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The conversion of biomass into sugar platform compounds is very important for the biorefinery industry. Pretreatment is essential to the biomass of the sugar platform, however, the lignin obtained by pretreatment, as a key part of lignocellulose, generally has a passive effect on the enzymatic hydrolysis of cellulose into sugars. In this study, p-TsOH (p-toluenesulfonic acid), DES (Deep eutectic solvent) and CAOSA (cooking with active oxygen and solid alkali) pretreatment ways were used to fraction lignin from bamboo biomass. After CAOSA treatment, the hydrolysis efficiency of the pulp was 95.57%. Moreover, the effect of different treatment methods on lignin properties was studied and the promotion effect of lignin was investigated by adding it to the cellulose enzymatic hydrolysis system. In this work, the results showed that CAOSA-extracted lignin with lower Đ (1.31–1.25) had a better adsorption effect on the enzyme protein. p-TsOH-extracted lignin with a larger S/G ratio enhanced the inhibition of enzymatic hydrolysis. In addition, the presence of -COOHs in lignin could reduce its inhibitory effect on cellulose saccharification.

This article aims to review the various techniques used to produce diesel from lignocellulosic biomass. Data were collected using the Web of Science database to identify trends, barriers, and prospects associated with the alternative methods used. The analysis reviewed 359 papers published between 2006 and 2021, focusing on three key areas: biomass pretreatment, biomass conversion, and biorefining. Pretreatment technologies require extensive research to reduce excessive energy and reagent consumption, thereby reducing overall costs. Fast pyrolysis and lipid‐producing microorganisms have been shown to be the most promising conversion routes due to their versatility in utilizing different lignocellulosic residues and producing a wide range of marketable co‐products. The most widely used method used for refining is hydroprocessing coupled with catalysts, with the objective of improving bio‐oil quality. Two of the main challenges are the excessive cost of the overall process and the limitations imposed by the technology. These limitations require processing optimization to achieve sustainable production and valuable co‐products. The growth of lignocellulosic diesel production will depend on the integration with other biodiesel and biofuel production processes by the optimization of new processes and the generation of new bioproducts to increase efficiency and reduce costs for commercial viability. [ABSTRACT FROM AUTHOR]

This study aimed to propose a method for producing 1,4-butanediol (1,4-BDO) from inedible lignocellulosic biomass (e.g., kenaf). The process involved high-pressure CO2-catalyzed hydrolysis and dehydration to obtain furfural from kenaf and the conversion of furfural into 1,4-BDO. In the furfural production process, the yield of furfural increased with increasing temperature and reaction time, but a further increase in reaction time led to the formation of unwanted byproducts such as humins. The highest furfural yield (based on kenaf) was 3.78 mg g−1 at 220 °C with a 10-min reaction time. Further, furfural can be converted to 1,4-BDO using a bifunctional Pt/TiO2–ZrO2 catalyst. The 1,4-BDO yield (based on kenaf) achieved potentially with the Pt/TiO2–ZrO2 catalytic system was 3.22 mg g−1. The sequential conversion of kenaf biomass to valuable chemicals showcases a sustainable approach, aligning with global efforts toward reduced environmental impact. [ABSTRACT FROM AUTHOR]

This study was carried out to investigate the continuous aqueous pretreatment of sugarcane bagasse (SCB) through twin-screw extrusion for a new integrated full valorization, where the solid residue (extrudate) was used for the production of bio-based materials by thermocompression and the filtrate for the production of high-value-added molecules. Two configurations, with and without a filtration module, were tested and the influence of the SCB composition and structure on the properties of the materials were determined. The impact of the liquid-to-solid (L/S) ratio was studied (0.65-6.00) in relation to the material properties and the biomolecule extraction yield in the filtrate (with the filtration configuration). An L/S ratio of at least 1.25 was required to obtain a liquid filtrate, and increasing the L/S ratio to 2 increased the extraction yield to 11.5 g/kg of the inlet SCB. The extrudate obtained without filtration yielded materials with properties equivalent to those obtained with filtration for L/S ratios of at least 1.25. Since the molecule extraction process was limited, a configuration without filtration would make it possible to reduce water consumption in the process while obtaining high material properties. Under the filtration configuration, an L/S ratio of 2 was the best tradeoff between water consumption, extraction yield, and the material properties, which included 1485 kg/m3 density, 6.2 GPa flexural modulus, 51.2 MPa flexural strength, and a water absorption (WA) and thickness swelling (TS) of 37% and 44%, respectively, after 24 h of water immersion. The aqueous pretreatment by twin-screw extrusion allowed for the overall valorization of SCB, resulting in materials with significantly improved properties compared to those obtained with raw SCB due to fiber deconstruction. [ABSTRACT FROM AUTHOR]

Impregnation of potassium can enhance thermal decomposition and thermal reactions of biomass. In this study, the addition of potassium to biomass using potassium carbonate (K2CO3) was investigated to better understand the effects of solution concentration and impregnation time on the pretreatment process of as-received (macro-scale) sugarcane bagasse (SCB). The morphology and thermal degradation of SCB were characterized by FTIR, XRD, and TGA. Following that, the optimal condition was determined by using response surface methodology (RSM). As a result, K2CO3 significantly disorders the cellulose structure and the thermal decomposition temperature of impregnated SCB which is lower than the untreated bagasse in the difference of 25–57 °C. In addition, K2CO3 has a significant impact on char formation, which results in increased char yield. In summary, the RSM results suggest that the appropriate condition for K2CO3 pretreatment is at the solution concentration of 0.25 M and impregnation time of 60 min, resulting in the lowest crystallinity index (59.88%) with an acceptable value of activation energy (77.98 kJ/mol). Furthermore, it is recommended that K2CO3 pretreatment condition is required to apply for SCB before undergoing the torrefaction process, which could practically improve the torrefaction of SCB for a biomass power plant application. [ABSTRACT FROM AUTHOR]

In this work, the chemical composition, chemical structures, and sugar release were evaluated for sweet sorghum bagasse (SSB) biomass in response to alkaline pretreatments and enzymatic hydrolysis. Five different ratios of 2 M sodium hydroxide (NaOH) and sodium carbonate (Na2CO3) solutions were used for biomass fractionation along with two heat treatment conditions, 85°C and 150°C for 1 h. Sugar yields from enzymatic hydrolysis were measured at different durations up to 72 h. SSB samples pretreated at high temperature using alkaline solutions containing equal amounts of Na2CO3 and NaOH favored retaining cellulose content (up to 90%) while effectively removing hemicellulose (65%) and lignin (92%). The high-temperature pretreatment conditions resulted in improved delignification, higher sugar concentrations, and sugar yields. Pretreatment solutions consisting of 50% or more NaOH produced higher glucose yields (85%–90%) and total sugar concentrations. Moreover, pretreatment solutions containing Na2CO3 improved the hydrolysis rates allowing SSB samples reach maximum yields faster than those without it, 48 versus 72 h. Results showed pretreatment methods combining NaOH and Na2CO3 were effective at promoting SSB biomass conversion, increasing sugar recovery after hydrolysis, and reducing the hydrolysis duration, all of which are desirable and cost beneficial.

