Utilization Of Lignocellulose Research Articles

Novel ternary deep eutectic solvent fractionation for effective utilization of willow

A novel ternary deep eutectic solvent (TDES), consisting of zinc chloride, ethylene glycol and alpha hydroxy carboxylic acids (i.e., glycolic acid, citric acid and malic acid), was first proposed to effectively fractionate and convert willow (Salix matsudana cv. Zhuliu) into fermentable sugar. In particular, the zinc chloride/ethylene glycol/malic acid (ZnCl2/EG/MA) TDES system showed remarkable fractionation performance with 91.66 % xylan and 90.12 % lignin removals at 130 °C for 1.5 h, resulting in 96.01 % glucose yield in the subsequent enzymatic hydrolysis stage. Moreover, the regenerated lignin showed regular nanoparticle morphology and good antioxidant properties. Even after four recycling, the TDES showed 70.16 % of delignification and 83.70 % glucose yield with the TDES pretreated willow. Overall, this study demonstrated an effective solvent fractionation approach to maximize the utilization of total lignocellulose under mild conditions.

Cellular ATP redistribution achieved by deleting Tgparp improves lignocellulose utilization of Trichoderma under heat stress.

Thermotolerance is widely acknowledged as a pivotal factor for fungal survival across diverse habitats. Heat stress induces a cascade of disruptions in various life processes, especially in the acquisition of carbon sources, while the mechanisms by which filamentous fungi adapt to heat stress and maintain carbon sources are still not fully understood. Using Trichoderma guizhouense, a representative beneficial microorganism for plants, we discover that heat stress severely inhibits the lignocellulases secretion, affecting carbon source utilization efficiency. Proteomic results at different temperatures suggest that proteins involved in the poly ADP-ribosylation pathway (TgPARP and TgADPRase) may play pivotal roles in thermal adaptation and lignocellulose utilization. TgPARP is induced by heat stress, while the deletion of Tgparp significantly improves the lignocellulose utilization capacity and lignocellulases secretion in T. guizhouense. Simultaneously, the absence of Tgparp prevents the excessive depletion of ATP and NAD+, enhances the protective role of mitochondrial membrane potential (MMP), and elevates the expression levels of the unfolded protein response (UPR)-related regulatory factor Tgire. Further investigations reveal that a stable MMP can establish energy homeostasis, allocating more ATP within the endoplasmic reticulum (ER) to reduce protein accumulation in the ER, thereby enhancing the lignocellulases secretion in T. guizhouense under heat stress. Overall, these findings underscored the significance of Tgparp as pivotal regulators in lignocellulose utilization under heat stress and provided further insights into the molecular mechanism of filamentous fungi in utilizing lignocellulose.

Copper and zinc-impregnated mesoporous gamma-alumina catalyst for hydrothermal liquefaction of alkali lignin

The complete utilization of lignocellulose is a sustainable key for bio-refineries, where the utilization of evitable lignin is a great challenge owing to its structural complexity. Here, the effect of Cu and Zn-loaded mesoporous γ-Al2O3 catalysts was examined for the first time for the hydrothermal liquefaction of alkali lignin in an ethanol/water solvent system. It showed excellent performance towards the liquefaction as compared to that of (commercial) com-5Cu/γ-Al2O3 catalyst. Here, the bio-oil yield was observed to be 47.7 wt% for com-5Cu/Al catalyst which was increased to 59.1% for syn-5Cu/Al. It was increased substantially to 65.4 wt% for syn-10Cu/Al. However, only a 40 wt% bio-oil yield was found for the non-catalytic (NC) reaction. Additionally, a further significant improvement to 74.7 wt% was noticed for Zn (5 wt%) modified syn-10Cu/Al catalyst. Here, the screening of the water-ethanol mixture, and reaction parameters were also evaluated which showed a small increase in bio-oil yield to 77.4 wt% for ethanol/water (75/25, v/v). The GC-MS analysis of bio-oil exhibited the high specificity of vanillin (69.3%) for syn-10Cu-5Zn/Al. The 1H NMR and FT-IR investigation also validate the diverse functionality of bio-oils. The reusability of the optimum catalyst (syn-10Cu-5Zn/Al) was also tested for three successive catalytic cycles that exhibited the good performance of the catalyst up to the second cycle.

