Search

Dry anaerobic digestion (dry-AD) is an attractive process for solid wastes such as agri-food waste. However, some limitations mainly associated to lack of effective mixing, can hinder the methane production capacity of the systems. Bulking agent (BA) has been proposed as a solution to the compaction issues in systems without mechanical agitation, such as leaching bed reactors. However, effects of BA are still not clear, and, thus, the factors to consider for its dose has not been optimized yet. This work studies the effect of BA in dry-AD. Two substrates with different characteristics were proposed as models, bean peel as a lignocellulosic substrate and a mixture of food waste as a readily biodegradable substrate. Inert plastic rings were used as BA at different BA:S ratios. Assessed BA:S ratio did not affect the performance of methane production for the lignocellulosic waste, but it did significantly affect to the easily biodegradable substrate, showing up to a 28% of methane production increase. This result could be due to the presence of lignocellulosic compounds in the bean peel, behaving like a natural BA. In assays with an increased bed height, the compaction of the system was more severe, resulting in the rapid acidification of the processes. At these conditions, the positive effect of BA addition was more marked, allowing methane production and no acidification of the system. Thus, the addition of BA is a suitable strategy for improving methane production or stability in dry-AD systems without requiring the stirring of the systems. • Bulking agent (BA) addition is assessed as alternative to stirring in dry AD. • Positive effects by BA was due to an increase of the porosity in the digester bed. • Optimal BA:S ratio was strongly dependent on the characteristics of the substrate. • Low lignocellulosic content substrates were more favoured by BA addition. • BA addition was able to avoid acidification by enhancing the methanogenic activity. [ABSTRACT FROM AUTHOR]

The valorization of lignocellulosic biomass, derived from various bio-waste materials, has received considerable attention as a sustainable approach to improve production chains while reducing environmental impact. Microbial enzymes have emerged as key players in the degradation of polysaccharides, offering versatile applications in biotechnology and industry. Among these enzymes, glycoside hydrolases (GHs) play a central role. Xylanases, in particular, are used in a wide range of applications and are essential for the production of xylose, which can be fermented into bioethanol or find use in many other industries. Currently, fungal secretomes dominate as the main reservoir of lignocellulolytic enzymes, but thermophilic microorganisms offer notable advantages in terms of enzyme stability and production efficiency. Here we present the genomic characterization of Geobacillus stearothermophilus GF16 to identify genes encoding putative enzymes involved in lignocellulose degradation. Thermostable GHs secreted by G. stearothermophilus GF16 were investigated and found to be active on different natural polysaccharides and synthetic substrates, revealing an array of inducible GH activities. In particular, the concentrated secretome possesses significant thermostable xylanase and β-xylosidase activities (5 ×103 U/L and 1.7 ×105 U/L, respectively), highlighting its potential for application in biomass valorization. We assessed the hemicellulose hydrolysis capabilities of various agri-food wastes using the concentrated secretome of the strain cultivated on xylan. An impressive 300-fold increase in xylose release compared to a commercially available cocktail was obtained with the secretome, underscoring the remarkable efficacy of this approach. [Display omitted] • Genome characterization of G. stearothermophilus GF16 reveals genes potentially involved in hemicellulose degradation. • The secretome of GF16 grown on a minimal medium enriched with 0.1 % xylan shows inducible xylanolytic properties. • G. stearothermophilus GF16 CAZymes are pivotal in converting agri-food wastes into value-added products, such as xylose. [ABSTRACT FROM AUTHOR]

The use of lignocellulosic biomass to create natural flavor has drawn attention from researchers. A key flavoring ingredient that is frequently utilized in the food industry is vanillin. In this present study, Pediococcus acidilactici PA VIT effectively involved in the production of bio-vanillin by using Ferulic acid as an intermediate with a yield of 11.43 µg/mL. The bio-vanillin produced by Pediococcus acidilactici PA VIT was examined using FTIR, XRD, HPLC, and SEM techniques. These characterizations exhibited a unique fingerprinting signature like that of standard vanillin. Additionally, the one variable at a time method, placket Burmann method, and response surface approach, were employed to optimize bio-vanillin. Based on the central composite rotary design, the most important process factors were determined such as agitation speed, substrate concentration, and inoculum size. After optimization, bio-vanillin was found to have tenfold increase, with a maximum yield of 376.4 µg/mL obtained using the response surface approach. The kinetic study was performed to analyze rate of reaction and effect of metal ions in the production of bio-vanillin showing Km of 10.25, and Vmax of 1250 were required for the reaction. The metal ions that enhance the yield of bio-vanillin are Ca2+, k+, and Mg2+ and the metal ions that affects the yield of bio-vanillin are Pb+ and Cr+ were identified from the effect of metal ions in the bio-vanillin production. • Identification and characterization of Pediococcus Acidilactici capable of catalyzing the production of bio vanillin. • Optimization of fermentation conditions to enhance the biotransformation efficiency and yield of vanillin. • Evaluating bio-vanillin produced through biotransformation, demonstrating its suitability for various applications. • A detailed kinetic study, shedding light on the reaction rates involved in the process of bio vanillin production. [ABSTRACT FROM AUTHOR]

Enzymatic hydrolysis contributes to obtaining fermentable sugars using pretreated lignocellulose materials for bioethanol generation. Unfortunately, the pretreatment of lignocellulose causes low substrate enzymatic hydrolysis, which is due to the structure changes of lignin to produce main phenolic by-products and non-productive cellulase adsorption. It is reported that modified lignin enhances the speed of enzymatic hydrolysis through single means to decrease the negative effects of fermentation inhibitors or non-productive cellulase adsorption. However, a suitable modified lignin should be selected to simultaneously reduce the fermentation inhibitors concentration and non-productive cellulase adsorption for saving resources and maximizing the enzymatic hydrolysis productivity. Meanwhile, the adsorption micro-mechanisms of modified lignin with fermentation inhibitors and cellulase remain elusive. In this review, different pretreatment effects toward lignin structure, and their impacts on subsequent enzymatic hydrolysis are analyzed. The main modification methods for lignin are presented. Density functional theory is used to screen suitable modification methods for the simultaneous reduction of fermentation inhibitors and non-productive cellulase adsorption. Lignin-fermentation inhibitors and lignin-cellulase interaction mechanisms are discussed using different advanced analysis techniques. This article addresses the gap in previous reviews concerning the application of modified lignin in the enhancement of bioethanol production. For the first time, based on existing studies, this work posits the hypothesis of applying theoretical simulations to screen efficient modified lignin-based adsorbents, in order to achieve a dual optimization of the detoxification and saccharification processes. We aim to improve the integrated lignocellulose transformation procedure for the effective generation of cleaner bioethanol. [Display omitted] • Effects of pretreatment in lignin structure and enzymatic hydrolysis are analyzed. • Lignin modification is the promising enhancement process to bioethanol production. • DFT calculation contributes to screening the suitable lignin modification methods. • Advanced methods to study inhibitors-lignin-cellulase interactions are reviewed. [ABSTRACT FROM AUTHOR]