The range of applications for industrial hemp has consistently increased in various sectors over the years. For example, hemp hurd can be used as a resource to produce biodegradable packaging materials when incorporated into a fungal mycelium composite, a process that has been commercialized. Although these packaging materials can be composted after usage, they may present an opportunity for valorization in a biorefinery setting. Here, we demonstrate the potential of using this type of discarded packaging composite as a feedstock for biofuel production. A one-pot ionic liquid-based biomass deconstruction and conversion process was implemented, and the results from the packaging material were compared with those obtained from untreated hemp hurd. At a 120 °C reaction temperature, 7.5% ionic liquid loading, and 2 h reaction time, the packaging materials showed a higher lignocellulosic sugar yield and sugar concentrations than hemp hurd. Hydrolysates prepared from packaging materials also promoted production of higher titers (1400 mg/L) of the jet-fuel precursor bisabolene when used to cultivate an engineered strain of the yeast Rhodosporidium toruloides. Box-Behnken experiments revealed that pretreatment parameters affected the hemp hurd and packaging materials differently, evidencing different degrees of recalcitrance. This study demonstrated that a hemp hurd-based packaging material can be valorized a second time once it reaches the end of its primary use by supplying it as a feedstock to produce biofuels.

1-Alkyl-3-methylimidazolium ionic liquids are common cellulose solvents and biomass pretreatment agents, while beta-irradiation ("e-beaming") is often used to decrease the recalcitrance of biomass towards hydrolysis or saccharification. Aiming at the general goal of elucidating the interaction between lignocellulosics, imidazolium-based ionic liquids, and beta-irradiation, we studied the effect of beta-irradiation on the pure ILs 1-ethyl-3-methylimidazolium and 1-butyl-3-methylimidazolium, both as chloride and acetate. Contrary to the expectation of inertness, irradiation caused degradation of the ILs, which was proportional to irradiation dosage, i.e., to irradiation time and intensity. At a dosage of 2400 kGy, 0.2% (2000 ppm) of the IL were chemically altered. The main degradation pathway is the formation of imidazole and N-methylimidazole with concomitant dealkylation. The cleaved-off alkyl groups, apparently in cationic form, react with the anions present, accounting for the formation of alkyl chlorides and alkyl acetates from the chloride ILs and acetate ILs, respectively. A second, minor pathway comprises the degradation of the imidazole ring under conversion of the C2-unit from the former C4-C5 moiety into ethylenediamine and reaction of the C1-unit from the former C2 with the IL anions. Because of the non-neglible byproduct formation, the degradation of the ILs upon beta-irradiation and possible side reactions of the resulting byproducts need to be kept in mind for all setups that involve beta-irradiation and imidazolium ILs simultaneously. [ABSTRACT FROM AUTHOR]

The pretreatment step has a major role in ethanol production as it breaks the lignocellulosic material structure, which improves the digestibility in the enzymatic hydrolysis and increases the ethanol yield during fermentation. The purpose in this study was to pretreat green coconut fiber (GCF) with steam explosion (SE) to produce ethanol. Different severity factors (ranging between 2.18 and 4.24) were performed and the humidification process of the raw material before pretreatment was also evaluated. Considering that SE did not provide lignin removal nor significant improvement in enzymatic digestibility, a subsequent alkaline pretreatment was carried out to overcome these challenges. The alkaline pretreatment using NaOH increased delignification, either as a stand-alone or in the sequential pretreatment. The sequential SE/alkaline pretreatment provided higher values of hydrolysis yield (54.74%), total reducing sugars (29.17 ± 1.21 g/L), and glucose production (16.65 ± 0.82 g/L) when compared to the separated pretreatments. Thereafter, simultaneous saccharification and fermentation (SSF) and semi-simultaneous saccharification and fermentation (SSSF) strategies were evaluated using Saccharomyces cerevisiae PE2, Saccharomyces cerevisiae CAT-1, and Kluyveromyces marxianus ATCC 36,907 yeasts with different solid loadings (5, 10, and 15% w/v). The pre-saccharification step increased ethanol yield and ethanol concentration in all experiments. The highest ethanol concentration (24.88 ± 1.04 g/L) was achieved using SSSF with 15% (w/w) solid loading, while the ethanol obtained in SSF experiments was equal to 21.62 ± 0.87 g/L using the same solid loading. The sequential SE/alkaline pretreatment was a successful combination, improving sugars' production and leading to a high ethanol concentration. [ABSTRACT FROM AUTHOR]

β-glucosidase is an essential enzyme for the enzymatic hydrolysis of lignocellulosic biomass, as it catalyzes the final stage of cellulose breakdown, releasing glucose. This paper aims to produce β-glucosidase from Saccharomyces cerevisiae and evaluate the enzymatic degradation of delignified sugarcane bagasse. S. cerevisiae was grown in yeast peptone dextrose medium. Partial purification of the enzyme was achieved through precipitating proteins with ethanol, and the optimal activity was measured by optimizing pH and temperature. The effects of ions, glucose tolerance, and heat treatment were evaluated. Delignified sugarcane bagasse was hydrolyzed by the enzyme. β-glucosidase showed a specific activity of 14.0712 ± 0.0207 U mg−1. Partial purification showed 1.22-fold purification. The optimum pH and temperature were 6.24 and 54 °C, respectively. β-glucosidase showed tolerance to glucose, with a relative activity of 71.27 ± 0.16%. Thermostability showed a relative activity of 58.84 ± 0.91% at 90 °C. The hydrolysis of delignified sugarcane bagasse showed a conversion rate of 87.97 ± 0.10% in the presence of Zn2+, an ion that promoted the highest increase in enzymatic activity. S. cerevisiae produced an extracellular β-glucosidase with good stability at pH and temperatures conventionally applied in the hydrolysis of lignocellulosic biomass, showing viability for industrial application. [ABSTRACT FROM AUTHOR]

Globally, the fossil fuel reserves are depleting rapidly and the escalating fuel prices as well as plethora of the pollutants released from the emission of burning fossil fuels cause global warming that massively disturb the ecological balance. Moreover, the unnecessary utilization of non-renewable energy sources is a genuine hazard to nature and economic stability, which demands an alternative renewable source of energy. The lignocellulosic biomass is the pillar of renewable sources of energy. Different conventional pretreatment methods of lignocellulosic feedstocks have employed for biofuel production. However, these pretreatments are associated with disadvantages such as high cost of chemical substances, high load of organic catalysts or mechanical equipment, time consuming, and production of toxic inhibitors causing the environmental pollution. Nanotechnology has shown the promised biorefinery results by overcoming the disadvantages associated with the conventional pretreatments. Recyclability of nanomaterials offers cost effective and economically viable biorefineries processes. Lignolytic and saccharolytic enzymes have immobilized onto/into the nanomaterials for the higher biocatalyst loading due to their inherent properties of high surface area to volume ratios. Nanobiocatalyst enhance the hydrolyzing process of pretreated biomass by their high penetration into the cell wall to disintegrate the complex carbohydrates for the release of high amounts of sugars towards biofuel and various by-products production. Different nanotechnological routes provide cost-effective bioenergy production from the rich repertoires of the forest and agricultural-based lignocellulosic biomass. In this article, a critical survey of diverse biomass pretreatment methods and the nanotechnological interventions for opening up the biomass structure has been carried out. [ABSTRACT FROM AUTHOR]

