Plants play a crucial role in bioregenerative life support systems (blsss) for long-term human habitation in space, due to their potential to revitalize the atmosphere (e.g., O2 production and CO2…

This is a $99,864 cooperative agreement awarded by NASA to Montana State University to research the use of mixed microbial communities to convert plant waste from bioregenerative life support systems (BLSS) into value-added products. The project aims to optimize microbial synergies and improve the bioconversion of lignocellulosic biomass (LCB) to close the plant/food production loop in BLSS, reducing the need for resupplying resources from Earth. The work builds on existing NASA efforts at Kennedy Space Center on LCB waste transformation and could benefit human health, life support, and habitation technology areas. This is not a set-aside contract.

Plants play a crucial role in bioregenerative life support systems (blsss) for long-term human habitation in space, due to their potential to revitalize the atmosphere (e.g., O2 production and CO2 removal) while producing edible biomass. Plant cultivation in blsss will require a continuous supply of nutrients and will result in the production of inedible plant wastes that still contain valuable nutrients and carbon that could be reused, recycled, or upcycled for other purposes. In this funding announcement, appendix eiii (spaceflight-compatible recycling of non-edible biomass, space crop production GAP 1.d.1.0.1), NASA recognizes the need for alternatives to improve processes that can convert plant waste (lignocellulosic biomass, LCB), into value-added materials and recycle resources to achieve a higher degree of self-sustainability in blsss. The microbial conversion of LCB into value-added products is a natural process suitable for long-term human habitation in space and a promising alternative to existing physicochemical methods. Typically, LCB bioconversion is performed using pure cultures or communities of either fungi or bacteria however, the use of mixed microbial communities, particularly fungal-bacterial cultures (e.g., biofilms), has not been widely explored. In nature, LCB degradation is performed by communities of diverse microbes that metabolize LCB in a synergistic, dynamic, and time-dependent fashion. Importantly, mixed cultures typically display improved adaptability and substrate utilization compared to monocultures. Thus, we hypothesize that mixed microbial communities will be more efficient at utilizing and converting LCB into useful products. Based on our hypothesis and experience establishing mixed fungal-bacterial biofilms, we are proposing to use and engineer (through culture conditions) mixed cultures of LCB-degrading organisms (phanerochaete chrysosporium, pleurotus ostreatus, trametes versicolor, pseudomonas putida, bacillus subtilis) to improve LCB bioconversion to further close the plant/food production loop in blsss. Specifically, we aim to use mixed cultures (e.g., biofilms) to transform plant waste (lettuce, tomato) to value-added products (e.g., nutrients, ethanol, fungal-derived bioplastics for 3D-printing), and even fungal biomass that could be used as an alternative food source. We aim to do this by optimizing the microbial growth, interactions, substrate utilization, and enzyme production in LCB-degrading mixed cultures to promote microbial synergisms and improve LCB bioconversion. The specific tasks proposed are: (1) establishing LCB-degrading mixed cultures and characterizing their potential synergistic interactions (2) optimizing culture conditions to establish mixed cultures for LCB bioconversion and (3) developing bioreactor designs that can provide the required growth conditions to maintain mixed cultures and enhance LCB bioconversion. The completion of this study will provide foundational knowledge and reactor designs for converting LCB into value-added products and recover & recycle resources from LCB to close the plant/food production loop in blsss (addresses appendix eiii), while decreasing the costs and dependency on resupplying resources from earth. This project is synergistic with current efforts on LCB waste transformation (i.e. physicochemical pretreatment) by NASA s kennedy space center, and could be relevant to human health, life support and habitation systems technology areas. We have had conversations with NASA s scientists aubrie o'rourke and ralph fritsche at kennedy space center, who have expressed their excitement regarding our project proposal and their willingness to guide our overall efforts. Moreover, optimizing the LCB bioconversion can help achieve a more sustainable agriculture system, which could also be relevant to other agencies (e.g., recently signed -DEC 2020- NASA-USDA agreement to improve agricultural, earth science research) and the general public.