Lignin is the main component of plant cell walls, conferring upon lignocellulosic biomass both excellent mechanical and barrier properties. At the same time, the considerable number of unsaturated groups and conjugated structures present in lignin render it a promising candidate for applications in the optical domain. In recent years, the development of the optical properties of lignin and lignin-derived optical materials has paved the way for a novel avenue of lignin valorization. This review is concerned with the mechanisms of lignin-derived optical materials, with particular emphasis on the physical and chemical structures that are linked to their optical performance, including UV absorption, photothermal conversion, and photoluminescence. Additionally, the potential applications of these materials in energy storage, bioimaging, structural materials, and photonic crystal are also presented, demonstrating the unique optical properties of lignin. Finally, the challenges and future directions of lignin as an optical material are presented, with the objective of developing lignin into a polymer biobased raw material that can serve advanced emerging industries. [ABSTRACT FROM AUTHOR]

Corn cobs consist primarily of a lignocellulosic material comprising hemicellulose, cellulose, and lignin in a crystalline state, which is resistant to microbial saccharification. Bioethanol production from corn cobs has rarely been attempted, especially using chemical pretreatment methods. The present study deals with the production and purification of fungal (Phanerochaete chrysosporium MTCC 787 and Pleurotus florida PAU 22‐01) extracellular ligninolytic enzymes – lignin peroxidase (LiP), manganese peroxidase (MnP), and laccase (Lac) – followed by their utilization for the biological pretreatment of corn cobs along with saccharification using commercial cellulase. Crude LiP, MnP, and Lac demonstrated specific activity of 2.23, 2.1, and 2.63 U/mg, respectively. The one‐step purification of crude enzyme using diethyl amino ethyl (DEAE) cellulose ion exchange chromatography resulted in 11.3, 10.1 and 8.62‐fold purification of LiP, MnP and Lac activity, respectively, with corresponding specific activity of 25.1 U/mg (LiP), 21.2 U/mg (MnP) and 22.7 U/mg (Lac) in the partially purified ligninozymes. Using the latter, biological pretreatment of 2.5 g corn cobs in a reaction volume of 30 mL containing approximately 200 units of Lac, Lip and MnP enzymes (in phosphate buffer, pH 6) resulted in a maximum of 78.4% delignification with a saccharification efficiency of 97.1% using commercial cellulases. [ABSTRACT FROM AUTHOR]

Interest has emerged recently in addressing the long‐standing issue of waste plastic disposal and environmental challenges through the co‐liquefaction of waste plastics with eco‐friendly renewable biomass resources, including microalgae biomass and lignocellulosic biomass, to produce biofuels. Co‐liquefaction provides a viable alternative for managing plastic waste while contributing to biofuel production. The purpose of this article is to provide a comprehensive review of the advances in the co‐liquefaction of various mixtures of plastic waste and different types of biomass feedstocks (lignocellulosic and algal) for the production of biofuels. The influence of various reaction parameters, such as feedstock composition (blending ratio), temperature, catalyst type and loading, solvents, and reaction time on the product yield are explored. The synergistic interaction during the co‐liquefaction of biomass and plastic and the distribution and properties of biofuel products are also discussed. The findings demonstrate that maximum product yields vary depending on the final temperature, and the blending ratio plays a crucial role in determining the distribution of liquefaction products. Of particular interest is biocrude oil, the components of which are influenced by the composition of the feedstock material. The distribution of organic elements in the biochar is contingent upon the type of plastic used. Although the analysis of gas‐phase components is often overlooked, the reaction medium's composition is shown to impact the resulting gas composition. Finally, based on the insights gleaned from the literature, this review presents future perspectives on the subject matter. In general, the co‐liquefaction process offers a viable option for sustainable biofuel production and is a promising approach to address the waste plastics disposal challenges effectively, contributing to the valorization of plastic waste to achieve a circular bioeconomy in the future. [ABSTRACT FROM AUTHOR]

Hydrothermal liquefaction is a new, sustainable pathway to generate biogenic liquids from organic resources. The technology is compatible with a wide variety of resources such as lignocellulosic resources, organic waste, algae, and sewage sludge. The chemistry is complex and predictions of yields are notoriously difficult. Understanding and modeling of hydrothermal liquefaction is currently mostly based on a simplified biochemical analysis and product yield data. This paper presents a large dataset of 2439 experiments in batch reactors that were extracted from 171 publications in the scientific literature. The data include biochemical composition data such as fiber content and composition, proteins, lipids, carbohydrates, and ash. The experimental conditions are recorded for each experiment as well as the reported yields. The objective of this paper is to make a large database available to the scientific community. This database is analyzed with machine‐learning tools. The results show that there is no consensus on the analysis techniques, experimental procedures, and reported data. There are many inconsistencies across the literature that should be improved by the scientific community. Machine‐learning tools with a large dataset allow the generation of reliable yield production tools with a large application field. Given the accuracy of the data, the overall precision of prediction in an extrapolation to new results can be expected to be around 10%. [ABSTRACT FROM AUTHOR]

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]