The contents of ash and chlorine, and the heating value are important factors for the utilization of biomass. In this work, the washing of corn straw with water for de-ash, de-chlorination, and increase of the heating value was investigated. Before washing, the corn straw was ground to powders and fractionated into different particle sizes. The particles less than 38 μm were found in higher content of chlorine, and thus were removed and only the powders in the range of 38–250 μm were examined. Three independent variables of the liquid/solid ratio (L/S), the washing time (t), and the washing temperature (T) were investigated in the washing experiments. A mathematical model was constructed by response surface methodology (RSM). The results showed that the parameter of L/S was most significant, followed by the order of t, the interaction between L/S and t, and T. The reliability of the model was verified by analysis of variance and by comparison with laboratory results. According to the model prediction, the optimal conditions of L/S, washing time, and temperature were respectively determined as 39.98 mL/g, 11.55 min, and 30 °C. The details of the washing influence were further investigated, by characterizations of the eluate and the solid samples before and after washing. [ABSTRACT FROM AUTHOR]

This work investigated hydrogen production from biomass feedstocks (i.e., glucose, starch, lignin and cellulose) using a 100 mL h-type proton exchange membrane electrolysis cell. Biomass electrolysis is a promising process for hydrogen production, although low in technology readiness level, but with a series of recognised advantages: (i) lower-temperature conditions (compared to thermochemical processes), (ii) minimal energy consumption and low-cost post-production, (iii) potential to synthesise high-volume H2 and (iv) smaller carbon footprint compared to thermochemical processes. A Lewis acid (FeCl3) was employed as a charge carrier and redox medium to aid in the depolymerisation/oxidation of biomass components. A comprehensive analysis was conducted, measuring the H2 and CO2 emission volume and performing electrochemical analysis (i.e., linear sweep voltammetry and chronoamperometry) to better understand the process. For the first time, the influence of temperature on current density and H2 evolution was studied at temperatures ranging from ambient temperature (i.e., 19 °C) to 80 °C. The highest H2 volume was 12.1 mL, which was produced by FeCl3-mediated electrolysis of glucose at ambient temperature, which was up to two times higher than starch, lignin and cellulose at 1.20 V. Of the substrates examined, glucose also showed a maximum power-to-H2-yield ratio of 30.99 kWh/kg. The results showed that hydrogen can be produced from biomass feedstock at ambient temperature when a Lewis acid (FeCl3) is employed and with a higher yield rate and a lower electricity consumption compared to water electrolysis. [ABSTRACT FROM AUTHOR]

This study evaluates the microwave pretreatment of sugarcane (Saccharum officinarum) trash and oil palm (Elaeis guineensis Jacq.) empty fruit bunch (OPEFB) to yield-reducing sugars using Al2(SO4)3 as the catalyst and water as the medium. Pretreatment using 1% oxalic acid was also carried out to compare the total reducing sugar yield for both biomasses. The effects of the pretreatment on the changes in functional groups, crystallinity, and surface morphology of the biomass are discussed. Microwave heating of sugarcane trash and OPEFB particles at 180 °C for 5 min with and without the addition of 100 and 200 µmol/g biomass of Al2(SO4)3 catalyst were performed, and the total reducing sugar yield from the pretreatment hydrolysate and the enzymatic hydrolysis was improved, recorded as 0.56 and 0.51 g/g of initial biomass, respectively, representing 88.8 and 81.6% of the theoretical yield. The use of 1% oxalic acid in the pretreatment of sugarcane trash and OPEFB yielded different results of total reducing sugar yield as the two biomasses behaved differently. [ABSTRACT FROM AUTHOR]

We have identified a HRP enzyme with microcrystalline cellulose activity, which has not yet been explored. The current study investigated the effect of HRP pretreatment on the microcrystalline cellulose substrates, Avicel and filter paper. SEM findings showed that HRP pretreatment catalysed the para-microcrystalline regions of Avicel, cracking and opening the pores on the surface. On filter paper, HRP removed the para-microcrystalline regions exposing fibres. Crystallinity index (CrI) analysis confirmed that HRP increased the CrI of Avicel from 49 % to 54.19 % and filter paper from 42 % to 47 %. The cellulose crystallite sizes increased from 45 to 47 nm at the 002 lattices in Avicel, suggesting a reduction of crystalline cellulose. In addition, endoglucanase displayed 1.15-fold increased activity on HRP-pretreated Avicel, confirming reduced crystalline cellulose. These findings showed that HRP pretreatment changed the structural and chemical properties of Avicel, i.e., loosening crystalline cellulose to make the substrate accessible to enzymes during hydrolysis. Finally, these findings were supported by rooibos microcrystalline cellulose modification post-HRP pretreatment, resulting in a 95 % yield of soluble sugars at 25 mg enzyme cocktail/g biomass.

Abstract In recent years, low-temperature plasma-assisted processes, featuring high reaction efficiency and wide application scope, have emerged as a promising alternative to conventional methods for biomass valorization. It is well established that charged species, chemically energetic molecules and radicals, and highly active photons playing key roles during processing. This review presents the major applications of low-temperature plasma for biomass conversion in terms of (i) pretreatment of biomass, (ii) chemo fractionation of biomass into value-added chemicals, and (iii) synthesis of heterogeneous catalyst for further chemo-catalytic conversion. The pretreatment of biomass is the first and foremost step for biomass upgrading to facilitate raw biomass transformation, which reduces the crystallinity, purification, and delignification. The chemo-catalytic conversion of biomass involves primary reactions to various kinds of target products, such as hydrolysis, hydrogenation, retro-aldol condensation and so on. Finally, recent researches on plasma-assisted chemo-catalysis as well as heterogeneous catalysts fabricated via low-temperature plasma at relatively mild condition were introduced. These catalysts were reported with comparable performance for biomass conversion to other state-of-the-art catalysts prepared using conventional methods. Graphical Abstract