Aqueous amine enables sustainable monosaccharide, monophenol, and pyridine base coproduction in lignocellulosic biorefineries

Thought-out utilization of entire lignocellulose is of great importance to achieving sustainable and cost-effective biorefineries. However, there is a trade-off between efficient carbohydrate utilization and lignin-to-chemical conversion yield. Here, we fractionate corn stover into a carbohydrate fraction with high enzymatic digestibility and reactive lignin with satisfactory catalytic depolymerization activity using a mild high-solid process with aqueous diethylamine (DEA). During the fractionation, in situ amination of lignin achieves extensive delignification, effective lignin stabilization, and dramatically reduced nonproductive adsorption of cellulase on the substrate. Furthermore, by designing a tandem fractionation-hydrogenolysis strategy, the dissolved lignin is depolymerized and aminated simultaneously to co-produce monophenolics and pyridine bases. The process represents the viable scheme of transforming real lignin into pyridine bases in high yield, resulting from the reactions between cleaved lignin side chains and amines. This work opens a promising approach to the efficient valorization of lignocellulose.

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 ℃. The biocompatibility of TEG allowed direct enzymatic hydrolysis of the solid residue without washing, thus minimizing wastewater generation. Moreover, 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. Overall, the proposed TEG solvent system is promising for a green and sustainable biorefinery process to achieve the complete utilization of lignocellulose.

A novel liquid-liquid phase-change solvent with upper critical solution temperature for simultaneous pretreatment and separation of lignin, cellulose and hemicellulose from lignocellulosic biomass

The compact dimensional aggregate structure and the complex chemical components of lignocellulose go against its high value utilization. The mixture of dilute hydrochloric acid and n-butanol, which had a characteristic of homogeneous phase at high temperature and phase separation at low temperature, was proposed for lignocellulosic hydrolysis and hydrolysates separation. The results showed that lignocellulose was hydrolyzed under the synergy effect of hydrochloric acid and n-butanol in homogeneous condition, and hemicellulose and lignin hydrolysates were transferred automatically into dilute hydrochloric acid phase and n-butanol phase during the phase separation of the solvent after pretreatment, respectively. N-butanol accelerated lignin hydrolysis and protected β-O-4 linkage within lignin during the pretreatment. Meanwhile, the cellulose within solid phase product from the pretreatment was of high crystallinity, and its glucose yield in enzymatic saccharification at 48 and 72 h were 73.5% and 97.3%, respectively. This study provides a new method for lignocellulose hydrolysis and hydrolysates separation, and lays a theoretical foundation for lignocellulosic utilization of all component.

Upgrading dry acid pretreatment by post-hydrolysis for carbon efficient conversion of lignocellulose

Dry acid pretreatment (DAP) as a promising process for industrial biorefinery provide an efficient bioconversion of cellulose without free wastewater, although the partial xylan and lignin degrade to inhibitors or recondense. A biorefinery strategy for carbon efficient conversion of lignocellulose into bioethanol, xylose, and reactive lignin was developed by upgrading DAP with post-hydrolysis. The results showed that lignocellulose after mild DAP (175 °C, acid dosage of 15 mg/g dry material) obtained higher xylan recovery and lower inhibitors than that of general DAP. Subsequently, post-hydrolysis, simultaneous saccharification and ethanol fermentation were performed at solids loading of 20 wt% without detoxification and sterilization, resulting in xylose and ethanol yield of 71.8 % and 67.6 %. The fractionated lignin presented more reactive β-aryl ether linkages and less condensation than that from DAP. 66 % of lignocellulose carbon was recovered as ethanol, xylose and reactive lignin. This upgrading biorefinery strategy provided an easy-to-operate process for integrated utilization of lignocellulose.