The high cost of cellulolytic enzyme complexes (CECs) has been a significant impediment to the commercial production of bioproducts from lignocellulose biomass. This study aimed to develop a cost‐effective CEC derived from Penicillium ucsense (former Penicillium echinulatum), utilizing diverse forms of pretreated sugarcane bagasse as the primary carbon/inductor source. Among the different pretreatments used, the hydrothermal pretreatment followed by NaOH delignification (BHD) produced higher FPase and xylanase activities (4.5 FPU mL–1 and 120 IU mL–1) in bioreactor experiments at 20 g BHD L–1 initial concentration. A batch‐mode assay conducted across a range of initial carbon source (5 to 60 g L–1) confirmed the highest FPase activity (4.0 to 5.0 FPU mL–1 at 120 h), in the range of 20–40 g BHD L–1. During these assays the agitation rate, controlled by dissolved O2, tended to stabilize at lower levels, indicating substrate limitation. Conversely, higher initial carbon source concentrations led to an excess of glucose, likely triggering carbon catabolite repression and inhibiting cellulase production. This insight prompted the development of a controlled pulsed fed‐batch strategy, resulting in FPase activity of 11 FPU mL–1 at 220 h using 90 g L–1 BHD controlled fed into the bioreactor. An enzymatic hydrolysis procedure using the generated CEC was also optimized using a central composite rotational design (CCRD). The optimized enzyme hydrolysis conditions achieved a reducing sugar concentration of 80.9 g L–1 in 48 h using 170 g L–1 of BHD as the substrate at a ratio of 15 FPU of enzyme substrate per g of BHD. A preliminary economic assessment demonstrated that, for a first‐ and second‐generation (1G + 2G) ethanol biorefinery, the cost contribution of enzymes would be about US$0.2/L of biofuel. In conclusion, an efficient and highly productive procedure was developed successfully for the production of a CEC. It was particularly effective for the enzymatic hydrolysis of pretreated sugarcane bagasse. [ABSTRACT FROM AUTHOR]

Saccharomyces cerevisiae cannot assimilate xylose, second to glucose derived from lignocellulosic biomass. Here, the engineered S. cerevisiae strains INVSc-XI and INVSc-XI/XT were constructed using xylA and Xltr1p to co-utilize xylose and glucose, achieving economic viability and sustainable production of fuels. The xylose utilization rate of INVSc-XI/XT was 2.3-fold higher than that of INVSc-XI, indicating that overexpressing Xltr1p could further enhance xylose utilization. In mixed sugar media, a small amount of glucose enhanced the consumption of xylose by INVSc-XI/XT. Transcriptome analysis showed that glucose increased the upregulation of acetate of coenzyme A synthetase (ACS), alcohol dehydrogenase (ADH), and transketolase (TKL) gene expression in INVSc-XI/XT, further promoting xylose utilization and ethanol yield. The highest ethanol titer of 2.91 g/L with a yield of 0.29 g/g at 96 h by INVSc-XI/XT was 56.9% and 63.0% of the theoretical ethanol yield from glucose and xylose, respectively. These results showed overexpression of xylA and Xltr1p is a promising strategy for improving xylose and glucose conversion to ethanol. Although the ability of strain INVSc-XI/XT to produce ethanol was not very satisfactory, glucose was discovered to influence xylose utilization in strain INVSc-XI/XT. Altering the glucose concentration is a promising strategy to improve the xylose and glucose co-utilization. HIGHLIGHTS: INVSc-XI and INVSc-XI/XT strains were newly constructed to utilize xylose and glucose. XylA, in combination with xylose transporter Xltr1p, enhances xylose consumption. A small amount of glucose enhanced xylose utilization in INVSc-XI/XT strain. The expression of ACS, ADH, and TKL genes is upregulated in the media containing mixed sugars. The highest ethanol yield of 0.29 g/g was produced in a 2-L scale-up fermenter. [ABSTRACT FROM AUTHOR]

Lignocellulosic biomass, the most abundant natural resource on earth, can be used for cellulosic ethanol production but requires a pretreatment to improve enzyme access to the polymeric sugars while obtaining value from the other components. γ‐Valerolactone (GVL) is a promising candidate for biomass pretreatment since it is renewable and bio‐based. In the present work, the effect of a pretreatment based on GVL on the enzymatic saccharification of white birch was evaluated at a laboratory scale and the importance of the washing procedure for the subsequent saccharification was demonstrated. Both the saccharification yield and the production of cellulosic ethanol were higher using a noncommercial enzyme crude from Talaromyces amestolkiae than with the commercial cocktail Cellic CTec2 from Novozymes. Furthermore, the production of extracellular cellulases by T. amestolkiae has been optimized in 2 L bioreactors, with improvements ranging from 40% to 75%. Finally, it was corroborated by isoelectric focus that optimization of cellulase secretion by T. amestolkiae did not affect the pattern production of the main β‐glucosidases and endoglucanases secreted by this fungus. [ABSTRACT FROM AUTHOR]

This study investigates the correlation between both the chemical compositions and physicochemical properties of pretreated oil palm empty fruit bunch (OPEFB) fibre and their enzymatic saccharification/total glucose yield (TGY). Twenty OPEFB samples, pretreated with various aqueous pretreatments, with diverse cellulose (25.63–44.23%), hemicellulose (0.01–42.49%), and lignin (3.7–47.1%) levels, were examined for their correlation with TGY (8.5–40%). The quadratic regression model was verified significant (p-value = 0.0006, R2 = 0.8006). It was found that the pre-refined OPEFB experienced greater cellulose loss (35%) compared to unrefined ones (9%), adversely affecting TGY. Among physicochemical properties analysed using SEM, FTIR, XRD, Py-GCMS, and XPS, only crystallinity index (CrI) was significantly correlated with TGY based on theoretical glucose concentration (TGC) (R2 = 0.77, 0.91). Other characteristics (morphology, functional groups, crystallite size, S/G ratio, and O/C ratio) exhibited no significant correlation to saccharification efficiency, exhibiting random trends (R2 < 0.5). OPEFB fibres with CrI of 30–40 could achieve 100% TGY based on TGC. In conclusion, regardless of pretreatments, chemical compositions predominantly affected TGY in the enzymatic saccharification of biomass. Among commonly used physicochemical analytical methods, CrI is most significant in this evaluation and OPEFB should be unrefined before treatment to avoid cellulose loss. [ABSTRACT FROM AUTHOR]