Babassu (Orbignya phalerata) is a valuable oleaginous fruit in Brazil's economy. After processing to extract oil, large quantities of residual mesocarp are generated. Typically, this by-product finds reuse as an additive in animal feed or is sold as flour for human consumption. However, there is a pressing need for innovative approaches to valorize this residue and leverage new technologies to create value-added compounds. Most existing processes for lignocellulosic biomass suffer from low selectivity during pre-treatment, often neglecting essential fractions like lignin, which holds significant biotechnological potential. In this context, deep eutectic solvents (DES) have emerged as a promising alternative pre-treatment method, thanks to their remarkable properties, including the ability to solubilize lignin, recyclability, and catalytic capacity. This study investigates the dissolution of residual babassu mesocarp in various deep eutectic solvents at different temperatures (70–130 °C) and biomass:solvent ratios (0.05−0.1). Two initial candidates, choline chloride:acetic acid (CC:AA) and proline:acetic acid (PRO:AA), were chosen. Notably, CC:AA achieved an impressive dissolution yield of up to 97.6% by mass of the residual mesocarp, while PRO:AA reached up to 50.8% by mass, with the thermal effect proving highly significant. Interestingly, the biomass:solvent ratio showed minimal influence on dissolution yield. The analysis of liquid fractions revealed that, for CC:AA treatment, lignin content measured 2.3 mg/mL (70 °C), 9.8 mg/mL (100 °C), and 10.5 mg/mL (130 °C). In contrast, PRO:AA treatment resulted in lignin content of 3.1 mg/mL (70 °C), 2.3 mg/mL (100 °C), and 2.8 mg/mL (130 °C). Furthermore, PRO:AA treatment yielded a total carbohydrate concentration of 2.2 mg/mL (70 °C), 1.9 mg/mL (100 °C), and 3.9 mg/mL (130 °C). For CC:AA treatment, the respective values were 2.6 mg/mL (70 °C), 17.2 mg/mL (100 °C), and 29.6 mg/mL (130 °C). UV/VIS analyses confirmed the dissolution of lignin and hinted at the extraction of tannins and anthocyanins (in CC:AA), underscoring their catalytic potential. This study marks the initial step in dissolving babassu mesocarp in DES and presents a promising avenue for biomass valorization in the future. [ABSTRACT FROM AUTHOR]

In the present work, a new alternative of hydrodynamic cavitation–assisted pretreatment associated with an advanced oxidative process was proposed, together with a new approach to obtain bioproducts in sequential fermentations. Enzymatic hydrolysate of sugarcane bagasse (SCB) was fermented to ethanol by Saccharomyces cerevisiae. After distillation of this alcohol, the obtained vinasse was used to produce xylitol by Candida tropicalis. Influent variables in pretreatment were evaluated by performing experiments according to a statistical design, and, at optimum conditions (ozone flowrate of 10 mg/min, and H2O2 concentration of 0.61%), about 84% and 78% of glucan and xylan hydrolysis yields were obtained in enzymatic hydrolysis, respectively. In the sequential fermentations for ethanol and xylitol production, yield values of 0.41 g/g and 0.55 g/g, respectively, were obtained, with corresponding volumetric productivities of 8.33 g/Lh and 0.64 g/Lh, respectively. The proposed strategy was shown as a promising approach for biorefineries, considering the mild conditions of pretreatment and the possibility of high ethanol production using S. cerevisiae in a fermentation process similar to that one already available in sucro-alcoholic sector, followed by xylitol production in vinasse-based medium. [ABSTRACT FROM AUTHOR]

Environmentally acceptable and renewably sourced flame retardants are in demand. Recent studies have shown that the incorporation of the biopolymer lignin into a polymer can improve its ability to form a char layer upon heating to a high temperature. Char layer formation is a central component of flame-retardant activity. The covalent modification of lignin is an established technique that is being applied to the development of potential flame retardants. In this study, four novel modified lignins were prepared, and their char-forming abilities were assessed using thermogravimetric analysis. The lignin was obtained from date palm wood using a butanosolv pretreatment. The removal of the majority of the ester groups from this heavily acylated lignin was achieved via alkaline hydrolysis. The subsequent modification of the lignin involved the incorporation of an azide functional group and copper-catalysed azide–alkyne cycloaddition reactions. These reactions enabled novel organophosphorus heterocycles to be linked to the lignin. Our preliminary results suggest that the modified lignins had improved char-forming activity compared to the controls. 31P and HSQC NMR and small-molecule X-ray crystallography were used to analyse the prepared compounds and lignins. [ABSTRACT FROM AUTHOR]

This original research contributes to enhancing the viability of biorefineries through recovering valuable by‐products from the liquid remaining after the biomass pretreatment by hot liquid water. A novel downstream processing method is developed for the recovery of acetic acid, formic acid, furfural and 5‐hydroxymethylfurfural (HMF) by enhanced distillation. The major challenge in this research is the processing of the highly diluted initial solution (>96 wt% water) and the thermodynamic limitations owing to possible formation of several azeotropes. This new process recovers 78.7% of the acetic acid (99.8 wt%), while the rest of it is recycled back to the biomass pretreatment step together with most of the separated water from the initial solution. Over 99.5% of formic acid, furfural and HMF is also recovered, at purities of 74.7, 98.0 and 100 wt%, respectively. Vapor recompression and heat integration are implemented to decrease the energy use. The results demonstrate a 77.4% decrease in total annual costs (from $3.44 to 0.78/kgproduct), a 75.0% reduction in minimum average selling price (from $3.50 to 0.87/kgproduct), an 81.1% reduction in energy requirements (from 77.41 to 14.66 kWthh/kgproduct) and an up to 99.7% decrease in CO2 emissions (from 11.17 to 0.03 kgCO2/kgproduct). [ABSTRACT FROM AUTHOR]

Plant biomass, one of the most abundant and renewable resources obtained from plants has gained much interest among researchers. Recently, more attention has shifted towards aquatic plant biomass as a potential alternative feedstock for producing bioenergy and other high-value products. Regardless of the low lignin content, invasive aquatic plant (IAP) biomass should undergo pretreatments to disrupt the recalcitrant supramolecular structure to minimize the conversion time, operational cost, and ensure optimal yield. Three major types of Lignocellulosic biomass (LB) pretreatments including physical, chemical, and biological are predominantly applied independently or in combination depending on the type of biomass. This review was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) method for the compilation of existing literature on aquatic plant biomass pretreatment. A total of 185 peer-reviewed articles on the pretreatment of aquatic LB published between the year 2018 to 2022 were retrieved from the Elsevier, MDPI, and Springer databases. This study revealed the water hyacinth (WH) as the most researched IAP and thus identifies the need for more studies on a variety of IAPs that have proven to produce high-value products and biofuels that are comparable to petroleum products. [ABSTRACT FROM AUTHOR]

This study was carried out to investigate the continuous aqueous pretreatment of sugarcane bagasse (SCB) through twin-screw extrusion for a new integrated full valorization, where the solid residue (extrudate) was used for the production of bio-based materials by thermocompression and the filtrate for the production of high-value-added molecules. Two configurations, with and without a filtration module, were tested and the influence of the SCB composition and structure on the properties of the materials were determined. The impact of the liquid-to-solid (L/S) ratio was studied (0.65–6.00) in relation to the material properties and the biomolecule extraction yield in the filtrate (with the filtration configuration). An L/S ratio of at least 1.25 was required to obtain a liquid filtrate, and increasing the L/S ratio to 2 increased the extraction yield to 11.5 g/kg of the inlet SCB. The extrudate obtained without filtration yielded materials with properties equivalent to those obtained with filtration for L/S ratios of at least 1.25. Since the molecule extraction process was limited, a configuration without filtration would make it possible to reduce water consumption in the process while obtaining high material properties. Under the filtration configuration, an L/S ratio of 2 was the best tradeoff between water consumption, extraction yield, and the material properties, which included 1485 kg/m3 density, 6.2 GPa flexural modulus, 51.2 MPa flexural strength, and a water absorption (WA) and thickness swelling (TS) of 37% and 44%, respectively, after 24 h of water immersion. The aqueous pretreatment by twin-screw extrusion allowed for the overall valorization of SCB, resulting in materials with significantly improved properties compared to those obtained with raw SCB due to fiber deconstruction.

