A new way to grow cyanobacteria under Mars-like conditions

A: Bioreactor Atmos (“Atmospheric tester for organic systems bound to Mars”). B: A single ship in Atmos. C: Blueprint. Credit: C. Verseux / ZARM

NASA aims to work with other major space agencies to send its first manned Mars mission to Mars in the early 2030s, but companies like SpaceX may do so sooner. .. Astronauts on Mars need oxygen, water, food, and other consumables. These must be procured from Mars, as imports from Earth are unrealistic in the long run.To Microbiology FrontierFor the first time, scientists have shown that anabaena cyanobacteria can grow at low pressure with only local gas, water, and other nutrients. This makes it much easier to develop sustainable biological life support systems.

“Here we show that cyanobacteria can use the gas available in the atmosphere of Mars as a source of carbon and nitrogen at low total pressures. Under these conditions, cyanobacteria are only dust like Mars. May help maintain the ability to grow in water, including, and still sustain long-term missions to Mars, “said Applied Space Technology and Applied Space Microbiology Research at the Center for Microgravity (ZARM). Dr. Cyprien Verseux, the lead author of the space biologist and lead author, said. University of Bremen, Germany.

Low pressure atmosphere

Cyanobacteria have long been targeted as candidates for promoting biological life support in space missions, as all species produce oxygen by photosynthesis and some species can fix atmospheric nitrogen to nutrients. I have come. The difficulty is that it cannot grow directly in the atmosphere of Mars, where the total pressure is less than 1% of Earth (6-11 hPa, too low for the presence of liquid water), but the partial pressure of nitrogen gas is 0.2-0.3. is. hPa-too low to metabolize. However, it costs money to reproduce the atmosphere like the earth. To withstand the pressure difference, the gas needs to be imported and the culture system needs to be robust. Therefore, it is heavy and cargo. “Think of a pressure cooker,” says Verseux. .. So researchers sought an intermediate point in the atmosphere near Mars that would allow cyanobacteria to grow well.

Verseux etc. to find suitable atmospheric conditions. We have developed a bioreactor called Atmos (short for “atmospheric tester for organic systems bound to Mars”). This bioreactor allows cyanobacteria to grow at low pressure in the artificial atmosphere. Any input must come from the red planet itself: with the exception of nitrogen and carbon dioxide, the abundant gas in the atmosphere of Mars, and the water that can be mined from ice, the nutrients are “regolith”, planets and moons like the Earth. Should come from the dust that covers the. Regoliths on Mars have been shown to be rich in nutrients such as phosphorus, sulfur and calcium.

Anabaena: A versatile cyanobacteria grown in dust like Mars

Atmos has nine 1 L containers made of glass and steel, each of which is sterilized, heated, pressure controlled, digitally monitored and the culture inside is continuously agitated. The authors selected a strain of nitrogen-fixing cyanobacteria called Anabaena. Preliminary tests have shown that the PCC 7938 is particularly good at using Martian resources and helping other organisms grow. Closely related species have been shown to be edible, genetically engineered, and capable of forming specialized dormant cells to withstand harsh conditions.

Verseux and his colleagues first grew Anabaena under a mixture of 96% nitrogen and 4% carbon dioxide at a pressure of 100 hPa for 10 days. This is one tenth the pressure of the earth. Cyanobacteria grew as well as under the surrounding air. Next, I tested the combination of adjustment atmosphere and regolith. Since Regolith has never been brought in from Mars, we instead used a substrate developed by the University of Central Florida (called the “Mars Global Simulation”) to create the growth medium. As a control, Anabaena was grown in standard medium either in ambient air or in the same low pressure artificial atmosphere.

Cyanobacteria grew well under all conditions, including regolith, under low pressure, nitrogen and carbon dioxide rich mixtures. As expected, both atmospheres grew faster on standard media optimized for cyanobacteria than Mars Global Simulant. But this is still a huge success. Regolith is ubiquitous on Mars, while standard media need to be imported from Earth. “We want to use only those nutrient resources available on Mars,” says Verso.

We have succeeded in crushing dried Anabaena biomass, suspending it in sterile water, filtering it, and using it as a substrate for growing E. coli. This allows you to extract sugars, amino acids and other nutrients to nourish fewer other bacteria. It’s sturdy, but it’s a proven tool for biotechnology. For example, E. coli is easier to design than Anabaena and can produce foods and medicines on Mars that Anabaena cannot.

Researchers conclude that nitrogen-fixing, oxygen-producing cyanobacteria can grow efficiently on Mars under controlled conditions, using exclusively local ingredients, at low pressures.

Further improvement of the pipeline

These results are significant advances. However, the authors warn that further research is needed. “We want to move from this proof of concept to a system that can be used efficiently on Mars,” says Verseux. They suggest fine-tuning the optimal pressure, carbon dioxide, and nitrogen combinations for growth, perhaps while testing other genera of genetically tuned cyanobacteria for space missions. Mars cultivation systems also need to be designed.

“Our bioreactor, Atmos, is not a culture system used on Mars. It aims to test the conditions offered on Earth. But our results are the design of a culture system on Mars. For example, low pressure means that we can develop a lighter, easier-to-carry structure because we don’t have to withstand the big differences between the inside and the outside, ”Verseux concludes. I will.

Geologists simulate soil conditions to help grow plants on Mars

For more information:
“The low-pressure N2 / CO2 atmosphere is suitable for Martian cyanobacteria-based life support systems.” Microbiology Frontier, DOI: 10.3389 / fmicb.2021.611798, / articles / 1… icb.2021.611798 / full

Quote: Biotech for the Red Planet: A new way to grow cyanobacteria under Mars-like conditions (February 16, 2021) https: // -Obtained from planet-method on February 16, 2021-cyanobacteria.html

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A new way to grow cyanobacteria under Mars-like conditions

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