A team from the biology and the mathematics departments of Davidson College in North Carolina and Missouri Western State University added genes to E. coli bacteria to solve a classic mathematical puzzle, known as the burnt pancake problem.

The burnt pancake problem involves a stack of pancakes of different sizes, each of which has a golden and a burnt side.

This stack must be sorted so that the largest pancake is on the bottom and all pancakes are golden side up.

Each flip reverses the order and the orientation of one or several consecutive pancakes.

The aim of the exercise is to stack them correctly in the fewest number of flips.

To solve the problem, the researchers used fragments of DNA as the pancakes.

Genes were added from a different type of bacterium to enable the E. coli to flip the DNA 'pancakes'.

A gene that made the bacteria antibiotic-resistant was also added, but only when the DNA fragments had been flipped into the right order.

The time required to reach the mathematical solution with the bacteria reflects the minimum number of flips needed to solve the burnt pancake problem.

"The system offers several potential advantages over conventional computers" says Dr Karmella Haynes of Davidson College, a lead researcher.

"A single flask can hold billions of bacteria, each of which could potentially contain several copies of the DNA used for computing."

"These 'bacterial computers' could act in parallel with each other, meaning that solutions could potentially be reached quicker than with conventional computers, using less space and at a lower cost.