Biotech Fit for the Red Planet

New technique for growing cyanobacteria under Mars-like conditions.

NASA, in partnership with other leading area companies, intends to send its very first human objectives to Mars in the early 2030s, while business like SpaceX might do so even previously. Astronauts on Mars will require oxygen, water, food, and other consumables. These will require to be sourced from Mars, since importing them from Earth would be not practical in the long term. In Frontiers in Microbiology, researchers reveal for the very first time that Anabaena cyanobacteria can be grown with just regional gases, water, and other nutrients and at low pressure. This makes it a lot easier to establish sustainable biological life support group.

“Here we show that cyanobacteria can use gases available in the Martian atmosphere, at a low total pressure, as their source of carbon and nitrogen. Under these conditions, cyanobacteria kept their ability to grow in water containing only Mars-like dust and could still be used for feeding other microbes. This could help make long-term missions to Mars sustainable,” states lead author Dr Cyprien Verseux, an astrobiologist who heads the Laboratory of Applied Space Microbiology at the Center of Applied Space Technology and Microgravity (ZARM) of the University of Bremen, Germany.

Low-pressure environment

Cyanobacteria have actually long been targeted as prospects to drive biological life assistance on area objectives, as all types produce oxygen through photosynthesis while some can repair climatic nitrogen into nutrients. A trouble is that they cannot grow straight in the Martian environment, where the overall pressure is less than 1% of Earth’s – 6 to 11 hPa, too low for the existence of liquid water – while the partial pressure of nitrogen gas – 0.2 to 0.3 hPa – is too low for their metabolic process. But recreating an Earth-like environment would be costly: gases would require to be imported, while the culture system would require to be robust – thus, heavy to freight – to withstand the pressure distinctions: “Think of a pressure cooker,” Verseux states. So the scientists searched for a happy medium: an environment near Mars’s which enables the cyanobacteria to grow well.

To discover ideal climatic conditions, Verseux et al. established a bioreactor called Atmos (for “Atmosphere Tester for Mars-bound Organic Systems”), in which cyanobacteria can be grown in synthetic environments at low pressure. Any input should originate from the Red Planet itself: apart from nitrogen and co2, gases plentiful in the Martian environment, and water which might be mined from ice, nutrients need to originate from “regolith”, the dust covering Earth-like worlds and moons. Martian regolith has actually been revealed to be abundant in nutrients such as phosphorus, sulphur, and calcium.

Anabaena: flexible cyanobacteria grown on Mars-like dust

Atmos has 9 1 L vessels made from glass and steel, each of which is sterilized, heated, pressure-controlled, and digitally kept an eye on, while the cultures within are continually stirred. The authors picked a pressure of nitrogen-fixing cyanobacteria called Anabaena sp. PCC 7938, since initial tests revealed that it would be especially proficient at utilizing Martian resources and assisting to grow other organisms. Closely associated types have actually been revealed to be edible, ideal for genetic modification, and able to form customized inactive cells to make it through extreme conditions.

Verseux and his coworkers initially grew Anabaena for 10 days under a mix of 96% nitrogen and 4% co2 at a pressure of 100 hPa – 10 times lower than on Earth. The cyanobacteria grew along with under ambient air. Then they checked the mix of the customized environment with regolith. Because no regolith has actually ever been brought from Mars, they utilized a substrate established by the University of Central Florida (called “Mars Global Simulant”) rather to develop a development medium. As controls, Anabaena were grown in basic medium, either at ambient air or under the very same low-pressure synthetic environment.

The cyanobacteria grew well under all conditions, consisting of in regolith under the nitrogen- and carbon dioxide-rich mix at low pressure. As anticipated, they grew quicker on basic medium enhanced for cyanobacteria than on Mars Global Simulant, under either environment. But this is still a significant success: while basic medium would require to be imported from Earth, regolith is common on Mars. “We want to use as nutrients resources available on Mars, and only those,” states Verseux.

Dried Anabaena biomass was ground, suspended in sterilized water, filtered, and effectively utilized as a substrate for growing of E. coli germs, showing that sugars, amino acids, and other nutrients can be drawn out from them to feed other germs, which are less durable however tried-and-tested tools for biotechnology. For example, E. coli might be crafted more quickly than Anabaena to produce some foodstuff and medications on Mars that Anabaena cannot.

The scientists conclude that nitrogen-fixing, oxygen-producing cyanobacteria can be effectively grown on Mars at low pressure under regulated conditions, with solely regional active ingredients.

Further improvements in the pipeline

These outcomes are a crucial advance. But the authors warn that additional research studies are needed: “We want to go from this proof-of-concept to a system that can be used on Mars efficiently,” Verseux states. They recommend tweak the mix of pressure, co2, and nitrogen optimum for development, while checking other genera of cyanobacteria, maybe genetically customized for area objectives. A growing system for Mars likewise requires to be developed:

“Our bioreactor, Atmos, is not the cultivation system we would use on Mars: it is meant to test, on Earth, the conditions we would provide there. But our results will help guide the design of a Martian cultivation system. For example, the lower pressure means that we can develop a more lightweight structure that is more easily freighted, as it won’t have to withstand great differences between inside and outside,” concludes Verseux.

Reference: “A Low-Pressure, N2/CO2 Atmosphere Is Suitable for Cyanobacterium-Based Life-Support Systems on Mars” by Cyprien Verseux, Christiane Heinicke, Tiago P. Ramalho, Jonathan Determann, Malte Duckhorn, Michael Smagin and Marc Avila, 16 February 2021, Frontiers in Microbiology.
DOI: 10.3389/fmicb.2021.611798

The job was moneyed by the Alexander von Humboldt Foundation.