Characterization of a Thermophilic and Inhibitor-Tolerant GH1 β-Glucosidase Present in a Hot Spring

β-glucosidase is a key enzyme in the degradation of lignocellulosic biomass, which is responsible for the conversion of oligosaccharides from cellulose hydrolysates to glucose. However, its required high temperatures and the presence of inhibitors have limited its use in industry. In this study, a new β-glucosidase gene, named thbg2, was obtained from the metagenome Ruidian Hot Spring, Tengchong City, Yunnan Province, southwestern China. The gene was synthesized, cloned, heterologously expressed, and enzymatically characterized. Its optimum temperature and pH were 60 °C and pH 5.6, respectively. ThBg2 exhibited more than 60% relative activity in temperatures ranging from 40 °C to 70 °C and across a pH of 4.0–6.6. It maintained 100% relative activity after incubation at either 50 °C for 24 h or 60 °C for 12 h and more than 80% residual activity after incubation at pH 4.0–6.0 for 24 h. Moreover, it maintained more than 80% relative activity in the presence of heavy metal ions, ethanol, SDS etc. Furthermore, glucose yields from corn stalks increased by 20% after ThBg2 (0.05 mg/mL) was added to the commercial cellulase reaction system. Overall, this work identified a thermophilic and inhibitor-tolerant β-glucosidase with potential applications in commercial lignocellulose utilization and the bioenergy industry.

Pt/CeCrO2−x: A multifunctional catalyst for tandem catalysis of lignocellulose hydro-liquefaction and Guerbet reaction

Catalytic transfer hydrogenation (CTH) of lignocellulose liquefaction using renewable ethanol presents a promising alternative to conventional hydrogenation techniques. However, the development of efficient and stable multifunctional catalysts remains a significant challenge. Herein, a Pt/Ce9Cr1O2−x catalyst was developed to facilitate the CTH reactions and achieve nearly complete utilization of lignocellulose. Isotope labeling experiments were conducted to elucidate the mechanism of CTH. The introduction of Cr3+ increased the density of surface oxygen vacancies, consequently enhancing the hydrodeoxygenation ability and metal anchoring. The solid solution structure promotes the electrons transfer from Cr atoms to Pt atoms, forming electron-rich Ptδ+ species that promote ethanol dehydrogenation and lignocellulose hydrodeoxygenation. Furthermore, Pt/Ce9Cr1O2−x catalyst provided optimal acid-base sites and hydroxyl groups, thereby improving ethanol upgrading efficiency and wettability.

Heterogeneous catalytic oxidation for lignin valorization into aromatic compounds over acid-redox bifunctional polyoxometalates

Lignin, as the largest renewable aromatic resource on the planet, has significant potential for the production of value-added platform chemicals. In this work, we synthesized a series of cesium-exchanged acid-redox bifunctional polyoxometalates (POMs) and evaluated their performance as catalysts for the depolymerization of birch lignin into low molecular weight aromatic compounds. The Cs3H2PMOV2O40 catalyst exhibited the highest activity, resulting in a monomer yield of approximately 13.6 %. Gel permeation chromatography (GPC), heteronuclear single quantum coherence (HSQC) spectroscopy, and gas chromatography-mass spectrometry (GC-MS) analysis confirmed the effective cleavage of β-O-4, β-5, and β-β linkages in the lignin polymer. The proposed reaction mechanism for the lignin depolymerization over cesium-exchanged POMs was also discussed. Our results demonstrate the potential of cesium-exchanged POMs as effective catalysts for the conversion of lignin into value-added chemicals, thereby contributing to the complete sustainable utilization of lignocellulose.

Two-Step Upcycling Process of Lignocellulose into Edible Bacterial Nanocellulose with Black Raspberry Extract as an Active Ingredient.

(1) Background: Bacterial nanocellulose (BNC) has gained in popularity over the years due to its outstanding properties such as renewability, biocompatibility, and bioavailability, and its use as an eco-friendly material of the future for replacing petrochemical products. (2) Methods: This research refers to the utilization of lignocellulose coming from wood waste via enzymatic hydrolysis to produce biopolymer BNC with an accumulation rate of 0.09 mg/mL/day. Besides its significant contribution to the sustainability, circularity, and valorization of biomass products, the obtained BNC was functionalized through the adsorption of black raspberry extract (BR) by simple soaking. (3) Results: BR contained 77.25 ± 0.23 mg GAE/g of total phenolics and 27.42 ± 0.32 mg CGE/g of total anthocyanins. The antioxidant and antimicrobial activity of BR was evaluated by DPPH (60.51 ± 0.18 µg/mL) and FRAP (1.66 ± 0.03 mmol Fe2+/g) and using a standard disc diffusion assay, respectively. The successful synthesis and interactions between BNC and BR were confirmed by FTIR analysis, while the morphology of the new nutrient-enriched material was investigated by SEM analysis. Moreover, the in vitro release kinetics of a main active compound (cyanidin-3-O-rutinoside) was tested in different release media. (4) Conclusions: The upcycling process of lignocellulose into enriched BNC has been demonstrated. All findings emphasize the potential of BNC-BR as a sustainable food industry material.

