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At least 55 records · Page 3

Bioreactor Development for CO2-Based In Situ Resource Utilization Manufacturing

Sustainable long-duration manned missions on both the Moon and Mars will require in situ resource utilization (ISRU). Carbon dioxide (CO2) has great potential as a harvestable resource, making up 95% of the atmosphere on Mars and being produced as respiratory waste in spacecraft and future planetary habitats. Through ISRU, biomanufacturing has the capability to produce a near limitless array of products from local space resources, which include pharmaceuticals, bioplastics, chemical feedstocks, and industrial enzymes. Here, a CO2-based ISRU recombinant protein bioreactor and associated biomanufacturing organisms were designed to produce a highly stable carbonic anhydrase (CA). Initial work characterized candidate organisms for growth on acetate and formic acid, carbon substrates that can be synthesized via electrochemical conversion of CO2. To improve growth on the CO2 producing substrate formic acid and for direct integration of ISRU CO2, a synthetic Calvin-Benson-Bassam cycle was designed for use in Cyberlindnera jadinii and Escherichia coli. Genetic modifications in E. coli will be facilitated by a tailored CRISPR/Cas9 and λ red recombineering two-vector system. For expression of CA, a blue light regulated T7 promoter was employed for dynamic and small molecule free induction. Efficient bioproduction through a fed-batch exponential feeding strategy was determined via mass balance calculations from ISRU substrates to biomass and CA yield. Flux balance analysis was used to model ISRU substrate metabolism and metabolic pathway engineering in candidate organisms under cultivation strategy conditions for both metabolism reconstruction and pathway design optimization. Finally, a small-scale, disposable bag bioreactor concept for use in the NASA Bioculture System infrastructure was designed to enable CO2-based CA production in reduced-gravity environments.

Biomanufacturing, Pathway Engineering, Flux Balanc↗

Possible Applications of Photoautotrophic Biotechnologies at Lunar Settlements

The most ambitious goal of the Vision of Space Exploration is to extend human presence across the solar system. Today, however, missions would have to bring all of the propellant, air, food, water, habitable volumes and shielding needed to sustain settlers beyond Earth. That is why resources for propellants, life support and construction of support systems and habitats must be found in space and utilized if humans hope to ever explore and colonize the solar system. The life support, fuel production and material processing systems currently proposed for spaceflight are essentially disconnected. Only traditional crop production has been proposed as a segment for bioregenerative life support systems, although the efficiency of higher plants for air regeneration is generally low. Thus, the investigation of air bioregeneration techniques based on the activity of photosynthetic organisms with higher rates of CO2 scrubbing and O2 release is very timely and important. Future systems for organic waste utilization in space may also benefit from the use of specific microorganisms. This janitorial job is efficiently carried out by microbes on Earth, which drive and connect different elemental cycles. It is likely that environmental control and life support systems based on bioregeneration will be capable of converting both organic and inorganic components of the waste at lunar settlements into edible biomass. The most challenging technologies for future lunar settlements are the extraction of elements (e.g. Fe, O, Si, etc) from local rocks for industrial feedstocks and the production of propellants. While such extraction can be accomplished by purely inorganic processes, the high energy requirements of such processes motivates the search for alternative technologies with lower energy requirements and appropriate efficiency. Well-developed terrestrial industrial biotechnologies for metals extraction and conversion could therefore be the prototypes for extraterrestrial biometallurgy.

McKay, David S.↗

Hydrogen Production from Polyethylene Pyrolysis

Hydrogen is anticipated to play a pivotal role in the future of clean energy and decarbonization efforts, serving as an energy storage medium, a power generation source, and a clean fuel for transportation. While most hydrogen is produced from carbonaceous fossil feedstocks like natural gas, petroleum, and coal, there is growing interest in using refuse-derived fuels such as waste plastics and municipal solid waste (MSW) as alternative feedstocks. Thermochemical processes such as pyrolysis and catalytic cracking can convert nonrecyclable plastics and organic MSW components to produce hydrogen with lower life cycle greenhouse gas emissions when coupled with CO 2 capture. Such approaches not only address waste-management challenges but also reduce methane emissions from landfills. Furthermore, waste feedstocks are low cost and can support meeting demands for hydrogen across various industries. In this work we examined production of hydrogen from high-density polyethylene (HDPE) as a model polymer using pyrolysis. Analytical studies of pyrolysis utilizing gas chromatography–mass spectrometry (GC/MS) provide insights into conversion pathways for plastic waste, potentially reducing the environmental footprint of traditional hydrogen production methods. This work generates a baseline methodology for hydrogen production from plastic pyrolysis with and without a catalyst and the necessary product distribution baseline from key single plastics. The effect of pyrolysis temperature on the conversion of HDPE was evaluated both with and without a catalyst(s), and the product distributions measured via GC/MS were identified and hydrogen formation was quantified. These results will help guide future research efforts to optimize catalysts and processes for more efficient hydrogen production and mixed plastic waste management.

