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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 CO2-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. [ABSTRACT FROM AUTHOR]

Lignin can affect the enzymatic hydrolysis efficiency of lignocellulose. In this study, the lignin isolated from sugarcane bagasse (SCB) pretreated with p-toluenesulfonic acid (PL) was firstly aminated, and then the effects of PL and aminated PL (APL) on the bagasse enzymatic hydrolysis efficiency (EHE) were investigated. The results showed that the addition of PL and APL promoted the EHE, and EHE with APL (73.82 %) was higher than PL (51.39 %). To explore the reason, the data were further analyzed including cellulase adsorption capacity, enzyme activity, cellulase-lignin interaction, and molecular docking. It was found that APL adsorbed more cellulase (27.83 mg protein/g lignin) than PL (4.96 mg protein/g lignin), resulting from the greater interaction force and lower binding free energy between APL and cellulase. The addition of APL more remarkably enhanced the cellobiohydrolase and endoglucanase activities than PL due to more effectively inducing cellulase conformation optimization. [Display omitted] • Enzymatic hydrolysis of cellulosic substrate was enhanced from 45.83 % to 73.82 % by aminated lignin. • Aminated lignin adsorbed more cellulase molecules. • Activities of cellobiohydrolase (CBH) and endoglucosidase (EG) were promoted by aminated lignin. • Aminated lignin owned lower binding energy with cellulase. [ABSTRACT FROM AUTHOR]

• Wood, paper, agricultural waste offers renewable resources for high-value chemicals. • Biorefineries need to combine biotechnological and physico-chemical approaches. • Industrial lignocellulosic waste has high potential in circular bioeconomy. Lignocellulosic biomass has a promising role in a circular bioeconomy and may be used to produce valuable molecules for green chemistry. Lignocellulosic biomass, such as food waste, agricultural waste, wood, paper or cardboard, corresponded to 15.7% of all waste produced in Europe in 2020, and has a high potential as a secondary raw material for industrial processes. This review first presents industrial lignocellulosic waste sources, in terms of their composition, quantities and types of lignocellulosic residues. Secondly, the possible high added-value chemicals obtained from transformation of lignocellulosic waste are detailed, as well as their potential for applications in the food industry, biomedical, energy or chemistry sectors, including as sources of polyphenols, enzymes, bioplastic precursors or biofuels. In a third part, various available transformation treatments, such as physical treatments with ultrasound or heat, chemical treatments with acids or bases, and biological treatments with enzymes or microorganisms, are presented. The last part discusses the perspectives of the use of lignocellulosic waste and the fact that decreasing the cost of transformation is one of the major issues for improving the use of lignocellulosic biomass in a circular economy and green chemistry approach, since it is currently often more expensive than petroleum-based counterparts. [ABSTRACT FROM AUTHOR]

• An effective recovery of antioxidants was obtained from breweŕs spent grain. • A comparison among chemical, enzymatic and hydrothermal hydrolysis was conducted. • The highest ferulic acid yield was 7.2 g FA/kg BSG for the hydrothermal treatment. • Alkaline hydrolysis showed the lowest operating costs: €34.5/kg FA at 100 kgBSG/m3. Brewers' spent grain (BSG) is the main byproduct from the brewing industry, which accounts for 85 % of the total waste generated during beer production. This lignocellulosic material is traditionally used as livestock feed and sold at a low price. However, BSG can be used as a low-cost feedstock for the production of bioactive molecules and chemicals precursors, upgrading the value of this byproduct. In this context, BSG is a promising feedstock for the extraction of antioxidants like ferulic acid (FA) and p-coumaric acid (p -Cu). The effectiveness of three hydrolysis treatments were evaluated for the extraction of FA and p -Cu from BSG, namely enzymatic (based on the synergistic cooperation between a feruloyl esterase and an endo -1,4-β-xylanase), alkaline and hydrothermal. The hydrothermal treatment produced the highest extraction yields (7.2 g/kgBSG and 1.4 g/kgBSG for FA and p -Cu, respectively) in a short extraction time (an hour). On the other hand, enzymatic hydrolysis extracted 4.3 g/kgBSG for FA and negligible yields for p -Cu in 4 h of incubation at 25 °C. Yields of 5.5 g/kgBSG for FA and 0.6 g/kgBSG for p -Cu were obtained in more than 5 h of alkaline treatment at 120 °C. The mass and energy balances revealed the high dependence of the operating costs on the concentration of BSG used during the extraction process, with costs of 34.5 €, 6607 € and 205.5 € per kg of FA for the chemical, enzymatic and hydrothermal extraction methods at 100 kg BSG/m3. [ABSTRACT FROM AUTHOR]

Background: Wood-feeding termites have been employed as sources of novel and highly efficient lignocellulolytic enzymes due to their ability to degrade lignocellulose efficiently. As a higher wood-feeding termite, Globitermes sulphureus (Blattaria: Termitidae) plays a crucial role as a decomposer in regions such as Vietnam, Singapore, Myanmar, and Yunnan, China. However, the diversity of its gut microbiome and carbohydrate-active enzymes (CAZymes) remains unexplored. Here, we analyzed the diversity of hindgut microbial communities and CAZymes in a higher wood-feeding termite, G. sulphureus, and a lower wood-feeding termite, Coptotermes formosanus (Blattaria: Rhinotermitidae). Results: 16S rRNA sequencing revealed that Spirochaetota, Firmicutes, and Fibrobacterota were the dominant microbiota in the hindgut of the two termite species. At the phylum level, the relative abundances of Proteobacteria and Bacteroidota were significantly greater in the hindgut of C. formosanus than in G. sulphureus. At the genus level, the relative abundances of Candidatus_Azobacteroides and Escherichia-Shigella were significantly lower in the hindgut of G. sulphureus than in C. formosanus. Metagenomic analysis revealed that glycoside hydrolases (GHs) with cellulases and hemicellulases functions were not significantly different between G. sulphureus and C. formosanus. Interestingly, the cellulases in G. sulphureus were mainly GH5_2, GH5_4, GH6, GH9, and GH45, while the hemicellulases were mainly GH11, GH8, GH10, GH11, GH26, and GH53. In C. formosanus, the cellulases were mainly GH6 and GH9, and the hemicellulases were mainly GH5_7, GH5_21, GH10, GH12, and GH53. In addition, β-glucosidase, exo-β-1,4-glucanase, and endo-β-1,4-glucanase activities did not differ significantly between the two termite species, while xylanase activity was higher in G. sulphureus than in C. formosanus. The bacteria encoding GHs in G. sulphureus were mainly Firmicutes, Fibrobacterota, and Proteobacteria, whereas Bacteroidota and Spirochaetota were the main bacteria encoding GHs in C. formosanus. Conclusions: Our findings characterized the microbial composition and differences in the hindgut microbiota of G. sulphureus and C. formosanus. Compared to C. formosanus, G. sulphureus is enriched in genes encoding for hemicellulase and debranching enzymes. It also highlights the rich diversity of GHs in the hindgut microbiota of G. sulphureus, including the GH5 subfamily, GH6, and GH48, with the GH6 and GH48 not previously reported in other higher termites. These results strengthen the understanding of the diversity of termite gut microbiota and CAZymes. [ABSTRACT FROM AUTHOR]

Microcrystalline cellulose (MCC) is a valuable material produced from sengon wood sawdust (SWS). Conventionally, the material is produced by combination base treatment for delignification and acid treatment for hydrolysis. This method will cost a high waste treatment duty that reduces fabrication efficiency and sustainability. Biodelignification by fungal treatment is an eco-friendly method that can reduce the lignin content of lignocellulosic material. Hydrothermal is an excellent hydrolysis method that can be modified by sodium hypochlorite (NaOCl) solution addition to lignin derivative residue binding. Therefore, this study set out to investigate the modified biodelignification method that is combined with hydrothermal in NaOCl as a bleaching agent to produce MCC from SWS. From the result, the fungal treatment can reduce the lignin content to 0.85% within 50 days of treatment and increase the cellulose content to 50.60%. The MCC from SWS addition was successfully produced by the hydrothermal process with NaOCl solution with a cellulose content of 62.45% and relative crystallinity degree (RCD) of 79.446%. [ABSTRACT FROM AUTHOR]

