Numbers add up for hydrogen

The much-touted hydrogen economy depends on improving ways to create the element swiftly and affordably. Now scientists at

have used mathematical models to show how bacteria could be pressed into service to achieve that goal.

Like all living creatures, bacteria sustain themselves through their metabolism, a huge sequence of chemical reactions that transform nutrients into energy and waste.

Using mathematical computer models, the Sheffield team has mapped the metabolism of a type of bacteria called Nostoc. This fixes nitrogen and, in doing so, releases hydrogen that can then potentially be used as fuel.

Fixing nitrogen is an energy intensive process and it was not entirely clear how the bacterium produces the energy it needs to perform. The system has been used to map out how this happens.

Until now, scientists have had difficulties identifying bacteria metabolic pathways. The bacterial metabolism is a huge network of chemical reactions, and even the most sophisticated techniques can only measure a small fraction of its activity.