Catalysts↗

Catalytic deconstruction of organic additive-containing plastics

Plastics waste ends up in landfills, oceans, and incinerators, posing major environmental and human health threats. Catalytic deconstruction is emerging as a key technological solution to handle complex plastics and has successfully converted virgin polymers into various products. Here, we investigate the resilience of chemical deconstruction technologies to organic additives, which are ubiquitous in plastics. We study catalyst-additive interactions experimentally and via first-principles calculations for plastics additives representative of entire classes. We reveal two deactivation mechanisms and demonstrate that many recently developed catalysts are inadequate for polyolefin conversion due to poisoning caused by the strong adsorption of most additives or their small fragments. Furthermore, we also identify conditions and catalysts that can circumvent the challenge of deconstruction in the presence of additives challenge.

10 SYNTHETIC FUELS↗

Universal Approach for the Depolymerization of Polyamides via Photothermal Conversion

Polyamides (PAs) exhibit excellent chemical stability and mechanical resistance, yet these same characteristics lead to their widespread accumulation in the environment as pollution. In this work, we developed an inclusive and operationally simple photothermal strategy to recycle PAs, overcoming the high energy barriers necessary to break down these materials. PAs can be depolymerized using photothermally mediated ring-closing depolymerization and acidic hydrolysis to afford cyclic and linear monomers using carbon black as a photothermal agent (PTA) under visible light irradiation. We showed that polyamide 6 is efficiently depolymerized to ε-caprolactam with 74% yield in 10 min. Similarly, in 1 h, the photothermal acidic hydrolysis of polyamide 6,6 afforded hexamethylene diamine and adipic acid with 97 and 96% yields, respectively. This method was further applied to a variety of aliphatic and aromatic PAs and mixed PA waste. Both photothermally promoted processes effectively depolymerize pigment-containing postconsumer waste by leveraging existing black pigments as PTAs. Here, photothermal conversion provided a general and rapid route for PA depolymerization under visible light irradiation, enabling high monomer yields with inexpensive reagents and a general tolerance to additives, demonstrating this approach’s potential for a circular plastic economy.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Surface engineering of Pt nanocatalysts with transition metal oleates for selective catalysis: a case study on the hydrogenation of α,β-unsaturated aldehydes

Selective and active catalysts enable effective use of feedstocks, reduced energy consumption and waste generation. Tuning the electronic structure of heterogeneous metal nanocatalysts via their surface modifications is a promising strategy to design highly selective and active catalysts for the synthesis of harder to make and more cost-efficient products. Here, we introduce transition metal oleates as a new class of ligands to engineer the catalytically active and very selective surface in organic solvents. Using citral hydrogenation and 5 nm Pt NPs as a model reaction and model catalytic system, respectively, we show that surface engineering of Pt nanocatalysts with metal oleates allows synthesis of desired partially hydrogenated product (geraniol) with ∼90% conversion with selectivity over 93%. We demonstrate that the selective synthesis of the unsaturated alcohols catalyzed by Pt NPs modified by adsorption of the transition metal salts cannot be explained by the widely accepted mechanism of preferred coordination of C$=$O groups by Lewis acids (e.g. partially oxidized transition surface metals). Our results indicate that C$=$O groups prefer to bind to negatively charged surfaces. We propose the explanation on how the adsorption of transition metal oleates can result in the increased electron density at the surface of Pt nanoparticles. Our study not only provides reliable solutions to selective hydrogenation but opens a new possibility of using metal oleates for the electronic ligand effect.

