In the future, space explorers will travel to planets with a
suitcase full of engineered microbes to help us build a life --
including a bacterium that breaks down urea into chemicals that
will cement dusty Mars rock into bricks.
The idea is, instead of hauling supplies to space, we make what
we need using a nifty carry-on filled with billions of spaceworthy
bugs that multiply by feeding on local materials. These microbes
will be engineered to help create things like fuel, plastics and
The project is part of a two-year long collaboration between
Nasa and synthetic biologists at Brown and Stanford universities.
The team insert specially engineered gene sequences, known as biobricks, into microbes to cause their behaviour to change
dramatically. With biocement project REGObricks, for instance, the
team makes use of use the Sporosarcina pasteurii
bacterium, which breaks down urea and produces ammonium. This
ammonium would make the Mars landscape alkaline enough for calcium
carbonate cements to form.
The idea is a group of new Mars residents can feed the bacteria
with their urine to make enough calcium carbonate crystals to glue
together dusty Mars sand and rock, making building bricks. Ordinary
Sporosarcina pasteurii might not be sturdy enough in the
atmosphere, so they identified and extracted the genetic sequence
that helps in cement-building and inserted this into the E. coli
bacteria. Thus, the team hopes Mars bricks will be made using
On their website, the synthetic biologists explain that "the crystals aggregate in the gaps between sand
particles, linking them in tight compact structures", and that
during experiments this process was shown to generate bricks with
"compressive strengths up to 30 megapascals, comparable to that of
concrete or limestone". According to a report in New Scientist, this process took two weeks.
It's not just space bricks that could be created using synthetic
biology. Small bacteria boxes accompanying astronauts could contain
billions of helpful microbes. Another key bacterium is Anabaena,
which can exist in carbon dioxide and nitrogen-rich alien
atmospheres. Anabaena can not only thrive in these conditions, but
it converts those gases to sugars. By inserting a biobrick from
E.coli into Anabaena, the team increased its sugar output, which
could then be used to feed other oil, plastics or fuel-building
microbes brought along.
According to MRC Laboratory molecular biologist Paul Dear,
synthetic biology will be the only way to building a life on
"Every gram delivered to Mars or other planets translates into
huge additional costs and energy demands. Biology rather than
physical engineering is the only realistic way to do things on a
planetary scale," Dear said.