Energy and resource intensive mechanical and chemical pretreatment along with the use of hazardous chemicals are major bottlenecks in widespread lignocellulosic biomass utilization. Herein, the study investigated different pretreatment methods on spruce wood namely supercritical CO2 (scCO2) pretreatment, ultrasound-assisted alkaline pretreatment, and acetosolv pulping-alkaline hydrogen peroxide bleaching, to enhance the enzymatic digestibility of wood using optimized enzyme cocktail. Also, the effect of scCO2 pretreatment on enzyme cocktail was investigated after optimizing the concentration and temperature of cellulolytic enzymes. The impact of scCO2 and ultrasound-assisted alkaline pretreatments of wood were insignificant for the enzymatic digestibility, and acetosolv pulping-alkaline hydrogen peroxide bleaching was the most effective pretreatment that showed the release of total reducing sugar yield (TRS) of ∼95.0 wt% of total hydrolyzable sugars (THS) in enzymatic hydrolysis. The optimized enzyme cocktail showed higher yield than individual enzymes with degree of synergism 1.34 among the enzymes, and scCO2 pretreatment of cocktail for 0.5–1.0 h at 10.0–22.0 MPa and 38.0–54.0 °C had insignificant effect on the enzyme's primary and global secondary structure of cocktail and its activity.

Biomass pretreatment incurs 40% of the overall cost of biorefinery operations. The usage of mushroom cultivation as a pretreatment/delignification technique, and bio-ethanol production from spent mushroom substrates, after subsequent pretreatment, saccharification and fermentation processes, have been reported earlier. However, the present pilot-scale, entirely-organic demonstration is one of the very first biorefinery models, which efficiently consolidates: biomass pretreatment; in-situ cellulase production and saccharification; mushroom cultivation, thereby improving the overall operational economy. During pretreatment, the oyster mushroom, Pluerotus florida VS-6, matures into distinct substrate mycelia and fruiting bodies. Consequential variations in the kinetics of growth, biomass degradation/substrate utilization, oxygen uptake and transfer rates, and enzyme production, have been analyzed. Signifying the first-time usage of a biomass mixture, comprising vegetative waste and e-commerce packaging waste, the 30 day-long, bio-economical, non-inhibitor-generating, catabolite repression-limited, solid-state in-situ pretreatment-cum-saccharification, resulted in: 78% lignin degradation; 13.25% soluble-sugar release; 18.25% mushroom yield; 0.88 FPU/g.ds cellulase secretion. The in-situ saccharified biomass, when sequentially subjected to ex-situ enzymatic hydrolysis and fermentation, showed 37.35% saccharification, and a bio-ethanol yield of 0.425 g per g of glucose, respectively. Apart from yielding engine-ready bio-ethanol, the model doubles as an agripreneurial proposition, and encourages mushroom cultivation and consumption. [ABSTRACT FROM AUTHOR]

In recent years, low-temperature plasma-assisted processes, featuring high reaction efficiency and wide application scope, have emerged as a promising alternative to conventional methods for biomass valorization. It is well established that charged species, chemically energetic molecules and radicals, and highly active photons playing key roles during processing. This review presents the major applications of low-temperature plasma for biomass conversion in terms of (i) pretreatment of biomass, (ii) chemo fractionation of biomass into value-added chemicals, and (iii) synthesis of heterogeneous catalyst for further chemo-catalytic conversion. The pretreatment of biomass is the first and foremost step for biomass upgrading to facilitate raw biomass transformation, which reduces the crystallinity, purification, and delignification. The chemo-catalytic conversion of biomass involves primary reactions to various kinds of target products, such as hydrolysis, hydrogenation, retro-aldol condensation and so on. Finally, recent researches on plasma-assisted chemo-catalysis as well as heterogeneous catalysts fabricated via low-temperature plasma at relatively mild condition were introduced. These catalysts were reported with comparable performance for biomass conversion to other state-of-the-art catalysts prepared using conventional methods. [ABSTRACT FROM AUTHOR]

The production of biofuels and biochemicals requires a pretreatment to cleave the composite-like structure of lignocellulosic biomass and thus facilitate further conversion. In the case of liquid-based pretreatment, it is important to know which pretreatment liquids allow for an effective conversion of biomass. For the development of effective pretreatment strategies, simple criteria for a fast evaluation of pretreatment results are advantageous. In this study, we use the example of acetosolv pretreatment of beech wood to explore the influence of composition of the employed acetosolv liquids. To this end, we investigate pretreatment phenomena on different scales including macroscopic disintegration, overall mass balances and compositional changes of beech wood. We relate the investigated phenomena with the type and amount of catalyst acid as well as water content of the employed acetosolv liquids. The results show that disintegration increases with both a higher concentration and acidity of the catalyst acid, while excessive disintegration can be balanced by an increased water content up to equimolar ratios of water and acetic acid. Furthermore, an increasing disintegration correlates with an increasing non-recovered fraction up to a maximum of 40 wt%. The non-recovered fraction in turn linearly depends on the amount of removed hemicellulose and lignin. Overall, a low lignin content together with complete disintegration after pretreatment in acetosolv liquids with a high water content allows for increased sugar yields in subsequent enzymatic hydrolysis. Thus, disintegration and non-recovered fraction serve as a simple indicator for a first assessment of pretreatment effectiveness. [ABSTRACT FROM AUTHOR]

The iron and steel industry remains one of the most energy-intensive activities with high CO2 emissions. Generally, the use of fossil coal as chemical energy in an electric arc furnace (EAF) makes up 40–70% of the total direct emissions in this steelmaking process. Therefore, substituting conventional fossil fuels with alternatives is an attractive option for reducing CO2 emissions. In this study, the environmental impacts of EAF-produced steel were comprehensively assessed using pulverized hydrochar as the charged and injected material as a replacement for fossil coal. An environmental analysis was performed based on the LCA methodology according to the framework of ISO 14044. This study evaluated two different outlines: the use of fossil coal and its replacement with hydrochar from the winemaking industry as a carbon source in the EAF steelmaking process. The environmental impacts from the manufacturing of the hydrochar were calculated using different scenarios, including novel industrial ways to use vinasse as a moisture source for the co-hydrothermal carbonization of vine pruning and exhausted grape marc (EGM). The environmental impacts per unit of steel were reported as a function of the ratio between the fixed carbon of the injected material and the material amount itself. The results highlight the sustainability of the hydrothermal carbonization process and the use of the hydrochar in EAF steelmaking. Moreover, the electricity mix used for the EAF process has significant relevance. The main outline of the results might assist decision-makers to determine which technological route is most likely to be effective in reducing future CO2 emissions from the iron and steel industry. [ABSTRACT FROM AUTHOR]

