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At least 55 records · Page 3

Rewiring metabolism of Clostridium thermocellum for consolidated bioprocessing of lignocellulosic biomass poplar to produce short-chain esters

Consolidated bioprocessing (CBP) of lignocellulosic biomass uses cellulolytic microorganisms to enable enzyme production, saccharification, and fermentation to produce biofuels, biochemicals, and biomaterials in a single step. However, understanding and redirecting metabolisms of these microorganisms compatible with CBP are limited. Here, a cellulolytic thermophile Clostridium thermocellum was engineered and demonstrated to be compatible with CBP integrated with a Co-solvent Enhanced Lignocellulosic Fractionation (CELF) pretreatment for conversion of hardwood poplar into short-chain esters with industrial use as solvents, flavors, fragrances, and biofuels. The recombinant C. thermocellum engineered with deletion of carbohydrate esterases and stable overexpression of alcohol acetyltransferases improved ester production without compromised deacetylation activities. These esterases were discovered to exhibit promiscuous thioesterase activities and their deletion enhanced ester production by rerouting the electron and carbon metabolism. Ester production was further improved up to 80-fold and ester composition could be modulated by deleting lactate biosynthesis and using poplar with different pretreatment severity.

59 BASIC BIOLOGICAL SCIENCES↗

Development of a universal method for high yield of furfural and hydrogen from raw lignocellulosic biomass

In order to develop a universal method for the co-production of furfural and hydrogen from raw lignocellulosic biomass, three types of substrates (maple wood, wheat straw, and tall fescue) were investigated, integrating chemical and electrochemical technologies. The results show both furfural and pure hydrogen were produced from all the biomass substrates, and the substrate type, composition, concentration, and size all affected furfural and hydrogen production. The highest furfural production of 154 mg g -1 substrate was achieved from wheat straw. The highest conversion rate of 67% for the waste furfural residue was realized, and 335 ml pure hydrogen per gram of furfural residue with a Faradaic efficiency of 99.3% was obtained with a new electrolytic cell. A reaction mechanism for hydrogen evolution from furfural residue and a rule for co-production of furfural and hydrogen from raw biomass were proposed. The facts show that a promising universal method for the co-production of furfural and hydrogen from lignocellulosic biomass has been developed.

08 HYDROGEN↗

Structure-guided utilization of lignocellulose for catalysis, energy, and biomaterials

As a complex composite of cellulose, hemicellulose, and lignin, plant lignocellulose has long served as a major resource for biomass conversion, materials engineering, and bio-based product development. High-resolution structural insights enabled by solid-state nuclear magnetic resonance (ssNMR) now allow the mapping of polymer interfaces, identification of functional group accessibility, and tracking of molecular organization during processing, all of which are critical factors for optimizing catalytic strategies. These insights could drive transformative progress in lignocellulose-based applications, including selective depolymerization, improved pretreatment design, and efficient upcycling of lignin into resins, plastics, and biomedical materials. In industry-relevant contexts, such as biofuel generation and renewable material manufacturing, understanding the hydration dynamics, cross-linking patterns, and structural heterogeneity is also essential. The ability to visualize these features in native biomass presents a unique opportunity to develop new strategies for sustainability and performance. As the structural toolbox continues to expand, it is becoming a central enabler for innovations in renewable energy, green chemistry, and advanced bioproducts.

bioproduct↗

Deep Eutectic Solvents for Efficient Fractionation of Lignocellulose to Produce Uncondensed Lignin and High-Quality Cellulose

