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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 721 records · Page 40
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Techno‐economic feasibility analysis of engineered energycane‐based biorefinery co‐producing biodiesel and ethanol

Abstract High feedstock cost and low oil yields per unit of land from temperate oilseed crops limit the growth of commercial‐scale biodiesel production. Recently, highly productive crops, such as sugarcane and energycane, have been engineered to accumulate triacylglycerides (TAGs) that allow the production of far more industrial vegetable oil than previously possible. A proof‐of‐concept suggests that biodiesel production from engineered energycane will be possible. However, before making efforts for scale‐up, it is critical to understand the commercial feasibility and economic competitiveness of this process. This study performs techno‐economic analysis of a unique biorefinery processing energycane to co‐produce biodiesel and ethanol. Comprehensive process simulation models were developed for two scenarios: (i) biodiesel from TAGs and ethanol from fermentation of sugars in juice and (ii) biodiesel from TAGs and ethanol from fermentation of sugars in juice and hydrolysis of carbohydrates in bagasse. Based on the target levels, the analysis was performed for energycane containing 0%, 5%, and 7.7% TAGs (d.b.). The biodiesel from engineered energycane was found economically viable and competitive to soybean biodiesel. Although the capital investment is higher compared to the soybean biodiesel plant, the biodiesel production costs ($0.66–$0.9/L) were lower than soybean biodiesel ($0.91/L). Biorefinery‐scenario‐1 processing energycane containing 7.7% TAG produces biodiesel with profitability (IRR 7.84) slightly lower than soybean biodiesel (IRR 8.3), but yields five times of biodiesel per unit land and is self‐sustainable for energy requirements. The surplus electricity can displace fossil electricity and provide environmental benefits. Monte Carlo simulation indicated that biorefinery is profitable with a 29%–65% probability (NPV > 0) which is largely controlled by feedstock composition and biodiesel market price. It is important to note that energycane can be grown on the marginal rainfed lands in S.E. USA, where soybean would not be viable. Biodiesel from engineered energycane would therefore be complementary to soydiesel in the United States.

09 BIOMASS FUELS↗
DOE OSTI2020

Hydration and reaction mechanisms on sodium silicate glass surfaces from molecular dynamics simulations with reactive force fields

Recent development of reactive force fields have enabled molecular dynamics simulations of interactions between silicate glasses and water at the atomistic scale. While multicomponent silicate glasses encompass a wide variety of compositions and properties, one common structural feature in these glasses is the combination of the network structure that is made up of silica tetrahedra linked through corner sharing interspersed with network modifiers like alkali and alkaline-earth ions that break up the Si–O–Si linkages by forming nonbridging oxygen. In reactions with water, ion exchange between alkali ions in the glass and proton or hydronium in the solution, as well as hydrolysis reaction of the Si–O–Si linkages and subsequent silanol formation, is observed and well documented. Furthermore, we have used a set of recently developed reactive force field to investigate the reactions between water and the surfaces of silica and sodium silicate glasses of different compositions for reactions up to 8 nanoseconds. Our results indicate sodium leaching into water and diffusion of water molecules up to 25 Å into the glass surface. We examined the structural and compositional changes inside the glass and around the diffused ions and use these to explain the rates of silanol formation at the surface. We also observed proton transport in the glass which has an indirect influence on the silanol formation rates. While the surface of the glass was rough to start with, it undergoes further modification into a hydrated gel-like structure in the glass for up to 5 Å in the higher alkali containing glasses. It was found that the leached sodium ions remain close to the interface and that fragments of silicate network from the surface is capable of dislodging from the bulk glass and enter the aqueous solution. These simulations thus provide insights into the formation and structure of an alteration layers commonly observed in multicomponent silicate glasses corroded in aqueous solutions.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Topological controls on aluminosilicate glass dissolution: Complexities induced in hyperalkaline aqueous environments

