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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 199 records · Page 11
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Curating a comprehensive set of enzymatic reaction rules for efficient novel biosynthetic pathway design

Enzyme substrate promiscuity has significant implications for metabolic engineering. The ability to predict the space of possible enzymatic side reactions is crucial for elucidating underground metabolic networks in microorganisms, as well as harnessing novel biosynthetic capabilities of enzymes to produce desired chemicals. Reaction rule-based cheminformatics platforms have been implemented to computationally enumerate possible promiscuous reactions, relying on existing knowledge of enzymatic transformations to inform novel reactions. However, past versions of curated reaction rules have been limited by a lack of comprehensiveness in representing all possible transformations, as well as the need to prune rules to enhance computational efficiency in pathway expansion. To this end, we curated a set of 1224 most generalized reaction rules, automatically abstracted from atom-mapped MetaCyc reactions and verified to uniquely cover all common enzymatic transformations. Additionally, we developed a framework to systematically identify and correct redundancies and errors in the curation process, resulting in a minimal, yet comprehensive, rule set. These reaction rules were capable of reproducing more than 85% of all reactions in the KEGG and BRENDA databases, for which a large fraction of reactions is not present in MetaCyc. Our rules exceed all previously published rule sets for which reproduction was possible in this coverage analysis, which allows for the exploration of a larger space of known enzymatic transformations. By leveraging the entire knowledge of possible metabolic reactions through generalized enzymatic reaction rules, we are able to better utilize underground metabolic pathways and accelerate novel biosynthetic pathway design to enable bioproduction towards a wider range of new molecules.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2021

Versatile Synthetic Platform for Polymer Membrane Libraries Using Functional Networks

Poly(ethylene glycol) (PEG) diacrylate copolymer networks containing pentafluorophenyl active esters can be quantitatively substituted with a wide variety of primary amines, enabling the development of a versatile synthetic platform for the preparation of polymer hydrogel and membrane libraries. Here, by tuning the starting network, a high degree of control over cross-linking density, water uptake, and functional group incorporation can be reproducibly achieved, which is vital for elucidating structure–property relationships in ion transporting membranes. From the same cross-linked scaffold, a diversity of basic, acidic, and solute-chelating moieties were obtained through functionalization, which allows for tailored uptake of basic and acidic organic dyes and metal chloride salts. Ion permeation and sorption measurements for a series of polymer networks with controlled cross-linking density and varied imidazole grafting densities illustrate the ability of this platform to isolate the effect of chemical functionality on ion transport from the effects of cross-linking density and water content.

36 MATERIALS SCIENCE↗
DOE OSTI2026

Bio-based oxalic acid production in Issatchenkia orientalis enables sustainable rare earth recovery

The growing demand for rare earth elements (REEs) in clean energy and high-tech industries underscores the need for sustainable recovery methods and a reliable supply of processing chemicals. Here, we establish a microbial platform using the acid-tolerant yeast Issatchenkia orientalis SD108 to produce bio-oxalic acid for REE recovery. By introducing an oxaloacetate cleavage pathway and applying metabolic engineering, the engineered strain produces 39.53 g·L -1 oxalic acid at pH 4.0 in fed-batch fermentation. The crude fermentation broth, used without purification, efficiently precipitates over 99% neodymium (Nd), 99% dysprosium (Dy), and 98% lanthanum (La) from individual REE chloride solutions. Recovery from a low-grade ore leachate achieves over 99% total recovery. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) confirm that REE oxalates precipitated with bio-oxalic acid closely resemble those obtained using commercial oxalic acid. Techno-economic analysis (TEA) and life cycle assessment (LCA) further demonstrate that bio-oxalic acid can be produced at a competitive price of $1.79·kg -1 while reducing carbon intensity (CI) by 112% to 63.5% with and without electricity displacement, respectively, relative to the fossil-based benchmark. These results highlight bio-oxalic acid as a green, economically viable alternative to synthetic oxalate for sustainable REE recovery.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2019

Hybrid plasmonic Au–TiN vertically aligned nanocomposites: a nanoscale platform towards tunable optical sensing

Tunable plasmonic structure at the nanometer scale presents enormous opportunities for various photonic devices. In this work, we present a hybrid plasmonic thin film platform: i.e., a vertically aligned Au nanopillar array grown inside a TiN matrix with controllable Au pillar density. Compared to single phase plasmonic materials, the presented tunable hybrid nanostructures attain optical flexibility including gradual tuning and anisotropic behavior of the complex dielectric function, resonant peak shifting and change of surface plasmon resonances (SPRs) in the UV-visible range, all confirmed by numerical simulations. Lastly, the tailorable hybrid platform also demonstrates enhanced surface plasmon Raman response for Fourier-transform infrared spectroscopy (FTIR) and photoluminescence (PL) measurements, and presents great potentials as designable hybrid platforms for tunable optical-based chemical sensing applications.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2024