Sugar palm starch waste (SPSW) was biomass that produce from processing of sugar palm starch. SPSW contain high cellulose, hemicellulose, and lignin. Using lignocellulose from SPSW needs a pretreatment method to obtain highpurity cellulose and create an environmentally friendly method. The investigation focuses on determining the optimal NaOH concentration, temperature, and duration for hydrothermal-alkali treatment to remove hemicellulose and lignin, achieving high-purity cellulose. There is no further research regarding optimal conditions related to NaOH concentration, temperature, and duration for hydrothermal-alkali treatment to remove hemicellulose and lignin, achieving high-purity cellulose. This study aims to define optimal conditions for lignin and hemicellulose removal to obtain cellulose with high purity. The delignification process is carried out by hydrothermal and hydrothermal alkali activation. The hydrothermal activation removes hemicellulose, whereas the hydrothermal alkali activation removes lignin. In this study, Response surface methodology (RSM) was used to determine optimum conditions. The results were then structural and morphological identification using XRD, FTIR, and SEM. The optimization results obtained parameter values of 2% NaOH, temperature 120 °C for 120 minutes. The desirability value was 0.774, with a response value of 2.9 ± 1.7% for hemicellulose, 92.35 ± 1.06% for cellulose, and 2.45 ± 0.1% for lignin. FTIR results showed that lignin was absent during the delignification process. Meanwhile, in XRD, during the delignification process, the crystallization index (CI) decreases, and the crystallization size (CS) increases. SEM analysis results show that the morphology of the delignified SPSW becomes smoother after pretreatment, which indicates a decrease in hemicellulose and lignin content and a high level of cellulose purity. Further research is needed on other parameters, such as cellulose yield, energy consumption, and environmental impact. This research should also consider other potential pretreatment factors, such as pressure and catalysts in the hydrothermal process. [ABSTRACT FROM AUTHOR]

Highly porous and lightweight aerogels of cellulose nanofibers (CNFs) have emerged as a promising class of material. This study delves into the impact of the composition (lignocellulose nanofibers–LCNFs and CNFs) and the drying methods (supercritical drying and freeze-drying) on the morphology and the properties of nanocellulose-based aerogels. The investigation evaluates the concentrations of nanofibers and the influence of lignin, a constituent of LCNFs recognized for enhancing the rigidity of plant cell walls, on the aerogel's properties. The shrinkage rates, density, pore structure, and mechanical properties of the obtained aerogels are comprehensively compared. Supercritical drying proves advantageous for aerogel formation, resulting in materials with lower density and higher surface area than their freeze-dried counterparts at each concentration level. The use of acetone for supercritical drying contributes to reduce the shrinkage rates compared to ethanol. This decrease is attributed to the formation of a more rigid hydrogel during solvent exchange. Freeze-drying exhibits the lowest shrinkage rates and relatively higher porosity. The presence of lignin in the nanofibers influences the microstructure, yielding smoother and thicker pore walls. This study contributes to the comprehensive understanding of the intricate factors shaping nanocellulose aerogel properties, paving the way for the development of innovative and environmentally-friendly materials. [ABSTRACT FROM AUTHOR]

Deep Eutectic Solvents (DESs) have emerged as promising eco-friendly pre-treatment agents for lignocellulosic biomass, offering considerable advantages for the nanofibrillation process. This study investigates the impact of DESs on cellulose fibers morphology, focusing on solubilization phenomena in the amorphous regions that may facilitate cellulose nanofiber production. The pre-treatment process combining a DES (triethylmethylammonium chloride and imidazole, TEMA:IMD) with microwave (MW) energy was optimized to enhance the solubility of cellulosic fibers. A response surface methodology (RSM) was employed to optimize the DES-MW-assisted pre-treatment. Results show that the reaction time and the temperature significantly influence the solubility of cellulosic fibers. The optimized conditions resulted in cellulose fibers with low content of hemicellulose and lignin, high crystallinity index, and improved thermal stability. The effectiveness of DES-MW pre-treatment in producing cellulose nanofibers (CNFs) from native and pre-treated fibers was investigated. Cellulose fibers pre-treated with a DES yielded CNFs with a narrower diameter distribution. Overall, optimized DES-MW pre-treatment offers a promising strategy for the efficient and sustainable extraction of CNFs. [ABSTRACT FROM AUTHOR]

Introduction: Several species of cellulolytic bacteria display cellulosomes, massive multi-cellulase containing complexes that degrade lignocellulosic plant biomass (LCB). A greater understanding of cellulosome structure and enzyme content could facilitate the development of new microbial-based methods to produce renewable chemicals and materials. Methods: To identify novel cellulosome-displaying microbes we searched 305,693 sequenced bacterial genomes for genes encoding cellulosome proteins; dockerin-fused glycohydrolases (DocGHs) and cohesin domain containing scaffoldins. Results and discussion: This analysis identified 33 bacterial species with the genomic capacity to produce cellulosomes, including 10 species not previously reported to produce these complexes, such as Acetivibrio mesophilus. Cellulosome-producing bacteria primarily originate from the Acetivibrio, Ruminococcus, Ruminiclostridium , and Clostridium genera. A rigorous analysis of their enzyme, scaffoldin, dockerin, and cohesin content reveals phylogenetically conserved features. Based on the presence of a high number of genes encoding both scaffoldins and dockerin-fused GHs, the cellulosomes in Acetivibrio and Ruminococcus bacteria possess complex architectures that are populated with a large number of distinct LCB degrading GH enzymes. Their complex cellulosomes are distinguishable by their mechanism of attachment to the cell wall, the structures of their primary scaffoldins, and by how they are transcriptionally regulated. In contrast, bacteria in the Ruminiclostridium and Clostridium genera produce 'simple' cellulosomes that are constructed from only a few types of scaffoldins that based on their distinct complement of GH enzymes are predicted to exhibit high and low cellulolytic activity, respectively. Collectively, the results of this study reveal conserved and divergent architectural features in bacterial cellulosomes that could be useful in guiding ongoing efforts to harness their cellulolytic activities for bio-based chemical and materials production. [ABSTRACT FROM AUTHOR]

Modeling hydrothermal carbonization (HTC) and pyrolysis carbonization (PLC) for the conversion of biomass into high-quality biochar for various applications shows promise. Unlike the extensive modeling studies on lignocellulosic biomass, research on aquatic biomass (AB) had not been reported until now. In this study, we compiled 586 data points from existing literature and trained five tree-based models to predict the yields of hydrochar and pyrochar and their properties, including nitrogen recovery degree, energy density, energy recovery degree, and residual sulfur degree, based on 10 feedstock and process parameters. The random forest regression (RFR) model demonstrated the highest predictive accuracy among these models. It achieved R2 values ranging from 0.89 to 0.98 for hydrochar yield, nitrogen recovery degree of hydrochar, energy recovery degree of hydrochar, and residual sulfur degree of hydrochar. The extreme gradient boosting (XGB) model also showed exemplary performance, with R2 values between 0.84 and 0.94 for energy density of hydrochar, pyrochar yield, and nitrogen recovery degree of pyrochar. Results on feature importance highlighted that, beyond the well-documented impact of process parameters, the properties of biochar were significantly influenced by the elemental compositions, such as nitrogen and sulfur contents of the feedstock. The relationship between these factors was further elucidated using partial dependence plots. Finally, we used RFR model for hydrochar yield and XGB model for pyrochar yield as examples, to test generalization ability of developed models with new data, further explaining their application methods. Overall, this study provided valuable insights into predicting and understanding the HTC and PLC processes of AB to produce high-quality biochar for various applications using low resources and time costs. Besides, we presented an iterative learning application method where the developed models demonstrated exceptionally high performance with new data. This method is highly versatile and can be adopted across various directions in the field of machine learning. Highlights: • A machine-learning framework for producing biochar from aquatic biomass was developed. • XGB and RFR models showed the excellent performance for biochar yield and properties. • The developed models had high generalization ability (R2 = 0.97–0.98) through appropriate iterative operation. [ABSTRACT FROM AUTHOR]