The purpose of this research was to develop an integrated biorefinery process of solid-state anaerobic digestion (SS-AD) and hydrothermal carbonization (HTC) for the co-production of methane and hydrochar using elephant dung (ED) as substrate. With a leachate recirculation rate of 4 times/day, the SS-AD presented the highest cumulative methane yield of 83.2 ± 1.7 NmL/g volatile solid (VS)added and VS removal efficiency of 53.9 ± 0.3%. In subsequent HTC, the maximum higher heating value (HHV) of 10,078.5 ± 288.5 MJ/ton dry wt. was achieved for the digested ED without leachate recirculation under HTC temperature of 170 °C. In addition, the maximum mass and energy yields were 76.3 ± 0.8% and 84.1 ± 0.3%, respectively. The produced hydrochar had higher HHV compared to the raw digestate. Moreover, the HHV of the hydrochar was higher, and ash content was identical to conventional coal (lignite). An assessment of a full-scale elephant-sanctuary waste management scheme integrating SS-AD and HTC indicates that more than 10,078.5 ± 288.5 MJ of energy and 563.0 ± 5.2 kg dry weight of hydrochar could be recovered per ton dry weight of ED. The developed elephant dung management platform could enhance energy yield from ED while addressing environmental issues. [ABSTRACT FROM AUTHOR]

The influence of ionic liquid (IL) characteristics, lignocellulosic biomass (LCB) properties, and process conditions on LCB pretreatment is not well understood. In this study, a total of 129 experimental data on LCB (grass, agricultural, and forest residues) pretreatment using imidazolium, triethylamine, and choline-amino acid ILs were compiled to develop machine learning (ML) models for cellulose, hemicellulose, lignin, and solid recovery. Following data imputation, a bilayer artificial neural network (ANN) and random forest (RF) regression, the two most widely adopted ML models, were developed. The full-featured ANN following Bayesian hyperparameter (HP) optimisation offered excellent fit on training (R2: 0.936–0.994), though cross-validation (R2CV) performance remained marginally poor, i.e. between 0.547 and 0.761. The fitness of HP-optimised RF models varied between 0.824 and 0.939 for regression, and between 0.383 and 0.831 in cross-validation. Temperature and pretreatment time had been the most important predictors, except for hemicellulose recovery. Bayesian predictor selection combined with HP optimisation improved the R2CV boundary for ANN (0.555–0.825), as well as for RF models (0.474–0.824). As predictive performance of the models varied depending on target response, use of a larger homogeneous dataset may be warranted. The predictive modelling framework for LCB pretreatment, developed in this study, can be extended to similar biochemical process systems. [ABSTRACT FROM AUTHOR]

This study investigated the anaerobic co-digestion of sugarcane vinasse (V) and elephant grass silage (S) to produce methane. Box-Behnken experimental design was applied to verify the statistical effects of the elephant grass ensiling time (40, 80 and 120 days), alkaline pretreatment of elephant grass silage (0.5, 2.25 and 4.00% w/v NaOH) and S:V mixture ratio (25:75, 50:50 and 75:25) on the methane yield. The results showed that the ensiling process resulted in the low degradation of lignocellulosic substances, emphasizing the need for pretreatment using more efficient techniques, such as thermo-alkaline, to improve the breakdown of elephant grass fibres. COD removals varied between 35 and 85%, and carbohydrate consumptions ranged from 63 to 72%, with the higher efficiencies for both parameters occurring in the reactors with lower percentages of silage. Cumulative methane yield ranged from 190.77 mLCH4/gVS (in the reactor with S:V of 75:25, 0.50% w/v NaOH and 80 ensiling days) to 1729.80 mLCH4/gVS (in the reactor with S:V of 25:75, 2.25% w/v NaOH and 120 ensiling days). According to ANOVA, S:V ratio was the only variable with a significant effect (p < 0.05) on cumulative methane yield. Therefore, the findings indicate that the relative composition of substrates within the mixture exerted the most significant influence on the process, underscoring the critical role of vinasse as a co-substrate in enhancing methane production despite silage pretreatments. [ABSTRACT FROM AUTHOR]

The presence of hemicellulose inhibits the enzymatic hydrolysis of lignocellulosic biomass. The purpose of this study is to investigate the effect of different hemicellulose fractions on the enzymatic hydrolysis and the way to eliminate the inhibiting effect caused by hemicellulose. Four kinds of hemicelluloses, namely, HXF, H15, H30, and H60, were first extracted from corn stover by ethanol fractional precipitation. The structures of hemicellulose samples were analyzed using Fourier transform infrared spectroscopy, 1H and 13C nuclear magnetic resonance, and high-performance ion chromatography. The results show that H30 has the strongest inhibition on the enzymatic hydrolysis of Avicel and corn stover, presenting inhibition ratio of 13.35% and 9.98%, respectively. The inhibition ratios of other hemicelluloses in Avicel and corn stover are 8–12% and 5–9%, respectively. However, the inhibiting effect caused by H30 is removed by adding hemicellulase, which even presents a 4.99% increase in the efficiency of enzymatic hydrolysis of corn stover. The corresponding glucose concentration reached 68.11 g/L. This research could help design effective processes to promote the enzymatic hydrolysis of lignocellulosic biomass. [ABSTRACT FROM AUTHOR]

Lignocellulosic biomass is of significant industrial and scientific interest. Residues derived from different activities (agro-industrial work, food consumption, wood use, urban solid waste, etc.) and their subsequent use are key to extending circularity models to the different technological sectors that are beginning to implement circular economy cycles. Biorefineries are integrated platforms that value waste conversion into various value-added products. The generation of bioproducts derived from lignocellulosic waste (green fuels, green chemicals, and biomaterials) has promoted a shift from a fossil fuel–based economy to a more sustainable one. In addition, integrating biorefineries into the circular economy framework promotes a comprehensive approach to resource management, waste reduction, and sustainable development, which contributes to the overall resilience and efficiency of societal systems. There has been increased focus on the application of "canonical microorganisms" for residual biomass conversion, such as fungi, bacteria, and yeast. However, there is a plethora of other potential microorganisms that can be candidates for new biotechnological applications. This review aims to describe the valorization of different sources of lignocellulosic biomass in the global context, with a focus on Brazilian practice, and to emphasize how the use of microbial diversity is critical to enhancing current technologies, such as advanced liquid fuels. Finally, there is a discussion of the potential of anaerobic fungi, archaea, protists, and oomycetes as microbial product conversion technologies. [ABSTRACT FROM AUTHOR]