Kwon, Soon Gu [Argonne National Laboratory (ANL), ↗

A review of recent activities in the NASA CELSS program

A CELSS (Controlled Ecological Life Support System) is a device that utilizes photosynthetic organisms and light energy to regenerate waste materials into oxygen and food for a crew in space. The results of studies with the CELSS program suggest that a bioregenerative life support system is a useful and effective method of regenerating consumable materials for crew sustenance. The data suggests that the operation of a CELSS in space is practical if plants can be made to behave predictably in the space environment. Much of the work centers on the biological components of the CELSS system. Ways of achieving high efficiency and long term stability of all components of the system are examined. Included are explorations of the conversion of nonedible cellulose to edible materials, nitrogen fixation by biological and chemical methods, and methods of waste processing. A description is provided of the extent to which a bioregenerative life support system can meet the constraints of the space environment, and the degree is assessed to which system efficiency and stability can be increased during the next decade.

Macelroy, R. D.↗

Challenges and Opportunities in the Enzymatic Recycling of Nylons

Enzymatic depolymerization has the potential to contribute to nylon waste recycling. However, the implementation of a viable industrial process still lags far behind progress in enzymatic polyester recycling. Here we review the current biocatalytic nylon recycling landscape, highlighting biochemical, structural, and materials science barriers that currently limit depolymerization extents. We detail efforts to identify, engineer, and characterize new nylon depolymerases, where currently even the best biocatalysts rarely exceed ~1 wt% conversion of solid polymer to products. Based on our analyses, we suggest that limited substrate accessibility due to substrate crystallinity and hydrogen bonding, rather than intrinsic enzyme inefficiency or instability, is the primary bottleneck to enhanced depolymerization. Guided by successes in polyester enzymatic recycling, we outline a research roadmap combining nylonase engineering with polymer pretreatment, chemo-enzymatic cascades, and process analyses to accelerate development of viable enzymatic nylon recycling processes.

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A review of recent activities in the NASA CELSS program

A CELSS (Controlled Ecological Life Support System) is a device that utilizes photosynthetic organisms and light energy to regenerate waste materials into oxygen and food for a crew in space. The results of theoretical and practical studies conducted by investigators within the CELSS program suggest that a bioregenerative life support system can be a useful and effective method of regenerating consumable materials for crew sustenance. Experimental data suggests that the operation of a CELSS in space will be practical if plants can be made to behave predictably in the space environment. Much of the work currently conducted within the CELSS program centers on the biological components of the CELSS system. The work is particularly directed at ways of achieving high efficiency and long term stability of all components of the system. Included are explorations of the conversion of nonedible cellulose to edible materials, nitrogen fixation by biological and chemical methods, and methods of waste processing. It is the intent of the presentation to provide a description of the extent to which a bioregenerative life support system can meet the constraints of the space environment, and to assess the degree to which system efficiency and stability can be increased during the next decade.

Macelroy, R. D.↗

Bioregenerative life support: not a picnic

If humans are to live permanently in space, regenerative life support systems are an enabling technology and must replace the picnic approach of taking all supplies required for each mission. These systems are classified by technologies as either physical/chemical or bioregenerative. Both of these system-types can recycle water, remove carbon dioxide, produce oxygen, and recover essential elements from waste products. Bioregenerative can also produce food, thus, making it essential if humans are to exist in space independent of earth. A solely bioregenerative life support system includes plants as a biomass production module and microbial organisms in bioreactors as a resource recovery module. In the Advanced Life Support Program, bioregenerative life support systems are being investigated through a research and technology development project which includes large scale testing as part of the Breadboard Project and human tests conducted in the soon to be constructed BioPlex facility. Research and technology development efforts are directed toward optimizing biomass productivity in controlled chambers by developing light weight, energy efficient, and automated systems; recycling liquid and solid wastes; baselining the operation of bioreactors; determining system microbial stability; assessing chemical contamination; and building models required for long term system operations. The program will include space flight studies in the near future to determine if these life support technologies will function in microgravity. When a bioregenerative system is finally incorporated into a mission, the conversion from a picnic and resupply mentality to permanent recycling and independence from earth will be complete.

