Scientists in Japan have invented the first motor to be powered by bacteria. The micro-motor relies on bacteria gliding along a silicon track to spin a silicon dioxide rotor. Moving at speeds of up to 5 micrometers per second, the bacteria can power the 20 micrometer diameter rotors at rates of up to 2.6 rpm. The work, led by Yuichi Hiratsuka, used bacteria of the species Mycoplasma mobile. However, they point out that many species of bacteria are mobile, moving towards light or to certain chemical attractants, creating a wide range of potential power sources for micro-pumps or micro-robots, or might be used in the construction of electrical generating systems which could convert abundant energy sources like glucose into electrical energy. The motor relies on a circular tracking system accessed by a door at the edge of the basin where the bacteria are contained, which directs most of the bacteria onto a similar path. The scientists suggest that improvements in optimizing the movement of the bacteria could further improve the efficiency of the system.