In the recent past, an increasing interest is mostly observed in using microwave and ultrasonic irradiation to aid the biological conversion of waste materials into value-added products. This study is focused on various individual impacts of microwaves and ultrasonic waves for the treatment of biomass before the synthesis of value-added products. Following, a comprehensive review of the mechanisms governing microwaves and ultrasonication as the treatment methods, their effects on biomass disruption, solubilization of organic matter, modification of the crystalline structure, enzymatic hydrolysis and production of reducing sugars was performed. However, based on the lab-scale experiments evaluated, microwaves and ultrasonication were studied to be economically and energetically ineffective despite their beneficial effects on the waste biomass. This article reviews some of the difficulties associated with using microwaves and ultrasonic irradiation for the efficient processing of waste biomasses and identified some potential directions for future study. [ABSTRACT FROM AUTHOR]

Proton-type ionic liquids have been proved to be promising for the pretreatment of lignocellulosic biomass, because they can provide high yield cellulase hydrolysis and high lignin removal rate. In this work, three proton-type ionic liquids, ethyl methanesulfonamide (EAM), ethyl amine nitrate (EAN) and ethyl amine acetate (EAN[OAc]), were successfully synthesized to pretreat corn straw, and five sugar platform organic solvents were selected as co-solvents for biomass pretreatment. The experimental results showed that under the optimal pretreatment conditions (10 wt% EAM, 130 °C, 2 h, 7 wt% straw loading in PDO solvent), the delignification rate of corn straw could reach 96 wt%, the sugar yield of cellulose-rich substrate could reach 95 wt% in 96 h, the regeneration rate of lignin dissolved in the solvent was 86 wt%, and the remainder of the solvent was small molecular compound, the hemicellulose dissolved in the solvent is degraded to monomolecular sugars (xylose and arabinose). The XRD, SEM characterization data and spectrograms of cellulosic substrate also fully proved that the lignin was successfully dissolved and separated from corn straw by pretreatment of composite system, and in the remaining straw the content and crystallinity of cellulose was improved. In this paper, density functional theory (DFT) is used to explore the pretreatment principle. From the optimized structure, it can be seen that the interaction energy between the ionic liquid cosolvent system and lignin is higher than that in the pure ionic liquid system. The simulation results, experimental analysis and characterization can effectively explain the essence of the system for efficient straw pretreatment, and the system can provide new ideas for the development of biomass pretreatment. [ABSTRACT FROM AUTHOR]

Lignocellulosic biomass is a significant source of sustainable fuel and high-value chemical production. However, due to the complex cross-linked three-dimensional network structure, lignin is highly rigid to degradation. In natural environments, the degradation is performed by wood-rotting fungi. The process is slow, and thus, the use of lignin degradation by fungi has not been regarded as a feasible technology in the industrial lignocellulose treatment. Fungi produce a wide variety of ligninolytic enzymes that can be directly introduced in industrial processing of lignocellulose. Within this study, screening of ligninolytic enzyme production using decolorization of ABTS and Azure B dyes was performed for 10 fungal strains with potentially high enzyme production abilities. In addition to standard screening methods, media containing lignin and hay biomass as carbon sources were used to determine the change in enzyme production depending on the substrate. All selected fungi demonstrated the ability to adapt to a carbon source limitation; however, four strains indicated the ability to secrete ligninolytic enzymes in all experimental conditions—Irpex lacteus, Pleurotus dryinus, Bjerkandera adusta, and Trametes versicolor—respectively displayed a 100%, 82.7%, 82.7%, and 55% oxidation of ABTS on lignin-containing media and 100%, 87.9%, 78%, and 70% oxidation of ABTS on hay-containing media after 168 h of incubation. As a result, the most potent strains of fungi were selected to produce lignocellulose-degrading enzymes and to demonstrate their potential application in biological lignocellulose pretreatment. [ABSTRACT FROM AUTHOR]

Lignocellulosic residues represent a low cost, high quality, and abundantly available alternative carbon sources that offer potential solutions to challenges linked to the growing demand for sustainability. In this study, the potential for the production of holocellulolytic enzymes induced by Paecilomyces formosus with agro-industrial coffee residues as substrates was evaluated. Enzymatic screening of eight strains revealed three major producers of pectinases (strains 3RET13, 3RE14, and 3RE21). For accurate molecular identification, sequence analysis was performed using the internal transcribed spacer regions 1 and 2 of nuclear ribosomal DNA, calmodulin, and β-tubulin gene regions as DNA barcode markers. Response surface analysis was employed to determine the most appropriate pretreatment and cultivation conditions for the induction of pectinase, mannanase, xylanase, and endoglucanase enzyme activities. Different factors related to pretreatment (biomass concentration, exposure time, and temperature) and cultivation (pH, agitation, temperature, and nitrogen supplementation) were evaluated. Pectinase profiles were described for P. formosus strain 3RE21. A low-severity treatment with a lower biomass concentration (140 °C, 6 min, 1%) and milder cultivation conditions (20 °C, 87 rpm, pH 4.0, with no nitrogen supplementation) was considered optimal for the production of pectinases due to the high and rapid induction of these enzymes by the resulting liquor, with 2.11 UI/ml enzymatic activity, 11% reduction in total lignin content and 71% solubilization of the cellulosic and hemicellulosic portion observed with these conditions. The use of low-severity pre-treatments is widely used due to the financial and temporal investment of industries, as the compounds of interest are quickly and easily extracted from biomass as they are less exposed to the aggressive conditions of pre-treatments. [ABSTRACT FROM AUTHOR]

Abstract The difficulty of degrading lignin is the main factor limiting the high-value conversion process of lignocellulosic biomass. The biodegradation of lignin has attracted much attention because of its strong environmental friendliness, but it still faces some dilemmas such as slow degradation rate and poor adaptability. The microbial consortia with high lignin degradation efficiency and strong environmental adaptability were obtained in our previous research. To further increase the lignin degradation efficiency, this paper proposes a composite treatment technology of steam explosion combined with microbial consortium degradation to treat three kinds of biomass. We measured the lignin degradation efficiency, selectivity value (SV) and enzymatic saccharification efficiency. The structural changes of the biomass materials and microbial consortium structure were also investigated. The experimental results showed that after 1.6 MPa steam explosion treatment, the lignin degradation efficiency of the eucalyptus root reached 35.35% on the 7th days by microbial consortium. At the same time, the lignin degradation efficiency of the bagasse and corn straw treated by steam explosion followed by microbial biotreatment was 37.61–44.24%, respectively, after only 7 days of biotreatment. The microbial consortium also showed strong selectivity degradation to lignin. The composite treatment technology can significantly improve the enzymatic saccharification efficiency. Saccharomycetales, Ralstonia and Pseudomonadaceae were the dominant microorganisms in the biomass degradation systems. It was proved that the combined treatment technology of steam explosion and microbial consortium degradation could overcome the drawbacks of traditional microbial pretreatment technology, and can facilitate the subsequent high-value conversion of lignocellulose.