Methods such as gas stripping and vacuum-assisted gas stripping (VAGS) result in significant removal of water from the bioreactor, thus requiring continuous water replenishment in the bioreactor. In this study, we developed a hydrophobic stainless steel meshes capable of selectively recovering concentrated ABE stream from the bioreactor during VAGS. Three stainless steel meshes with pore sizes of 180 µm, 300 µm, and 425 µm were made hydrophobic and oleophilic with zinc oxide (ZnO) and polydimethylsiloxane (PDMS). Butanol concentrations in the model solutions range from 3 to 10 g/L which mimic concentrations typically produced during batch ABE fermentation. The meshes were integrated in a 5-L bioreactor containing 2.5 L of operational ABE model solution followed by the evaluation of selective extraction of ABE from both cell-free and Clostridium beijerinckii-rich ABE model solutions. The results show that the 180-µm ZnO/PDMS-coated mesh retained 54–64% more water in the bioreactor without C. beijerinckii cells and 61–65% more water with cells compared to the uncoated mesh. Furthermore, the butanol concentration of condensates recovered with 180-µm ZnO-PDMS-coated mesh was up to 10.8-fold greater than that of uncoated counterpart. Our data demonstrate that the developed ZnO-PDMS mesh can recover high concentrations of ABE while selectively retaining water in the bioreactor. Additionally, this technology demonstrates the potential for real-time ABE recovery during the fermentation of lignocellulosic and colloidal materials, without the concern of clogging the separation system. Key points: • Hydrophobic mesh enhanced water retention in the bioreactor by up to 1.65-fold. • Butanol concentration in the collected condensate was increased by up to 10.8-fold. • Hydrophobic mesh is compatible with fermentation of lignocellulose. [ABSTRACT FROM AUTHOR]

Background: Acetate is an important chemical feedstock widely applied in the food, chemical and textile industries. It is now mainly produced from petrochemical materials through chemical processes. Conversion of lignocellulose biomass to acetate by biotechnological pathways is both environmentally beneficial and cost-effective. However, acetate production from carbohydrate in lignocellulose hydrolysate via glycolytic pathways involving pyruvate decarboxylation often suffers from the carbon loss and results in low acetate yield. Results: Escherichia coli BL21 (DE3) was confirmed to have high tolerance to acetate in this work. Thus, it was selected from seven laboratory E. coli strains for acetate production from lignocellulose hydrolysate. The byproduct-producing genes frdA, ldhA, and adhE in E. coli BL21 (DE3) were firstly knocked out to decrease the generation of succinate, lactate, and ethanol. Then, the genes pfkA and edd were also deleted and bifunctional phosphoketolase and fructose-1,6-bisphosphatase were overexpressed to construct an EP-bifido pathway in E. coli BL21 (DE3) to increase the generation of acetate from glucose. The obtained strain E. coli 5K/pFF can produce 22.89 g/L acetate from 37.5 g/L glucose with a yield of 0.61 g/g glucose. Finally, the ptsG gene in E. coli 5K/pFF was also deleted to make the engineered strain E. coli 6K/pFF to simultaneously utilize glucose and xylose in lignocellulosic hydrolysates. E. coli 6K/pFF can produce 20.09 g/L acetate from corn stover hydrolysate with a yield of 0.52 g/g sugar. Conclusion: The results presented here provide a promising alternative for acetate production with low cost substrate. Besides acetate production, other biotechnological processes might also be developed for other acetyl-CoA derivatives production with lignocellulose hydrolysate through further metabolic engineering of E. coli 6K/pFF. [ABSTRACT FROM AUTHOR]

Replacing petrochemicals with refined waste biomass as a sustainable chemical source has become an attractive option to lower global carbon emissions. Popular methods of refining lignocellulosic waste biomass use thermochemical processes, which have significant environmental downsides. Using electrochemistry instead would overcome many of these downsides, directly driving chemical reactions with renewable electricity and revolutionizing the way many chemicals are produced today. This review mainly focuses on two furanic platform chemicals that are produced from the dehydration of cellulose, 5-hydroxymethylfurfural and furfural, which can be electrochemically reduced or oxidized to replace fuels and monomers that today are obtained from petrochemicals. Critical parameters such as electrode materials and electrolyte pH are discussed in relation to their influence on conversion efficiency and product distribution. This article is part of the discussion meeting issue 'Green carbon for the chemical industry of the future'. [ABSTRACT FROM AUTHOR]

The physiochemical pretreatment was performed using different concentrations of oxalic acid (OA) as a simultaneous pretreatment and saccharification (SPS) process on rice straw to obtain reducing sugar from two‐phasic SPS process using enzymatic and acidic hydrolysis to subsequently ferment to bioethanol in order to maximize the yield of bioethanol. The optimal condition for pretreating rice straw using 0.5, 0.75, 1, and 1.5 M OA at 120°C for 1 h was evaluated. The morphological and structural changes after simultaneous pretreatment and SPS process were evaluated using Fourier‐transform infrared (FTIR), thermogravimetric analysis (TGA), X‐ray diffraction (XRD), and field‐emission scanning electron microscopy (FESEM) analysis. It was evaluated that optimum pretreatment conditions using a lesser concentration of OA had resulted in 30.37% of xylan removal from pretreated rice straw obtained after simultaneous pretreatment and SPS process. The ethanol production yield ranged from 0.42 to 0.37 g/g with fermentation efficiency of up to 57.18% and an overall ethanol production yield of 42.84% from the obtained hydrolysate of the two‐phasic SPS process. The highest ethanol concentration from the obtained hydrolysate was produced at 120°C for 1 h with 0.75 M OA; under this condition, maximum degradation of utilized lignocellulosic biomass takes place. [ABSTRACT FROM AUTHOR]

Delignification of lignocellulose using basic ionic liquids (BILs) such as choline lysinate ([Ch][Lys]) is a promising method due to its high efficiency, mild conditions, and low toxicity. Typically, the following precipitation of lignin by adding acid media makes it challenging to recycle BILs. Herein, we explored a series of low-cost and recyclable alcohols as anti-solvents, including methanol (MeOH), ethanol (EtOH), iso-propanol (i-PrOH), and tert-butanol (t-BuOH), for recovering [Ch][Lys] and precipitating lignin without adding an acid from water-free [Ch][Lys] (case 1) and aqueous [Ch][Lys] (case 2). For case 1, lignin recovery followed the order of EtOH > i-PrOH > t-BuOH (MeOH was not able to recover lignin and [Ch][Lys]), which was negatively correlated with their pKa values, indicating the effect of the inhibited generation of a basic anion (e.g. EtO− from EtOH) from –NH2 in [Ch][Lys] on lignin precipitation. t-BuOH showed the highest lignin recovery of 99.7%, ensuring the high purity of the recovered [Ch][Lys] (recovery of 94.7%). Lignin deprotonation and depolymerization were detected. For case 2, t-BuOH also facilitated the recovery of lignin from an aqueous lignin–[Ch][Lys] system with a nearly quantitative lignin recovery, yet with lower [Ch][Lys] recovery of 81.7% and 64.0% at the [Ch][Lys] : water ratios (w/w) of 7 : 3 and 1 : 9, respectively. The lower recovery of [Ch][Lys] might be due to the poor dispersity of lignin solid in t-BuOH, and water also enhanced the deprotonation of lignin, thus making lignin precipitation more difficult. Based on the results, a deprotonation-based lignin dissolution mechanism has been proposed, which also helps to understand lignin dissolution and precipitation in a [Ch][Lys]-based system. [ABSTRACT FROM AUTHOR]

Biomass is the most abundant and renewable resource in the pursuit of bio-value added chemicals. Platinum-group metals and typical nonprecious transition metals are considered as the active metals for catalytic conversion of biomass into value added chemicals and fuels. Rhenium (Re) in particular is a versatile, oxophilic element with a broad variety of easily accessible oxidation states ideally suited for catalytic applications. Taking advantage of Re's unique properties and the green concept of biomass, the catalytic transformation of lignocellulose with Re-based catalysts has gained considerable attention, leading to the preparation of value-added chemicals including olefins through deoxydehydration from the conversion of polyols, aromatics through depolymerization of lignin, and alkane fuels through a hydrodeoxygenation reaction. This review focuses on the catalytic conversion of lignocellulosic main components (cellulose, hemicellulose, and lignin) and their derived platform chemicals into value-added chemicals and fuels over homogeneous and heterogeneous Re-based catalysts. The reaction pathways for biomass conversion over Re-based catalysts are introduced based on different feedstocks or chemical bonds. The unique role of Re species in tailoring the active sites of catalysts for these reactions is summarized and possible reaction mechanisms are discussed. Finally, an outlook is provided to underscore both the challenges and opportunities associated with this interesting and important field, offering a comprehensive overview on the current state of Re catalysis with a low carbon footprint. [ABSTRACT FROM AUTHOR]