Abstract Fly ash, an aluminosilicate composite consisting of disordered (major) and crystalline (minor) compounds, is a low‐carbon alternative that can partially replace ordinary portland cement (OPC) in the binder fraction of concrete. Therefore, understanding the reactivity of fly ash in the hyperalkaline conditions prevalent in concrete is critical to predicting concrete's performance; including setting and strength gain. Herein, temporal measurements of the solution composition (using inductively coupled plasma‐optical emission spectrometry: ICP‐OES) are used to assess the aqueous dissolution rate of monophasic synthetic aluminosilicate glasses analogous to those present in technical fly ashes, under hyperalkaline conditions (10 ≤ pH ≤ 13) across a range of temperatures (25°C ≤ T≤45°C). The dissolution rate is shown to depend on the average number of topological constraints per atom within the glass network (n c , unitless), but this dependence weakens with increasing pH (>10). This is postulated to be on account of: (a) time‐dependent changes in the glass’ surface structure, that is, the number of topological constraints; and/or (b) a change in the dissolution mechanism (eg from network hydrolysis to transport control). The results indicate that the topological description of glass dissolution is most rigorously valid only at very short reaction times (ie at high undersaturations), especially under conditions of hyperalkalinity. These findings provide an improved basis to understand the underlying factors that affect the initial and ongoing reactivity of aluminosilicate glasses such as fly ash in changing chemical environments, for example, when such materials are utilized in cementitious composites.

Oey, Tandré↗
DOE OSTI2022

Predicting initial dissolution rates using structural features from molecular dynamics simulations

Predicting chemical durability of glass materials is important for various applications from daily life such as drink glass and kitchen ware to advanced technologies such as nuclear waste disposal and biomedicine. In this work, we explored prediction of initial dissolution rate through structural features from molecular dynamics (MD) simulations for a wide range of glass compositions (total 28) including borosilicate and aluminosilicate glasses, ZrO 2 -containing and V 2 O 5 -containing boroaluminosilicate glasses. The initial dissolution rates (r 0 ) measured experimentally at 90 °C with varying solution conditions were correlated with structural features (e.g., polyhedral linkages and non-bridging oxygen species) obtained from MD simulations, either from this study or from literature. Since hydrolysis of the glass network through breaking of the network former linkages (e.g., Si-O-Si, Si-O-Al, etc.) is a critical step of network glass dissolution, the statistics of these linkages obtained from MD were correlated to r0 through linear regression, where the coefficient of determination (R 2 ) and root mean square error are found to be 0.949 and 0.681, respectively. This model was compared and discussed with existing models developed by various approaches including machine learning, the kinetic rate equation, topological constraint theory, and other descriptors from MD simulations. The discussion provides insights on future model improvements to predict glass dissolution. In addition, the impact of V 2 O 5 on the glass dissolution was examined in detail, implicating that the impact is not the same across all glass compositions and test conditions.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Askival: An altered feldspathic cumulate sample in Gale crater

Askival is a light-toned, coarsely crystalline float rock, which was identified near the base of Vera Rubin Ridge in Gale crater. We have studied Askival, principally with the ChemCam instrument but also using APXS compositional data and MAHLI images. Askival and an earlier identified sample, Bindi, represent two rare examples of feldspathic cumulate float rocks in Gale crater with >65% relict plagioclase. Bindi appears unaltered whereas Askival shows textural and compositional signatures of silicification, along with alkali remobilization and hydration. Askival likely experienced multiple stages of alteration, occurring first through acidic hydrolysis of metal cations, followed by deposition of silica and possible phyllosilicates at low T and neutral-alkaline pH. Through laser-induced breakdown spectroscopy compositional analyses and normative calculations, we suggest that an assemblage of Fe-Mg silicates including amphibole and pyroxene, Fe phases, and possibly Mg-rich phyllosilicate are present. Thermodynamic modeling of the more pristine Bindi composition predicts that amphibole and feldspar are stable within an upper crustal setting. This is consistent with the presence of amphibole in the parent igneous rocks of Askival and suggests that the paucity of amphiboles in other known Martian samples reflects the lack of representative samples of the Martian crust rather than their absence on Mars.

