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At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Feasibility of Process Intensification of Water-Gas Shift Reaction Using a Microreactor with Integrated Cooling

Hydrogen is an increasingly attractive low-carbon energy carrier for a variety of stationary and mobile applications. The water-gas shift (WGS) reaction is a key processing step used for large-scale hydrogen production via the steam methane reforming process. However, the thermodynamics and kinetics of the reaction are such that standard two-stage adiabatic reactors used in these systems are large, increasing catalyst volume and cost. To intensify the process and realize the economical distributed production of hydrogen, adiabatic WGS microreactors with integrated cooling directly regulate the reaction temperature via integrated coolant channels to promote higher conversion within a smaller reactor volume. This study investigates the conversion efficiency of a single WGS microchannel operating under such cooling conditions. A COMSOL Multiphysics model is developed and validated with isothermal experimental data from the literature. The model is then used to evaluate improvements in conversion efficiency when the reaction is cooled via a specified wall temperature profile. Lastly, the model is modified to include cooling channels with a secondary fluid that can practically achieve a similar conversion profile as the specified wall temperature profile previously applied. Initial results show that reactor conversion can be significantly increased by the inclusion of appropriate cooling and that there is a potential for the recovery of energy from the reaction stream that can be used for other applications within the overall process.

energy recovery↗
DOE OSTI2021

Whole Genome Sequencing Links Mycobacterium bovis From Cattle, Cheese and Humans in Baja California, Mexico

Mycobacterium bovis causes tuberculosis (TB) in cattle, which in turn can transmit the pathogen to humans. Tuberculosis in dairy cattle is of particular concern where the consumption of raw milk and dairy products is customary. Baja California (BCA), Mexico, presents high prevalence of TB in both cattle and humans, making it important to investigate the molecular epidemiology of the disease in the region. A long-term study was undertaken to fully characterize the diversity of M. bovis genotypes circulating in dairy cattle, cheese and humans in BCA by whole-genome sequencing (WGS). During a 2-year period, 412 granulomatous tissue samples were collected from local abattoirs and 314 cheese samples were purchased from local stores and vendors in BCA and sent to the laboratory for mycobacterial culture, histology, direct PCR and WGS. For tissue samples M. bovis was recovered from 86.8%, direct PCR detected 90% and histology confirmed 85.9% as mycobacteriosis-compatible. For cheese, M. bovis was recovered from 2.5% and direct PCR detected 6% of the samples. There was good agreement between diagnostic tests. Subsequently, a total of 345 whole-genome SNP sequences were obtained. Phylogenetic analysis grouped these isolates into 10 major clades. SNP analysis revealed putative transmission clusters where the pairwise SNP distance between isolates from different dairies was ≤3 SNP. Also, human and/or cheese isolates were within 8.45 (range 0–17) and 5.8 SNP (range 0–15), respectively, from cattle isolates. Finally, a comparison between the genotypes obtained in this study and those reported previously suggests that the genetic diversity of M. bovis in BCA is well-characterized, and can be used to determine if BCA is the likely source of M. bovis in humans and cattle in routine epidemiologic investigations and future studies. In conclusion, WGS provided evidence of ongoing local transmission of M. bovis among the dairies in this high-TB burden region of BCA, as well as show close relationships between isolates recovered from humans, cheese, and cattle. This confirms the need for a coordinated One Health approach in addressing the elimination of TB in animals and humans. Overall, the study contributes to the knowledge of the molecular epidemiology of M. bovis in BCA, providing insight into the pathogen's dynamics in a high prevalence setting.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2022

A Study of Support Effects for the Water-Gas-Shift Reaction over Cu

The water–gas-shift (WGS) reaction was studied on a series of supported Cu catalysts in which the MgAl 2 O 4 (MAO) support was modified by depositing ZnO, CeO 2 , Mn2O 3 and CoO using Atomic Layer Deposition (ALD). Addition of Cu by one ALD cycle gave rise to catalysts with nominally 1-wt% Cu. A 1.1-wt% Cu/MAO catalyst prepared by ALD exhibited twice the dispersion but ten times the WGS activity of a 1-wt% Cu/MAO catalyst prepared by impregnation, implying that the reaction is structure sensitive. However, Cu catalysts prepared with the ZnO, CeO 2 , and Mn 2 O 3 films showed negligible differences from that of the Cu/MAO catalyst, implying that these oxides did not promote the reaction. Cu catalysts prepared on the CoO film showed a slightly lower activity, possibly due to alloy formation. The implications of these results for the development of better WGS catalysts is discussed.