Engineered poplar for bioproduction of the triterpene squalene

Building sustainable platforms to produce biofuels and specialty chemicals has become an increasingly important strategy to supplement and replace fossil fuels and petrochemical-derived products. Terpenoids are the most diverse class of natural products that have many commercial roles as specialty chemicals. Poplar is a fast growing, biomassdense bioenergy crop with many species known to produce large amounts of the hemiterpene isoprene, suggesting an inherent capacity to produce significant quantities of other terpenes. Here we aimed to engineer poplar with optimized pathways to produce squalene, a triterpene commonly used in cosmetic oils, a potential biofuel candidate, and the precursor to the further diversified classes of triterpenoids and sterols. The squalene production pathways were either re-targeted from the cytosol to plastids or co-produced with lipid droplets in the cytosol. Squalene and lipid droplet co-production appeared to be toxic, which we hypothesize to be due to disruption of adventitious root formation, suggesting a need for tissue specific production. Plastidial squalene production enabled up to 0.63 mg/g fresh weight in leaf tissue, which also resulted in reductions in isoprene emission and photosynthesis. These results were also studied through a technoeconomic analysis, providing further insight into developing poplar as a production host.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2025

Enhanced spectral purity of WSe 2 quantum emitters via conformal organic adlayers

Quantum emitters in solid-state materials are typically embedded in the bulk of their hosts, making their electronic transitions inaccessible to surface modification. In contrast, two-dimensional materials, with their all-surface nature, offer a platform for tuning quantum emitters via chemical functionalization. Because of its semiconducting properties that enable electrical addressability, monolayer WSe 2 is a promising candidate for quantum emission, although the complex interplay between point defects and the localized strain needed to activate quantum emission leads to poor spectral purity. Here, we demonstrate that functionalizing monolayer WSe 2 with conformal adlayers of 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) improves quantum emission spectral purity. Optical spectroscopy reveals that PTCDA functionalization lowers defect activation energies by 10 meV and induces a 30 nm redshift in quantum emission wavelength, while preserving the bright and dark exciton energies of monolayer WSe 2 . First-principles calculations corroborate these findings, thus providing molecular-level insight into the underlying mechanism of enhanced spectral purity.

Ananth, Riddhi [Northwestern Univ., Evanston, IL (↗
DOE OSTI2021

Co-expression of a β-d-xylosidase from Thermotoga maritima and a Family 10 xylanase from A. cellulolyticus significantly improves the xylan degrading activity of the Caldicellulosiruptor bescii exoproteome

Caldicellulosiruptor species are hyperthermophilic, Gram-positive, anaerobes and the most thermophilic cellulolytic bacteria so far described. They have been engineered to convert switchgrass to ethanol without pretreatment and represent a promising platform for the production of fuels, chemicals and materials from plant biomass. Xylooligomers such as xylobiose and xylotriose that result from the breakdown of plant biomass more strongly inhibit cellulase activity than do glucose or cellobiose. High concentrations of xylobiose and xylotriose, are present in C. bescii fermentations after 90 h incubation and removal or breakdown of these types of xylooligomers is crucial to achieve high conversion of plant biomass to product. In previous studies the addition of exogenous β-d-xylosidase substantially improved the performance of glucanases and xylanases in vitro. β-d-Xylosidases are, in fact, essential enzymes in commercial preparations for efficient deconstruction of plant biomass. In addition, the combination of xylanase and β-d-xylosidase is known to exhibit synergistic action on xylan degradation. In spite of its ability to grow efficiently on xylan substrates, no extracellular β-d-xylosidase was identified in the C. bescii genome. Here we report that the co-expression of a thermal stable β-d-xylosidase from Thermotoga maritima and a xylanase from Acidothermus cellulolyticus in a C. bescii strain containing the A. cellulolyticus E1 endoglucanase significantly increased the activity of the exoproteome as well as growth on xylan substrates. The combination of these enzymes also resulted in increased growth on crystalline cellulose in the presence of exogeneous xylan.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2025

Modification and analysis of context-specific genome-scale metabolic models: methane-utilizing microbial chassis as a case study