Biochar with enhanced performance prepared from bio-regulated lignocellulose for efficient removal of organic pollutants from wastewater

This work presented a novelty method for preparing lignocellulosic materials with reinforced performances, that is, the lignocellulose of corn straw was bio-regulated into cellulose, hemicellulose, and lignin via three types of microorganisms (Aspergillus niger, Myrothecium verrucaria, Trichoderma reesei) with cross treatment. Three different types of biochar were then prepared by the carbonization and combined alkali activation processes. The results showed that the great quantity of micro/mesopores endowed biochars ultra-high specific surface areas up to 2881, 2986, and 2878 m2 g−1. Biochars exhibited ultra-high maximum adsorption capacities for crystal violet (CV) and tetracycline hydrochloride (TC), which was higher than that of most adsorbents including the corn straw-based carbon and multi-walled carbon nanotube. After five cycles, the samples maintained a removal rate of over 70% for CV and over 60% for TC, proving their good potential for recycling. This study showed that the bio-regulation of lignocellulose was not only an effective method to develop materials with enhanced adsorption performances, but also provided a feasible idea for the comprehensive utilization of lignocellulose.

Lignocellulose Degradation Efficiency of Agaricus bisporus Strains Grown on Wheat Straw-Based Compost.

The cultivation of Agaricus bisporus was investigated with two commercial strains, A15 and W192. Nitrogen and lignocellulose were analyzed in absolute amounts based on mass balance to accurately compare the degradation efficiency of the compost, and the correlation between the degradation efficiency and extracellular enzyme activity of the mycelium was analyzed. Lignocellulose utilization efficiency positively correlated with mushroom yield. For the same strain, the compost with high lignocellulose content resulted in high utilization efficiency, which increased the yield of A. bisporus. For the same compost, the lignocellulose utilization efficiency of A15 was higher than that of W192. The activities of manganese-dependent peroxidase and β-glucosidase indicated that W192 may have a higher demand for lignin and cellulose. Therefore, a higher yield of W192 was obtained with high-lignocellulose compost. The metabolism of cellulose and hemicellulose in the mycelial growth stage seemed to be conducive to high mushroom yield.

Hydrogen generation from bamboo biomass using enzymatic hydrolysis and subsequent microbial electrolysis in a single chamber microbial electrolysis cell

Sustainable, economical. and clean energy production technologies acutely needed abundant supply of raw materials (biomass) and superior process engineering techniques to deliver the desired throughput. In this endeavour, here we demonstrated the utilization of lignocellulose (Bambusa bambos) by successive enzymatic treatment and microbial electrolysis in a single chamber MEC for generating clean fuel-hydrogen. In addition, we studied MEC (V=400 mL) by modifying an anode (graphene with 100 cm2 area) with monodisperse iron oxide nanoparticles (IONPs). Enzymatically (10% w/w laccase) pretreated Bambusa bambos with 40.31% reduced lignin was subjected to batch hydrolysis (20% w/w enzyme-to-substrate ratio) using cellulase. The glucose produced (99.54 ± 4 mg/dL) after 96 h of incubation was further operated in single chamber MEC equipped with highly efficient IONPs coated electrodes for hydrogen production. Engineering parameters namely-applied voltage (0.6-1.0 V) and mixing characteristics (0–400 rpm) were also investigated to improve the system performance. The MEC with IONPs coated anode offered hydrogen production efficiency 1.14 times higher as compared to MEC with the uncoated anode. The maximum hydrogen production of 0.02 g (224 mL) per gram of biomass was obtained in MEC with the coated anode at an applied voltage of 0.8 V under the influence of moderate mixing (200 rpm).