The role of buffer in modulating the enzymatic hydrolysis environment of lignocellulose is crucial. However, studies on the impact of buffer on high-solid enzymatic hydrolysis remain limited. This study discovered that utilizing deionized water as a reaction medium, rather than the conventional buffer, did not influence the enzymatic hydrolysis of steam-exploded corn stover when the solid loading ranged between 15 and 25%. At 15% solid loading, the glucan conversion in the group treated with buffer was recorded at 89.8%, with a corresponding glucose concentration of 51.1 g/L. In contrast, the group without buffer exhibited a conversion of 88.9% and a glucose concentration of 50.5 g/L. The increase of acid groups in lignin was attributed to the formation of phenolic hydroxyls during steam explosion, which provided the substrate with the necessary conditions for buffering effects. Sequentially, during the high-solid enzymatic hydrolysis process, the substrate's increased pore volume and specific surface area could potentially offset the buffering capacity, which led to the buffering effect becoming ineffective. Leveraging the self-buffering effect of the substrate, a fed-batch strategy was developed. This strategy replaced the water supplementation with buffers, augmenting the solid loading from 20 to 33% across six distinct feeding sessions over a span of 72 h. This not only reduced costs but also laid the foundation for the industrial viability of lignocellulosic high-concentration sugar production, thereby advancing the biofuels and bioproducts sector. These findings provide valuable insights for the exploration of solid reaction processes. [ABSTRACT FROM AUTHOR]

One of the most important problems and the main obstacle of this process is the transformation of the complex structure of lignocellulose. One of the ways to break the lignocellulosic structure is to use suitable pretreatment compounds and nanoparticles with appropriate concentration. For this purpose, the synergistic effect of 6%NaOH pretreatment with different magnetite nanoparticle (MNP) concentrations was assessed for maximizing the biogas production. In this study, the optimal mixing ratio of MSW and SS codigestion was determined from our previous studies (MSW:SS 60:40). Application of the 6%NaOH pretreatment alone increased biogas and methane production by 24.6 and 35.4%, respectively, compared to the control. Also, the 6%NaOH pretreatment alone elevated cellulose by 85% while reducing lignin and hemicellulose by 64 and 33%, respectively. The greatest biogas and methane production was obtained in the reactor of 6%NaOH with an MNP concentration of 110 ppm, experiencing an 86 and 162% increase compared to the control. The greatest reduction in total solids and volatile solids was also obtained in this digestor by 76.6 and 79%, respectively, compared to the control reactor. [ABSTRACT FROM AUTHOR]

The characteristics of biochar vary widely depending on the type of biomass and thermochemical conversion method. In this study, four types of biomass (kenaf, rice husk, corncob, and wood chips) were subjected to hydrothermal carbonization and torrefaction at 220 °C, 260 °C, and 300 °C for 30 min. The acquired biochars showed significant differences in the type of reaction and biomass. At each temperature, the decomposition of volatiles was more severe in hydrochar (HC) than in torrefied char (TC). The mass yields of HC were 44.30–61.63 wt.% (220 °C), 20.89–37.04 wt.% (260 °C), and 12.59–29.19 wt.% (300 °C), whereas the mass yields of TC were 94.73–97.69 wt.% (220 °C), 87.19–95.04 wt.% (260 °C), and 68.22–80.78 wt.% (300 °C). The elemental and thermal characteristics of TC changed gradually as the reaction temperature increased, and the characteristics of HC were enhanced rapidly. Wood chip biochar that was reacted at 300 °C showed the highest heating values of 28.77 MJ/kg (HC) and 21.09 MJ/kg (TC). The results of chemical analyses showed that hydrothermal carbonization strongly affected the cleavage of inter- and intra-molecular carbon bonds in cellulose and hemicellulose. In contrast, torrefaction removed the thermally fragile moisture and hemicellulose content from biomass. [ABSTRACT FROM AUTHOR]

Co-pyrolysis behaviors of peanut shells (PS) and tea plant branches (TPB) were explored with a focus on the physicochemical properties, thermal degradation behavior, synergistic effect, and thermo-kinetic analyses. The differences between individual biomass and the equivalent blend were also highlighted. Results showed that the blend sample showed an enhancement in fixed carbon content but a reduction in moisture and ash contents, when compared to those of the individual PS. The average activation energies (Ea) of the equivalent blend estimated by three isoconversional methods (i.e., Friedman, KAS, and Starink methods) were 181.65, 166.87, and 167.14 kJ/mol, respectively. The average Ea and ΔH of the blend were quite lower than those of the TPB but slightly higher than those of the PS. During pyrolysis, ΔH and ΔG exhibited positive values which showed the decomposition was endothermic and non-spontaneous. Negative ΔS values were first observed, followed by positive ΔS values at late conversion stage. [ABSTRACT FROM AUTHOR]

The unwashed alkali-treated lignocellulose can be directly enzymatically hydrolyzed and fermented via pH adjustment with acids. The use of acids would give a burden on production cost. Furfural residue (FR) which is the acidic solid waste from lignocellulose-derived furfural production process was employed in this study as a pH regulator. The corn cob-derived FR was used to adjust the pH value of alkali-treated corn stover (PCS) to 4.8 for enzymatic hydrolysis and ethanol fermentation. The unwashed PCS adjusted by FR got higher enzymatic hydrolysis efficiency (EHE) than the washed PCS samples. Meanwhile, the mixing of PCS and FR had a synergistic effect on the EHE of PCS. The fermentation of enzymatic hydrolysate from unwashed PCS-FR mixture at 20% solid concentration could attain ethanol production of 26.54 ± 0.02 mg/mL with a yield of 89.53 ± 0.08%. This work created a novel recycling way of FR as a pH regulator for improving the bioconversion of alkali-treated lignocellulose. It also provided a novel clue for the valuable valorization of wastes from corn production. [ABSTRACT FROM AUTHOR]

