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At least 757 records · Page 42

Tradeoffs in forest resilience to satellite-based estimates of water and productivity losses

Climate change is expected to intensify the global hydrological cycle via increased evapotranspiration (ET). Changes in ET have important consequences for water-related ecosystem services as well as for forest productivity. Forests play a critical role in ET: active trees sequester carbon at the expense of losing water, yet if they are not active, water remains in the trees, but productivity stalls. Here, we estimated the capacity of forests to recover (resilience) from extreme water or productivity losses based on modeled ET through remote sensing methods across the conterminous USA. Results show there is a spatial tradeoff in resilience to water or productivity losses. Forests were more resilient to water loss in the drier west, and more resilient to productivity loss in the wetter east. Still, resilience was highly heterogeneous across the continent. Projections under climate change indicate both declines and increases of up to 13% in forest resilience, with broad regional trends but high spatial heterogeneity within regions. This study brings crucial satellite-based insights on how water dynamics, and consequentially productivity and water provision in forests, might be impacted by climate change.

54 ENVIRONMENTAL SCIENCES↗

Renewable biohydrogen production from lignocellulosic biomass using fermentation and integration of systems with other energy generation technologies

Biohydrogen is a clean and renewable source of energy. It can be produced by using technologies such as thermochemical, electrolysis, photoelectrochemical and biological, etc. Among these technologies, the biological method (dark fermentation) is considered more sustainable and ecofriendly. Dark fermentation involves anaerobic microbes which degrade carbohydrate rich substrate and produce hydrogen. Lignocellulosic biomass is an abundantly available raw material and can be utilized as an economic and renewable substrate for biohydrogen production. Although there are many hurdles, continuous advancements in lignocellulosic biomass pretreatment technology, microbial fermentation (mixed substrate and co-culture fermentation), the involvement of molecular biology techniques, and understanding of various factors (pH, T, addition of nanomaterials) effect on biohydrogen productivity and yield render this technology efficient and capable to meet future energy demands. Further integration of biohydrogen production technology with other products such as bio-alcohol, volatile fatty acids (VFAs), and methane have the potential to improve the efficiency and economics of the overall process. In this study, various methods used for lignocellulosic biomass pretreatment, technologies in trends to produce and improve biohydrogen production, a coproduction of other energy resources, and techno-economic analysis of biohydrogen production from lignocellulosic biomass are reviewed.

09 BIOMASS FUELS↗

Integrated techno-economic framework for nuclear hydrogen production: assessing the role of high temperature steam electrolysis and safety considerations

This manuscript presents a comprehensive techno-economic assessment of nuclear integrated hydrogen production through high-temperature steam electrolysis (HTSE) in the U.S. Gulf Coast region. Given the significant role of hydrogen as an energy carrier and chemical feedstock, the research evaluates the feasibility of co-locating HTSE facilities with existing nuclear power plants (NPPs) to enhance hydrogen production efficiency and cost-effectiveness. Here, the study highlights the advantages of HTSE over traditional low-temperature electrolysis, particularly in leveraging thermal and electrical energy from NPPs. A novel framework for hydrogen deployment is introduced, integrating hydrogen market analysis, techno-economic evaluation (TEA), and safety assessments. The findings underscore the economic viability of hydrogen production in light of current market conditions, including fluctuating natural gas prices and the impact of production tax credits under the Inflation Reduction Act. A case study in the Gulf Coast region demonstrates the potential for strategic hydrogen production to meet growing industrial demand while ensuring safety and regulatory compliance. Overall, this research contributes to the advancement of nuclear integrated hydrogen production as a sustainable energy solution.

08 - HYDROGEN↗

Engineering Rhodosporidium toruloides for production of 3-hydroxypropionic acid from lignocellulosic hydrolysate

Microbial production of valuable bioproducts is a promising route towards green and sustainable manufacturing. The oleaginous yeast, Rhodosporidium toruloides, has emerged as an attractive host for the production of biofuels and bioproducts from lignocellulosic hydrolysates. 3-hydroxypropionic acid (3HP) is an attractive platform molecule that can be used to produce a wide range of commodity chemicals. This study focuses on establishing and optimizing the production of 3HP in R. toruloides. As R. toruloides naturally has a high metabolic flux towards malonyl-CoA, we exploited this pathway to produce 3HP. Upon finding the yeast capable of catabolizing 3HP, we then implemented functional genomics and metabolomic analysis to identify the catabolic pathways. Deletion of a putative malonate semialdehyde dehydrogenase gene encoding an oxidative 3HP pathway was found to significantly reduce 3HP degradation. We further explored monocarboxylate transporters to promote 3HP transport and identified a novel 3HP transporter in Aspergillus pseudoterreus by RNA-seq and proteomics. Combining these engineering efforts with media optimization in a fed-batch fermentation resulted in 45.4 g/L 3HP production. This represents one of the highest 3HP titers reported, and the highest titer produced from lignocellulosic hydrolysate to the best of our knowledge. This work demonstrates microbial production of 3HP in R. toruloides from lignocellulosic hydrolysate at high titers, and it represents a significant step toward enabling industrial production of 3HP in the future.