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

Identification and Characterization of ten Escherichia coli Strains Encoding Novel Shiga Toxin 2 Subtypes, Stx2n as Well as Stx2j, Stx2m, and Stx2o, in the United States

The sharing of genome sequences in online data repositories allows for large scale analyses of specific genes or gene families. This can result in the detection of novel gene subtypes as well as the development of improved detection methods. Here, we used publicly available WGS data to detect a novel Stx subtype, Stx2n in two clinical E. coli strains isolated in the USA. During this process, additional Stx2 subtypes were detected; six Stx2j, one Stx2m strain, and one Stx2o, were all analyzed for variability from the originally described subtypes. Complete genome sequences were assembled from short- or long-read sequencing and analyzed for serotype, and ST types. The WGS data from Stx2n- and Stx2o-producing STEC strains were further analyzed for virulence genes pro-phage analysis and phage insertion sites. Nucleotide and amino acid maximum parsimony trees showed expected clustering of the previously described subtypes and a clear separation of the novel Stx2n subtype. WGS data were used to design OMNI PCR primers for the detection of all known stx1 (283 bp amplicon), stx2 (400 bp amplicon), intimin encoded by eae (221 bp amplicon), and stx2f (438 bp amplicon) subtypes. These primers were tested in three different laboratories, using standard reference strains. An analysis of the complete genome sequence showed variability in serogroup, virulence genes, and ST type, and Stx2 pro-phages showed variability in size, gene composition, and phage insertion sites. The strains with Stx2j, Stx2m, Stx2n, and Stx2o showed toxicity to Vero cells. Stx2j carrying strain, 2012C-4221, was induced when grown with sub-inhibitory concentrations of ciprofloxacin, and toxicity was detected. Taken together, these data highlight the need to reinforce genomic surveillance to identify the emergence of potential new Stx2 or Stx1 variants. The importance of this surveillance has a paramount impact on public health. Per our description in this study, we suggest that 2017C-4317 be designated as the Stx2n type-strain.

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRSDate not supplied

Benchmarking Computational Tools for Calling SNPs and Indels in Complex Microbial Populations

The NASA BioNutrients missions seek to understand the suitability of microorganisms for bioproduction during space flight. One topic of interest is the stability of microbial genomes during long-term ambient storage and subsequent rehydration and growth. To address these questions, samples from 8 species were flown to ISS for 5 years of desiccated storage at ambient temperature (Stasis Packs) and 2 species were packaged along with powdered media inside a bioreactor system to allow hydration and growth in microgravity (Production Packs). For both systems, Whole Genome Sequencing (WGS) of the DNA extracted from the returned samples and paired ground controls will be conducted to identify changes in genome stability due to time, storage conditions and growth in space. Across the technical replicates, ground controls, 10 timepoints, and multiple experimental conditions, ~300 samples have been selected for initial analysis with WGS sequencing to 100x coverage. A flexible and resource efficient mutation calling pipeline is needed to process this large dataset and allow for comparisons between species. Many bioinformatics tools for calling Indels and Single Nucleotide Variants (SNVs) are designed for use with pure isolates, where true variations from the reference genome are expected to dominate the reads aligning to the location of mutation. In contrast, DNA from the Stasis Pack (SP) samples was collected directly after recovery from desiccated storage and the Production Pack (PP) samples were collected after fermentation. In this context, reads with mutations are expected to be less frequent than reads that align with the reference genome, as each sample will include multiple lines of cells. Thus, BioNutrients samples are expected to be similar to samples from cancer cell or “pooled” sequencing approaches. In preparation for the analysis of the BioNutrients samples, we have tested three mutation calling tools (GATK for Microbes, BreSeq and DiscoSNP) designed for complex samples. A challenge of validating mutation identification pipelines is a lack of “Ground Truth” datasets, especially for complex samples. To compare these three tools, we sought to identify mutations in pre-existing WGS data collected from populations of Chlamydomonas reinhardtii that were exposed to UV mutagenesis and growth in LEO as part of the Space Algae-1 mission. Here we present a summary of these tools against the analysis originally conducted using the CRISP tool. Critical metrics are compared such as runtime, the number of SNPs, the number and size of Indels, and patterns of transversion and transitions identified by each tool are reported. By sharing these benchmarking results collected in support of the BioNutrients mission, we aim to guide others seeking to identify SNVs in similarly complex microbial samples.