This work proposes a valorization route for spent coffee grounds (SCG), a widespread lignocellulosic residue, encompassing the production of: biomethane, lignin, and oligosaccharides as value-added products obtained simultaneously during a mild alkaline (NaOH) pretreatment. The studied operational variables were the reaction time (60–240 min), temperature (25–75 °C), and the NaOH concentration (0–2.5 M). The severity factor suitably describes the global process kinetics, with higher severities (log Mo = 5.5) yielding high product yields, 18.02% and 13.25% (on dry SCG basis) for lignin and oligosaccharides (XGMOS), respectively. Solid yield is negatively impacted by all studied variables (at the 95% confidence level). Conversely, XGMOS yield is positively influenced both by time and catalyst concentration, whereas lignin yield is only (positively) influenced by catalyst concentration. Optimal balance between product formation and potential operational costs is putatively achieved when using 0.625 M NaOH, at 50 °C for 60 min. The mild alkaline pretreated biomass (MAP-SCG) was compared to untreated SCG for biomethane production by anaerobic co-digestion with pig slurry (PS), using a ratio of biomass/PS = 1/3 (volatile solids (VS) basis). The proposed valorization route enabled the sequential production of 6.25 kg lignin, 6.36 kg oligosaccharides, and 138.05 kg biomethane per 100 kg of non-extracted SCG (and 287.60 kg pig slurry), in an integrated process that is technically feasible and promotes the circular bioeconomy. [ABSTRACT FROM AUTHOR]

Supercritical carbon dioxide (SCCO2) was employed as pretreatment of blue agave bagasse (BAB) to enhance enzymatic hydrolysis (EH) to simple sugars in preparation for bioethanol fermentation. Processing time (10–120 min), temperature (24–120 °C), and pressure (80–350 bar) were evaluated to obtain maximum total reducing sugar (TRS) after EH with commercial cellulase. Effect of water activity (aw) (0.082–0.973) of BAB was evaluated after optimum pretreatment conditions for maximum TRS (100 °C, 280 bar, and 10 min) were established. Higher values of temperature or pressure degraded simple sugars as determined by relative furan analysis. Treated samples were also characterized by scanning electronic microscopy and porosimetry, showing structural and morphological modifications that enhance enzymatic digestibility as compared to untreated controls. Processing with SCCO2 results in 40% increment in TRS compared with untreated BAB. Hydration level defined by aw resulted in the main variable affecting sugar yields, with lowest aw of pretreated BAB generating the highest TRS valued. It is proposed that at low hydration levels, diffusivity of CO2 is greater facilitating infiltration into the matrix and a more extensive deconstruction of the tight lignocellulosic matrix by explosion when pressure is released. [ABSTRACT FROM AUTHOR]

One of the requirements for efficient biological conversion of lignocellulose to bioproducts is the compatibility of biological catalysts with the processes employed to solubilize and depolymerize the lignocellulosic components. The red yeasts Rhodosporidium toruloides and Rhodotorula mucilaginosa were evaluated for their ability to assimilate sugars and aromatic compounds extracted from two engineered lines of Arabidopsis thaliana with modified lignin or the wild-type using ionic liquid, acid or alkaline pretreatments. Differential amounts of monomeric sugars, organic acids and, in the case of the engineered lines, either 4-hydroxybenzoic or protocatechuic acid were additionally released from the biomass and found to be tolerated and consumed by both microorganisms. Genetically-engineered strains of the two red yeasts successfully converted the depolymerized products into the biofuel precursor bisabolene when cultivated on hydrolysates or synthetic media containing specific sugars, acids and aromatics found in the hydrolysates.

The difficulty of degrading lignin is the main factor limiting the high-value conversion process of lignocellulosic biomass. The biodegradation of lignin has attracted much attention because of its strong environmental friendliness, but it still faces some dilemmas such as slow degradation rate and poor adaptability. The microbial consortia with high lignin degradation efficiency and strong environmental adaptability were obtained in our previous research. To further increase the lignin degradation efficiency, this paper proposes a composite treatment technology of steam explosion combined with microbial consortium degradation to treat three kinds of biomass. We measured the lignin degradation efficiency, selectivity value (SV) and enzymatic saccharification efficiency. The structural changes of the biomass materials and microbial consortium structure were also investigated. The experimental results showed that after 1.6 MPa steam explosion treatment, the lignin degradation efficiency of the eucalyptus root reached 35.35% on the 7th days by microbial consortium. At the same time, the lignin degradation efficiency of the bagasse and corn straw treated by steam explosion followed by microbial biotreatment was 37.61–44.24%, respectively, after only 7 days of biotreatment. The microbial consortium also showed strong selectivity degradation to lignin. The composite treatment technology can significantly improve the enzymatic saccharification efficiency. Saccharomycetales, Ralstonia and Pseudomonadaceae were the dominant microorganisms in the biomass degradation systems. It was proved that the combined treatment technology of steam explosion and microbial consortium degradation could overcome the drawbacks of traditional microbial pretreatment technology, and can facilitate the subsequent high-value conversion of lignocellulose. [ABSTRACT FROM AUTHOR]

The torrefaction assays were carried out at temperatures of 240, 260, and 280 °C for 30 and 60 min to investigate the chlorine (Cl) behavior in Eucalyptus sp. from the region of Paraiba Valley, Brazil. The solid product obtained from the reactions — torrefied wood — was analyzed for mass loss, elemental analysis, calorific value, scanning electron microscopy, and chlorine content. The results showed that the mass loss ranged from 11.5 to 16.7% at the lowest temperatures tested, reaching 37.2% at 280 °C for 60 min. The samples torrefied at 260 and 280 °C for 60 min showed characteristics similar to lignite and peat, which have higher heating values. However, torrefied reactions of 30 min had better energy yields (97.6%). It is noteworthy that during torrefaction at 240 °C and 260 °C for 30 min, the chlorine reduction was 88 and 95% respectively, in relation to raw wood, resulting in concentrations of 30 and 13 mg kg−1 of chlorine in the torrefied samples, meeting the specification of the ENplus standard (< 200 mg kg−1). Thus, torrefaction is a pretreatment process for Eucalyptus sp. from Paraiba Valley, state of São Paulo (Brazil), to produce biofuel with low chlorine content, enabling its commercialization in the European market. [ABSTRACT FROM AUTHOR]