58 GEOSCIENCES↗
DOE OSTI2024

The expression of genes encoding novel Sesame oleosin variants facilitates enhanced triacylglycerol accumulation in Arabidopsis leaves and seeds

Summary Triacylglycerols (TAG), accumulate within lipid droplets (LD), predominantly surrounded by OLEOSINs (OLE), that protect TAG from hydrolysis. We tested the hypothesis that identifying and removing degradation signals from OLE would promote its abundance, preventing TAG degradation and enhancing TAG accumulation. We tested whether mutating potential ubiquitin‐conjugation sites in a previously reported improved Sesamum indicum OLE ( SiO ) variant, o3‐3 Cys‐OLE ( SiCO herein), would stabilize it and increase its lipogenic potential. SiCOv1 was created by replacing all five lysines in SiCO with arginines. Separately, six cysteine residues within SiCO were deleted to create SiCOv2. SiCOv1 and SiCOv2 mutations were combined to create SiCOv3. Transient expression of SiCOv3 in Nicotiana benthamiana increased TAG by two‐fold relative to SiCO. Constitutive expression of SiCOv3 or SiCOv5 , containing the five predominant TAG‐increasing mutations from SiCOv3 , in Arabidopsis along with mouse DGAT2 ( mD ) increased TAG accumulation by 54% in leaves and 13% in seeds compared with control lines coexpressing SiCO and mD. Lipid synthesis rates increased, consistent with an increase in lipid sink strength that sequesters newly synthesized TAG, thereby relieving the constitutive BADC‐dependent inhibition of ACCase reported for WT Arabidopsis. These OLE variants represent novel factors for potentially increasing TAG accumulation in a variety of oil crops.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2022

Metabolic engineering of p –hydroxybenzoate in poplar lignin

Ester-linked p-hydroxybenzoate occurs naturally in poplar lignin as pendent groups that can be released by mild alkaline hydrolysis. These ‘clip-off’ phenolics can be separated from biomass and upgraded into diverse high-value bioproducts. We introduced a bacterial chorismate pyruvate lyase gene into transgenic poplar trees with the aim of producing more p-hydroxybenzoate from chorismate, itself a metabolic precursor to lignin. By driving heterologous expression specifically in the plastids of cells undergoing secondary wall formation, this strategy achieved a 50% increase in cell-wall-bound p-hydroxybenzoate in mature wood and nearly 10 times more in developing xylem relative to control trees. Comparable amounts also remained as soluble p-hydroxybenzoate-containing xylem metabolites, pointing to even greater engineering potential. Mass spectrometry imaging showed that the elevated p-hydroxybenzoylation was largely restricted to the cell walls of fibres. Finally, transgenic lines outperformed control trees in assays of saccharification potential. Here, this study highlights the biotech potential of cell-wall-bound phenolate esters and demonstrates the importance of substrate supply in lignin engineering.

4-hydroxybenzoic acid↗
DOE OSTI2023

Acetylation of homogalacturonan and rhamnogalacturonan‐I is catalyzed by a suite of trichome birefringence‐like proteins

SUMMARY Plant cell wall polysaccharides, including xylan, mannan, xyloglucan, and pectins, are often acetylated and members of the domain of unknown function 231 (DUF231)/trichome birefringence‐like (TBL) family have been shown to beO‐acetyltransferases mediating the acetylation of xylan, mannan, and xyloglucan. However, little is known about theO‐acetyltransferases responsible for pectin acetylation. In this report, we biochemically characterized a suite of Arabidopsis DUF231/TBL proteins for their roles in pectin acetylation. We generated 24 TBL recombinant proteins in mammalian cells and demonstrated that 10 of them were able to transfer acetyl groups from acetyl‐CoA onto the pectins homogalacturonan (HG) or rhamnogalacturonan‐I (RG‐I), and thus were named pectinO‐acetyltransferase 1 to 10 (POAT1 to 10). It was found that POAT2,4,9,10 specifically acetylated HG and POAT5,6 acetylated RG‐I, whereas POAT1,3,7,8 could act on both HG and RG‐I. The acetylation of HG and RG‐I by POATs was further corroborated by hydrolysis with pectin acetylesterases and by nuclear magnetic resonance spectroscopy. In addition, mutations of the conserved GDS and DXXH motifs in POAT3 and POAT8 were shown to lead to a loss of their ability to acetylate HG and RG‐I. Furthermore, simultaneous RNA interference downregulation ofPOAT1,3,6,7,8resulted in reduced cell expansion, impaired plant growth, and decreased pectin acetylation. Together, our findings indicate that these POATs are pectinO‐acetyltransferases involved in acetylation of the pectin polysaccharides HG and RG‐I.