3-Hydroxypropionic acid↗

Water Availability for Biorefineries in the Contiguous United States and the Implications for Bioenergy Production Distribution

Renewable biofuel production depends on many factors, including feedstock availability, refinery and shipment infrastructure, and in particular, water availability. This study assesses water requirement and availability for mainstream biorefinery technologies in the contiguous United States (CONUS). The assessment is conducted in newly defined spatial units, namely, biorefinery planning boundaries, considering feedstock availability, transportation cost, and refinery capacity requirement for cost-effectiveness. The results suggest that the total biorefinery water use in the CONUS by 2030 will be low compared to the total water availability. However, biorefinery water requirements can aggravate the water stress situation in many regions, including the Great Plains, California Central Valley, and the upper Columbia-Snake River basin in Washington. Bioenergy productions in these regions can be largely constrained by water. Here, it is projected that biofuel production will concentrate in Northern Plains, Lake States, and Corn Belt regions, which contribute 94.4% of the conventional, 86.1% of biodiesel, and 54.8% of cellulosic biofuel production mandated by the renewable fuel standard. If biorefineries are constrained to use less than 10% of the locally available water, up to 7% of planned cellulosic biofuel production will be affected. Findings from this study can aid the sustainable planning of national bioenergy production.

54 ENVIRONMENTAL SCIENCES↗

Enabling Stable and Salt-Free Formic Acid Production via Reactive Interface Optimization in Forward-Bias Bipolar-Membrane CO2 Electrolyzers

Electrochemical conversion of CO2 to liquid products is limited by parasitic reactions that consume products and destabilize operation. Here, we show that salt-free formic acid synthesis in a forward-bias bipolar-membrane CO2 electrolyzer is governed by a coupled reaction-transport instability driven by parasitic anode formic acid oxidation. Operando mass spectrometry reveals that this process proceeds through CO-mediated poisoning, identifying catalyst tolerance to CO as a key descriptor of anode selectivity. Among the catalysts examined, PtRu/C preferentially promotes hydrogen oxidation over formic acid oxidation. Coupling this catalyst with transport-interface engineering improves product removal, enhances Faradaic and energy efficiency, and enables stable operation at 200 mA/cm2 for 190 h with a voltage decay of 0.64 mV/h. Techno-economic analysis indicates an 18% reduction in minimum selling price and highlights product concentration as the dominant cost lever. These results establish a general framework for suppressing product oxidation in liquid-product electrolyzers.

Hu, Leiming↗

Engineering the Novel Extremophile Alga Chlamydomonas pacifica for High Lipid and High Starch Production as a Path to Developing Commercially Relevant Strains

Microalgae offer a compelling platform for the production of commodity products, due to their superior photosynthetic efficiency, adaptability to nonarable lands and nonpotable water, and their capacity to produce a versatile array of bioproducts, including biofuels and biomaterials. However, the scalability of microalgae as a bioresource has been hindered by challenges such as costly biomass production related to vulnerability to pond crashes during large-scale cultivation. This study presents a pipeline for the genetic engineering and pilot-scale production of biodiesel and thermoplastic polyurethane precursors in the extremophile species Chlamydomonas pacifica. This extremophile microalga exhibits exceptional resilience to high pH (>11.5), high salinity (up to 2% NaCl), and elevated temperatures (up to 42 °C). Initially, we evolved this strain to also have a high tolerance to high light intensity (>2000 μE/m 2 /s) through mutagenesis, breeding, and selection. We subsequently genetically engineered C. pacifica to significantly enhance lipid production by 28% and starch accumulation by 27%, all without affecting its growth rate. We demonstrated the scalability of these engineered strains by cultivating them in pilot-scale raceway ponds and converting the resulting biomass into biodiesel and thermoplastic polyurethanes. This study showcases the complete cycle of transforming a newly discovered species into a commercially relevant commodity production strain. This research underscores the potential of extremophile algae, including C. pacifica, as a key species for the burgeoning sustainable bioeconomy, offering a viable path forward in mitigating environmental challenges and supporting global bioproduct demands.

