05.31.2020

Mars Settlers Could Use CO2, Water, & Sunlight To Make Drugs & Plastic

colonize Mars. However, as you could imagine, shipping things to the big red planet is not easy. It’s ridiculously expensive, and there’s a limited amount of space available in a spaceship for cargo. But the settlers will need things to survive! And yet, Mars lacks a wide range of organic compounds humans can’t live without, but that can’t be shipped from Earth. So, the peoples’ best bet is to send compact devices that can manufacture those necessities. A team of NASA funded chemists from Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California, Berkeley, has a plan. Their research, now almost a decade in the making, has resulted in the development of a hybrid system of nanowires and bacteria that spits out the building blocks of organic molecules. The biohybrid, essentially a nano-power-plant, captures the energy from sunlight to convert water and carbon dioxide into these building blocks. Both water and CO2 are abundant on Mars. Project leader Peidong Yang, the S. K. and Angela Chan Distinguished Chair in Energy at UC Berkeley and a professor of chemistry, said:

On Mars, about 96% of the atmosphere is CO2. Basically, all you need is these silicon semiconductor nanowires to take in the solar energy and pass it on to these bugs to do the chemistry for you. For a deep space mission, you care about the payload weight, and biological systems have the advantage that they self-reproduce: You don’t need to send a lot. That’s why our biohybrid version is highly attractive.
Mars Settlers Could Use CO2, Water, & Sunlight To Make Drugs & Plastic
The device consisting of a chamber that contains the nanowire/bacteria hybrid (on the left) and a chamber where oxygen is produced (on the right). Credit: UC Berkeley / Peidong Yang
The device itself is a scaffold of nanowires – microscopic silicone wires used as electronic components, sensors, and solar cells – of which the bacteria attach. The nanowires draw in electrons that serve as food for the bacteria, which then convert the particles into acetate molecules – basically acetic acid or vinegar. The byproduct could enable a variety of key ingredients to be manufactured on-planet. Yang said:
These silicon nanowires are essentially like an antenna: They capture the solar photon just like a solar panel. Within these silicon nanowires, they will generate electrons and feed them to these bacteria. Then the bacteria absorb CO2, do the chemistry and spit out acetate.
Mars Settlers Could Use CO2, Water, & Sunlight To Make Drugs & Plastic
A scanning electron micrograph of the bacteria tightly packed around the nanowires. This shows the nanowire-bacteria hybrid operating at the optimal acidity. Like this, the conversion of solar energy to carbon bonds is most efficient. Credit: UC Berkeley / Peidong Yang
Many different kinds of organic molecules can be made with acetate molecules. Furthermore, organic products could be made through biosynthesis using acetate in conjunction with genetically engineered organisms, such as yeast or bacteria. Acetate can even make plastic! Meanwhile, Yang is developing a system to produce carbohydrates and sugars from sunlight and CO2 as a means of providing food for the Mars settlers. And he and his team carry on with the biohybrid research, continually finding ways to make it more efficient and versatile to make it capable of producing as many varieties of organic compounds as possible. Bringing this conversation back down to Earth, the biohybrid system even has the potential to help with the climate crisis. It can be used to pull CO2 from the air and make useful products. For now, the researchers are still exploring bacteria options and evolving the device for practical use.   This article appeared on the Intelligent Living website at https://www.intelligentliving.co/mars-co2-water-sunlight-make-drugs-plastic/]]>

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