Bioscience in Orbit: Biomanufacturing Nutrients for Space Travel

Within the vast panorama of human endeavors, few pursuits capture the essence of curiosity, wonder, and the boundless spirit of discovery like space exploration. It is a journey that goes beyond the limitations of earthly existence, revealing the beautiful essence of our mesmerizing cosmos. Space food exploration remains the key aspect of human space exploration. Much like on Earth, astronauts’ well-being and peak performance before, during, and after spaceflight depends significantly on their nutrition. Food flown on-orbit is not only required to be nutritious, it must be appetizing too. While adhering to the requirements of food safety, limited storage space, limited preparation options, and the difficulties of eating in microgravity, many new devices and approaches have been made toward the solution.

As humans venture further into space, the need for plants becomes increasingly important, both for aesthetics and practicality. Plants not only enhance the psychological well-being of astronauts but also play a crucial role in maintaining their health on long-duration missions. In the confines of the International Space Station, fresh flowers and gardens bring a touch of Earth’s beauty to space and boost astronauts’ mental well-being. They can further serve to resolve the challenges posed by the prepackaged meals and supplements curated for the far beyond missions.

Vitamins degrade over time, potentially jeopardizing astronaut health. NASA is actively exploring ways to provide astronauts with vital nutrients through freshly grown fruits and vegetables. The challenge lies in creating a closed environment in space, that is normally devoid of sunlight and Earth’s gravity, where these essential crops can thrive and offer a sustainable source of nutrition for deep-space missions.

One of the remarkable tools of this endeavor is the Advanced Plant Habitat (APH), a sophisticated enclosed growth chamber on the space station designed for plant research. It utilizes LED lights and a porous clay substrate with controlled-release fertilizer to provide water, nutrients, and oxygen to plant roots. Unlike Veggie (The Vegetable Production System, known as Veggie, is a space garden residing on the space station operating in microgravity conditions), it operates with minimal crew intervention controlling water distribution, atmosphere composition, moisture levels, and temperature automatically. Their focus includes the study of plant lignin content, akin to the bones in the human body, which provides structural support to plants. Understanding how space affects lignin content holds the potential to enhance nutrient absorption and waste management in space-grown plants. It has been believed that fundamental science will guide strategies for deep space exploration and colonization, acknowledging the remarkable progress space science has made, turning once-fictional possibilities into reality.

Plants are not the only focus of our cosmic curiosity. The Biological Research in Canisters (BRIC) is a facility used for studying the impact of space on small organisms that can grow in petri dishes, including yeast and microbes. The latest version, BRIC-LED, incorporates light-emitting diodes (LEDs) to support the growth of plants, mosses, algae, and cyanobacteria that require light for photosynthesis. Currently, BRIC-LED is undergoing hardware validation tests to ensure the LEDs do not overheat and to conduct system checks. Scientists, like Dr. Simon Gilroy from the University of Wisconsin-Madison, are using BRIC-LED to investigate how gene expression in the model plant, Arabidopsis, changes in the unique environment of space. They’ve noticed differences in genes related to gravity and increased stress due to oxidation in plants grown in space. To dig deeper into these effects, researchers plan to manipulate protein receptors by exposing these plants to a harmless solution called “flag-22.” This experiment spans ten days, during which the tiny plants are exposed to flag-22, their responses are observed, and their RNA is analyzed back on Earth. The ultimate goal is to gain a deep understanding of how space affects plant health, which is crucial for sustaining life during long space missions. This research enhances NASA’s knowledge of how to maintain healthy plant growth in space, a critical aspect of successful space exploration missions.

In 1965, microbiologists pioneered a food production method using hydrogen-oxidizing bacteria (HOB) as a source of single-cell protein (SCP). NASA later experimented with this technology for space applications. HOB, like Cupriavidus necator, are rich in protein (63%) and carbohydrates (6%), with an amino acid profile similar to algae or soybeans. They can be pasteurized and dried into a powder, akin to dried milk. The process involves electrolysis to split water into oxygen and hydrogen, which HOB uses for growth. Currently, the efficiency of converting electricity into calories from SCP is approximately 20%, far surpassing photosynthesis at 3%. This technology holds promise for space missions and terrestrial catastrophes disrupting agriculture. To feed Earth during such crises, HOB can be employed cost-effectively, supplemented with other foods.