Composites based on polylactic acid (PLA) were developed, using lignocellulosic nanofibers (LCNF) dispersed in polyethylene glycol (PEG). To evaluate the impact of LCNF sources, suspensions were prepared from different pulps, including only cellulose; other with cellulose and hemicellulose; and cellulose, hemicellulose, and lignin. The PLA/PEG ratio was 80/20, with LCNF concentrations of 1.25%, 2.5%, and 3.75% (w/w) relative to the PLA/PEG weight. The best results were achieved with 2.5% (w/w) of LCNF containing a blend of cellulose and hemicellulose, showing a 26% increase in tensile strength and 102% in Young's modulus compared with the PLA/PEG matrix. The hemicellulose in LCNF acts as a physical barrier between cellulose chains, demonstrating a lower tendency for agglomeration and greater compatibility with PEG and PLA, as evidenced by decreased zeta potential due to the adsorption of PEG and shifts in the CO peak in the FTIR spectra. At 3.75 LCNF concentration, micrometer‐sized fibers were observed in SEM images, impacting the mechanical properties of the composites. Thermograms show no phase separation, and the change in crystallinity due to the addition of nanofibers has minimal influence on mechanical properties. These findings highlight the importance of selecting appropriate lignocellulosic nanoparticles for improved material performance. [ABSTRACT FROM AUTHOR]

In this study, four types of "Juá" stem barks (Ziziphus joazeiro) were investigated for the removal of Cu(II) from aqueous solutions. The tested samples included natural coarse barks, and barks washed with water, ethanol–water, and NaOH solutions. The solvent-modified materials simulated the waste of the industrial extraction of saponins from bark. The valorization of these processing residues as sorbents was evaluated. The NaOH-washed sorbent exhibited the highest sorption capacity for Cu(II) (maximum sorption capacity ≈ 32 mg g−1). Ion exchange process between copper and exchangeable surface cations and electrostatic attraction of copper with carboxylate and phenolate groups were identified as the primary sorption mechanisms. Desorption tests revealed that a large portion of the metal sorbed (80%) was easily released from the sorbent thus suggesting, in line with the proposed mechanisms, the existence of weak sorbate-sorbent interactions. The sorptive process was found to be exothermic (∆H° = − 48.1 ± 13.5 kJ.mol−1) and thermodynamically favorable at lower temperatures. [ABSTRACT FROM AUTHOR]

Lignocellulosic biomass (LCB) comprising of wheat bran, coconut husk, rice husk, cereals straw, and other hardwood and softwoods is a good source for the production of xylooligosaccharides (XOS) (prebiotic). XOS produced are nondigestible carbohydrates being stable under stomach pH and digestive enzymes so they can be easily delivered to the intestine in native form, thus stimulating the growth of probiotics. Here we review about the raw material, production, purification, and application of XOS with health benefits. Importance of XOS being valuable food ingredient is increasing as they perform a variety of functions, including reduction in cholesterol levels, gastrointestinal health maintenance, anticancer and antioxidant properties, and modulation of immune system. We also discuss the different characterization methods which are necessary to determine the degree of polymerization (DP) of XOS. Low DP (xylobiose and xylotriose) is usually preferred for the application of XOS in various sectors. This review emphasizes the growing significance of XOS as a prebiotic, serving as nourishment for probiotics. [ABSTRACT FROM AUTHOR]

Practical Application Spent coffee grounds (SCG) are the waste byproducts of coffee brewing. While SCG can be valorized to produce functional biopolymers due to their valuable structural components, the lignocellulosic structure of SCG is resistant to degradation because of the tightly bound lignin. Therefore, a pretreatment step is required before pulping with peracetic acid (PAA), an eco‐friendlier alternative to traditional pulping methods, to facilitate the extraction of these desired cellulosic materials. Formic acid:acetic acid:deionized water (FA:AA:W = 30:50:20) or 60% (v/v) ethanol pretreatments were applied to SCG to compare the characteristics of the resulting cellulosic materials after PAA pulping. Lignocellulose analysis showed that the lignin content (7.06%) of ethanol pretreated SCG was significantly lower (p < 0.05), and the cellulose content (29.52%) was significantly higher (p < 0.05) than the untreated SCG (15.50% and 11.50%, respectively), indicating that an adequate amount of lignin was removed to obtain the cellulosic materials after the pretreatment process. Morphological and structural changes in the lignin and hemicellulose were observed in all the pretreated SCG, which further confirmed that these components were degraded with pretreatments and pulping. Ethanol pretreated SCG showed the most optimal results based on the greatest lignin decrease seen from its lignocellulose composition, appearance, and structure. This study exemplified a conversion process to extract cellulosic materials from SCG more efficiently to utilize for cellulose‐based products and verify its potential to be valorized as a waste byproduct.Coffee companies can provide the spent coffee grounds (SCG) they produce to develop cellulose‐based materials to make biodegradable packaging products rather than throwing them out or burning them. Using SCG for producing cellulose‐based materials can help promote sustainability and reduce food waste worldwide. SCG can be utilized as an alternative source based on their abundance and desired biopolymeric properties, providing innovative solutions to industries and increasing consumer awareness of this cause. [ABSTRACT FROM AUTHOR]

The valorization and dissolution of lignin using ionic liquids (ILs) is critical for developing sustainable biorefineries and a circular bioeconomy. This review aims to critically assess the current state of computational and machine learning methods for understanding and optimizing IL-based lignin dissolution and valorization processes reported since 2022. The paper examines various computational approaches, from quantum chemistry to machine learning, highlighting their strengths, limitations, and recent advances in predicting and optimizing lignin-IL interactions. Key themes include the challenges in accurately modeling lignin's complex structure, the development of efficient screening methodologies for ionic liquids to enhance lignin dissolution and valorization processes, and the integration of machine learning with quantum calculations. These computational advances will drive progress in IL-based lignin valorization by providing deeper molecular-level insights and facilitating the rapid screening of novel IL-lignin systems. [ABSTRACT FROM AUTHOR]

This study developed mycelial biochar composites, BQH-AN and BQH-MV, with stable physicochemical properties and significantly improved adsorption capabilities through microbial modification. The results showed that the specific surface area and porosity of BQH-AN (3547.47 m2 g−1 and 2.37 cm3 g−1) and BQH-MV (3205.59 m2 g−1 and 2.46 cm3 g−1) were significantly higher than those of biochar BQH (2641.31 m2 g−1 and 1.81 cm3 g−1), which was produced without microbial treatment. In adsorption experiments using rhodamine B (RhB), tetracycline hydrochloride (TC), and Cr (VI), BQH-AN showed maximum adsorption capacities of 1450.79 mg g−1 for RhB, 1608.43 mg g−1 for TC, and 744.15 mg g−1 for Cr(VI). BQH-MV showed similarly strong performance, with 1329.85 mg g−1 for RhB, 1526.46 mg g−1 for TC, and 752.27 mg g−1 for Cr(VI). These values were not only higher than those of BQH but also outperformed most other biochar adsorbents. Additionally, after five reuse cycles, the pollutant removal efficiency of the mycelial biochar composites remained above 69%, demonstrating excellent regenerative ability. This study not only produced biochar with superior adsorption properties but also highlighted microbial modification as an effective way to enhance lignocellulosic biochar performance, paving the way for further biomass development. [ABSTRACT FROM AUTHOR]

