Paint designed to improve the air quality in a Martian colony may contain
microorganisms from the desert that consume sunlight, absorb carbon dioxide,
and release oxygen.
Scientists have created a biocoating for
Chroococcidiopsis cubana
that reduces the quantity of carbon dioxide in the surrounding air while
emitting quantifiable amounts of oxygen on a daily basis. According to a
team led by microbiologist Simone Krings of the University of Surrey in the
UK, this has consequences not just for space travel but also for life on
Earth.
"We need innovative, environmentally friendly, and sustainable materials
with the rise in greenhouse gasses, particularly CO2, in the atmosphere and
concerns about water shortages due to rising global temperatures," says
University of Surrey bacteriologist
Suzie Hingley-Wilson.
"Mechanically robust, ready-to-use biocoatings, or 'living paints,' could
help meet these challenges by reducing water consumption in typically
water-intensive bioreactor-based processes."
There is an odd tiny genus of beasties called Chroococcidiopsis. There's a
good chance that a species of this bacteria exists somewhere on Earth where
it seems impossible for life to exist. It uses an unusual kind of
photosynthesis that can thrive in extremely low light levels and has a
fallback survival strategy for even darker environments. It has been
discovered in the utter darkness of very deep caverns as well as in the
lower crust of Earth just below the ocean level.
Sometimes, Chroococcidiopsis cubana inhabits deserts with circumstances
akin to those on Mars. In addition, its metabolism shares several
advantageous traits with other cyanobacteria. The bacteria absorbs CO2,
fixes it, and uses photosynthesis to convert it into organic molecules.
During this process, oxygen is released.
Krings' group aimed to create a
biocoating
that takes use of these characteristics. These are coatings, similar to
paint, that have layers of live bacteria added to them. They must be robust
and free of anything that can damage the microorganisms within.
This is harder than it sounds: the biocoating matrix must be strong and
physically durable, yet porous to permit cell movement and hydration. By
combining latex with nanoclay particles, the team was able to accomplish
these characteristics and securely encapsulate their germs.
The next stage was to confirm that the paint was functioning as planned and
that the little bacteria within were still leading contented, small lives.
The group measured the amount of CO2 and oxygen produced while keeping an
eye on their coating for 30 days.
They discovered that throughout the course of the month, the paint
continuously released oxygen at a rate of up to 0.4 grams of oxygen per gram
of biomass every day. For every kilogram (35 ounces) of paint, that equates
to up to 400 grams (14 ounces) of oxygen. Furthermore, CO2 was absorbed by
the paint. Green Living Paint is the name given to the creation by the
researchers.
A team of astronauts residing on Mars for a year would require an estimated
500 metric tons of oxygen, so that output would probably not be enough for a
habitat there. However, every bit of oxygen that can be extracted on the red
planet will lessen the amount of oxygen that space missions will need to
transport there on a spacecraft.
"The photosynthetic Chroococcidiopsis have an extraordinary ability to
survive in extreme environments, like droughts and after high levels of UV
radiation exposure,"
adds Krings. "This makes them potential candidates for Mars colonization."
The research has been published in
Microbiology Spectrum.