Biology↗
DOE OSTI2022

Integrated Water-Gas-Shift Pre-combustion Carbon Capture Process

TDA Research, Inc (TDA) has developed a highly efficient integrated WGS pre-combustion carbon capture technology and demonstrated its techno-economic viability for use in the Integrated Gasification Combined Cycle (IGCC) power plants that process coal. The new system uses a warm gas CO 2 scrubber integrated with a Water-Gas-Shift (WGS) catalyst to capture greater than 90% of the carbon emissions, which does not increase the cost of electricity (COE) as much as conventional carbon capture technologies.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2021

Economizing on Precious Metals in Three-Way Catalysts: Thermally Stable and Highly Active Single-Atom Rhodium on Cera for NO Abatement under Dry and Industrially Relevant Conditions

We show for the first time that atomically dispersed Rh cations on ceria, prepared via high-temperature atom trapping synthesis, are the active species for (CO+NO) reaction. This provides a direct link with the organometallic homogeneous Rh(I) complexes capable of catalyzing dry (CO+NO) reaction but without the stability concern. In particular, thermally stable Rh cations in 0.1wt% Rh1/CeO2 achieve full NO conversion with a TOF of ~ 330 hr-1 per Rh atom at 120 °C. Under dry conditions, the main product above 100 °C is N2 with N2O being the minor product. The presence of water promotes low-temperature activity of 0.1wt% Rh1/CeO2 starting at 50 °C with full NO conversion at ~120 °C. In the case with the wet stream, however, ammonia and nitrogen are the main products with only minor N2O amounts. NH3 formation at such low temperatures is attractive because of the potential to use this as a passive SCR system. Because of the uniformity of Rh ions on the support, we are able to observe the intermediates of (CO+NO) reaction via infrared measurements on Rh cations on zeolite and ceria. Furthermore, we show that ammonia formation correlates with the WGS activity of the material and thus, rhodium hydride Rh-H species are involved in this reaction: we detect Rh(CO)Hx species on ceria using isotopic IR measurements. These findings provide new mechanistic understanding for the catalytically active species in TWC catalysis and open up a new avenue for the synthesis of novel emissions control catalysts with 100% atom economy of ultra-expensive precious metals such as Rh.

Khivantsev, Konstantin↗
DOE OSTI2020

A reactive separation process for pre-combustion CO 2 capture employing oxygen-blown coal gasifier off-gas

In this paper, we present an experimental study of a reactive separation system, consisting of a membrane reactor (MR) and an adsorptive reactor (AR) operating in tandem, with the MR’s reject stream serving as the AR’s feed. We investigates the feasibility of applying this MR-AR system for high-purity H 2 production and simultaneous CO 2 capture via the water gas shift (WGS) reaction in the context of Integrated Gas Combined Cycle (IGCC) power generation employing oxygen-blown gasifier syngas from biomass and coal. We previously studied this MR-AR system for the IGCC process employing air-blown gasifier syngas, for which it demonstrated good performance, attaining high conversion exceeding equilibrium, producing ultra-pure H 2 for power generation, and a CO 2 stream ready for sequestration. In this study, we focus on oxygen-blown gasifier off-gas that contains no N 2 , with composition distinctly different from the air-blown gasifier syngas which has a large N 2 content. We employ a carbon molecular sieve membrane (CMSM), a commercial sour-shift WGS catalyst, and a hydrotalcite (HTC) adsorbent. We carried out experiments to determine membrane performance and to identify promising operating conditions in an IGCC-relevant environment. The CMSM proved robust during a long-term (~344 hr run) experimental run under high temperature and pressure maintaining a high He/N 2 selectivity (~170). Multi-cycle runs were carried out during which the MR-AR system displayed superior performance to that of a PBR, by producing a high purity H 2 product directly usable in power generation. Therefore, the findings from this study demonstrate the ability of the MR-AR system to operate stably for a broad range of gasifier off-gas compositions, and indicate its potential for integration into IGCC plants for power generation with CO 2 capture.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2020