ABSTRACT Context-specific genome-scale model (CS-GSM) reconstruction is becoming an efficient strategy for integrating and cross-comparing experimental multi-scale data to explore the relationship between cellular genotypes, facilitating fundamental or applied research discoveries. However, the application of CS modeling for non-conventional microbes is still challenging. Here, we present a graphical user interface that integrates COBRApy, EscherPy, and RIPTiDe, Python-based tools within the BioUML platform, and streamlines the reconstruction and interrogation of the CS genome-scale metabolic frameworks via Jupyter Notebook. The approach was tested using -omics data collected for Methylotuvimicrobium alcaliphilum 20Z R , a prominent microbial chassis for methane capturing and valorization. We optimized the previously reconstructed whole genome-scale metabolic network by adjusting the flux distribution using gene expression data. The outputs of the automatically reconstructed CS metabolic network were comparable to manually optimized i IA409 models for Ca-growth conditions. However, the CS model questions the reversibility of the phosphoketolase pathway and suggests higher flux via primary oxidation pathways. The model also highlighted unresolved carbon partitioning between assimilatory and catabolic pathways at the formaldehyde-formate node. Only a very few genes and only one enzyme with a predicted function in C1 metabolism, a homolog of the formaldehyde oxidation enzyme ( fae1-2 ), showed a significant change in expression in La-growth conditions. The CS-GSM predictions agreed with the experimental measurements under the assumption that the Fae1-2 is a part of the tetrahydrofolate-linked pathway. The cellular roles of the tungsten (W)-dependent formate dehydrogenase ( fdhAB ) and fae homologs ( fae1-2 and fae3 ) were investigated via mutagenesis. The phenotype of the f dhAB mutant followed the model prediction. Furthermore, a more significant reduction of the biomass yield was observed during growth in La-supplemented media, confirming a higher flux through formate. M. alcaliphilum 20Z R mutants lacking fae1-2 did not display any significant defects in methane or methanol-dependent growth. However, contrary to fae1, the fae1-2 homolog failed to restore the formaldehyde-activating enzyme function in complementation tests. Overall, the presented data suggest that the developed computational workflow supports the reconstruction and validation of CS-GSM networks of non-model microbes. IMPORTANCE The interrogation of various types of data is a routine strategy to explore the relationship between genotype and phenotype. An efficient approach for integrating and cross-comparing experimental multi-scale data in the context of whole-genome-based metabolic network reconstruction becomes a powerful tool that facilitates fundamental and applied research discoveries. The present study describes the reconstruction of a context-specific (CS) model for the methane-utilizing bacterium, Methylotuvimicrobium alcaliphilum 20Z R . M. alcaliphilum 20Z R is becoming an attractive microbial platform for the production of biofuels, chemicals, pharmaceuticals, and bio-sorbents for capturing atmospheric methane. We demonstrate that this pipeline can help reconstruct metabolic models that are similar to manually curated networks. Furthermore, the model is able to highlight previously overlooked pathways, thus advancing fundamental knowledge of non-model microbial systems or promoting their development toward biotechnological or environmental implementations.

Kulyashov, M. A.↗
NASA NTRS1982

Space Research and Technology Program: Program and specific objectives, document approval

A detailed view of the Space Research and Technology program work breakdown structure is provided down to the specific objective level. Goals or objectives at each of these levels are set forth. The specific objective narratives are structured into several parts. First, a short paragraph statement of the specific objective is given. This is followed by a list of subobjectives. A list of targets is then provided for those areas of the specific objective that are amenable to a quantitative description of technical accomplishment and schedule. Fluid and thermal physics, materials and structures, computer science and electronics, space energy conversion, multidisciplinary research, controls and human factors, chemical propulsion, spacecraft systems, transportation systems, platform systems, and spacecraft systems technology comprise the principal research programs.

Source record↗
DOE OSTI2021

Unprecedented Fluorophore Photostability Enabled by Low‐Loss Organic Hyperbolic Materials

Abstract The dynamics of photons in fluorescent molecules plays a key role in fluorescence imaging, optical sensing, organic photovoltaics, and displays. Photobleaching is an irreversible photodegradation process of fluorophores, representing a fundamental limitation in relevant optical applications. Chemical reagents are used to suppress the photobleaching rate but with exceptionally high specificity for each type of fluorophore. Here, using organic hyperbolic materials (OHMs), an optical platform to achieve unprecedented fluorophore photostability without any chemical specificity is demonstrated. A more than 500‐fold lengthening of the photobleaching lifetime and a 230‐fold increase in the total emitted photon counts are observed simultaneously. These exceptional improvements solely come from the low‐loss hyperbolic dispersion of OHM films and the large resultant Purcell effect in the visible spectral range. The demonstrated OHM platform may open up a new paradigm in nanophotonics and organic plasmonics for super‐resolution imaging and the engineering of light–matter interactions at the nanoscale.