NASA Center KSC↗

Interaction and Synergism of Microbial Fuel Cell Bacteria within Methanogenesis

Biological hydrogen production from waste biomass has both terrestrial and Martian advanced life support applications. On earth, biological hydrogen production is being explored as a greenhouse neutral form of clean and efficient energy. In a permanently enclosed space habitat, carbon loop closure is required to reduce mission costs. Plants are grown to revitalize oxygen supply and are consumed by habitat inhabitants. Unharvested portions must then be recycled for reuse in the habitat. Several biological degradation techniques exist, but one process, biophotolysis, can be used to produce hydrogen from inedible plant biomass. This process is two-stage, with one stage using dark fermentation to convert plant wastes into organic acids. The second stage, photofermentation, uses photoheterotrophic purple non-sulfur bacteria with the addition of light to turn the organic acids into hydrogen and carbon dioxide. Such a system can prove useful as a co-generation scheme, providing some of the energy needed to power a larger primary carbon recovery system, such as composting. Since butyrate is expected as one of the major inputs into photofermentation, a characterization study was conducted with the bacterium Rhodobacter sphaeroides SCJ, a novel photoheterotrophic non-sulfur purple bacteria, to examine hydrogen production performance at 10 mM-100 mM butyrate concentrations. As butyrate levels increased, hydrogen production increased up to 25 mM, and then decreased and ceased by 100 mM. Additionally, lag phase increased with butyrate concentration, possibly indicating some product inhibition. Maximal substrate conversion efficiency was 8.0%; maximal light efficiency was 0.89%; and maximal hydrogen production rate was 7.7 Umol/mg/cdw/hr (173 ul/mg cdw/hr). These values were either consistent or lower than expected from literature.

Klaus, David↗

Chemical Recycling of Plastic Waste to Higher Value Lubricants

The aim of this project was to develop scalable methods to convert plastic waste to petrochemical-equivalent feedstocks and demonstrate their utility in lubricant base oil and wax applications. These objectives were partially accomplished, by scaling up the synthesis of platinum-on-strontium titanate catalysts to twenty gram batches, scaling up the conversion of plastic waste to twenty-five grams of plastic, producing high-melt waxes and characterizing their properties, and demonstrating the purification of high-melt waxes. High-melt waxes are one petrochemical-equivalent feedstock that can be made from plastic waste, consisting of a hard wax with a melt point above 65 C. They are used as ingredients in hot melt adhesives, coatings, and cosmetics. Producing a petrochemical-equivalent feedstock from plastic waste provides an advantage in lower carbon footprint and manufacturing cost, as the waste feedstock costs less than crude oil.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Treatment of Lagoon Dairy Manure Wastewater via Iron Electrocoagulation, Microfiltration, and Adsorption

Dairy manure wastewater generated by flushing barn cow waste contains nutrients, pathogens, and organic and inorganic contaminants. This study utilized a process consisting of iron electrocoagulation (Fe-EC), microfiltration (MF), and activated carbon (AC) adsorption to treat farm wastewater and explore the reclamation of clean water for irrigation and livestock consumption. Significant removal (>99.9%) of chemical oxygen demand (COD), total organic carbon (TOC), phosphorus (P), turbidity, and microorganisms, as well as ions including magnesium, calcium, sulfur, and silica was achieved by the combined EC-MF-AC process. Specifically, a charge loading of ∼37,500 C/L in a continuous-flow EC configuration, followed by MF, achieved more than 95% removal of TOC and COD. Characterization of produced flocs and foam via scanning-electron microscopy with energy-dispersal spectroscopy and Fourier transform infrared spectroscopy confirmed the removal of ions, including calcium, sulfur, and silica. A key finding was the electrocatalytic conversion of nitrogen species to ammonia gas through the intermediate reduction of nitrate/nitrite, which led to ∼60% total nitrogen (TN) removal. AC treatment further improved TN removal to ∼70%. The Fe-EC process also eradicated >99.9% of bacteria. Preliminary process cost assessment, based on recycled materials for EC electrodes, showed significant cost savings (∼2 times) compared to commercial electrodes.

