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480 records · Page 27
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Affinity and Treatment of LDR Organics in Low Activity Waste by Cementitious Materials – 26109

The physiochemical interactions between organic contaminants, minerals, and polymer additives in grout/cementitious materials are being identified. This research supports a proposed Resource Conservation and Recovery Act (RCRA) treatment variance relevant to the Land Disposal Restriction (LDR) organics present in Hanford tank waste. It provides the technical basis to address the aspects documented by the Environmental Protection Agency in a draft memo necessary to establish that organics can be immobilized/stabilized in a cementitious matrix. The organic species may interact with cementitious minerals, including slag, fly ash, cement, and other components/dopants like activated carbon. A list of 132 reasonably expected LDR organics associated with Hanford tank waste (RPP-RPT-63493, Rev 1a) was screened by functional groups, octanol-water partitioning coefficients, and detection frequency in Hanford tank waste samples. A subset of 15 compounds spanning the identified properties was tested using sorption and leachate tests. These compounds were subjected to traditional batch sorption tests and leaching tests on/from Cast Stone cementitious material with and without activated carbon (a potential organic adsorption additive). The interactions between organic compounds were observed in traditional batch sorption and modified TCLP leachate tests for surrogate Cast Stone material with and without activated carbon addition. Specifically, phthalic acid (negatively charged) and 4-chloroaniline (polar) sorbed strongly to unmodified Cast Stone, while a group of three phenolic compounds (2,4,6-Trichlorophenol, Pentachlorophenol, o-Cresol) sorbed to and were retained by Cast Stone with a 1% activated carbon amendment. Mixtures of these compounds demonstrated visible retention of the organics within the matrix with a quantifiable affinity of the organics to the cement. This novel testing supports the notion that organics within Hanford tank waste would be retained onto the cement phase with the addition of simple materials easily added to the formulation as part of the treatment process. To further provide additional support to this claim, models employing Flory-Huggins theory in conjunction with macromolecular and organic molecule solubility parameters and species activity coefficients are being utilized to better understand these interactions. Within this context, Van Krevelen (VK) and Hansen organic and polymer solubility parameters were used to inform the Flory-Huggins interaction parameter, allowing for a quantifiable method of evaluating polymer-solvent compatibility and, by extension, interactions with proposed binding additives (e.g., activated carbon). These models and measurement should test the hypothesis for our systems understanding and applicability of Flory-Huggins theory, and whether the prediction of organics in the polymer phase versus the aqueous phase can be confidently made using this strategy. The estimation of the organic molecular activity coefficient in these high salt-saturated aqueous systems is another factor that will be assessed. This project aims to predict and understand complicated organic interactions in these heterogenous systems, guiding optimal treatment and stabilization methodologies.

Jolin, Will [Savannah River National Laboratory (S↗
DOE OSTI2022

Elucidating the Reaction Pathways of Veratrylglycero-β-Guaiacyl Ether Degradation over Metal-Free Solid Acid Catalyst with Hydrogen

Efficient cleavage of β-O-4 bonds in lignin to high-yield aromatic compounds for the potential production of fuels and chemicals is vital for the economics of the modern biorefinery industry. This work is distinct in that a detailed mechanistic analysis of the reaction pathways of veratrylglycero-β-guaiacyl ether (VGE) catalyzed by transition-metal-free solid acid zeolite in aqueous conditions at high hydrogen pressure has been performed. VGE degradation produced high monomers yields (≈87 %), including guaiacol (48.2 %), 1-(3,4-dimethoxyphenyl)ethanol (10.3 %), 1-(3,4-dimethoxyphenyl)-2-propanol (6.1 %), 3,4-dimethoxyphenylpropanol (4.7 %), 3,4-dimethoxycinnamyl alcohol (4.1 %), and 1,2-dimethoxy-4-propylbenzene (2 %). The products were identified and confirmed by the in situ solid-state magic angle spinning (MAS) 13 C NMR spectroscopy in real-time conditions and the two-dimensional gas chromatography (GC×GC). A variety of products reveal the crucial role of hydrogen, water, and acid sites for heterolytic cleavage of the β-O-4 bond in VGE. Decarbonylation, hydrogenolysis, hydrogenation, and dehydration reaction pathways are proposed and further validated using first-principles calculations.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Soil aggregate-mediated microbial responses to long-term warming

