ways to make production of some pharmaceuticals easier and greener. It could also help with the decaffeination of coffee, tea, and cocoa.
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