Dutta, Swapnamoy [ORNL]↗

The Effects of Controlled Environment on the Growth of Hydrogenomonas Bacteria in Continuous Cultures

The continuous culture of Hydrogenomonas is the intermediate step of a three-step closed life support cycle directed to the conversion of the human metabolic wastes, urea and carbon dioxide, into breathable oxygen and a food supplement. The potential advantages of this scheme have been discussed in an earlier paper. The other two steps of the complete cycle are: (1) The collection and recovery of the C02 removed from the cabin atmosphere by a regenerable C02 absorber, so that relatively pure C02 gas can be fed into the gas phase of the continuous culture; and (2) the electrolysis of water to produce breathable oxygen for the cabin supply, and by-product hydrogen, which is also fed to the gas phase of the closed culture vessel. There are three specific advantages in the use of this culture: (1) the bacteria use waste urea as a sole nitrogen source during growth, together with the C02 waste as a carbon source; the harvested excess of cells from a steady-state culture is a potential food for man; (2) the organism is not photosynthetic, so the equipment designer need not confine the culture in thin layers to have light available to all parts as is necessary in photosynthesis; and (3) the culture uses the by-product hydrogen from electrolysis as an energy source. Some oxygen must also be supplied to the culture environment, because the energy of the growth process is derived from the metabolic hydrogen-oxygen reaction, with the production of water that can be recycled to the electrolysis cell.

ENVIRONMENTAL CONTROL↗

Robust engineered catalyst for the conversion of brown grease to renewable diesel via decarboxylation/decarbonylation

A novel engineered Ni–Cu/Al 2 O 3 decarboxylation/decarbonylation catalyst achieved quantitative conversion of brown grease, excellent yield of diesel-like hydrocarbons, effective heteroatom removal, and remarkable resistance to deactivation for hundreds of hours on stream. This offers an industrial alternative to hydrotreating for transforming waste oleaginous feedstocks into renewable diesel and sustainable aviation fuel.

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Progress on Photo‐, Electro‐, and Photoelectro‐Catalytic Conversion of Recalcitrant Polyethylene, Polypropylene, and Polystyrene ‐ A Review

Abstract Recalcitrant waste plastics such a polyethylene, polypropylene, and polystyrene are difficult to recycle and are mostly disposed of in landfills and eventually leached into the environmental as micro‐ and nano‐plastics. This review explores how photo‐, electro‐, and combined photoelectro‐catalytic processes can assist in the degradation and upcycling of waste plastic into different chemicals and mitigate their release to the environment. In this work, we discuss how the different reaction mechanisms proceed, explore the current relevant literature, and highlight the developments needed to advance the field.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Immobilization of Urease for continuous flow conversion of waste urea

An efficient and robust system for the urease catalyzed conversion of urea to ammonia has been developed using urease immobilized on modified agarose beads. Two different immobilization strategies, adsorption and covalent binding were studies using six different types of modified agarose beads. The immobilization of urease on each of the beads was studied at different concentrations and times using immobilization efficiency as a measure of success. The data from these experiments was used to identify potential candidates for immobilization scale up and implementation into the continuous flow system. The enzyme was then immobilized on the candidates in a packed bed reactor and the optimal flow rate and storage stability was determined. Future work will utilize the data obtained from these experiments to expand to other resins and enzymes.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Low Carbon Intensity Formic Acid Chemical Synthesis from Direct Air Captured CO 2 Utilizing Chemical Plant Waste Heat - Final Technical Report

The primary objective of Low Carbon Intensity Formic Acid Chemical Synthesis from Direct Air Captured CO 2 Utilizing Chemical Plant Waste Heat (ChemFADAC) is to execute and complete a FEED study for an integrated direct air capture (DAC) and carbon conversion system (together, the DACUS system) co-located at a Nutrien nitric acid production facility in Kennewick, WA capable of capturing and converting a minimum of 5,000 MT/year net atmospheric CO 2 to low carbon intensity formic acid (FA) using industrial waste heat and renewable electricity. The goal will be achieved through the completion of four objectives using a collaborative approach with community stakeholders. Objective 1. Conduct a FEED study and Class 3 project cost estimate for the proposed DACUS system that maximizes use of thermal energy from the Nutrien KFO host site to produce low carbon intensity FA from atmospheric CO 2 . Objective 2. Perform a cradle-to-gate life-cycle analysis of the DACUS system to determine the environmental sustainability and carbon intensity (CI) of the proposed project and product from the results of the FEED study. Objective 3. Perform a business case analysis from results of the LCA, FEED study and cost estimate to justify investment to build the DACUS project at the Nutrien KFO site. Objective 4. Quantify how deployment of the proposed technology will promote and prepare a ready workforce for clean energy and manufacturing jobs and coordinate with community stakeholders to perform an environmental justice and a preliminary economic revitalization and job creation outcomes analysis.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