Enriched hydrogen production over air and air-steam fluidized bed gasification in a bubbling fluidized bed reactor with CaO: Effects of biomass and bed material catalyst

Gasification is one of the methods of generating biopower or biofuels from biomass waste. In this study, a benchscale fluidized bed reactor was used for biomass air and air-steam gasification. Gasification was performed under constant operating conditions (~780 °C, equivalence ratio = ~0.32) to investigate the effect of biomass (switchgrass, pine residues) and bed materials (sand, CaO+ sand, Al 2 O 3 , and CaO + Al 2 O 3 ). All gasification products, such as synthesis gas (syngas), contaminant gases, tar, and biochar (solid) were comprehensively analyzed. The composition of biomass significantly impacted CO and H 2 yield from volatile combustible matter and fixed carbon. Further, the presence of CaO made the condition favorable for the water-gas shift (WGS) reaction combined with the CO 2 carbonation reaction, which increased H 2 concentration. Additional steam with CaO increased H 2 concentration closer to 50% (N 2 free condition) through the combination reactions of steam hydrocarbon reforming and WGS by producing 44 g H 2 /kg dry biomass and 143 g CO /kg dry biomass . The usage of steam reduced the overall yield of contaminant gases, whereas the usage of CaO or Al 2 O 3 decreased the amount of gasification tar by approximately 5.8–6.5 g tar /kg dry biomass . In conclusion, this study can provide valuable experimental data for biomass waste to produce better quality syngas.

08 HYDROGEN↗
DOE OSTI2020

A carbon molecular sieve membrane-based reactive separation process for pre-combustion CO 2 capture

In this study, we discuss a hybrid system combining a membrane reactor (MR) and an adsorptive reactor (AR), with the MR's reject stream serving as the AR's feed. We apply this system for the water gas shift (WGS) reaction for H 2 generation and simultaneous CO 2 capture in the context of the Integrated Gas Combined Cycle (IGCC) process for power generation from coal and biomass. This MR-AR system attains a high conversion exceeding equilibrium, produces a pure H 2 product for power generation, and delivers a high-pressure CO 2 stream ready for sequestration. Specifically, in our study we use carbon molecular sieve membranes (CMSMs) and a commercial sour-shift WGS catalyst. Lab experiments were carried-out to determine the membrane characteristics, and the MR performance under IGCC-relevant conditions, i.e., for temperatures up to 250 °C and pressures up to 25 bar, employing a model coal gasifier syngas. The CMSM and the catalyst have displayed robust and stable performance during a long-term run (~750 h of syngas exposure). We evaluated the MR-AR system in multi-cycle runs and it has demonstrated superior performance to that of a conventional packed-bed reactor, producing a high-purity H 2 product directly useable in a turbine for power generation. We conclude from the study, that the CMSM-based MR-AR system is a good candidate technology for environmentally-benign power generation. We are currently constructing a pilot-scale system for field demonstration of the technology.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Insights into the Mechanism of Methanol Steam Reforming Tandem Reaction over CeO 2 Supported Single-Site Catalysts

We demonstrated how the special synergy between a noble metal single site and neighboring oxygen vacancies provides an "ensemble reaction pool" for high hydrogen generation efficiency and carbon dioxide (CO 2 ) selectivity of a tandem reaction: methanol steam reforming. Specifically, the hydrogen generation rate over single site Ru 1 /CeO 2 catalyst is up to 9360 mol H 2 per mol Ru per hour (579 mL H2 g Ru -1 s -1 ) with 99.5% CO 2 selectivity. Reaction mechanism study showed that the integration of metal single site and O vacancies facilitated the tandem reaction, which consisted of methanol dehydrogenation, water dissociation, and the subsequent water gas shift (WGS) reaction. In addition, the strength of CO adsorption and the reaction activation energy difference between methanol dehydrogenation and WGS reaction play an important role in determining the activity and CO 2 selectivity. Our study paves the way for the further rational design of single site catalysts at the atomic scale. Furthermore, the development of such highly efficient and selective hydrogen evolution systems promises to deliver highly desirable economic and ecological benefits.