One of the key strategies for improving biomass-based SCP production is through a rational engineering approach. This involves the manipulation of transcription factors, transporters, and metabolic pathways to achieve desired phenotypes. Another approach to enhancing biomass accumulation is through adaptive lab evolution (ALE), chemical mutagenesis, and genome engineering. ALE has been used to evolve strains with higher growth rates and increased tolerance to inhibitors. Furthermore, strategies commonly used to improve heterologous protein expression can also be applied to enhance protein production in SCPs. These strategies include reducing mRNA and protein degradation, as well as enhancing protein folding and refolding. Stabilizing mRNA levels, coexpressing chaperones for proper protein folding, and developing protease-deficient microbes are some of the techniques that can potentially increase total protein yields.

The other frontier of hope is the Filamentous fungi, which with their intricate mycelial networks, play a pivotal role in global ecosystems by participating in carbon and nutrient cycling. Their metabolic diversity, secretion capabilities, and unique mycelial structures are increasingly harnessed for commercial applications. These applications span from enzyme and bioactive compound production to sustainable food and material production, environmental cleanup, and enhanced agriculture. Despite their ecological and biotechnological significance, filamentous fungi, including molds and mushrooms, have not been extensively explored in the realm of synthetic biology, unlike other industrial cell factories such as Escherichia coli, Saccharomyces cerevisiae, and Komagataella phaffii.

Exploration among various synthetic biology and computational tools for optimizing filamentous fungi as bioproduction platforms have been made. These tools encompass genetic engineering, mutagenesis, experimental evolution, and computational modeling, addressing challenges like slow mycelial growth, low production yields, suboptimal growth on alternative feedstocks, and purification difficulties. Specifically within biomanufacturing, we delve into efforts to improve key bottlenecks by targeting protein processing and secretion pathways, hyphal morphogenesis, and transcriptional control. The incorporation of synthetic biology into the realm of filamentous fungi promises to expand the roster of host organisms suitable for environmentally sustainable bioproduction of enzymes, chemicals, therapeutics, foods, and materials.

In essence, filamentous fungi’s unique ecological and structural properties offer vast potential for a wide array of applications, from biomanufacturing to environmental remediation and beyond.

The Space Food Systems Laboratory is actively involved in the research and development of nutritious and high-quality meals for future long-duration missions. Foods on these missions will need to be safe, nutritious, and palatable for up to five years with very limited resources to ensure the system supports crew health and performance through the challenges of exploration, but still there exists a large and increasing amount of unorganized data on how living organisms react to environmental conditions in space. The research field is burgeoning and study types or methods are not always similar, further complicating data analysis and scientific conclusions. There is a need for a well-curated, microgravity-specific database to analyze and organize the increasing amount of microgravity-related gene expression data that is piling up. Currently, there are no databases that are specific to microgravity research. Furthermore, available databases are restricted to specific types of experiments including analysis of either RNA-seq or microarray datasets.

As we dig deeper into the matters of food nutrition for space exploration, we come across commendable work produced by iGEM Team Concordia 2020. AstroBio is a valuable tool — a meticulously curated, open-source software and database. Its purpose is to compile and present the collective knowledge from scientific research regarding changes in gene expression caused by exposure to microgravity in yeast, bacteria, and plants. But what sets AstroBio apart is its user-friendliness. It offers a straightforward interface for users to explore this wealth of information. It also allows easy searches for specific genes, microorganisms, or species, and provides insights into how gene activity responds to microgravity, distinguishing between space and Earth-based experiments, and revealing the research method used, whether RNA sequencing or microarrays. AstroBio is invaluable for comparing research across different studies, helping determine if changes in specific genes are unique to microgravity stress or caused by other factors. In summary, AstroBio simplifies the complex exploration of how microgravity impacts gene expression in various microorganisms, making it an essential resource for researchers and enthusiasts in this captivating field of study.

In space exploration, nutrition isn’t just about food, it’s a crucial component of astronaut health. Plants boost the well-being of the astronauts but long missions challenge packaged meals. With multiple challenges on hand, several advances have been made in research as we explore NASA’s Plant Habitat to BRIC-LED which explores gene changes in space and many other studies. As we sow seeds of new revolution in the biomanufacturing of nutrients for space exploration we embark on a journey of discovery and innovation that will shape our cosmic future.

References:

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