Plant Sciences↗
DOE OSTI2021

Reflection absorption infrared spectroscopy of the surface chemistry of furfural on Pd(111)

The hydrolysis and subsequent acidic dehydration of biomass leads to the production of smaller oxygenates, including furfural, which can undergo subsequent reactions such as hydrogenation to produce value-added products. Palladium has been found to be an active catalyst for this process. As a result, the surface chemistry of furfural is investigated on a Pd(111) single-crystal surface using reflection-absorption infrared spectroscopy as a basis for understanding the catalytic conversion of furfural to value-added products. Following adsorption at 90 K, furfural adopts a flat-lying geometry at low coverages, but converts to a tilted species as the coverage approaches saturation. Heating to ~175 K forms a tilted η 1 (O) species that appears to deprotonate on heating to above 200 K to form an intermediate with a tilted furyl ring and a carbonyl group close to parallel to the surface. Further heating to ~250 K and above caused this species to decarbonylate to form adsorbed carbon monoxide and an infrared invisible furyl intermediate. This can then undergo a ring-opening reaction to produce further CO and form a C 3 H 3 intermediate that can hydrogenate to produce propylene. Finally, this reaction sequence is in good agreement with previous density functional theory calculations and with the products observed in temperature-programmed desorption.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Quantitative evaluation of perfluorinated alkanethiol molecular order on gold surfaces

Self-assembled monolayers (SAMs) of perfluoroalkanethiols [CF3(CF2)xCH2CH2SH (x = 3, 5, 7, and 9)] on gold were characterized by x-ray photoelectron spectroscopy (XPS), near edge x-ray absorption fine structure (NEXAFS), and static time-of-flight secondary ion mass spectrometry (ToF-SIMS). Perfluoroalkanethiols of several chain lengths were synthesized using a known hydride reduction method for transforming commercially available perfluoroalkyliodides to corresponding perfluoroalkanethiols. This strategy provides improved product yields compared to other known routes based on hydrolysis from the common thioacetyl perfluoroalkyl intermediate. Angle-dependent XPS analysis revealed that CF3(CF2)xCH2CH2SH (x = 5, 7, and 9; F6, F8, and F10, respectively) SAMs on gold exhibited significant enrichment of the terminal CF3 group at the outer monolayer surface with the sulfur present as a metal-bound thiolate located at the monolayer-gold interface. XPS of the CF3(CF2)3CH2CH2SH (F4) monolayer revealed a thin film with a significant (>50%) amount of hydrocarbon contamination consistent with poorly organized monolayers, while the longest thiol (F10) showed XPS signals attributed to substantial ordering and anisotropy. ToF-SIMS spectra from all four SAMs contained molecular ions representative of the particular perfluorinated thiol used to prepare the monolayer. NEXAFS methods were used to determine degrees of ordering and average tilt for molecules comprising monolayers. The SAMs prepared from the longest (F10) thiols exhibited the highest degree of ordering with the molecular axis nearly perpendicular to the gold surface. The degree of ordering decreased significantly with decreasing length of the perfluorocarbon tail.

Biophysics↗
DOE OSTI2021

A universal wet-chemistry synthesis of solid-state halide electrolytes for all-solid-state lithium-metal batteries

Solid-state halide electrolytes have gained revived research interests owing to their high ionic conductivity and high-voltage stability. However, synthesizing halide electrolytes from a liquid phase is extremely challenging because of the vulnerability of metal halides to hydrolysis. In this work, ammonium-assisted wet chemistry is reported to synthesize various solid-state halide electrolytes with an exceptional ionic conductivity (>1 microsiemens per centimeter). Microstrain-induced localized microstructure change is found to be beneficial to lithium ion transport in halide electrolytes. Furthermore, the interfacial incompatibility between halide electrolytes and lithium metal is alleviated by transforming the mixed electronic/ionic conductive interface into a lithium ion–conductive interface. Such all-solid-state lithium-metal batteries (ASSLMBs) demonstrate a high initial coulombic efficiency of 98.1% based on lithium cobalt oxide and a high discharge capacity of 166.9 microampere hours per gram based on single-crystal LiNi 0.6 Mn 0.2 Co 0.2 O 2 . This work provides universal approaches in both material synthesis and interface design for developing halide-based ASSLMBs.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Regulation of translation by ribosomal RNA pseudouridylation