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

Activation and Conversion of Methane to Syngas over ZrO 2 /Cu(111) Catalysts near Room Temperature

Enzymatic systems achieve the catalytic conversion of methane at room temperature under mild conditions. Here, in this study, varying thermodynamic and kinetic parameters, we show that the reforming of methane by water (MWR, CH 4 + H 2 O → CO + 3H 2 ) and the water-gas shift reaction (WGS, CO + H 2 O → H 2 + CO 2 ), two essential processes to integrate fossil fuels toward a H2 energy loop, can be achieved on ZrO 2 /Cu(111) catalysts near room temperature. Measurements of ambient-pressure X-ray photoelectron spectroscopy and mass spectrometry, combined with density functional calculations and kinetic Monte Carlo simulations, were used to study the behavior of the inverse oxide/metal catalysts. The superior performance is associated with a unique zirconia-copper interface, where multifunctional sites involving zirconium, oxygen, and copper work coordinatively to dissociate methane and water at 300 K and move forward the MWR and WGS processes.

03 NATURAL GAS↗
DOE OSTI2021

Mechanism of methanol synthesis on Ni(110)

Planewave density functional theory (DFT-PW91) calculations are employed to study the methanol synthesis through CO 2 and CO hydrogenation, as well as the two side reactions: the water gas shift (WGS) reaction and formic acid formation, on Ni(110). For the WGS reaction on Ni(110), we find that the redox mechanism is favored over the carboxyl-mediated mechanism. We show that the formate pathway is the dominant one for formic acid formation. For methanol synthesis through CO 2 and CO hydrogenation on Ni(110), our results reveal that the formic-acid- and dioxymethylene-mediated pathways coexist, in contrast to methanol synthesis on Cu(111) where the formic-acid-mediated pathway dominates. We also find that on Ni(110), hydrogenation of CH 2 O* to CH 3 O* and that to CH 2 OH* both contribute to MeOH synthesis. Based on the derived energetics, we ascertain that CH 3 O* hydrogenation to CH 3 OH* is likely the rate-determining step along the CH 3 O* pathway on Ni(110). Remarkably, CH 3 O* hydrogenation can be facilitated by the presence of HCO*, demonstrating the promotional effect of CO. Furthermore, we show that CO also participates in methanol synthesis directly via its hydrogenation to HCO* and further to CH 2 O*. Additional microkinetic modeling by considering feed composition and reaction conditions would provide further mechanistic insights into methanol synthesis on Ni(110).

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

Echogenic Segmentation for Ultrasonic Measurements of Spatially Distributed Properties in Solids

An ultrasonic (US) pulse propagating between transducer-receiver responds cumulatively to distributed material properties it encounters, such as temperature distribution. Such convolution makes the unique reconstitution of distributions impossible short of applying tomographic techniques. However, spatial heterogeneity in material properties is readily revealed by segmenting the US propagation path with echogenic features (EF), producing a train of echoes delayed as a function of segmentally localized properties. Unfortunately, in low attenuating waveguides (WGs), primary and trailing echoes (TE) interfere, limiting the number, density, and placement of EFs we can use. We report the design guidelines for creating US-segmented WGs for measuring distributed properties, in which the impact of TEs is minimized or eliminated. Two waveguide designs using these principles have been tested in spatially distributed temperature measurements in high-temperature or restrictive environments.

Walton, Kenneth↗
DOE OSTI2023

High-throughput functional trait testing for bacterial pathogens

Functional traits are characteristics that affect the fitness and metabolic function of a microorganism. There is growing interest in using high-throughput methods to characterize bacterial pathogens based on functional virulence traits. Traditional methods that phenotype a single organism for a single virulence trait can be time consuming and labor intensive. Alternatively, machine learning of whole-genome sequences (WGS) has shown some success in predicting virulence. However, relying solely on WGS can miss functional traits, particularly for organisms lacking classical virulence factors. We propose that high-throughput assays for functional virulence trait identification should become a prominent method of characterizing bacterial pathogens on a population scale. This work is critical as we move from compiling lists of bacterial species associated with disease to pathogen-agnostic approaches capable of detecting novel microbes. We discuss six key areas of functional trait testing and how advancing high-throughput methods could provide a greater understanding of pathogens.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2022

