New Developments in the World of Science
1.
Rhodopseudomonas palustris - Microbe which ‘eats’ electricity
In a new study, Harvard scientists show that the bacterium
Rhodopseudomonas palustris can use natural conductivity to pull electrons
from minerals located deep in soil and sediment while remaining at the
surface, while remaining at the surface, where they absorb the sunlight
needed to produce energy. In the wild, the microbes rely on iron to provide
the electrons they need to fuel energy generation, but tests in the lab
suggest the iron itself isn’t critical for this process. By attaching an
electrode to colonies of the microbes in the lab, researchers observed that
they could take up electrons from a non-ferrous source, suggesting they
might also use other electron-rich minerals – such as other metals and
sulfur compounds – in the wild. The microbes seem to take up electrons
through naturally occurring conductive minerals. Also, as the microbes pull
electrons away from iron, they create iron oxide crystals which precipitate
into the soil around them. Over time, those crystals can become conductive
and act as “circuits,” allowing the microbes to oxidize minerals they
otherwise couldn’t reach. Using genetic tools, researchers were also able to
identify a gene that is critical to the ability to take up electrons. When the
gene was turned off, the microbes’ ability to take up electrons dropped by
about a third. Besides performing EET for energy generation via fuel cells,
these microbes could also be put to use in the pharmaceutical industry.
SOURCE:
Harvard University, Feb. 26, 2014