Simultaneously inhibiting lignin condensation and cellulose degradation remains a major challenge for achieving holistic valorization of lignocellulose. Here, we developed a deep eutectic solvent (DES), composed of l-cysteine (Cys) and lactic acid (LA), to fractionate both uncondensed lignin and high-quality cellulose from eucalyptus wood by leveraging the unique properties of Cys, i.e., highly nucleophilic groups (–SH) and hydrogen bond acceptor/donor groups (–NH 2 and –COOH). The nucleophilic –SH in Cys effectively quenches the benzylic carbocations (C α + ions, formed at the benzylic sites of lignin) that lead to lignin condensation. This enables the high yield of uncondensed lignin (81%) with high retention of β–O–4 bonds (up to 90%). The separated uncondensed lignin is further depolymerized to prepare monophenols in a satisfactory 43% yield, equivalent to 73% of the theoretical yield. Moreover, the –NH 2 and –COOH groups in Cys form extensive hydrogen bonds with the hydroxyl groups in cellulose, thus decreasing the interaction energy of DES on cellulose. As a result, the cellulose achieves an astonishing 99% retention and maintains a high degree of polymerization of 1160. The obtained high-quality cellulose is further conversed into cellulose nanofibers for strong and transparent films. Furthermore, this study provides new insights into the efficient separation of uncondensed lignin and high-quality cellulose from lignocellulose by a novel DES system.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Evaluating the Transport Mechanism for Lignocellulosic Inhibitors in Zymomonas mobilis

The conversion of lignocellulosic biomass to biofuels and bioproducts is limited by small inhibitory molecules generated during the pretreatment process. The diverse compounds within the cell wall hydrolysate including aldehydes, carboxylic acids, phenolics, and alcohols inhibit microbial growth by disrupting microbial membranes. Although Zymomonas mobilis combines high ethanol productivity with hopanoid-rich membranes that confer solvent tolerance, hydrolysate compounds still inhibit microbial growth. One proposed mitigation strategy is to pump these molecules out through active transport processes, reducing direct toxicity. However, if passive permeation rates are high, active transport would create a futile cycle where the exported molecules diffuse back in, creating a net drag on fitness. To investigate this hypothesis, we measure the passive permeation for thirty-three lignocellulose derived compounds using atomistic molecular dynamics simulations with enhanced sampling. Permeability coefficients determined spanned more than eight orders of magnitude driven largely by the balance between hydrophobicity and polarity. Hydrophobic inhibitors such as aromatic acids, aldehydes, and short chain alcohols readily partitioned into the membrane and showed high permeability consistent with rapid passive influx and strong toxicity. Most polar molecules have lower but still appreciable permeation rates, with only the most polar sugars having low permeabilities. By integrating these predictions together with hydrolysate composition information, we find that most of these molecules are so permeable that futile cycles where passive permeation overwhelms efflux is highly likely. These findings provide a predictive framework for strain engineering, highlighting that, for highly permeable inhibitors, reducing extracellular inhibitor concentrations through hydrolysate detoxification, pretreatment optimization, or dilution may be necessary to mitigate futile cycling and improve microbial productivity in industrial biorefineries.

Zymomonas mobilis↗

Improving tolerance of yeast to lignocellulosic-derived feedstocks and products

Combined substrate-product toxicity remains one of the main obstacles hampering the scale-up and cost-effectiveness of bioprocesses harnessing lignocellulosic feedstocks, the most abundant, renewable terrestrial resource. Hydrolytic pretreatments release numerous inhibitors impinging on cell viability: the three most acute to yeast S. cerevisiae (the industry dominant biocatalyst) — and universal to all plant sources — are furfural, hydroxymethylfurfural (HMF), and acetic acid. Likewise, desired fermentation products, such as fuel ethanol or commodity organic acids, are toxic to microbes, typically via unknown biological mechanisms. Here, we have engineered both hydrolysate and end-product tolerance in yeast by combining previously-shown alcohol protective modifications with evolved genetic activities targeting the major pretreatment inhibitors. When tested on a wide sampling of genuine lignocellulosic feedstocks, ethanol production increased by >30% on average to titers >100 g/L, achieving parity with clean-sugar equivalents where conditions permit. Furthermore, we designed the tolerance capability to be fully transferable to pre-existing metabolic chassis strains. As such, we “drop-in” hydrolysate competence into one producing lactic acid, demonstrating the first-ever production of a cellulosic plastic at industrial titers. Our advances thus renew the potential of cellulosic biomass utilization for sustainable fuel and non-fuel products at scale.