Characterization of a 2016-2017 Human Seasonal H3 Influenza A Virus Spillover Now Endemic to U.S. Swine

In 2017, the Iowa State University Veterinary Diagnostic Laboratory detected a reverse-zoonotic transmission of a human seasonal H3 influenza A virus into swine (IAV-S) in Oklahoma. Pairwise comparison between the recently characterized human seasonal H3 IAV-S (H3.2010.2) hemagglutinin (HA) sequences detected in swine and the most similar 2016–2017 human seasonal H3 revealed 99.9% nucleotide identity. To elucidate the origin of H3.2010.2 IAV-S, 45 HA and 27 neuraminidase (NA) sequences from 2017 to 2020 as well as 11 whole-genome sequences (WGS) were genetically characterized. Time to most recent common human ancestor was estimated between August and September 2016. The N2 NA was of human origin in all but one strain from diagnostic submissions with NA sequences, and the internal gene segments from WGS consisted of matrix genes originating from the 2009 pandemic H1N1 and another 5 internal genes of triple reassortant swine origin (TTTTPT). Pigs experimentally infected with H3.2010.2 demonstrated efficient nasal shedding and replication in the lungs, mild pneumonia, and minimal microscopic lung lesions and transmitted the virus to indirect contact swine. Antigenically, H3.2010.2 viruses were closer to a human seasonal vaccine strain, A/Hong Kong/4801/2014, than to the H3.2010.1 human seasonal H3 viruses detected in swine in 2012. This was the second sustained transmission of a human seasonal IAV into swine from the 2010 decade after H3.2010.1. Monitoring the spillover and detection of novel IAV from humans to swine may help vaccine antigen selection and could impact pandemic preparedness.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2023

First report of Staphylococcus pseudintermedius ST71-SCCmec III and ST45-ΨSCCmec57395 from canine pyoderma in Argentina

Abstract Staphylococcus pseudintermedius is an opportunistic pathogen commonly associated with skin infections in dogs. Twenty-three methicillin-resistant S. pseudintermedius (MRSP) isolated in Argentina from dogs with pyoderma were analyzed using whole genome sequencing (WGS) and classified into sequence types (ST) by multilocus sequence typing (MLST) and staphylococcal chromosome cassette mec (SCC mec ) types. Based on the WGS analysis, MLST, and SCC mec type results, we report for the first time in Argentina two MRSP strains, one each, belonging to ST71-SCC mec III and ST45-ΨSCC mec 57395 from dogs with pyoderma. We also identified seven isolates with ST339, which had been previously reported in only two isolates in Argentina. Additionally, we identified ten MRSP isolates harboring variants of the SCC mec V found in S. aureus , seven SCC mec V (5C2&5) with two ccr C1 recombinases, and three SCC mec V (5C2) with one ccr C1 recombinase. Our findings provide important insights into the evolution and geographic spread of these hypervirulent dominant clones that threaten the health of our companion animals and represent a significant risk for zoonotic infections.

Srednik, Mariela E.↗
DOE OSTI2026

Data for Engineering and Evolution of Yarrowia lipolytica for Producing Lipids from Lignocellulosic Hydrolysates

Yarrowia lipolytica , an oleaginous yeast, shows promise for industrial fermentation due to its robust acetyl-CoA flux and well-developed genetic engineering tools. However, its lack of an active xylose metabolism restricts the conversion of cellulosic sugars to valuable products. To address this, metabolic engineering, and adaptive laboratory evolution (ALE) were applied to the Y. lipolytica PO1f strain, resulting in an efficient xylose-assimilating strain (XEV). Whole-genome sequencing (WGS) of the XEV followed by reverse engineering revealed that the amplification of the heterologous oxidoreductase pathway and a mutation in the GTPase-activating protein gene (YALI0B12100g) might be the primary reasons for improved xylose assimilation in the XEV strain. When a sorghum hydrolysate was used, the XEV strain showed superior xylose consumption and lipid production compared to its parental strain (X123). This study advances our understanding of xylose metabolism in Y. lipolytica and proposes effective metabolic engineering strategies for optimizing lignocellulosic hydrolysates.

Hydrolysate↗