Straw, a predominant agricultural residue, represents a significant waste product. Harnessing its potential is of paramount importance both in terms of research and economic value. In this study, chemically pretreated corn straw was infused with distinct microbial fungal mycelium variants and subsequently transformed into a series of biochars through a process involving carbonization and activation. The findings revealed enhancements in the specific surface area and total pore volume of mycelium-doped straw biochars compared to the original corn straw biochar (BCS). Additionally, discernible disparities were observed in their physical and chemical attributes, encompassing functional groups, surface chemistry, and micro-morphology. Notably, in water-based antibiotic removal experiments focusing on tetracycline hydrochloride (TH) and chloramphenicol (CP), the mycelium-doped straw biochars outperformed BCS. Their maximum adsorption capacities for TH and CP surpassed those of alternative adsorbents, including other biochars. Impressively, even after five cycles, the biochar exhibited a removal rate exceeding 80%, attesting to its robust stability. This study successfully emphasized the efficacy of incorporating fungal mycelium to enhance the adsorption properties of straw-based biochar, introducing a new theoretical basis for the development of lignocellulosic materials. [ABSTRACT FROM AUTHOR]

New asphalt mixtures have been improved by using fibers (polypropylene, polyester, asbestos, carbon, glass, nylon, lignin, coconut, sisal, recycled rubber, PET, wood, bamboo, and cellulose), reducing the temperature and compaction energy for their collocation, minimizing the impact on the environment, increasing the tenacity and resistance to cracking of hot mix asphalt (HMA), preventing asphalt drainage in a Stone Mastic Asphalt (SMA). Hence, this paper aims to evaluate the influence of the chemical (lignin content, ash, viscosity, degree of polymerization, and elemental analysis), morphological (SEM), spectroscopic (FTIR-ATR and XRD), and calorimetric (ATG and DSC) properties of celluloses from bagasse Agave tequilana Weber var. Azul (ABP), corrugated paperboard (CPB) and commercial cellulose fiber (CC) as Schellenberg drainage (D) inhibitors of the SMA. The ABP was obtained through a chemical process by alkaline cooking, while CPB by a mechanical refining process. The chemical, morphological, spectroscopic, and calorimetric properties were similar among the analyzed celluloses, but CPB and ABP cellulose are excellent alternatives to CC cellulose for inhibiting drainage. However, CPB is the most effective at low concentrations. This is attributed to its morphology, which includes roughness, waviness, filament length, orientation, and diameter, as well as its lignin content and crystallinity. [ABSTRACT FROM AUTHOR]

This study investigates lignocellulosic biocomposites' physicochemical properties and strength parameters with varying thermoplastic content. Biocomposites were prepared using wood (Pinus sylvestris) or hemp shives (Cannabis sativa L.) combined with 25% and 50% ABS regranulate. The research focused on evaluating the mechanical energy consumption during the compaction of wood-ABS biocomposites with different pine fractions pretreated with hot water extraction (HWE) and analyzing the relationship between strength and thermoplastic content. Results indicate that the composition of the mixture and the size of the hemp shives fraction did not significantly influence energy consumption during densification. Energy values ranged from 1.234 × 10⁻8 J to 8.296 × 10⁻8 J. While the densification of pine after HWE was unsuccessful without ABS, preheating the mixtures with ABS facilitated the production of a uniform composite. The work required for densification ranged from 1.404 × 10⁻5 J to 2.711 × 10⁻5 J for fractions without ABS. For mixtures with ABS, the work required was 1.954 × 10⁻5 J for fraction 0 ÷ 0.4 (f1) and 0.042 × 10⁻5 J for fraction 0.4 ÷ 0.8. [ABSTRACT FROM AUTHOR]

Energy security and the transition to a thriving lowcarbon economy are essential for a developing nation like India. We examined the life-cycle greenhouse gas emissions (GHG) and environmental impact of bioethanol production from jute and kenaf feedstock. It was observed that net GHG emissions from crop production and bio-refinery from jute and kenaf ethanol were 3.45 and 5.88 g MJ-1 respectively. This result is much lower than any other feedstock like sugarcane bagasse, corn stover, rice straw and wheat straw. Life cycle assessment revealed that ethanol produced from jute and kenaf biomass can reduce GHG emissions by 78-81% when compared with petrol. Bioethanol has the least negative effects (rice straw > sugarcane bagasse > wheat straw > corn stover > jute, kenaf) on the environment and resource depletion. It might deliver 60% of the ethanol requirement annually and may prove to be a workable technology for meeting ethanol-to-petrol blend targets. [ABSTRACT FROM AUTHOR]

The development of manufacturing industries is crucial for national progress, with a growing emphasis on green and sustainable practices. This study investigates the development and performance of hybrid polymer composites based on poly lactic acid (PLA) reinforced with lignocellulosic fillers: bagasse fiber (BF), tamarind seed fiber (TSF), Terminalia chebula fiber (TCF), and a hybrid filler of bagasse, tamarind seed, and Terminalia chebula (BTSTCF). Five types of composites were fabricated with varying filler compositions: PLA, PLA/BF, PLA/TSF, PLA/TCF, and PLA/BTSTCF, consisting of 30% BF, TSF, or TCF with 70% PLA, and an additional 10% of each filler in the BTSTCF composite. The results demonstrated that the PLA/BTSTCF hybrid composite outperformed others regarding mechanical strength, thermal stability, and interfacial adhesion. Specifically, it exhibited superior flexural strength, impact strength, and tensile strength. The findings indicate that incorporating a combination of bagasse, tamarind seed, and Terminalia chebula fillers into PLA significantly enhances its properties and performance. This study contributes to advancing sustainable and green manufacturing practices and holds promise for economic growth through the development of high-performance, eco-friendly materials. [ABSTRACT FROM AUTHOR]

The utilization of lignocellulosic biomass for the generation of diverse value‐added biochemicals and biofuels is crucial in modern biorefineries and bioenergy initiatives, contributing significantly to the pursuit of a climate‐neutral future. Agricultural, forest and industrial sources of lignocellulosic biomass serve as exceptionally renewable precursors in biorefinery processes. In spite of its abundance, the effective breakdown of biomass poses a significant challenge. Thus, it is essential to integrate various unit processes, including biochemical, thermochemical, physical, enzymatic and catalytic conversion, to generate a wide array of bio‐based products. Intensive integration of these processes not only enhances yield and reduces reaction time but also proves to be economically efficient. Furthermore, these process integration approaches may contribute to the establishment of a circular bioeconomy through biorefineries, effectively reducing both bioresource waste and greenhouse gas emissions. This review offers fundamental insights into biomass and its chemistry, with a detailed discussion on lignocellulosic conversion systems. It explores how integrating conversion processes can facilitate the transition toward a circular economy. Additionally, it summarizes the challenges and prospects associated with advancing integrated biorefineries and circular economy principles to achieve complete biomass valorization. [ABSTRACT FROM AUTHOR]

Background: Escherichia coli JU15 is a metabolically engineered strain capable to metabolize C5 and C6 sugars with a high yield of d-lactic acid production at its optimal growth temperature (37 °C). The simultaneous saccharification and fermentation process allow to use lignocellulosic biomass as a cost-effective and high-yield strategy. However, this process requires microorganisms capable of growth at a temperature close to 50 °C, at which the activity of cellulolytic enzymes works efficiently. Results: The thermotolerant strain GT48 was generated by adaptive laboratory evolution in batch and chemostat cultures under temperature increments until 48 °C. The strain GT48 was able to grow and ferment glucose to d-lactate at 47 °C. It was found that a pH of 6.3 conciliated with GT48 growth and cellulase activity of a commercial cocktail. Hence, this pH was used for the SSF of a diluted acid-pretreated corn stover (DAPCS) at a solid load of 15% (w/w), 15 FPU/g-DAPCS, and 47 °C. Under such conditions, the strain GT48 exhibited remarkable performance, producing d-lactate at a level of 1.41, 1.42, and 1.48-fold higher in titer, productivity, and yield, respectively, compared to parental strain at 45 °C. Conclusions: In general, our results show for the first time that a thermal-adapted strain of E. coli is capable of being used in the simultaneous saccharification and fermentation process without pre-saccharification stage at high temperatures. [ABSTRACT FROM AUTHOR]