Degenerate strains of Clostridium acetobutylicum lack the ability to produce solvents and sporulate and remain in a permanent acidogenic state, allowing continuous hydrogen and organic acid production through anaerobic fermentation. Eichhornia crassipes, an invasive aquatic plant, emerges as a promising source of fermentable sugars for hydrogen production via anaerobic fermentation. In this study, a degenerated strain of Clostridium acetobutylicum was isolated and subsequently cultivated in the presence of a hydrolysate solution obtained from the alkaline pre-treatment and enzymatic hydrolysis of Eichhornia crassipes. The hydrolysate was mixed with a defined medium and served the dual purpose of providing essential nutrients and mitigating inhibitors, eliminating the need for an additional detoxification step. A pure defined culture medium served as a control. The extraction methods employed led to the release of low concentrations of inhibitors, reaching 0.1 g/L of furfural and 0.18 g/L of HMF. Kinetic characterization revealed that in the presence of Eichhornia crassipes hydrolysate, the degenerate strain exhibited lower specific growth rates ranging from 0.114 to 0.156 h−1, compared with the control medium which ranged from 0.131 to 0.179 h−1. This was accompanied by lower yields, ranging from 0.115 to 0.167 gDCW/g in the presence of hydrolysate versus 0.178 to 0.190 gDCW/g in the control medium, and diminished butyric acid production of 1.318 to 2.932 g/L in the presence of hydrolysate versus 1.749 to 3.471 g/L in control cultures. Despite reduced growth, high biohydrogen volumetric productivity was achieved, reaching 7.3 L/L·d, along with a significant yield of 2.642 mol of hydrogen per mole of glucose consumed. This represents 66.05% of the maximum stoichiometric yield calculated when acetic acid is the sole byproduct. Apparently, the presence of low concentrations of furfural and HMF released during the pre-treatment of Eichhornia crassipes not only negatively affects growth capacity but also diminishes butyric acid production, favoring biohydrogen production. [ABSTRACT FROM AUTHOR]

The main objective of this study was to develop a citric acid-catalyzed hydrothermal pretreatment to reach the maximum sugar recovery from soybean hull (SH), in the context of a biorefi nery concept. A central composite design (CCD) was used to optimize pretreatment conditions through the analysis of citric acid concentration, time, and temperature effects. Optimized conditions were defined as 3.56% w/w, 46.1 min, and 135.7 °C. From the solid fraction, 99.5% and 83.0% of glucose and xylose conversion, respectively, were obtained after enzymatic hydrolysis. Sugars were fermented successfully to L-lactic acid by Lactobacillus pentosus. In fact, SH hydrolysate presented no trace of inhibitor compounds, and glucose was totally consumed during fermentation. After 24 h of fermentation, a conversion rate of 0.724 g/g of sugars to lactic acid and 80.5% of the stoichiometric theoretical yield were reached. In addition, from the liquid fraction, 47.8 mg/g of xylooligosaccharides (XOS) was produced. This work demonstrates the potential of SH to be exploited as feedstock, with mild and efficient pretreatment process, for medium- to high-value bioproducts production in biorefineries. [ABSTRACT FROM AUTHOR]

Tomato waste (TW) is a plentiful lignocellulosic resource, mainly composed of seeds and skins, that can be converted into high-value compounds. This study explored the enhancement of TW enzymatic and fungal biovalorization using novel ecofriendly approaches, including advanced technology, pulsed electric fields (PEF). Crude laccase first produced on TW was used for enzymatic treatment, and the white rot fungus Trametes versicolor K1 was used in fungal treatment under SmF (submerged) or SSF (semi-solid) fermentation conditions. The physical PEF treatment had increased tenfold sugar extraction yield (83.4 mg/g) and twofold polyphenol extraction yield (4.43 g/g), with respect to the control. PEF–laccase innovative combination, reported for the first time, has enhanced significantly sugar extraction yield (100.6 mg/g), twofold higher than those released from TW after laccase treatment alone. However, the PEF treatment had no effect on polyphenol extraction yield when combined to laccase or fungal treatments. The treated TW was subjected to polysaccharide enzymatic hydrolysis. The combination of PEF with laccase or fungal treatment did not impact sugar yields; however, it allowed polyphenol liberation. During fungal treatment (i.e., T. versicolor K1 grown on TW), comparable maximal laccase activities of 2574.28 U/L and 2577.06 U/L were measured in the culture supernatants, in SmF and SSF conditions, respectively. The findings demonstrate the high potential of PEF for recovering phenols and sugars. When combined to fungal treatment, it offers high yields of valuable products, making it a potential cost-effective approach, providing new prospects for TW valorization. [ABSTRACT FROM AUTHOR]

Industrialization increases day by day and hence the demand of Cr (VI) compounds are also increased in tanning, electroplating, printing and in dyeing industries, which has resulted in considerable amounts of waste containing Cr(VI) being emitted. Environmental scientists are quite concerned about how much Cr(VI) is present in water since it creates a severe harm to the ecosystem and humans. Because of their functional diversity, high efficacy, economic viability, and simplicity of technical operation, low-cost biosorbents made of lignocellulosic biomasses have drawn attention for elimination of Cr(VI). One versatile and efficient approach to address Cr(VI) pollution is through the use of lignocellulosic materials, for biosorption. Within this comprehensive review, we conduct an impartial evaluation of the biosorption capabilities of various lignocellulosic biosorbents, while also examining the underlying mechanisms involved in the biosorption process by focusing on crucial variables including pH, contact time, dosage, and temperature. In addition, we assemble a list of investigated lignocellulose-based biosorbents that may be beneficial. In addition to offering our recommendations for future views, the review's objective is to highlight existing trends, potential study areas, and obstacles to the practical use of the biosorption process. [ABSTRACT FROM AUTHOR]

Water hyacinth (Eichhornia crassipes) as a aquatic weed has become a source of concern for value addition. This study aimed to determine the feasibility of the weedy biomass in sustainable bioethanol production using Phanerochaete chrysosporium and Saccharomyces cerevisiae. The results indicated that P. chrysosporium significantly utilized 70.9% of cellulose and 70% of hemicellulose from raw lignocellulose of water hyacinth with significant microbial enzyme production of 1.26 IU/ml. Moreover, the microbial treatment resulted in a significant amount of soluble protein (194.30 mg/g) and reducing sugar (34.20 g/l). XRD, SEM and FTIR analyses revealed that the crystalinity of cellulose was increased with the microbial treatment and hence, the yield of sugar also. Under submerged fermentation, Saccharomyces cerevisiae produced a maximum of 20.17 g/l of ethanol. The promising results of the present study explored the microbial treatment with P. chrysosporium and fermentation with S. cerevisiae as a successful and sustainable method for ethanol production from lignocellulosic weedy biomass. [ABSTRACT FROM AUTHOR]