Pseudouridine is enriched in ribosomal, spliceosomal, transfer, and messenger RNA and thus integral to the central dogma. The chemical basis for how pseudouridine affects the molecular apparatus such as ribosome, however, remains elusive owing to the lack of structures without this natural modification. Here, we studied the translation of a hypopseudouridylated ribosome initiated by the internal ribosome entry site (IRES) elements. We analyzed eight cryo–electron microscopy structures of the ribosome bound with the Taura syndrome virus IRES in multiple functional states. We found widespread loss of pseudouridine-mediated interactions through water and long-range base pairings. In the presence of the translocase, eukaryotic elongation factor 2, and guanosine 5'-triphosphate hydrolysis, the hypopseudouridylated ribosome favors a rare unconducive conformation for decoding that is partially recouped in the ribosome population that remains modified at the P-site uridine. The structural principles learned establish the link between functional defects and modification loss and are likely applicable to other pseudouridine-associated processes.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2024

Changes in an enzyme ensemble during catalysis observed by high-resolution XFEL crystallography

Enzymes populate ensembles of structures necessary for catalysis that are difficult to experimentally characterize. We use time-resolved mix-and-inject serial crystallography at an x-ray free electron laser to observe catalysis in a designed mutant isocyanide hydratase (ICH) enzyme that enhances sampling of important minor conformations. The active site exists in a mixture of conformations, and formation of the thioimidate intermediate selects for catalytically competent substates. The influence of cysteine ionization on the ICH ensemble is validated by determining structures of the enzyme at multiple pH values. Large molecular dynamics simulations in crystallo and time-resolved electron density maps show that Asp 17 ionizes during catalysis and causes conformational changes that propagate across the dimer, permitting water to enter the active site for intermediate hydrolysis. ICH exhibits a tight coupling between ionization of active site residues and catalysis-activated protein motions, exemplifying a mechanism of electrostatic control of enzyme dynamics.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2024

Magnetic resonance insights into the heterogeneous, fractal-like kinetics of chemically recyclable polymers

Moving toward a circular plastics economy is a vital aspect of global resource management. Chemical recycling of plastics ensures that high-value monomers can be recovered from depolymerized plastic waste, thus enabling circular manufacturing. However, to increase chemical recycling throughput in materials recovery facilities, the present understanding of polymer transport, diffusion, swelling, and heterogeneous deconstruction kinetics must be systematized to allow industrial-scale process design, spanning molecular to macroscopic regimes. To develop a framework for designing depolymerization processes, we examined acidolysis of circular polydiketoenamine elastomers. We used magnetic resonance to monitor spatially resolved observables in situ and then evaluated these data with a fractal method that treats nonlinear depolymerization kinetics. This approach delineated the roles played by network architecture and reaction medium on depolymerization outcomes, yielding parameters that facilitate comparisons between bulk processes. These streamlined methods to investigate polymer hydrolysis kinetics portend a general strategy for implementing chemical recycling on an industrial scale.

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

Microbial sulfate reduction and organic sulfur formation in sinking marine particles

Climate change is driving an expansion of marine oxygen-deficient zones, which may alter the global cycles of carbon, sulfur, nitrogen, and trace metals. Currently, however, we lack a full mechanistic understanding of how oxygen deficiency affects organic carbon cycling and burial. In this work, we show that cryptic microbial sulfate reduction occurs in sinking particles from the eastern tropical North Pacific oxygen-deficient zone and that some microbially produced sulfide reacts rapidly to form organic sulfur that is resistant to acid hydrolysis. Particle-hosted sulfurization could enhance carbon preservation in sediments underlying oxygen-deficient water columns and serve as a stabilizing feedback between expanding anoxic zones and atmospheric carbon dioxide. A similar mechanism may help explain more-extreme instances of organic carbon preservation associated with marine anoxia in Earth history.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2021

Structural analysis of the PTEN:P-Rex2 signaling complex reveals how cancer-associated mutations coordinate to hyperactivate Rac1