D-xylose is the second most abundant monosaccharide found in lignocellulose and is of biotechnological importance for producing second-generation ethanol and other high-value chemical compounds. D-xylose conversion to ethanol is promoted by microbial fermentation, mainly by bacteria, yeasts, or filamentous fungi. Among yeasts, species belonging to the CTG(Ser1) or CTG(Ala) clade display a remarkable ability to ferment D-xylose to ethanol and other compounds; however, these yeasts are not employed on an industrial scale given their poor fermentative performance compared to that of conventional yeasts, such as Saccharomyces cerevisiae, and because of the lack of a molecular toolbox for the development of new strains tailored to fermentation stress tolerance and performance. Thus, the purpose of this review was to evaluate the major genetic engineering tools (e.g., transformation markers and techniques, vectors, regulatory sequences, and gene editing techniques) available for the most studied yeasts of the CTG(Ser1) clade, such as Scheffersomyces , Spathaspora , Candida , and Yamadazyma species, and the CTG(Ala) clade, representative Pachysolen tannophilus. Furthermore, we systematized state-of-the-art molecular developments and perspectives to design D-xylose-fermenting yeast strains. • Review of genetic tools in CTG(Ser1) and CTG(Ala) yeasts for bioethanol production. • CTG codon reassignment impairs the use of conventional genetic engineering tools. • CTG(Ser1) yeasts can use genetic tools from clinically important Candida strains for research. [ABSTRACT FROM AUTHOR]

The development of a cost-effective and environment-friendly conversion method to overcome the recalcitrance of biomass is a challenging task for enhancing the value-added potential of lignocellulosic compounds. In this study, a photo-enzyme composite catalyst by immobilizing laccase on Fe 3 O 4 /TiO 2 (denoted as LC-Fe 3 O 4 /TiO 2) was applied to the pretreatment and enzymatic saccharification of Spartina alterniflora Loisel (SAL) under the action of alternating light/dark cycles. The effect of the pretreatment temperature, pretreatment time, LC-Fe 3 O 4 /TiO 2 concentration, mass concentration of straw particles, and hydrolysis time on delignification efficiency and reducing sugar yield was investigated by a central composite design (CCD). Under the selected conditions (48 ℃, pretreatment time of 70 min, LC-Fe 3 O 4 /TiO 2 concentration of 4.9 mg/mL, mass concentration of straw particles of 22 % (w/v), hydrolysis time of 55 h), 92.53 % delignification and 129.85 mg/g reducing sugar yield were achieved. The enzymatic hydrolysis efficiency was higher compared to conventional methods. Moreover, the LC-Fe 3 O 4 /TiO 2 showed good recyclability and reusability. Developed LC-Fe 3 O 4 /TiO 2 particles have a high potential for use in biomass utilization. [Display omitted] • Laccase-Fe 3 O 4 /TiO 2 integrated catalyst (LC-Fe 3 O 4 /TiO 2) is first synthesized. • Effects of LC-Fe 3 O 4 /TiO 2 on pretreatment and saccharification is studied. • LC-Fe 3 O 4 /TiO 2 can enhance sugar yield under the alternation of light and dark. • LC-Fe 3 O 4 /TiO 2 could be efficiently reused up to 3 cycles. [ABSTRACT FROM AUTHOR]

In polymer matrix composites (PMCs), reinforced lignocellulosic fibres are one of the excellent endeavours; doing so eliminates the need for the more commonplace synthetic fibres. In this respect, the fibres from Enset ventricosum (EV), one of the underutilized which have not been studied extensively, were focused to carry out an investigation on PMCs applications using the particles of Limonia acidissima fruit shell powder (LASP) as reinforcing agent. The study set out to evaluate the adeptness of altered LASP and EV plant fibres by 4% NaOH treatment. The results from morphological, physicochemical, XRD, FTIR, and thermal aspects of alkali-treated samples of LASP and EV fibres revealed that the alkali treatment significantly improved the compatibility of biomaterial' property to utilize the natural fillers in the epoxy–EV fibre composites. The first-degree polynomial model was fitted using the response surface analysis to optimize the impact energy, water absorption, tensile, and flexural strength of reinforced fibre with respect to composition and fibre length. Using RSM numerical model, aforementioned properties were analysed to develop the ideal epoxy–EV fibre composite for attaining a minimal water absorption, a high tensile modulus, flexural strength, and impact energy. Accordingly, 3 mm of fibre length reinforcement with 38.3 wt % of biomaterials loading reinforcement was found to be optimized for idealistic epoxy–EV fibre composite. [ABSTRACT FROM AUTHOR]

Lignin is classified as the second most abundantly available biopolymer after cellulose and as a main aromatic resource material. Lignin structure differs based on sources of origin and species of biomass with around 15–40% of lignin content based on dry weight. It is extracted from various types of lignocellulosic biomass through different pulping extraction methods. After extraction, lignin can be further functionalized through different chemical reactions to meet the requirements and specifications before being used in end products. Therefore, in this review paper, the details on extraction and the type of lignin, as well as chemical functionalization, are discussed. The chemical functionalization can be used to modify the lignin such through phenolic depolymerization or by other aromatic compounds, creating novel chemical active sites to impact a reactivity of lignin and through functionalization of hydroxyl functional group for enhancing its reactivity. Furthermore, the recent sustainable application of lignin was discussed in different fields such as nanocomposite, flame retardant, antioxidant, cosmetic, natural binder and emulsifier. This review hence provides a summary of the current stateoftheart in lignin technology and future outlook of potential application areas. [ABSTRACT FROM AUTHOR]

Coffee is one of the most consumed beverages worldwide. Its production generates a large amount of waste, and its use is of vital importance to prevent it from becoming a source of environmental pollution. Cuba is a country with a well-known coffee-growing tradition. Although coffee production has decreased, it is vitally important to use the waste generated in these productions to reduce environmental pollution. To know the possible use or application of coffee waste, it is necessary to know its composition. In this article, three Cuban Arabica coffee wastes (husk, parchment and spent coffee grounds) were characterized using chemical, physical and physicochemical methods. In the characterization of these wastes, SEM and EDX were used to determine their microscopic form and chemical composition. The Chesson–Datta method, ATR and TGA were used to determine whether these materials were lignocellulosic. Ash, pH and density of the waste were determined as characterization methods. The extractive content was determined and a phytochemical screening was performed to determine the groups of the secondary metabolites present. [ABSTRACT FROM AUTHOR]

The production of bioethanol from lignocellulosic biomass requires the efficient conversion of glucose and xylose to ethanol, a process that depends on the ability of microorganisms to internalize these sugars. Although glucose transporters exist in several species, xylose transporters are less common. Several types of transporters have been identified in diverse microorganisms, including members of the Major Facilitator Superfamily (MFS) and Sugars Will Eventually be Exported Transporter (SWEET) families. Considering that Saccharomyces cerevisiae lacks an effective xylose transport system, engineered yeast strains capable of efficiently consuming this sugar are critical for obtaining high ethanol yields. This article reviews the structure-function relationship of sugar transporters from the MFS and SWEET families. It provides information on several tools and approaches used to identify and characterize them to optimize xylose consumption and, consequently, second-generation ethanol production. [ABSTRACT FROM AUTHOR]

To evaluate the potential of compost based on municipal solid waste (MSW) and 20% legume pruning under a pyrolysis process, generated products, including solids (biochar), liquids (bio-oil), and gases (non-condensable gases), through experimentation in a pilot plant with a fluidized bed reactor at 450°C and gas chromatography/mass spectrometry have been analysed. In addition, the compost kinetic behaviour by thermogravimetric analysis (TGA), using the Flynn–Wall–Ozawa (FWO) method, has been investigated. Four different reaction zones, associated with lignocellulosic materials (hemicellulose, cellulose, and lignin) with a first step for water evaporation, in TGA curve have been observed. A biochar with low stability and aromaticity, considering high and low O/C and H/C ratios, respectively, has been obtained. The obtained pyrolytic liquids contain a high concentration of phenolic compounds because of a significant presence of lignins and other high molecular weight compounds in the original material. Moreover, the generated non-condensable gases consist mainly of short-chain compounds, such as alcohols, aldehydes, and alkenes produced from hemicellulose, cellulose, and proteins. [ABSTRACT FROM AUTHOR]