Dissolution of lignocellulose with high lignin content in AlCl3/ZnCl2 aqueous system and properties of the regenerated cellulose film

Herein, a novel method for dissolving lignocellulose at room temperature is proposed by combining deep eutectic solvents (DES) pretreatment and subsequent dissolution in AlCl3/ZnCl2 aqueous system. Results showed that DES pretreatment could significantly increase the dissolubility of lignin-containing cellulose (CL) samples in AlCl3/ZnCl2 aqueous system. The dissolution ratio of the CL sample with 15.6 % lignin content in AlCl3/ZnCl2·3H2O solvent was as high as 90 %. Besides, the mechanism for the remarkable dissolution of CL samples in low water AlCl3/ZnCl2 aqueous solvent was also proposed. Moreover, the dissolved CL sample was regenerated for the production of lignocellulose films, which have excellent ultraviolet (UV) blocking, hydrophobic, mechanical strength, and natural degradation properties. In particular, the films could be completely naturally degraded after 10 days, which provided a promising way to prepare biodegradable lignocellulose materials, and to encourage the potential utilization of renewable lignocellulose in packaging industry.

Synergizing mitigated spatial confinement and chemical stabilization of lignin facilitates full utilization of lignocellulose

A novel concept is introduced for fractionating biomass, specifically softwood, by employing a unique strategy that combines chemical protection and mitigation of lignin spatial confinement during the extraction process.

Towards furfural and biomass char production from Camellia oleifera husks using dilute hydrochloric acid pretreatment: a comprehensive investigation on adsorption performance

The whole component utilization of lignocellulose was achieved, and hemicellulose was used to prepare FF which was adsorbed with S-8 macroporous resin and purified. The residue including cellulose and lignin was converted to biomass char, which was used for the adsorption of methylene blue dye.

Ni5Fe5/Al2O3 catalytic hydrogenolysis of lignin: mechanism investigation and selectivity regulation

The development of novel catalysts to regulate product selectivity and insight into the mechanism of lignin hydrogenolysis are important for the comprehensive utilization of lignocellulose.

Efficient downstream valorization of lignocellulose after organosolv fractionation: Synergistic enhancement of waterborne coatings by co-assembled lignin@cellulose nanocrystals

The simultaneous downstream valorization of cellulose and lignin is an important aspect of efficiently extracting value from lignocellulose. The present work, we demonstrated the preparation of a novel bio-based filler by the co-assembly of cellulose and lignin obtained from a one-pot ethanosolv lignocellulose fractionation process. The cellulose was valorized by forming cellulose nanocrystals (CNCs) through simple bleaching and ultrasonication processes. The lignin fractions demonstrated greater solubility (19.2 mg/mL) and lower molecular weight (6980 g/mol) than conventional industrial lignins. Various lignin@CNCs specimens were prepared via a facile co-assembly of the lignin and CNCs. These entirely bio-based materials could be used as a multifunctional filler to enhance the properties of a waterborne coating (WBC). Specifically, the mechanical properties, coating performance and ultraviolet resistance of a WBC were all significantly improved, demonstrating a synergistic enhancement effect obtained from the CNCs and lignin. In this manner, both cellulose and lignin components were efficiently transformed to value-added fillers for WBC, demonstrating a highly efficient pathway for lignocellulose utilization and downstream value-added applications.

Lignocellulose Biopolymers and Electronically Conducting Polymers: Toward Sustainable Energy Storage Applications

The demand for the development of electrochemical energy storage systems from abundant, renewable, eco-friendly, and cost-effective materials has been the focal and driving point in the advancement of electronic devices. This task and demand can be addressed with a resource that is abundant and possesses the attributes of being developed into efficient electrochemical energy storage systems. Lignin and cellulose, which are collectively known as lignocellulose, are the two most abundant biopolymers available, and they possess the attributes and the qualities to meet this demand. Lignocellulose biopolymers possess unique characteristics such as mechanical flexibility, porosity, and tunability because of their abundant and diverse functional groups. These qualities enable suitable pairing with electronically conducting polymers as enhanced materials for the development of sustainable energy storage devices. This Review highlights the challenges and the utilization of lignocellulose with electronically conducting polymers in supercapacitors applications and battery applications in various capacities as electrodes, separators, binders, and electrolytes.