Long-duration missions to planetary bodies and deep space will require new technological developments that support human habitation in transit and on distant bodies. Microorganisms are unique from the standpoint that they can be employed as self-replicating bio-factories to produce both native and engineered mission-relevant bio-products. Methane (CH4) usage in In-Space Manufacturing (ISM) platforms has been discussed previously for human exploration and has been proposed to be used in physicochemical systems as a propulsion fuel, supply gas, and in fuel cells.
Carbon dioxide (CO2) is abundant on Mars and manned spacecraft. On the International Space Station (ISS), NASA reacts excess CO2 with hydrogen (H2) to generate CH4 and water (H2O) using the Sabatier System. The resulting water is recovered in the ISS but the methane is vented to space. Recapturing this methane and using it for microbial manufacturing could provide a unique approach in development of in-space bio-manufacturing. Thus, there is a need for systems that convert methane into valuable materials. Methane is a potential carbon substrate for methanotrophic microorganisms that are able to metabolize CH4 into biomass.
ISRU using ISM to generate mission-relevant products could be logical for many applications. Products that consist of a significant amount of carbon (e.g. fuels, foods, etc.) could potentially be derived from single-carbon molecules available on long-duration missions. NASA Ames has developed a novel patent-pending technology for in-space bio-manufacturing of mission-relevant bio-products using methane as the sole carbon substrate.
The innovative technology ports Soluble Methane Monooxygenase (sMMO) to Pichia; that is, it moves the methane metabolism into a robust microbial factory (Pichia pastoris). The yeast Pichia pastoris is a refined microbial factory that is used widely by industry because it efficiently secretes products. Pichia could produce a variety of useful products in space. Pichia does not consume methane but robustly consumes methanol, which is one enzymatic step removed from methane. This novel innovation engineers Pichia to consume methane thereby creating a powerful methane-consuming microbial factory and utilizing methane in a robust and flexible synthetic biology platform.