Lignocellulosic mass consists of cellulose, hemicelluloses, and lignin. Although biomass promises to be efficiently used for biofuel production and many other value‐added products, lignin present in lignocellulosic biomass affects the hydrolysis of cellulose and hemicelluloses, making it necessary to develop techniques that provide better lignin removal efficiency and high cellulose hydrolysability. The current work aims to maximize lignin removal in sawdust and develop an understanding of the hydrolysis of pretreated biomass for sugar production. Different parameters such as solvent to solid ratio, temperature, and reaction time have been considered based on the design of experiment to understand the effect on the delignification and saccharification processes. After treating sawdust for 1.5 h, it was observed that a maximum of 85% lignin was removed at a temperature of 131°C and solid loading of 16 g. Subsequent hydrolysis of delignified sawdust at 131°C temperature, solvent to solid ratio 15, and 0.5 h resulted in a maximum reducing sugar production of 26.82 mg/mL. The study elucidated the optimum conditions for the effective processing of sawdust in terms of delignification and saccharification, leading to maximum benefits in lignin removal and sugar production. [ABSTRACT FROM AUTHOR]

Renewable and sustainable energy production has gained significant attention to meet sustainable development goals (SDGs). Pine needles, an abundant typical forestry residue, can be used as a renewable biomass source for sustainable energy production. Pyrolysis is a well‐established and commercialized technique for the thermochemical valorization of lignocellulosic biomass. The present work focuses on improving the bio‐oil yield by introducing SiO2‐Al2O3‐based catalysts, including different zeolites and SiO2‐Al2O3 materials with varying SiO2‐Al2O3 ratios, during the pyrolysis. Bio‐oil yield increased from 45.2 wt.% to 47.2 wt.% with the introduction of SiO2‐Al2O3 catalysts and increased to 51.2 wt.% and 50.6 wt.% with HZSM‐5 and Y‐zeolite, respectively, and decreased to 40.0 wt.% with β‐zeolite catalyst. The pyrolysis experiments of physically mixed biomass and catalyst were carried out in a fixed‐bed down‐flow reactor. Various process parameters such as temperature, retention time, and catalyst‐to‐biomass ratio were examined to evaluate their effect on product yield. The catalyst's introduction slightly decreased phenolic compound content, enhancing carbonyl and hydrocarbon production. Maximum improvement in bio‐oil yield by 6 wt.% was achieved using an H‐ZSM‐5 catalyst at 450°C temperature and 30 min residence time with a catalyst‐to‐biomass ratio of 1:4. [ABSTRACT FROM AUTHOR]

The efficient fractionation and recovery of monosaccharides (xylose and glucose) from lignocellulosic biomass facilitates subsequent sugar-based derivative production. This study introduces a one-pot γ-valerolactone/ CuCl2 biphasic pretreatment system (100-mmol·L-1 CuCl2, 180 °C, 60 min) capable of achieving removal rates of 92.25% and 90.64% for xylan and lignin, respectively, while retaining 83.88% of cellulose. Compared to other metal chlorides (NaCl, LiCl, FeCl3, and AlCl3), the γ-valerolactone/CuCl2 system recovered 121.2 mg·(g eucalyptus)-1 of xylose and 55.96 mg·(g eucalyptus)-1 of glucose during the pretreatment stage and 339.2 mg·(g eucalyptus)-1 of glucose during the enzymatic hydrolysis stage (90.78% of glucose yield), achieving a total monosaccharide recovery of 86.31%. In addition, the recovery of γ-valerolactone was 79.33%, exhibiting minimal changes relative to the pretreatment performance. The method proposed in this study allows a high total monosaccharides recovery and a circular economy-oriented pretreatment approach, offering a viable pathway for biorefinery. [ABSTRACT FROM AUTHOR]

AbstractGlobal waste production is rapidly increasing and its inefficient recycling has caused significant pollution. Agricultural waste represents a big proportion of it and utilization of this waste in developing biodegradable packaging material has gained interest among research scientists. The incorporation of living systems into it has attracted considerable attention for the synthesis of sustainable and environmentally friendly materials. Thus, mycelium-based foams and composites are an evolving class of biocomposites that are based on growing fungal mycelium (specifically white rot fungus) on lignocellulosic agricultural wastes. The physical, structural, mechanical, biological and chemical characteristics of these composites are affected by the type of substrate, fungal strain and manufacturing process. Hence, the current review focuses on the substrates and fungal strains used for manufacturing these biocomposite materials as well as their impact on their properties. As a result of their stiffness, elasticity, porousness, less density, fast growth, and low cost, mycelium-derived materials can be used in a variety of applications, including construction, packaging, medicine, and cosmetics. Moreover, the biodegradability, renewability, bioavailability, and nontoxicity of these eco-friendly materials further help mitigate the impact of plastic and agricultural pollution on the environment. [ABSTRACT FROM AUTHOR]

Laccase, the selectively lignin degrader, vital to the initiation of lignocellulosic deconstruction was immobilized onto activated agarose beads to increase its reuse potential. Laccase cross-linked beads (~ 3.42 mm) recorded a specific activity of 23 Umg− 1, retaining about 80.43% enzyme activity after 45 days of storage. The immobilization yield and efficiency were 89% and 97% respectively. The equilibrium data fitted the Freundlich equation (R2 = 0.9987) demonstrating multilayer adsorption and the presence of Cu, Fe, and S in the elemental analysis of immobilized beads established effective binding between activated agarose beads and the laccase protein. Characterization studies of the immobilized laccase-treated crop residues revealed significant differences in the lignin polymer after each treatment cycle. An increase in digestibility of 26.21% and 7.62% was observed in paddy and finger millet-treated straws respectively, over the controls corroborating efficient lignin depolymerization. The propitious performance of laccase beads authenticated in the batch enzymatic reactor to treat crop residues paves headway as a sustainable green technology in the deconstruction of crop residues for use as ruminant feed, augmenting productivity. [ABSTRACT FROM AUTHOR]

The utilization of biomass as a carbon source for the synthesis of renewable solid acid catalysts (SA) has emerged as a prominent research direction in the field of heterogeneous catalysis. Based on the challenges associated with reusing residues from lignocellulosic biorefining, the biomass‐based SA (BCSA) were prepared using poplar sawdust (PS), hydrothermally pretreated PS (PPS), and the residue of PPS's enzymatic hydrolysis (ER). The characterization revealed that all three types of BCSA were loaded with catalytic groups, and the BCSA synthesized using ER rich in lignin components exhibited a highly efficient catalytic structure. Furthermore, the catalysis of a 20 g/L xylose solution with BCSA‐ER as SA also achieved the highest furfural yield (89.3%) and furfural selectivity (90.3%). The findings of this study suggested that lignin holds significant potential as a carbon carrier for SA, thereby offering a viable solution for utilizing by‐products from lignocellulosic biorefining. [ABSTRACT FROM AUTHOR]

Lignins, abundant aromatic biopolymers and one of the major components of lignocellulosic biomass, remain the most underutilized renewable bioresources of aromatics and hydrocarbons on the Earth. Numerous physical and chemical processes have been developed for lignin valorization; however, they generally suffer from environmentally unfriendly, harsh conditions and lack reaction specificity. On the other hand, milder methods involving biocatalysts exist but are impeded by many limitations, such as cofactor regeneration, deleterious enzyme–lignin interactions, and low stability. In this work, we attempt to eliminate the constrains encountered in enzyme‐based lignin valorization processes through the development of a novel electrochemically assisted bioprocess. This “all‐in‐one” biocathode incorporates a hybrid electrocatalytic interface combining a hydrogen peroxide‐generating passive air‐breathing gas diffusion electrode with an immobilized hydrogen peroxide‐consuming lignin peroxidase on a single surface and catalyzing the depolymerization of lignins. The ligninolytic potential of this bioelectrochemical device is demonstrated using both lignin models (veratryl alcohol and veratrylglycerol β‐guaiacyl ether) and a technical lignin at room temperature in aqueous media with the reaction efficiency of 14.9% per hour. [ABSTRACT FROM AUTHOR]