59 BASIC BIOLOGICAL SCIENCES↗

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↗

Assessment of Plant and Microalgal Oil-Derived Nonisocyanate Polyurethane Products for Potential Commercialization

Green pathways for nonisocyanate polyurethane (NIPU) production have attracted increasing levels of interest. The reaction between 5-membered cyclic carbonate and polyamines is one of the most promising pathways to produce NIPU polymers. Though promising, major technical hurdles such as slow polymerization rate and poor performance hinder the commercialization of NIPU. In this paper, we screened several commercially available triglyceride oil feedstocks for NIPU products, focusing on polymerization kinetics and product performance for industrial application. The impact of carbonated group density on polymerization rate and mechanical strength was determined. We have demonstrated a remarkably higher reactivity of carbonated oil derived from feedstocks with polyunsaturated fatty acid (PUFA). The NIPU derived from such feedstocks also showed improved performance for industrial application. Unlike traditional polyurethane foam production that uses isocyanate and water to generate CO2 as a blowing reagent, there is no gas formation in NIPU polymerization. We have demonstrated a practical and cost-effective approach to produce NIPU foam material using bicarbonate as a blowing reagent. Furthermore, we conducted the first-ever technoeconomic analysis (TEA), revealing that profitable commercial NIPU production can be achieved when operating at sufficient production capacities.

09 BIOMASS FUELS↗

Thermostable Enzyme Variants in the Lower Mevalonate Pathway Improve Isoprenoid Production by Cell-Free Biocatalysis

Cell-free biocatalysis is a rapidly evolving field with great potential for sustainably producing valuable chemicals. Some challenges in cell-free biocatalysis include reaction longevity, enzyme stability, and the cost of the biocatalysts. Here, the challenge of enzyme instability was addressed by employing thermophilic enzymes to improve the productivity of the lower mevalonate pathway, using limonene as an example isoprenoid product. The Classical mesophilic mevalonate pathway was compared to a newly assembled set of thermophilic enzymes comprising the Archaea I mevalonate pathway. The thermophilic pathway enzymes were thermostable to at least 60 °C and exhibited a 6× longer operating lifetime at 22 °C. Thus, despite lower initial activity rates at ambient temperature, the thermophilic pathway was longer-lived and resulted in a more productive cell-free reaction overall, achieving 1.7× higher yield of limonene compared to using enzymes from mesophiles. Moreover, the thermostable pathway retained activity for longer with the challenge of solvent exposure, namely, ethanol and isoprenol, which broadens the scope of accessible substrates and/or products in cell-free reactions employing this pathway. Altogether, we showed significant improvement in the stability and productivity of the lower mevalonate pathway, which will enable more efficient cell-free biosynthesis of isoprenoid products. This represents a valuable strategy to increase the robustness of cell-free systems by carefully sourcing biocatalysts from thermophilic organisms, which have proven to be resilient to challenges unique to cell-free reaction systems.

09 BIOMASS FUELS↗

Simulated Hydrological Dynamics and Coupled Iron Redox Cycling Impact Methane Production in an Arctic Soil

The fate of organic carbon (C) in permafrost soils is important to the climate system due to the large global stocks of permafrost C. Thawing permafrost can be subject to dynamic hydrology, making redox processes an important factor controlling soil organic matter (SOM) decomposition rates and greenhouse gas production. In iron (Fe)-rich permafrost soils, Fe(III) can serve as a terminal electron acceptor, promoting anaerobic respiration of SOM and increasing pH. Current large-scale models of Arctic C cycling do not include Fe cycling or pH interactions. Here, a geochemical reaction model was developed by coupling Fe redox reactions and C cycling to simulate SOM decomposition, Fe(III) reduction, pH dynamics, and greenhouse gas production in permafrost soils subject to dynamic hydrology. In this study we parameterized the model using measured CO 2 and CH 4 fluxes as well as changes in pH, Fe(II), and dissolved organic C concentrations from oxic and anoxic incubations of permafrost soils from polygonal permafrost sites in northern Alaska, United States. In simulations of repeated oxic-anoxic cycles, Fe(III) reduction during anoxic periods enhanced CO 2 production, while the net effect of Fe(III) reduction on cumulative CH 4 fluxes depended on substrate C availability. With lower substrate availability, Fe(III) reduction decreased total CH 4 production by further limiting available substrate. With higher substrate availability, Fe(III) reduction enhanced CH 4 production by increasing pH. Our results suggest that interactions among Fe-redox reactions, pH and methanogenesis are important factors in predicting CH 4 and CO 2 production as well as SOM decomposition rates in Fe-rich, frequently waterlogged Arctic soils.