Soil microbial carbon use efficiency (CUE) is a combination of growth and respiration, which may respond differently to climate change depending on physical protection of soil carbon (C) and its availability to microbes. In a mid-latitude hardwood forest in central Massachusetts, 27 years of soil warming (+5 °C) has resulted in C loss and altered soil organic matter (SOM) quality, yet the underlying mechanisms remain unclear. In this work, we hypothesized that long-term warming reduces physical aggregate protection of SOM, microbial CUE, and its temperature sensitivity. Soil was separated into macroaggregate (250–2000 μm) and microaggregate (<250 μm) fractions, and CUE was measured with 18 O enriched water (H 2 18 O) in samples incubated at 15 and 25 °C for 24 h. We found that long-term warming reduced soil C and nitrogen concentrations and extracellular enzyme activity in macroaggregates, but did not affect physical protection of SOM. Long-term warming showed little effect on CUE or microbial biomass turnover time because it reduced both growth and respiration. However, CUE was less temperature sensitive in macroaggregates from the warmed compared to the control plots. Our findings suggest that microbial thermal responses to long-term warming occur mostly in soil compartments where SOM is less physically protected and thus more vulnerable to microbial degradation.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2025

Chemical Diversity of Oligomers in Biomass Fast Pyrolysis Oils, Part 2: Heavy Lignin-Derived Molecules and Highly Dehydrated Sugars from Dichloromethane-Insoluble Pyrolytic Lignin

Here, this paper, the second in a series, investigates the water-insoluble, dichloromethane (DCM)-insoluble residue of BTG pyrolysis oil, also known in the literature as high-molecular-weight pyrolytic lignin (HMW-PL). HMW-PL accounts for 9.2 wt % of the original bio-oil, which is known to increase upon aging and contribute to coke formation during bio-oil upgrading. Understanding its composition is crucial for managing pyrolysis oil during the processing. The HMW-PL was fractionated using a silica gel column with solvents of increasing polarity: ethyl acetate (EA), acetone (AC), isopropanol (ISO), and methanol (MeOH), yielding 49.2, 19.9, 8.2, and 8.1 wt %, respectively. Each subfraction was characterized by UV-fluorescence, FTIR, HSQC NMR, and (−)APCI-FT-Orbitrap MS. Analysis revealed that the EA subfraction primarily contained aromatic dimers (C 19 –C 20 ) and trimers (C 17 –C 13 ), while the MeOH subfraction was rich in oxygenated aliphatic monomers (C 8 –C 16 ) likely derived from sugar dehydration products. The resulting fractions were further separated via preparatory HPLC. Fifty-five candidate molecular structures were proposed based on the Orbitrap MS data, supported by UV-fluorescence, FTIR, and NMR results. This fractionation strategy defined four distinct subfractions, enabling the proposal of surrogate molecular structures and advancing the molecular-level understanding of the HMW-PL fraction in the pyrolysis bio-oil.

High-Molecular-Weight PL↗
DOE OSTI2020

Correction to Reconciling Work Functions and Adsorption Enthalpies for Implicit Solvent Models: A Pt (111)/Water Interface Case Study

This errata is to correct the acknowledgment in the original published article. G.B. (partial support), V.-A.G., M.-T.N., and R.R. were supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Chemical Sciences, Geosciences, and Biosciences Division. Computer resources were provided by Research Computing at Pacific Northwest National Laboratory and the National Energy Research Scientific Computing Center (NERSC), a U.S. Department of Energy Office of Science User Facility operated under Contract No. DE-AC02-05CH11231. PNNL is operated by Battelle for the U.S. Department of Energy under Contract DE-AC05-76RL01830. G.B. acknowledges the EPSRC for partial support in PhD funding. The authors acknowledge the use of the IRIDIS High Performance Computing Facility (IRIDIS 5) and associated support services at the University of Southampton in the completion of this work. We are grateful to the UK Materials and Molecular Modeling Hub (Thomas HPC) for computational resources, which is partially funded by EPSRC (EP/P020194/1).