The dual-specificity phosphatase PTEN functions as a tumor suppressor by hydrolyzing PI(3,4,5)P 3 to PI(4,5)P 2 to inhibit PI3K-AKT signaling and cellular proliferation. P-Rex2 is a guanine nucleotide exchange factor for Rho GTPases and can be activated by Gβγ subunits downstream of G protein–coupled receptor signaling and by PI(3,4,5)P 3 downstream of receptor tyrosine kinases. The PTEN:P-Rex2 complex is a commonly mutated signaling node in metastatic cancer. Assembly of the PTEN:P-Rex2 complex inhibits the activity of both proteins, and its dysregulation can drive PI3K-AKT signaling and cellular proliferation. Here, using cross-linking mass spectrometry and functional studies, we gained mechanistic insights into PTEN:P-Rex2 complex assembly and coinhibition. We found that PTEN was anchored to P-Rex2 by interactions between the PDZ-interacting motif in the PTEN C-terminal tail and the second PDZ domain of P-Rex2. This interaction bridged PTEN across the P-Rex2 surface, preventing PI(3,4,5)P 3 hydrolysis. Conversely, PTEN both allosterically promoted an autoinhibited conformation of P-Rex2 and blocked its binding to Gβγ. In addition, we observed that the PTEN-deactivating mutations and P-Rex2 truncations combined to drive Rac1 activation to a greater extent than did either single variant alone. These insights enabled us to propose a class of gain-of-function, cancer-associated mutations within the PTEN:P-Rex2 interface that uncouple PTEN from the inhibition of Rac1 signaling.

D’Andrea, Laura↗
DOE OSTI2025

Xylanolytic metabolism is regulated by coordination of transcription factors XynR and XylR in extremely thermophilic Caldicellulosiruptorales

ABSTRACT Global transcription factors (TFs) control metabolic processes in bacteria to efficiently utilize available carbon. The orderCaldicellulosiruptoraleshas drawn interest due to the ability of its members to degrade components of lignocellulosic biomass. Regulatory reconstruction ofAnaerocellum (f. Caldicellulosiruptor) besciiidentified two major global transcription factors for xylan utilization, XynR and XylR, and the corresponding putative transcription factor binding sites. Recombinant versions of XynR (LacI family) and XylR (ROK family) were subjected to fluorescence polarization (FP) and biolayer interferometry (BLI) analysis to confirm the predicted binding sites. Four XynR sites and two XylR sites were validated, accounting for 20 of 26 genes regulated by XynR and six of seven genes regulated by XylR. Bioinformatic analysis of the individual genes controlled by the two regulators showed an inter-dependent scheme for xylan conversion; the transport of xylooligosaccharides (XOS) is dependent on XylR, while enzymes responsible for hydrolysis are controlled by both regulators. For xylose catabolism by the xylose isomerase-xylulose kinase pathway, regulation is also split, with XylR controlling xylose isomerase and XynR controlling xylokinase. The XynR/XylR regulator pair withinA. besciiis conserved in all sequenced species ofCaldicellulosiruptorales, suggesting similarities in regulating linear xylan conversion. In other xylanolytic thermophiles, XylR homologs control xylan degradation, compared to just 6 out of 26 genes forA. bescii. These results show that two separate regulatory schemes (dual repression) are coordinated byA. besciito effectively regulate the hemicellulose inventory and xylan catabolism. IMPORTANCE To take full advantage of extreme thermophiles as platform metabolic engineering microorganisms, the tools for genetic manipulation must be further developed, and strategies that exploit a better understanding of metabolic regulation need to be discerned.Anaerocellum bescii, the most studied of the extremely thermophilic fermentative anaerobic bacteria that can utilize microcrystalline cellulose, can degrade microcrystalline cellulose and hemicellulose and has been metabolically engineered to convert the resulting sugars to products such as ethanol and acetone. For xylan, in particular, two major global transcription factors (TFs), XynR and XylR, play a role in sugar metabolism, although their predicted regulatory interdependence from bioinformatics analysis has not been elucidated experimentally. Here, fluorescence polarization (FP) and biolayer interferometry (BLI) were used to explore this issue to support metabolic engineering efforts aimed at improving carbohydrate processing to industrial chemicals.

Biotechnology & Applied Microbiology↗
DOE OSTI2022

Engineering Caldicellulosiruptor bescii with Surface Layer Homology Domain-Linked Glycoside Hydrolases Improves Plant Biomass Solubilization

Caldicellulosiruptor species hold promise as microorganisms that can solubilize the carbohydrate portion of lignocellulose and subsequently convert fermentable sugars into bio-based chemicals and fuels. Members of the genus have surface layer (S-layer) homology domain-associated glycoside hydrolases (SLH-GHs) that mediate attachment to biomass as well as hydrolysis of carbohydrates. Caldicellulosiruptor bescii , the most studied member of the genus, has only one SLH-GH.

Biotechnology & Applied Microbiology↗