Scientists studying a genus of the rock-dwelling bacteria called Shewanella have found out how the organisms can transform minerals by zapping them with tiny electrical currents. The discovery could lead to new types of fuel cells to generate electricity, to better environmental-cleanup techniques, and possibly even to a new generation of organically made materials.
Bacteria live in almost every environment on Earth, from the ocean's deepest trenches to the Himalayas' highest peaks. Perhaps the main reason is their supreme adaptability.
Even when scientists finally discovered that the organisms were using rocks instead of oxygen to purge electrons, they still couldn't figure out the exact molecular mechanism that made such metabolism possible.
Now, after 5 years of studies in laboratories in the United States and the United Kingdom, a team has discovered the elusive process. It turns out that Shewanella use a class of proteins on their surface that functions like an electrical wire between the bacteria's interior and exterior. The proteins--called deca-heme c-class cytochromes--bond with the rock molecules and convey electrons out through the cell membrane, the composition of which normally functions as an insulator.
Science News Staff , Science Magazine