Highlights The growing global demand for sustainable and environmentally friendly polymer materials is driving interest in cellulose‐based materials. In response to this need, lignocellulosic fillers (LF) were extracted from pruning waste of bing cherry tree (Prunus Avium L.) branches as an alternative source of filler materials. The extracted LF were characterized by Fourier transform infrared (FTIR) spectroscopy, X‐ray diffraction (XRD), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). Their chemical composition, density and particle size distribution (PSD) were also analyzed. In the second part of the study, biocomposites were prepared by incorporating fillers with particle sizes below 100 microns into an epoxy matrix at concentrations of 5%, 10% and 15% by weight. These biocomposites were then characterized by tensile test, three‐point bending test and SEM analyze to determine their mechanical and morphological properties. Among the biocomposites, the one with 5% wood filler showed the best properties with a tensile strength of 45 MPa, tensile modulus of 1883 MPa, flexural strength of 74 MPa and flexural modulus of 2559 MPa. The results demonstrate the effectiveness of lignocellulosic particles in improving polymer matrices and suggest their potential for use in non‐structural applications in the automotive and marine industries, such as interior panels. Cherry tree pruning waste has been characterized for the first time. The potential use of cherry tree pruning waste as a filler material in thermosets has been investigated for the first time. This study aims to contribute to the reduction of plastic consumption and the development of environmentally friendly products. [ABSTRACT FROM AUTHOR]

High-value metabolites, such as enzymes and biofuels, can be produced from various agro-industrial waste containing high percentages of cellulose and hemicellulose. Aspergillus niger ITV02 demonstrates high potential in cellulases production, the key enzyme for converting lignocellulosic materials into fermentable sugars to produce second-generation bioethanol (bioethanol 2G). This study evaluated five lignocellulosic residues of agricultural importance: sugarcane bagasse (SCB), sorghum bagasse (SB), corn stubble (CS), barley straw (BS) and rice husk (RH) as substrates for cellulase production. The temperature, pH and stirring conditions were optimized using a Box–Behnken design to identify the most suitable conditions for cellulase production while minimizing nitrogen concentrations. The results indicate that the best way of propagation A. niger ITV02 is through the use of spores as an inoculant, in conjunction with the use of materials with a high cellulose/lignin ratio, such as CS and SB for the generation of cellulases. These conditions promote the expression of cellulases towards β-glucosidase production, unlike materials with lower cellulose/lignin ratios like BS and RH, which exhibited lower cellulase activity. The optimal conditions for cellulase production by A. niger ITV02 were determined to be 33 °C, pH 5.3, and 200 rpm, resulting in a 1.7-fold increase in Exoglucanase (FPase activity) (from 0.127 to 0.215 U/mL). These findings demonstrate the potential to enhance FPase activity by utilizing substrates with high cellulose/lignin content and implementing optimal operational conditions without the need to raise the nitrogen content of the basal medium, thus mitigating the economic impact of cellulase production. [ABSTRACT FROM AUTHOR]

Summary Wood of broad‐leaf tree species is a valued source of renewable biomass for biorefinery and a target for genetic improvement efforts to reduce its recalcitrance. Glucuronoxylan (GX) plays a key role in recalcitrance through its interactions with cellulose and lignin. To reduce recalcitrance, we modified wood GX by expressing GH10 and GH11 endoxylanases from Aspergillus nidulans in hybrid aspen (Populus tremula L. × tremuloides Michx.) and targeting the enzymes to cell wall. The xylanases reduced tree height, modified cambial activity by increasing phloem and reducing xylem production, and reduced secondary wall deposition. Xylan molecular weight was decreased, and the spacing between acetyl and MeGlcA side chains was reduced in transgenic lines. The transgenic trees produced hypolignified xylem having thin secondary walls and deformed vessels. Glucose yields of enzymatic saccharification without pretreatment almost doubled indicating decreased recalcitrance. The transcriptomics, hormonomics and metabolomics data provided evidence for activation of cytokinin and ethylene signalling pathways, decrease in ABA levels, transcriptional suppression of lignification and a subset of secondary wall biosynthetic program, including xylan glucuronidation and acetylation machinery. Several candidate genes for perception of impairment in xylan integrity were detected. These candidates could provide a new target for uncoupling negative growth effects from reduced recalcitrance. In conclusion, our study supports the hypothesis that xylan modification generates intrinsic signals and evokes novel pathways regulating tree growth and secondary wall biosynthesis. [ABSTRACT FROM AUTHOR]

The synthesis of 5‐(halomethyl)furfurals (XMFs, X=F, Cl, Br, I), including 5‐(chloromethyl)furfural (CMF), 5‐(bromomethyl)furfural (BMF), 5‐(iodomethyl)furfural (IMF), and 5‐(fluoromethyl)furfural (FMF), from biomass represents a pivotal advancement in renewable chemistry and engineering. Harnessing waste biomass as a raw material offers a sustainable alternative to fossil‐based resources, mitigating environmental degradation and addressing pressing energy needs. CMF and BMF, characterized by their enhanced stability over the hydroxyl analog, 5‐(hydroxymethyl)furfural (HMF), exhibit promise as renewable building blocks for scale‐up and commercialization. The surge in research interest, particularly from 2010 to 2024, reflects a growing recognition of XMFs′ potential as novel platform chemicals. This review highlights the evolution of XMF synthesis methods, focusing on their transformation from saccharides and lignocellulosic biomass. Mechanistic insights and experimental setups are scrutinized for industrial feasibility and scalability, shedding light on technical challenges and avenues for further research. The analysis underscores the burgeoning significance of XMFs in the transition towards sustainable chemical production, emphasizing the importance of process optimization and mechanistic understanding for commercial deployment. [ABSTRACT FROM AUTHOR]

Lignocellulosic biomass offers substantial potential as an ideal feedstock for dark fermentative hydrogen production due to its sustainability and cost-effectiveness. The current study examined the influence of furfural on fermentative hydrogen production using lignocellulosic hydrolysate in the presence of furfural. Synthetic lignocellulosic hydrolysate, consisting primarily of 76% xylose, 10% glucose, 9% arabinose, and a mixture of other sugars such as galactose and mannose (85% pentose sugars and 15% hexose sugars), was employed as the substrate. Various substrate concentrations ranging from 2 to 32 g/L were tested, along with furfural concentrations of 0, 1, and 2 g/L. The investigation aimed to assess the effects of initial substrate concentration, initial furfural concentration, furfural-to-biomass ratio (F/B), and furfural-to-substrate ratio (F/S) on biohydrogen production yields. The maximum specific substrate utilization rates at different substrate concentrations were effectively characterized using Haldane's substrate inhibition model. Among the tested concentrations, the 16 g/L emerged as the optimal substrate concentration. The initial furfural concentration was identified as the most significant parameter impacting biohydrogen production, with complete inhibition observed at a furfural concentration of 2 g/L. Higher F/S ratios at substrate concentrations ranging from 2 to 16 g/L resulted in reduced maximum specific hydrogen production rates (MSHPR) and hydrogen yields. Substrate inhibition was observed at 24 g/L and 32 g/L. Lactate was the predominant metabolite in all batches containing 2-g/L furfural, as well as in batches with 1-g/L furfural and substrate concentrations of 24 and 32 g/L. Furfural at a concentration of 1 g/L was not inhibitory in any of the batches. Overall, the mixed cultures in this study could efficiently produce hydrogen from lignocellulosic hydrolysates and degrade furfural, providing new insights into fermentative hydrogen-producing bacteria with furfural tolerance. [ABSTRACT FROM AUTHOR]

Renewable alternatives for nonelectrifiable fossil-derived chemicals are needed and plant matter, the most abundant biomass on Earth, provide an ideal feedstock. However, the heterogeneous polymeric composition of lignocellulose makes conversion difficult. Lignin presents a formidable barrier to fermentation of nonpretreated biomass. Extensive chemical and enzymatic treatments can liberate fermentable carbohydrates from plant biomass, but microbial routes offer many advantages, including concomitant conversion to industrial chemicals. Here, testing of lignin content of nonpretreated biomass using the cellulolytic thermophilic bacterium, Anaerocellum bescii, revealed that the primary microbial degradation barrier relates to methoxy substitutions in lignin. This contrasts with optimal lignin composition for chemical pretreatment that favors high S/G ratio and low H lignin. Genetically modified poplar trees with diverse lignin compositions confirm these findings. In addition, poplar trees with low methoxy content achieve industrially relevant levels of microbial solubilization without any pretreatments and with no impact on tree fitness in greenhouse. [ABSTRACT FROM AUTHOR]