09 BIOMASS FUELS↗

Single-molecule imaging of lignocellulose deconstruction by SCATTIRSTORM microscopy

The goal of this project is to build a multimodal optical microscope to measure the binding, processive degradation, and pausing behaviors of cellulases as they interact with and degrade both synthetic and naturally occurring lignocellulosic walls. To achieve this, we will use high spatio-temporal single-molecule imaging to track cellulases, while visualizing specific molecular components of cellulose, lignin and hemicellulose, that make up their lignocellulose substrate. The microscope will combine Interferometric Scattering (iSCAT), which provides unprecedented spatiotemporal resolution; Total Internal Reflection Fluorescence (TIRF), which provides single-molecule resolution of multiple fluorophore-labeled molecules; and Stochastic Reconstruction (STORM), which allows for three-dimensional super-resolution imaging of intact plant cell walls during degradation. Initial studies will investigate cellulase dynamics on in vitro-assembled cell wall analogs, and later work will progress to using native plant cell walls.

09 BIOMASS FUELS↗

A Multiomic Approach to Understand How Pleurotus eryngii Transforms Non-Woody Lignocellulosic Material

Pleurotus eryngii is a grassland-inhabiting fungus of biotechnological interest due to its ability to colonize non-woody lignocellulosic material. Genomic, transcriptomic, exoproteomic, and metabolomic analyses were combined to explain the enzymatic aspects underlaying wheat–straw transformation. Up-regulated and constitutive glycoside–hydrolases, polysaccharide–lyases, and carbohydrate–esterases active on polysaccharides, laccases active on lignin, and a surprisingly high amount of constitutive/inducible aryl–alcohol oxidases (AAOs) constituted the suite of extracellular enzymes at early fungal growth. Higher enzyme diversity and abundance characterized the longer-term growth, with an array of oxidoreductases involved in depolymerization of both cellulose and lignin, which were often up-regulated since initial growth. These oxidative enzymes included lytic polysaccharide monooxygenases (LPMOs) acting on crystalline polysaccharides, cellobiose dehydrogenase involved in LPMO activation, and ligninolytic peroxidases (mainly manganese-oxidizing peroxidases), together with highly abundant H2O2-producing AAOs. Interestingly, some of the most relevant enzymes acting on polysaccharides were appended to a cellulose-binding module. This is potentially related to the non-woody habitat of P. eryngii (in contrast to the wood habitat of many basidiomycetes). Additionally, insights into the intracellular catabolism of aromatic compounds, which is a neglected area of study in lignin degradation by basidiomycetes, were also provided. The multiomic approach reveals that although non-woody decay does not result in dramatic modifications, as revealed by detailed 2D-NMR and other analyses, it implies activation of the complete set of hydrolytic and oxidative enzymes characterizing lignocellulose-decaying basidiomycetes.

59 BASIC BIOLOGICAL SCIENCES↗

Biocompatible organosolv fractionation via a novel alkaline lignin-first strategy towards lignocellulose valorization

Simultaneous valorization of both carbohydrate and lignin fractions in lignocellulose remains a great challenge. Herein, a novel lignin-first strategy using triethylene glycol (TEG) under alkaline conditions for effective biomass fractionation producing highly digestible carbohydrates and reactive lignin was developed. Delignification was over 80% and fermentable sugar yields were close to 90% after pretreatment at 90°C. The biocompatibility of TEG allowed direct enzymatic hydrolysis of the solid residue without washing, thus minimizing wastewater generation. Furthermore, the obtained lignin (TEGL) had an uncondensed structure with well-preserved β-O-4 linkage, leading to near-equal aromatic monomer yields compared to cellulolytic enzyme lignin after catalytic-free pyrolysis, demonstrating high valorization potential. Finally, the proposed TEG solvent system is promising for a green and sustainable biorefinery process to achieve the complete utilization of lignocellulose.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Beneficial effect of surfactant in adsorption/desorption of lignocellulose-degrading enzymes on/from lignin with different structure

