Last year we looked at how a research team had genetically engineered Escherichia coli, (E. coli), bacteria to solve a classic mathematical puzzle known as the burnt pancake problem. At the time the researchers indicated their intention to adapt 'bacterial computers' for other, related math problems, and it appears they’ve been true to their word by solving another classic mathematical problem, the Hamiltonian Path Problem.

The Hamiltonian Path Problem asks whether there is a route in a network from a beginning node to an ending node, visiting each node exactly once. The researchers modified the genetic circuitry of the bacteria to enable them to find a Hamiltonian path in a three-node graph. The bacteria that successfully solved the problem reported their success by fluorescing both red and green, resulting in yellow colonies.

The research team, consisting of faculty and undergraduate students from the biology and mathematics departments at Missouri Western State University in Missouri and Davidson College in North Carolina, USA, say their findings demonstrate that computing in living cells is feasible and illustrates the viability of extending the approach to other computationally challenging math problems.

Who knows? Maybe it won’t be too long before kids are using bacteria to help them with their homework.

The team’s findings can be found in the Journal of Biological Engineering.