Lee, Yeon Ui↗
DOE OSTI2025

Self‐Standing Carbon Nanofibers@Carbon Felt Electrodes to Boost Electrolyzer Productivity: Application to the Electro‐Manufacturing of trans ‐3‐Hexenedioic Acid and Adipic Acid

The industrial implementation of electrosynthesis for chemical manufacturing remains constrained by the limited surface area of conventional electrodes. Herein, this challenge is addressed by designing a carbon nanofiber@carbon felt (CNF@CF) electrode platform that combines the high conductivity, flexibility, and ease of handling of commercial carbon felts (CF) with the large surface area and tunable surface chemistry of carbon nanofibers (CNFs). CNFs are deliberately grown onto the CF scaffold to form a sword-in-sheath structure, where entangled nanofibers wrap the felt macrofibers to provide excellent mechanical stability and electrical conductivity without binders. CNF@CF is evaluated both as an electrode and as a catalyst support for the electrochemical hydrogenation of cis,cis-muconic acid (ccMA), a biobased platform molecule key to the production of performance polyamides and renewable Nylon 6,6. As a noncatalytic electrode for the partial hydrogenation to trans-3-hexenedioic acid, CNF@CF achieves a threefold increase in both cumulative productivity and Faradaic efficiency (FE) compared to bare CF. A similar boost in catalytic activity and energy efficiency is observed using Pd/CNF@CF for the hydrogenation of ccMA to adipic acid. These results highlight the opportunities of the CNF@CF platform for electro-organic synthesis and sustainable chemical manufacturing.

electrochemical hydrogenation↗
NASA NTRS2021

Venus Flagship Mission Concept: A Decadal Survey Study

More than any other known planet, Venus is essential to our understanding of the evolution and habitability of Earth-size planets throughout the galaxy. We address two critical questions for planetary science: 1) How, if at all, did Venus evolve through a habitable phase? 2) What circumstances affect how volatiles shape habitable worlds? More than any other group, volatile elements have a strong influence on the evolutionary paths of rocky bodies and are critical to understanding solar system evolution. It is clear that Venus experienced a different volatile element history from the Earth and provides the only accessible example of one end-state of habitable Earth-size planets. Venus will allow us to identify the mechanisms that operate together to produce and maintain habitable worlds like our own.The (VFM) concept architecture relies on five collaborative platforms: an Orbiter, Lander, variable-altitude Aerobot and two Small Satellites (SmallSats) delivered via a single launch on a Falcon 9 heavy expendable. The platforms would use multiple instruments to measure the exosphere, atmosphere and surface at multiple scales with high precision and over time. VFM would provide the first measurements of mineralogy and geochemistry of tessera terrain to examine rocks considered to be among the most likely to have formed in a habitable climate regime. Landed, descent, aerial and orbital platforms would work synergistically to measure the chemical composition of the atmosphere including the Aerobot operating for 60 days in the Venus clouds. Loss mechanisms would be constrained by the SmallSats in two key orbits. The baseline payload for VFM includes instruments to make the first measurements of seismicity and remanent magnetism, the first long-lived (60 day) surface platform and the first life detection instrument at Venus to interrogate what could be an inhabited world.The VFM concept directly addresses each of the three Venus Exploration Analysis Group (VEXAG) goals as well as several of the strategic objectives of the 2020 NASA Science Plan, Planetary Science Division, Heliophysics and Astrophysics. The simultaneous, synergistic measurements of the solid body, surface, atmosphere and space environment provided by the VFM would allow us to target the most accessible Earth-size planet in our galaxy, and gain a profound new understanding of the evolution of our solar system and habitable worlds.

Segura, Marcia↗
DOE OSTI2021

Chemical-damage MINE: A database of curated and predicted spontaneous metabolic reactions