Nonionic surfactant Tween 80 is effective in alleviating the adsorption of lignocellulose-degrading enzymes onto lignin. However, the impacts of lignin structural characteristics on this mitigation effect of Tween 80 were still not clear. Herein, effects of Tween 80 on cellulase and xylanase adsorption on different enzymatic residual lignins (ERLs) and poplar samples were investigated. Besides, effects of Tween 80 on desorption of the two enzyme preparations from different ERLs and poplar samples were also evaluated. By adding Tween 80, the inhibition of ERLs to cellulase hydrolysis was offset and the positive role of Tween 80 in Avicel hydrolysis with presence of ERLs was more effective. Binding strength of cellulase with ERLs was alleviated from 236.0 – 410.9 to 43.9 – 116.6 mL/g after adding 0.5 mg/mL Tween 80. When ERLs was more hydrophobic and had more condensed phenolic OH, the alleviation effect of Tween 80 on cellulase adsorption on ERLs was intensified but its positive effect on enhancing cellulase desorption was weakened. Tween 80 was effective in increasing xylanase activity and preventing xylanase deactivation. Further, with the increase of lignin content and phenolic OH in pretreated poplar, the effect of Tween 80 in alleviating xylanase adsorption on poplar samples was intensified but the effect in enhancing xylanase desorption from poplar samples was weakened. The results provided distinct findings to understand the interaction between Tween 80 and cellulase/xylanase in enzymatic saccharification of lignocelluloses.

59 BASIC BIOLOGICAL SCIENCES↗

Comparative transcriptomics of CAZy enzymes in white- and brown-rot agaricomycetes: Evolutionary insights into lignocellulose degradation and the relevance of GH16 glycoside hydrolase functional divergence

White-rot and brown-rot fungi (WRF and BRF, respectively) decompose lignocellulose, the main structural component of plant biomass, through distinct mechanisms. This study examines the transcriptomic responses of three WRF species (Pleurotus ostreatus, Phanerochaete chrysosporium, and Heterobasidion irregulare) and two BRF species (Fomitopsis schrenkii and Rhodonia placenta) grown on poplar wood (W) and glucose (G) as sole carbon sources. RNA-seq analysis revealed upregulation of carbohydrate-active enzymes (CAZymes) linked to lignocellulose degradation. WRF displayed a broader enzymatic repertoire, whereas BRF employed a more selective approach. Among these responses, GH16 glycoside hydrolases were consistently upregulated across all species, including BRF. Since GH16 enzymes are involved in both plant hemicellulose modification and cell wall remodeling, their wood-induced expression may reflect multiple processes rather than a single conserved wood-decay mechanism. Structural and phylogenetic analyses revealed species-specific divergence, consistent with potential functional specialization. These findings broaden our understanding of fungal enzymatic strategies and highlight GH16 enzymes as candidates for further study. Beyond the immediate context of wood decay, this work has broader implications for fungal ecology, evolutionary biology, and biotechnological applications such as biomass conversion and sustainable bioenergy.

Fungal ecological strategies↗

A techno-economic assessment of carbon dioxide removal pathways via biochemical conversion of lignocellulose to biofuels and bioplastics

Biomass carbon removal and storage (BiCRS) is a promising pathway to mitigate climate change via large scale removal of atmospheric carbon dioxide (CO 2 ). We modeled several fermentation technologies, producing a variety of bioproducts from lignocellulosic feedstocks, to understand their levelized cost of CO 2 removal under multiple scenarios. Lifecycle greenhouse gas (GHG) emissions are accounted to provide cradle-to-grave estimates of carbon intensity (CI). We did not account for the avoided fossil CO 2 emissions from the use of biofuels in our CO 2 removal cost calculations, because avoided emissions do not contribute to CO 2 removal. The main products from the fermentation technologies we modeled include renewable diesel, ethanol, sustainable aviation fuel (SAF), and polyethylene (PE), with co-products including CO 2 , adipic acid, steam, and electricity. PE, depending on its end-of-life management, can serve as a form of biogenic carbon storage. PE has the potential to remove 1.2–1.5 tCO 2 per dry t-biomass, whereas biofuels have the potential to remove 0.3–0.9 tCO 2 per dry t-biomass, indicating that PE production is a more efficient method of carbon removal. We quantify costs of CO 2 removal to be $\$$60 – $\$$675 per metric tCO 2 removed across the various fermentation pathways. Under the scenarios analyzed, bioplastic production from lignocellulosic biomass is a more cost-effective route to CO 2 removal than biofuel production, with costs of CO 2 removal via bioplastics being 50–90 % lower than that of biofuels. Future research should explore the potential benefits and drawbacks of expanding bioplastic production for large-scale CO 2 removal.