54 ENVIRONMENTAL SCIENCES↗

High yield production of 3-hydroxypropionic acid using Issatchenkia orientalis

Biomanufacturing provides a more sustainable alternative to fossil-based chemical manufacturing. 3-Hydroxypropionic acid (3HP) is a top Department of Energy value-added chemical and precursor to bioplastics, yet cost-effective microbial production remains elusive. Here, we establish the acid-tolerant yeast Issatchenkia orientalis as a robust host for low-pH 3HP biosynthesis. Genome-scale modeling identifies the β-alanine pathway as optimal, offering the highest theoretical yield and lowest oxygen requirement. Thermodynamic analysis confirms its favorability under acidic conditions. Using sequence similarity network analysis, we discover highly active aspartate 1-decarboxylase (PAND), β-alanine-pyruvate aminotransferase (BAPAT), and 3HP dehydrogenase (YDFG), which significantly improve the pathway efficiency. Next, to further elevate the production, pathway optimization through multi-copy PAND integration, byproduct elimination (knockouts of pyruvate decarboxylase and glycerol-3-phosphate dehydrogenase), and reinforcement of aspartate flux by overexpression of pyruvate carboxylase and aspartate amino transferase improves the titer to 29 g/L in shake flasks. Fed-batch fermentation at pH 4 with low-cost corn steep liquor medium further increases the production to 92 g/L with 0.7 g/g yield and 0.55 g/L/h productivity. Techno-economic analysis indicates that such performance could potentially enable a financially viable process for sustainable acrylic acid production. This work establishes I. orientalis as a next-generation platform for cost-effective 3HP production and paves the way toward industrial commercialization.

Biotechnology↗

Cross sections of 147–149 Sm( 6 Li,x) reactions for the production of 149 Tb for targeted alpha therapy

Terbium-149g (t 1/2 = 4.12 h) is of particular interest for targeted alpha therapy cancer treatment due to its ability to decay via both alpha and positron emission, making it a potential theranostic nuclide. Due to many challenges facing its production, there are limited facilities worldwide that have demonstrated the ability to produce this nuclide in quantities sufficient for medical research. Since the Cyclotron Institute at Texas A&M University is a specialized accelerator facility capable of accelerating a wide variety of ions, we are investigating production pathway options. One of the major challenges facing its production is the known co-production of the excited isomeric state, 149m Tb (t 1/2 = 4.1 min). However, this state does not decay to the ground state of 149g Tb, negating any potential contribution to its yield. Due to its short-half life, the cross section for the population of this state has never been measured. After calculating several potential reaction yields using predictive models, the reactions of 147–149 Sm( 6 Li,xn) 149 Tb were identified as candidates. Lithium-6 beams of varied energies between 45-65 MeV were impinged on enriched 147 Sm, 148 Sm, and 149 Sm targets at the Cyclotron Institute at Texas A&M University, and the reaction products were measured immediately following irradiation using high-purity germanium detectors, enabling detection of both 149m Tb and 149g Tb. Cross sections for all nuclides produced in sufficient activity in these reactions were also measured and reported here. We conclude that the population of 149m Tb is much preferred over population of the ground state for these 6 Li-induced reactions, and it is necessary to explore other options for 149g Tb production.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

A recirculation system for concentrating CO 2 electrolyzer products

Electrochemical carbon dioxide reduction represents a promising path to utilize CO 2 as a feedstock for generating valuable products such as fuels and chemicals. Faradaic efficiencies near 100% have been achieved for certain CO 2 reduction products such as CO, but the electrolyzer outlet streams usually contain large fractions of unreacted CO 2 , dropping the product concentrations below 1% in many cases. The system disclosed here recycles the unreacted CO 2 together with the products and flows them back into the CO 2 reduction reactor, enabling much higher CO 2 conversion rates without dropping the gas flow rate. However, simple recirculation is shown to accumulate significant amounts of hydrogen, impeding effective CO 2 reduction. In this looped system, an electrochemical H 2 pump is placed in series with the CO 2 reactor, which effectively removes all the H 2 from the recycled gas stream, increasing the concentrations of carbon-containing products. Here, the system was initially tested with a CO-generating catalyst and CO concentrations above 70% were achieved in the recycled gas stream, compared to a maximum CO concentration of 8% in single-pass configuration. Results with a CO 2 reactor targeting ethylene as the main product show that ethylene concentrations of at least 10% can be achieved, which is roughly 20 times higher compared to a single-pass system.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗

Plastic waste gasification for low-carbon hydrogen production: a comprehensive review

