Created a living computer from E. coli Bacteria that can solve complex mathematical problems (Jacob Aron; The Guardian, 24.07.09)

Posted by
Jacob Aron Friday 24 July 2009
guardian.co.uk

A team of US scientists have engineered bacteria that could solve complex mathematical problems faster than anything made from silicon.

The research can be used to solve a puzzle known as the Hamiltonian Path Problem. Imagine you want to tour the 10 biggest cities in the UK – one route might start in London (number 1) and finish in Bristol (number 10), for example. The solution to the Hamiltonian Path Problem would be the route that takes in each city just once.

This simple problem is surprisingly difficult to solve. There are over 3.5 million possible routes to choose from, and a regular computer must try them out one at a time to find the one that visits each city only once. Alternatively, a computer made from millions of bacteria can look at every route simultaneously. The biological world also has other advantages. As time goes by, a bacterial computer will actually increase in power as the bacteria reproduce.

Scanning electron micrograph of E. coli bacteria. A rapidly growing colony can be programmed to act as a hugely powerful parallel computer. Photograph: Getty

Programming such a computer is no easy task, however. The researchers coded a simplified version of the problem, using just three cities, by modifying the DNA of Escherichia coli bacteria. The cities were represented by a combination of genes causing the bacteria to glow red or green, and the possible routes between the cities were explored by the random shuffling of DNA. Bacteria producing the correct answer glowed both colours, turning them yellow.

In addition to proving the power of bacterial computing, the team have also contributed significantly to the field of synthetic biology. Just as electronic circuits are made from transistors, diodes and other devices, so too are biological circuits. Synthetic biologists have worked together to create the Registry of Standard Biological Parts, and this new research has contributed more than 60 new components to the list. http://www.guardian.co.uk/science/blog/2009/jul/24/bacteria-computer