Insect gut microbes represent a rich source of enzymes and metabolic pathways that can be harnessed to advance renewable energy production. This review explores the potential of insect gut microbiota in the context of biomass degradation and biofuel production. Insects, particularly wood‐feeding species like termites and beetles, harbour complex microbial communities in their guts that efficiently break down lignocellulosic materials into simple sugars. These sugars can then be fermented into biofuels such as ethanol and methane. Recent research has focused on identifying key microbial species and enzymes involved in this process, as well as on engineering these microbes to enhance their efficiency and substrate specificity. Additionally, the ecological roles of these microbes in insect digestion and their potential for biotechnological applications beyond biofuel production are discussed. Overall, understanding and harnessing insect gut microbes holds great promise for advancing sustainable and renewable energy solutions. [ABSTRACT FROM AUTHOR]

Bacteria within the Paenibacillus genus are known to secrete a diverse array of enzymes capable of breaking down plant cell wall polysaccharides. We studied the extracellular xylanolytic activity of Paenibacillus xylanivorans and examined the complete range of secreted proteins when grown on carbohydrate-based carbon sources of increasing complexity, including wheat bran, sugar cane straw, beechwood xylan and sucrose, as control. Our data showed that the relative abundances of secreted proteins varied depending on the carbon source used. Extracellular enzymatic extracts from wheat bran (WB) or sugar cane straw (SCR) cultures had the highest xylanolytic activity, coincidently with the largest representation of carbohydrate active enzymes (CAZymes). Scaling-up to a benchtop bioreactor using WB resulted in a significant enhancement in productivity and in the overall volumetric extracellular xylanase activity, that was further concentrated by freeze-drying. The enzymatic extract was efficient in the deconstruction of xylans from different sources as well as sugar cane straw pretreated by alkali extrusion (SCRe), resulting in xylobiose and xylose, as primary products. The overall yield of xylose released from SCRe was improved by supplementing the enzymatic extract with a recombinant GH43 β-xylosidase (EcXyl43) and a GH62 α-l-arabinofuranosidase (CsAbf62A), two activities that were under-represented. Overall, we showed that the extracellular enzymatic extract from P. xylanivorans, supplemented with specific enzymatic activities, is an effective approach for targeting xylan within lignocellulosic biomass. [ABSTRACT FROM AUTHOR]

Plant-based waste biomass with lignocellulose as an important component is produced in large quantities worldwide every year. The components of lignocellulose that typically exhibit high utilization value include cellulose and hemicellulose, as well as pentoses and hexoses derived from their hydrolysis. As a pretreatment for the hydrolysis process, delignification is a pivotal step to enhance cellulose/hemicellulose accessibility and achieve high yields of fermentable sugars. Additionally, deep eutectic solvents (DESs) are the most widely used solvents for delignification during biomass fractionation due to their clean and environmentally friendly attributes. DESs dissolve lignin by inducing a large amount of β-O-4 bond cleavage and partial carbon–carbon bond cleavage, retaining cellulose in the solid residue, while most of the hemicellulose is hydrolyzed in DES pretreatment. This article provides a comprehensive review of the influence of DESs in the lignocellulose separation process. Key factors such as lignin removal rate, sugar conversion rate, and product chemical structure are critically reviewed to assess the feasibility of employing DESs for lignocellulose separation. [ABSTRACT FROM AUTHOR]

Chemical pretreatment of lignocellulosic biomass (LCB) in the presence of an alkaline catalyst is one of the major pretreatment processes that recover cellulose, hemicellulose, and lignin at effective process conditions and also for the production of bioethanol. Replacement of conventional catalysts with waste‐derived catalysts in the pretreatment process will be helpful for the development of low‐cost biorefinery. The continuous impact of different mass transfer properties during the chemical pretreatment of LCB will affect the final yield of products at a high reaction time and has been reviewed in the current study. Intraparticle diffusion of an alkaline catalyst into LCB is going to determine the diffusion of the selected catalyst within the porous biomass structure, which helps in the enhancement of the final yield of the product recovery at low‐process conditions. The diffusion of the synthesized catalyst within the selected biomass during the chemical pretreatment process is a rate‐limiting step that influences the final recovery yield of desired products. Enhancement of the biomass pretreatment reaction through the assessment of the diffusivity using the modified Nernst–Einstein relation is also discussed. Determination of different unique mass transfer properties rate of diffusion, diffusivity flux, and mass transfer coefficient are also to be analyzed to advance the reaction rate of the pretreatment process. [ABSTRACT FROM AUTHOR]

Electronic waste is one of the environmental issues that is worsening rapidly around the globe and is of particular concern to developing nations. A significant quantity of e‐waste is dumped in landfills without regard for the recycling process, which has a potentially adverse impact on the global ecosystem. In this work, waste printed circuit boards (WPCB) and cassette discs (CD) are grinded into powder form and used as fillers with lignocellulosic kenaf woven fabric blended with epoxy resin. Fabrication is carried out by hand lay‐up techniques assisted by vacuum bagging. Laminates are made with different proportions of 5%, 10%, 15%, and 20% of e‐waste filler by weight percentage of kenaf fabric. Mechanical, water absorption, and surface roughness tests were carried out. The result shows that a 5% addition of waste printed circuit board filler and a 10% addition of waste cassette disc (WCD) filler gave better results. In comparison, waste printed circuit board filler laminates show higher strength than waste cassette disc filler laminates. Experimental results indicate that e‐waste filler can be reinforced with lignocellulosic biomass fiber composites and better used for domestic and industrial applications instead of being dumped into landfills, which causes environmental and health hazards. [ABSTRACT FROM AUTHOR]

The increasing global concern over the contamination of natural resources, especially freshwater, has intensified the need for effective water treatment methods. This article focuses on the utilization of Cellulose nanocrystals (CNCs), sourced from lignocellulosic materials, for addressing environmental challenges. CNCs a product of cellulose-rich sources has emerged as a versatile and eco-friendly solution. CNCs boast unique chemical and physical properties that render them highly suitable for water remediation. Their nanoscale size, excellent biocompatibility, and recyclability make them stand out. Moreover, CNCs possess a substantial surface area and can be modified with functional groups to enhance their adsorption capabilities. Consequently, CNCs exhibit remarkable efficiency in removing a wide array of pollutants from wastewater, including heavy metals, pesticides, dyes, pharmaceuticals, organic micropollutants, oils, and organic solvents. This review delves into the adsorption mechanisms, surface modifications, and factors influencing CNCs' adsorption capacities. It also highlights the impressive adsorption efficiencies of CNC-based adsorbents across diverse pollutant types. Employing CNCs in water remediation offers a promising, eco-friendly solution, as they can undergo treatment without producing toxic intermediates. As research and development in this field progress, CNC-based adsorbents are expected to become even more effective and find expanded applications in combating water pollution. [ABSTRACT FROM AUTHOR]