Hydrogen is one of the most important feedstocks for the chemical industry, power production, and the decarbonization of other sectors that rely on natural gas. The production of hydrogen from plastics enables sustainable use of plastic waste and offers significant environmental benefits. Gasification emerges as a promising route for chemical recycling, converting plastic into hydrogen and other valuable chemicals. Although the gasification of plastic waste has recently gained attention, the number of studies regarding low-carbon hydrogen production is still limited. The effective integration of carbon capture, utilization, and storage (CCUS) is essential for achieving low-carbon hydrogen production via gasification, which enables the efficient capture and storage of CO 2 emissions. Incorporating coal waste and biomass into plastic gasification can synergistically enhance reforming reactions for hydrogen production, reduce tar content, and resolve feeding issues caused by plastic stickiness. Based on the previous studies, this paper briefly reviews the mechanisms of plastic gasification including plastic depolymerization, reforming, tar and char formation, and gasification; the discussions on feedstocks and effects of operating conditions on H 2 production including plastic-type, temperature, steam/carbon ratio, equivalence ratio, and catalysts; and the integration of CCUS and alternative recovery processes in plastic gasification for low-carbon hydrogen.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Metabolic engineering strategies for sesquiterpene production in microorganism

Sesquiterpenes are a large variety of terpene natural products, widely existing in plants, fungi, marine organisms, insects, and microbes. Value-added sesquiterpenes are extensively used in industries such as: food, drugs, fragrances, and fuels. With an increase in market demands and the price of sesquiterpenes, the biosynthesis of sesquiterpenes by microbial fermentation methods from renewable feedstocks is acquiring increasing attention. Synthetic biology provides robust tools of sesquiterpene production in microorganisms. This review presents a summary of metabolic engineering strategies on the hosts and pathway engineering for sesquiterpene production. Advances in synthetic biology provide new strategies on the creation of desired hosts for sesquiterpene production. Especially, metabolic engineering strategies for the production of sesquiterpenes such as: amorphadiene, farnesene, bisabolene, and caryophyllene are emphasized in: Escherichia coli , Saccharomyces cerevisiae , and other microorganisms. Herein, challenges and future perspectives of the bioprocess for translating sesquiterpene production into practical industrial work are also discussed.

59 BASIC BIOLOGICAL SCIENCES↗

Exploring J/ψ Production Mechanism at the Future Electron-Ion Collider

We propose to use transverse momentum p T distribution of J/ψ production at the future Electron Ion Collider (EIC) to explore the production mechanism of heavy quarkonia in high energy collisions. We apply QCD and QED collinear factorization to the production of a $c\bar{c}$ pair at high p T , and non-relativistic QCD factorization to the hadronization of the pair to a J/ψ. We evaluate J/ψ p T -distribution at both leading and next-to-leading order in strong coupling, and show that production rates for various color-spin channels of a $c\bar{c}$ pair in electron-hadron collisions are very different from that in hadron-hadron collisions, which provides a strong discriminative power to determine various transition rates for the pair to become a J/ψ. We predict that the J/ψ produced in electron-hadron collisions is likely unpolarized, and the production is an ideal probe for gluon distribution of colliding hadron (or nucleus). We find that the J/ψ production is dominated by the color-octet channel, providing an excellent probe to explore the gluon medium in large nuclei at the EIC.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Pre-production results from ATLAS ITk Strip Sensors Quality Assurance Testchip

The production of strip sensors within the framework of the ATLAS Inner Tracker (ITk) development is a process which requires continuous evaluation during the full production period (about 4 years). Such an evaluation is divided into two different parts: Quality Control (QC), which focuses on the final product (the actual sensors) and tries to identify possible defects once the fabrication is completed, and Quality Assurance (QA), which aims to prevent deviations in the manufacturing process and uses specifically-designed test structures. The initial sensor pre-production consists of 5% (1041 sensors) of the total number of sensors expected during production. As part of pre-production, the collaboration has measured key parameters from miniature strip sensors (minis), monitor diodes (MD8), and the ATLAS Testchip, before and after irradiation. In this contribution we focus on the analysis of the results of the MD8 and the Testchip. All parameters have been obtained from the test structures (MD8, bias resistors, interdigitated structures, field oxide capacitors, coupling capacitors, punch-through protection structures and cross-bridge resistors) measured at the different test sites (KEK/Tsukuba, Birmingham, Toronto, Ljubljana, Valencia, Carleton, Prague, CNM-Barcelona). The results are compared to predefined pre- and post-irradiation specifications for each tested parameter.

47 OTHER INSTRUMENTATION↗