Background

    Global space industry's annual revenue could surpass $1 trillion by 2040, says a new report published by Citigroup analysts[1]. Former NASA administrator Michael Griffin said in a speech that there are acceptable and real reasons to explore space, the real reasons being our curiosity while the acceptable reasons are economic benefits and national security. "Who among us does not know the wonder and mystery and awe and magic of seeing something, even on television, never seen before, an experience brought back to us by a robotic space mission?" Griffin said, "when we do things for real reasons as opposed to acceptable reasons, we produce our highest achievements."[2] So why do we want to see space as well as the various planets out there? Because we WANT to, and because we can bring out the best in ourselves while trying.

    However, many obstacles stand in our way to space. Microgravity in space can cause increased pressure on visual nerves, and excessive space radiation can lead to cataracts, these are why astronauts cannot stay in space for more than three years. In addition, traveling to another habitable planet may take decades at the speed of current spacecraft, so it is not likely that we could survive the trip without the help of pharmaceuticals or nutrients......

    While synthetic biology can solve many problems and improve the quality of space travel by producing the essential substance from engineered microbes, it is barely possible to be fulfilled in space because of space radiation. For example, the effective dose of radiation for a day in the International Space Station (ISS) is about 30-50 times the amount a nuclear worker receives in a day, not to mention the electromagnetic waves harming the microbes in space. Under this situation, microorganisms can hardly survive in space, let alone produce valuable substances.

Approach

How Can Selenomelanin Protect Bacteria?

    Selenomelanin is a radiation-tolerant kind of melanin that reacts with selenocysteine (Sec), the 21^st amino acid, in vivo and in vitro. According to a previous study, the epithelial cells with selenomelanin could endure up to 6 GY doses of radiation, while 5 GY is lethal for humans[3]. It inspires us to engineer E. coli through synthetic biology, so that it can synthesize selenomelanin for self-protection.

    Aside from the synthesis of selenomelanin, our team also aims to prove that this compound can improve the production of space biomanufacturing. Thus, E. coli was engineered to produce γ-Aminobutyric acid (GABA), an inhibitory neurotransmitter, as astronauts are likely to have mental illnesses due to loneliness and stressfulness. Therefore, GABA was chosen as a demonstration of producing psychoactive drugs in space to solve this problem. E. coli is expected to synthesize GABA and selenomelanin at the same time under radiation, for selenomelanin protects microorganisms from harm.

What Help Can MerSe Project Offer to Space Traveling?

    The engineered E. coli is named “Se coli”, as it is covered by selenomelanin. With Se coli, we can assist the development of biomanufacturing in space and reduce the burden of space missions. Scientists can implement synthetic biology in space, synthesizing precious substances such as medicine, materials, and fuels. It enables astronauts to stay in space for a longer period of time without worrying about resource shortages. Furthermore, recent protection devices for microorganisms like containers and metals can be reduced since selenomelanin itself is a layer of protection. This also helps lower the cost of space traveling and reduce the weight of spacecraft.

How to Prove That Our Product Actually Helps People Survive in Space?

    Selenomelanin function test was conducted to measure its function (see Design and Experiments page). By exhibiting better radiation resistance than non-melanized and melanized E. coli, Se coli was verified to be 6 times more tolerant to radiation than non-melanized E. coli, and 3.6 times more radiation-tolerant than melanized-bacteria. Moreover, the quantification of GABA production was performed (see Experiments page) to confirm that Se coli can produce other substances at the same time while synthesizing selenomelanin. Combining these experiments, Se coli serves as a tool for humans to survive in space.

MerStage

    Microgravity is an unignorable property of space. As microorganisms often behave differently in such environments, taking microgravity into consideration is essential for all space-simulating experiments. However, current devices are lacking ideal simulation of microgravity, not to mention some other physical and experimental flaws.

    To overcome these limitations, our own hardware “MerStage” was built as a combination of a microfluidic chip and a UV stage to simulate microgravity and space radiation simultaneously. MerStage allows us to get closer to the real space environment while doing experiments on earth (see Hardware page).

Inspiration

    The two main reasons leading NCKU_Tainan to choose space synthetic biology protection are news and interest. When SpaceX launched the first sightseeing space mission, it was all over the news. Upon seeing that, the thought of applying synthetic biology to space immediately entered our minds. If we are all going to space one day, biosynthesized products will definitely be essential. Moreover, when doing research for space-related information around the world, it caught our attention that 77 countries have now set up space agencies with 16 of them capable of launching. With that information, we are certain that space will be our future, so it is necessary to start preparing right now.

    Moreover, there is a report focusing on a special kind of fungus that can transform harmful radiation into nutrients just like regular plants do photosynthesis. This made us wonder if synthetic biology could help E. coli survive under extreme conditions like the microbes mentioned in this report.