continuum solvation, metal/water interfaces, ab in↗
DOE OSTI2022

Evolution of p -coumaroylated lignin in eudicots provides new tools for cell wall engineering

Ester-linked p-coumarate (pCA) is a hallmark feature of the secondary cell walls in commelinid monocot plants. It has been shown that pCA groups arise during lignin polymerisation from the participation of monolignol conjugates assembled by p-coumaroyl-CoA:monolignol transferase (PMT) enzymes, members of the BAHD superfamily of acyltransferases. Herein we report that a eudicot species, kenaf (Hibiscus cannabinus), naturally contains p-coumaroylated lignin in the core tissues of the stems but not in the bast fibres. Moreover, we identified a novel acyltransferase, HcPMT, that shares less than 30% amino acid identity with known monocot PMT sequences. Recombinant HcPMT showed a preference in enzyme assays for p-coumaroyl-CoA and benzoyl-CoA as acyl donor substrates, and sinapyl alcohol as an acyl acceptor. Heterologous expression of HcPMT in hybrid poplar trees led to the incorporation of pCA in lignin but no improvement in the saccharification potential of the wood. This work illustrates the value in mining diverse plant taxa for new monolignol acyltransferases. Furthermore, the occurrence of pCA outside of monocot lineages may represent another example of convergent evolution in lignin structure. Furthermore, this discovery expands textbook views on cell wall biochemistry and provides a new molecular tool for engineering the lignin of biomass feedstock plants.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2025

Impact of shading following installation of agrivoltaic systems on eco-physiological and biochemical attributes of “Howes” cranberry in Massachusetts

Agrivoltaic (AV) systems, which integrate solar energy generation with crop production on the same piece of land, offer a sustainable solution for optimizing land-use efficiency. However, the impact of shading induced by solar panels on crop growth, physiology, and metabolic activities of cranberry is not known. Understanding these interactions is essential for assessing the feasibility of AV systems in cranberry production. In this study we evaluated eco-physiological and biochemical crop responses on a commercial ‘Howes’ cranberry bog grown under an agrivoltaics system using different row spacings in the year immediately following installation. Following installation of fixed tilt solar panels at a height of 3.0 m above the plant canopy, four shading treatments were evaluated: an uncovered control area and row spacings of 9.0 m, 7.0 m, and 5.0 m, corresponding to 30%, 35%, and 37% shading respectively. The shading effect was also evaluated at three different fruit developmental stages (green, blush, and full-red stage). Using microclimate sensors installed in the treatment areas, key eco-physiological and biochemical parameters, including leaf gas exchange, chlorophyll, anthocyanin, and antioxidant content, electrolyte leakage, proline and trehalose accumulation, were assessed. While moderate shading (30% and 35%) alleviated environmental stress, as reflected by improved leaf water status and reduced electrolyte leakage, these same treatments suppressed key physiological and metabolic functions, including photosynthetic activity, carbon reserve accumulation, and the biosynthesis of stress-related osmolytes and antioxidant compounds. Under higher shading (37%), these reductions were even more pronounced, indicating a potential threshold beyond which the benefits of shading are outweighed by declines in assimilate production and secondary metabolism. These findings highlight a trade-off between the stress-mitigating benefits of shading and the alterations in key physiological and metabolic processes under agrivoltaic systems. Minimizing these trade-offs by optimizing row spacing in agrivoltaics systems is critical to maintain cranberry physiological status. Since commercial cranberry is grown as a continuous plant canopy (no interrow spaces for equipment travel), damage caused by the installation process likely impacted crop response evaluated in the first year; multi-year studies are needed to fully understand the dynamics of a dual-use system. Notably, this work provides the first direct measurements of proline, trehalose content, and electrolyte leakage in cranberry grown under AV conditions, offering new insight into their physiological adjustments to shading.