Although the whole microalgal biomass is typically used as a feedstock for hydrothermal liquefaction (HTL), the conversion of a primary metabolite (i.e., carbohydrate) to biocrude is very low. In this study, a self-settling cyanobacterium (i.e., Chroococcidiopsis sp.) was used to understand the effect of carbohydrate removal, as a pretreatment, on the net energy recovery from the residual biomass. The optimum biocrude yields from pretreated and control biomass were 50.2% (350 °C) and 41.3% (300 °C), respectively. For the temperature range studied, the biocrude yield from the pretreated biomass was higher compared to that obtained from the control feedstock. Further, maximum alkane formation of 42.7 and 23.3% occurred for pretreated and control biomass, respectively, at 325 °C. Total organic carbon and total nitrogen values in the aqueous phase liquid obtained from pretreated biomass were at least 1.31 and 1.23 times lower when compared to the corresponding values obtained from control biomass. When APL was recycled as a source of nutrients, it reduced the biomass yield (24.1%) and pigment content (68.4%) in Chroococcidiopsis sp. Further, a model was developed to understand how the cellular carbohydrate content would affect the net energy recovery for the proposed biorefinery route. A schematic of microalgal bio-oil production from Chroococcidiopsis sp. using a biorefinery-approach. [Display omitted] [ABSTRACT FROM AUTHOR]

Supercritical CO2 extraction is a green method that combines economic and environmental benefits. Microalgae, on the other hand, is a biomass in abundance, capable of providing a vast variety of valuable compounds, finding applications in the food industry, cosmetics, pharmaceuticals and biofuels. An extensive study on the existing literature concerning supercritical fluid extraction (SFE) of microalgae has been carried out focusing on carotenoids, chlorophylls, lipids and fatty acids recovery, as well as the bioactivity of the extracts. Moreover, kinetic models used to describe SFE process and experimental design are included. Finally, biomass pretreatment processes applied prior to SFE are mentioned, and other extraction methods used as benchmarks are also presented. [ABSTRACT FROM AUTHOR]

Climatic changes and the growing population call for innovative solutions that are able to produce biochemicals by adopting environmentally sustainable procedures. The biorefinery concept meets this requirement. However, one of the main drawbacks of biorefineries is represented by the feedstocks' pretreatment. Lately, scientific research has focused on non-thermal plasma, which is an innovative and sustainable pretreatment that is able to obtain a high sugar concentration. In the present review, literature related to the use of non-thermal plasma for the production of fermentable sugar have been collected. In particular, its sugar extraction, time, and energy consumption have been compared with those of traditional biomass pretreatments. As reported, on one hand, this emerging technology is characterized by low costs and no waste production; on the other hand, the reactor's configuration must be optimized to reduce time and energy demand. [ABSTRACT FROM AUTHOR]

Vegetation has successfully been used for cleaning up metal(loid) polluted water bodies and lands through extracting and accumulating of contaminants in their aboveground biomass (phytoextraction). As this remediation technique is approaching extensive demonstration scale application and potential commercialisation, research efforts have been investigating new ways to achieve valorization of its by‐products, the heavy‐metal‐enriched biomass (HMEB). Biomass pyrolysis as an energy conversion technique represents a key step to numerous valorization options of HMEB. During the pyrolysis of HMEB, understanding the thermal decomposition pathways, and the migration and transformation of metal(loid)s are critical for the production of clean, safe and value‐added end‐products. This work performs a state‐of‐the‐art review of the studies conducted on phytoextraction and biomass pyrolysis of HMEB with emphasis on the properties of pyrolysis products as well as the behavior of heavy metal(loid)s during pyrolysis in relation to HMEB feedstock properties and the variables of the process. [ABSTRACT FROM AUTHOR]

This study explores an eco-friendly delignification technique for raw oil palm leaves (OPL), highlighting the optimized conditions of choline chloride-lactic acid deep eutectic solvent (DES)-mediated ball milling pretreatment to maximize the co-production yields of highly crystalline cellulose and lignin. Our five-level-four-factor Taguchi design identified the optimal reaction settings for cellulose production (85.83 % yield, 47.28 % crystallinity) as 90-minute milling, 1500 rpm, mill-ball size ratio of 30:10, ball-to-sample mass ratio of 20:1, DES-to-sample mass ratio of 3:1. Conversely, the maximal lignin extraction yield (35.23 %) occurred optimally at 120-minute milling, 600 rpm, mill-ball size ratio of 25:5, ball-to-sample mass ratio of 20:1 and DES-to-sample mass ratio of 9:1. Statistical results showed that milling frequency (p -value ≤ 0.0001) was highly significant in improving cellulose crystallinity and yield, while DES-to-sample mass ratio (p -value ≤ 0.0001) was the most impacting on lignin yield. The thermogravimetric method affirmed the elevated cellulose thermal stability, corroborating the enhanced cellulose content (40.14 % to 73.67 %) alongside elevated crystallinity and crystallite size (3.31 to 4.72 nm) shown by X-ray diffractograms. The increased surface roughness seen in micrographs mirrored the above-said post-treatment changes. In short, our optimized one-pot dual-action pretreatment effectively delignified the raw OPL to produce cellulose-rich material with enhanced crystallinity and lignin solidity. [Display omitted] • Effective DES-assisted ball milling pretreatment in biomass delignification • A single-step co-production of cellulose and lignin under optimized condition • Pretreated OPL enhanced the isolated cellulose crystallinity from 19.09 % to 47.28 %. • A 2-hour milling (600 rpm) at 1:9 sample-to-DES ratio maximized lignin yield (35.2 %). • Cellulose yield and crystallinity were maximized at 1500 rpm milling frequency. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel TDES was prepared to realize the double donor grafting of lignin. • Regenerated lignin had low condensation structure and high hydroxyl content. • The correlation between lignin structure and fluorescence properties was constructed. • Lignin-Lum-MDI with high fluorescence intensity was applied to information encryption. The high-valued utilization of biomass components through pretreatment technology can effectively alleviate the pressure of energy and environment. In this study, a ternary deep eutectic solvent (TDES) was prepared by using glycolic acid (GA) and ethylene glycol (EG) as double hydrogen donors and benzyl trimethyl ammonium chloride (TMBAC) as hydrogen acceptor. The corn stalk was separated by TDES to obtain cellulose-rich solid residue and low-condensed lignin. Moreover, the solid residue was converted into bio-oil by rapid pyrolysis, and the low-condensed lignin was converted into fluorescent lignin by grafting luminol for information encryption. The results showed that under the pretreatment condition of 150℃ for 3 h, TDES with the molar ratio of 1:1:2 had a lignin removal ratio of 90.60 %, and the yield of levoglucosan obtained from solid residue pyrolysis bio-oil reached 36.38 %. Furthermore, TDES prevented lignin from forming a C-C polycondensation structure and endowed it with polyhydroxy properties, which was beneficial to graft luminol to enhance the fluorescence intensity efficiently. The high-intensity fluorescent grafted lignin was used for information encryption of various materials. The mechanism of TDES pretreatment and luminol grafting were explored, and the mass balance of corn stalk during pretreatment was described. This study provides a green, environmentally friendly, and efficient pretreatment process for the high-value utilization of biomass. [ABSTRACT FROM AUTHOR]