Spontaneous reactions between metabolites are often neglected in favor of emphasizing enzyme-catalyzed chemistry because spontaneous reaction rates are assumed to be insignificant under physiological conditions. However, synthetic biology and engineering efforts can raise natural metabolites' levels or introduce unnatural ones, so that previously innocuous or nonexistent spontaneous reactions become an issue. Problems arise when spontaneous reaction rates exceed the capacity of a platform organism to dispose of toxic or chemically active reaction products. While various reliable sources list competing or toxic enzymatic pathways' side-reactions, no corresponding compilation of spontaneous side-reactions exists, nor is it possible to predict their occurrence. We addressed this deficiency by creating the Chemical Damage (CD)-MINE resource. First, we used literature data to construct a comprehensive database of metabolite reactions that occur spontaneously in physiological conditions. We then leveraged this data to construct 148 reaction rules describing the known spontaneous chemistry in a substrate-generic way. We applied these rules to all compounds in the ModelSEED database, predicting 180,891 spontaneous reactions. The resulting (CD)-MINE is available at https://minedatabase.mcs.anl. gov/cdmine/#/home and through developer tools. We also demonstrate how damage-prone intermediates and end products are widely distributed among metabolic pathways, and how predicting spontaneous chemical damage helps rationalize toxicity and carbon loss using examples from published pathways to commercial products. We explain how analyzing damage-prone areas in metabolism helps design effective engineering strategies. Finally, we use the CD-MINE toolset to predict the formation of the novel damage product N-carbamoyl proline, and present mass spectrometric evidence for its presence in Escherichia coli.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

Electrically Reconfigurable Liquid Metal Nanophotonic Platform for Color Display and Imaging

Dynamically tunable optical materials and device architectures are essential for future photonic technologies, yet conventional solid metals lack the intrinsic tunability required for advanced functionalities. Gallium-based liquid metals (LMs) present an appealing alternative thanks to their distinctive mechanical and optical properties; however, their practical integration in tunable photonic elements remains largely unexplored. Here, in this study, an electrochemically controlled nanophotonic platform is demonstrated that integrates a dynamically reconfigurable LM ground plane with gold nanoantenna arrays within a microfluidic system, enabling precise and reversible modulation of optical resonances across the visible to mid-infrared spectral ranges. By employing moderate operational voltages (1.5–3.0 V), real-time tuning of high-resolution structural color patterns is achieved through nanoscale control of the interfacial gap between the LM and Au nanoantennas. This innovative platform facilitates electrically programmable, high-contrast color patterns suitable for dynamic optical displays, secure anti-counterfeiting labels, and imaging applications. Additionally, this platform enables tunable mid-infrared spectral responses, which may be utilized for chemical and biological sensing applications. This versatile integrated LM-based nanophotonic platform opens new paths toward multifunctional, actively tunable/reconfigurable photonic device and system technologies.

Imaging↗
DOE OSTI2021

BETO 2021 Peer Review - Separations in Support of Arresting Anaerobic Digestion

In support of the Bioenergy Technologies Office in converting waste feedstocks to fuels and chemicals, this project develops and demonstrates an advanced system for the production of platform carboxylic acids by Arresting Anaerobic Digestion (AAD) of wet waste feedstocks. The project addresses three technology barriers in developing the bioeconomy; (1) Feedstock availability and cost (2) Selective separation of organic acid species, and (3) First-of-a-kind technology development. This project has developed an advanced AAD system with separations that can operate in high solids environments (> 10 wt.%) and is net positive in energy consumption compared to the energy content of the carboxylic acids. Operating an in situ product recovery (ISPR) system in high solids is required for fermentation produced intermediates beyond ethanol that have volatilities less than water (e.g. carboxylic acids). Carboxylic acids form a versatile platform for the production of renewable diesel fuel, aviation fuel, monomers, and chemicals. A high solids ISPR system expands the feedstocks for AAD, which have been restricted to thin stillage, to solid food waste. Additionally, current AAD technology employs separations that consume >200x the energy content of the produced acids. This project has developed and demonstrated the first AAD technology with ISPR that is net negative in energy value and operates in solids contents >10 wt.% to produce a mixed carboxylic acid product that is carbon negative.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
NASA NTRS2016

Sample Handling and Instruments for the In-Situ Exploration of Ice-Rich Planets

NASA's key science goals for the exploration of the solar system seek a better understanding of the formation and evolutionary processes that have shaped planetary bodies and emphasize the search for habitable environments. Efforts are also made to detect and quantify resources that could be used for the support of human exploration. These themes call for chemistry and physical property observations that may be best approached by in situ measurements. NASA's planetary missions have progressively evolved from remote reconnaissance to in situ exploration with the ultimate goal to return samples. This chapter focuses on the techniques, available or in development, for advanced geophysical and chemical characterization of icy bodies, especially Mars polar areas, Enceladus, Titan, Europa, and Ceres. These astrobiological targets are the objects of recent or ongoing exploration whose findings are driving the formulation of new missions that involve in situ exploration. After reviewing the overall objectives of icy body exploration (Section 9.1) we describe key techniques used for addressing these objectives from surface platforms via geophysical observations (Section 9.2) and chemical measurements (Section 9.3).

planets↗