09 BIOMASS FUELS↗

Porous carbon from lignocellulosic biomass with emphasis on corn plant waste residue for energy storage

The rising global demand for sustainable energy storage materials has driven the search for environmentally friendly and cost-effective electrode options. Hydrothermal conversion of lignocellulosic biomass has gained attention due to its low energy requirements and operation at relatively low temperatures, presenting a green alternative to traditional thermochemical methods. The resulting solid product, hydrochar, has been used as an adsorbent and soil amendment; however, chemical/thermal treatment significantly enhances its physical properties. These structural modifications transform hydrochar into an effective porous carbon electrode, offering abundant sites for electrolyte ion transport, critical for high-performance devices like supercapacitors and batteries. This review first discusses various waste biomass and sustainable feedstocks available globally. It compares two primary thermochemical conversion techniques, pyrolysis and hydrothermal carbonization/liquefaction, and examines their respective solid products, biochar and hydrochar, analyzing differences in their physical and chemical characteristics. The focus is placed on hydrochar, summarizing activation methods to produce porous carbon suitable for energy storage applications. Additionally, this review will include a dedicated section on the application of porous carbon derived from corn plant waste residue, considering that corn is one of the most abundant crops grown worldwide, which makes it an important and promising source for sustainable porous carbon production. The role of machine learning models in optimizing hydrothermal processes to produce high-quality hydrochar is also discussed, emphasizing how data-driven approaches can streamline process development. Finally, the review identifies the current challenges and prospects for lignocellulosic biomass-derived porous carbon as a sustainable electrode material in next-generation energy storage technologies.

25 ENERGY STORAGE↗

Innovative biphasic solvent systems for lignocellulosic biorefinery

Bioconversion of lignocellulosics to ethanol is significantly hindered by biomass recalcitrance and, therefore, often requires a biomass pretreatment step. Furan-based compounds such as furfural (FF) and 5-hydroxymethylfurfural (HMF) are versatile building blocks for fuels and chemicals. However, their production during pretreatment often suffers from low yield and low separation efficiency. Biphasic solvent systems are capable of reducing biomass recalcitrance and extracting furans into the organic phase, thus preventing their degradation, increasing their yield, and allowing much easier separation. The development of a sustainable biphasic solvent system is essential to the furan-driven biorefinery and has drawn significant attention. Finally, this review systematically summarizes recent advances in the development of biphasic solvent systems in lignocellulosic biorefinery for improving the production of liquid fuels and furan-based compounds.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Ionic-liquid-Assisted Fabrication of Lignocellulosic Thin Films with Tunable Hydrophobicity

Thin films with enhanced water repellency and mechanical strength can be fabricated from renewable lignocellulosic feedstock as a replacement for petrochemical-derived synthetic polymers, such that it minimizes life cycle impact on the environment and human health. In this work, hybrid poplar wood, either untreated (control) or pretreated with hot water at 160 °C for 20 min (HWE-20), 60 min (HWE-60), and 90 min (HWE-90), was dissolved in 1-ethyl-3-methylimidazolium acetate and regenerated to fabricate thin films. The HWE-90 films were enriched in lignin by 74%, specifically on the surface, which along with hemicellulose depletion imparted hydrophobicity (108° water contact angle) when compared to the control (56°), HWE-20 (77°), and HWE-60 (84°) films. They also exhibited 86% reduced water vapor sorption hysteresis and 75% improved storage modulus compared to the control. Thus, we demonstrate how to tune the lignocellulosic film properties via a combination of hot water pretreatment and ionic liquid dissolution.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Plasma technology for lignocellulosic biomass conversion toward an electrified biorefinery