14 SOLAR ENERGY↗
DOE OSTI2021

Identification of the Tyrosine- and Phenylalanine-Derived Soluble Metabolomes of Sorghum

The synthesis of small organic molecules, known as specialized or secondary metabolites, is one mechanism by which plants resist and tolerate biotic and abiotic stress. Many specialized metabolites are derived from the aromatic amino acids phenylalanine (Phe) and tyrosine (Tyr). In addition, the improved characterization of compounds derived from these amino acids could inform strategies for developing crops with greater resilience and improved traits for the biorefinery. Sorghum and other grasses possess phenylalanine ammonia-lyase (PAL) enzymes that generate cinnamic acid from Phe and bifunctional phenylalanine/tyrosine ammonia-lyase (PTAL) enzymes that generate cinnamic acid and p -coumaric acid from Phe and Tyr, respectively. Cinnamic acid can, in turn, be converted into p -coumaric acid by cinnamate 4-hydroxylase. Thus, Phe and Tyr are both precursors of common downstream products. Not all derivatives of Phe and Tyr are shared, however, and each can act as a precursor for unique metabolites. In this study, 13 C isotopic-labeled precursors and the recently developed Precursor of Origin Determination in Untargeted Metabolomics (PODIUM) mass spectrometry (MS) analytical pipeline were used to identify over 600 MS features derived from Phe and Tyr in sorghum. These features comprised 20% of the MS signal collected by reverse-phase chromatography and detected through negative-ionization. Ninety percent of the labeled mass features were derived from both Phe and Tyr, although the proportional contribution of each precursor varied. In addition, the relative incorporation of Phe and Tyr varied between metabolites and tissues, suggesting the existence of multiple pools of p -coumaric acid that are fed by the two amino acids. Furthermore, Phe incorporation was greater for many known hydroxycinnamate esters and flavonoid glycosides. In contrast, mass features derived exclusively from Tyr were the most abundant in every tissue. The Phe- and Tyr-derived metabolite library was also utilized to retrospectively annotate soluble MS features in two brown midrib mutants ( bmr6 and bmr12 ) identifying several MS features that change significantly in each mutant.

09 BIOMASS FUELS↗
DOE OSTI2022

Editorial: Phenylpropanoid Systems Biology and Biotechnology

Phenylpropanoids are specialized metabolites involved in several aspects of plant growth and development and in the responses of plants to environmental stimuli. These compounds are synthesized from key intermediates of the shikimate pathway, which are structurally modified by the combined activities of lyases, transferases, ligases, reductases and oxygenases, resulting in the organ- and developmental-specific synthesis and accumulation of diverse metabolites (Vogt, 2010). The phenylpropanoid pathway provides the building blocks for lignin, suberin, and condensed tannins that play a role in structural support and mechanical strength. Lignin is a major contributor to feedstock recalcitrance and negatively affects the conversion of plant biomass into downstream products in biorefineries (Liu et al., 2021). Further, this pathway is key for the production of anthocyanins for organ pigmentation, flavonols and flavones for UV protection, various flavonoids and isoflavonoids for plant-microbe interactions, and antimicrobial phytoalexins for protection against pathogens (Deng and Lu, 2017). In addition to their biological functions in planta, phenylpropanoids are economically important metabolites. They constitute important components in the human diet, acting as nutraceutical compounds with antioxidant, chemopreventive, antimitotic, neuroprotective, cardioprotective, and anti-inflammatory activities. Several phenylpropanoids are considered high-value biochemicals employed in the production of fragrances, pharmaceuticals and biopolymers (Lin and Eudes, 2020).

59 BASIC BIOLOGICAL SCIENCES↗