Lignocellulosic biomass conversion to renewable, carbon-neutral materials, fuels, and chemicals is the cornerstone of the transition to a sustainable future bioeconomy. Green energy in the form of electricity needs to be coupled with or substitute conventional thermally driven processes to realize small-scale, economically viable and environmentally friendly biorefineries. Gas discharge plasmas enable the conversion of renewable electric energy, supplied in the form of an electric field, to chemical energy through the formation of a highly reactive environment that can induce several transformations related to agricultural waste valorization processes. Herein, we review the application of plasma technology to lignocellulosic biomass upgrade, aiming to provide the scientific background and technical challenges in this rapidly emerging research field. To bridge the gap between plasma science and biomass valorization technologies, we initially present the technical aspects of plasma reactors related to biomass processing and further discuss the advances in plasma processing for each biomass conversion technology, providing insights into the related plasma chemistry and interaction mechanisms. Here, we first focus on the low and medium-temperature biomass conversion processes, including biomass pretreatment and delignification to promote enzyme or acid-catalyzed hydrolysis to sugars and biomass liquefaction using plasma electrolysis. Then we discuss the high and very high-temperature conversion processes, such as plasma-assisted pyrolysis and gasification to syngas and plasma application to tar removal, combustion, and vitrification. Overall, this review provides knowledge at the interface of plasma science and biomass conversion technology to promote the interaction between the individual communities, which is crucial for the further advancement of the field.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Economic and environmental sustainability of bio-based HMF production and recovery from lignocellulosic biomass

5-Hydroxymethyl furfurals (HMF) is one of the versatile platform chemicals. However, green routes to produce it directly from lignocellulosic biomass are lacking. A significant amount of HMF produced during the hydrothermal valorization of lignocellulosic biomass is considered undesired and ends up in a waste stream. The study transformed the undesired byproduct into a valuable coproduct by advancing the existing biofuel production process. A detailed economic and environmental sustainability analysis of the integrated biorefinery design was performed. The evaluation showed that the biorefinery could afford a maximum feedstock purchasing price of $\$115.17$ per MT and produce HMF with a minimum selling price of $\$4.54$ per kg which is ~75% lower than the commercial price of HMF. The median global warming potential of HMF was estimated to be 3.92 kg CO 2 -eq. per kg HMF which was ~32% less than its counterpart bio-based p-xylene. Diverse coproducts produced in the biorefinery using transgenic feedstock positively impacted sustainability.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Multi-scale computational screening and mechanistic insights of cyclic amines as solvents for improved lignocellulosic biomass processing

A computational screening workflow for the efficient deconstruction of cellulose, lignin and hemicellulose fractions of lignocellulosic biomass using cyclic amines as solvents. Lignocellulosic biomass is a promising feedstock for production of affordable fuels and chemicals from renewable resources. Effective solubilization and subsequent deconstruction of its cellulose, hemicellulose, and lignin fractions is essential for the viability of future biorefineries. This study used quantum chemistry-based equilibrium thermodynamics methods to evaluate the potential of 650 cyclic amines to solubilize cellulose, hemicellulose, and lignin. The activity coefficients of solvent - biopolymer interactions were predicted using the COSMO-RS (COnductor-like Screening MOdel for Real Solvents) method and used to identify cyclic amines that can efficiently dissolve and extract selective fractions of biopolymers during biomass pretreatment. Among the 650 cyclic amines, 1-piperazineethanmaine was predicted to be an effective solvent for extracting all three polymers and was experimentally shown to achieve the highest lignin removal (97.1%). Non-covalent interaction, reduced density gradient and quantum chemical calculations were performed to elucidate the dissolution mechanism of lignin, cellulose and hemicellulose and gain further molecular level insights into the interactions between the cyclic amines and biomass polymers that promote efficient solubilization and extraction. These analyses indicated that 1-piperazineethanmaine and 1-methylimidazole make noncovalent van der Waals, electrostatic interactions and hydrogen bonding with lignin, leading to enhanced lignin removal, while the strong intramolecular hydrogen bonding interactions in cellulose and hemicellulose result in weaker solvent-biopolymer interactions. Overall, the computational approach provided an efficient method for identifying cyclic amines tailored for optimal biomass pretreatment and resulted in the identification of a potential new class of solvents for effective biomass pretreatment.

Kumar, Nikhil↗