While the industry has produced sugar-derived ethanol from the conventional method of fermentation for hundreds of years, other effective routes involving the direct transformation of carbohydrates still remain extremely rare. Very recently, an innovative chemo-catalytic method driven by the aqueous-phase catalysis was created for the synthesis of cellulosic ethanol, making a great breakthrough in the common ways as it can theoretically utilize all of the carbon atoms in sugars with faster kinetics; up to now, results from the relevant studies have been accumulated to a certain extent, but the periodic conclusions in this field are unfortunately absent. For this reason, this work tries to offer an overview of the cellulosic ethanol produced by chemo-catalytic routes, highlighting the present knowledge in relation to the technical efficiency, catalytic mechanisms as well as practical applications. At first, the advanced progress on the increasing efficiency from a varied type of catalytic systems are extensively discussed, which involves the specific functions of hybrid components from different strategies; meanwhile, the general influences of processing conditions, such as the hydrothermal severity and aqueous environments, are also identified. Subsequently, possible mechanisms behind the chemo-catalytic processes are widely elaborated by analyzing a number of experimental cases associated with the reaction network and its kinetic models. After that, the actual effects of this technique on the real biomass are collected to identify the positive/negative interactions between multiple components, together with the potential solutions on the semi-continuous processes of pilot scale application. The techno-economic analysis (TEA) is also calculated and compared with other similar methods, such as fermentation and gasification. Finally, several proposals aimed at upgrading the whole chain of chemo-catalytic processes are clearly provided, which may function as a guideline for future studies on the production of bio-ethanol from lignocellulosic materials. [ABSTRACT FROM AUTHOR]

Proper waste management will reduce several pollutions arising out of burning of different agri-wastes such as stubble burning of rice. The lignocellulose in the dry matter, can be converted into various essential products including biofuel through gasification and pyrolysis. This will help to reduce the cost by minimizing the import of petroleum products. A productive sustainable strategy is the development of energy-efficient rice varieties possessing desirable biomass traits without undermining the yield potential. For this sufficient genetic variability should be available to develop suitable dual-purpose varieties. Considering these points, initially, the molecular diversity in popular varieties for biomass traits was explored using cellulose synthase specific markers. An archeopteryx tree constructed thereof indicated the presence of sufficient diversity among the varieties. Eight potential varieties, having sufficient diversity among each other, were selected as parents for developing dual- purpose hybrids. Some of the superior crosses identified concerning both grain and straw yield per plant were Kanchan/Meher, Kanchan/Pratikshya, Pratikshya/Ankit, Hiranmayee/Chandrama and Kanchan/Meher. The crosses including Kanchan/Pratikshya, Meher/Pratikshya, Meher/Ankit, Pratikshya/Hiranmayee, Hiranmayee/Gobinda, Hiranmayee/Pradeep and Gobinda/Pradeep exhibited both positive significant relative heterosis and heterobeltiosis for the biochemical traits. Non-additive gene action was reported to involve in the inheritance of traits viz., plant height, biochemical traits and grain yield, whereas additive gene action played a crucial role in the inheritance of traits viz., leaf area, seed weight and straw yield. [ABSTRACT FROM AUTHOR]

Background: Ectoine as an amino acid derivative is widely applied in many fields, such as the food industry, cosmetic manufacturing, biologics, and therapeutic agent. Large-scale production of ectoine is mainly restricted by the cost of fermentation substrates (e.g., carbon sources) and sterilization. Results: In this study, Halomonas cupida J9 was shown to be capable of synthesizing ectoine using xylose as the sole carbon source. A pathway was proposed in H. cupida J9 that synergistically utilizes both WBG xylose metabolism and EMP glucose metabolism for the synthesis of ectoine. Transcriptome analysis indicated that expression of ectoine biosynthesis module was enhanced under salt stress. Ectoine production by H. cupida J9 was enhanced by improving the expression of ectoine biosynthesis module, increasing the intracellular supply of the precursor oxaloacetate, and utilizing urea as the nitrogen source. The constructed J9U-P8EC achieved a record ectoine production of 4.12 g/L after 60 h of xylose fermentation. Finally, unsterile production of ectoine by J9U-P8EC from either a glucose-xylose mixture or corn straw hydrolysate was demonstrated, with an output of 8.55 g/L and 1.30 g/L of ectoine, respectively. Conclusions: This study created a promising H. cupida J9-based cell factory for low-cost production of ectoine. Our results highlight the potential of J9U-P8EC to utilize lignocellulose-rich agriculture waste for open production of ectoine. [ABSTRACT FROM AUTHOR]

Because of the association with other complex polysaccharides, extracting and utilizing cellulose from lignocellulosic materials requires the combined action of a broad range of carbohydrate‐active enzymes, including multiple glycoside hydrolases (GHs) and lytic polysaccharide monooxygenases (LPMOs). The interplay between these enzymes and the way in which Nature orchestrates their co‐existence and combined action are topics of great scientific and industrial interest. To gain more insight into these issues, we have studied the lignocellulose‐degrading abilities of an enzyme from Caldibacillus cellulovorans (CcLPMO10‐Man5), comprising an LPMO domain, a GH5 mannanase domain and two family 3 carbohydrate‐binding modules (CBM3). Using a natural softwood substrate, we show that this enzyme promotes cellulase activity, i.e., saccharification of cellulose, both by removing mannan covering the cellulose and by oxidatively breaking up the cellulose structure. Synergy with CcLPMO10‐Man5 was most pronounced for two tested cellobiohydrolases, whereas effects were smaller for a tested endoglucanase, which is in line with the notion that cellobiohydrolases and LPMOs attack the same crystalline regions of the cellulose, whereas endoglucanases attack semi‐crystalline and amorphous regions. Importantly, the LPMO domain of CcLPMO10‐Man5 is incapable of accessing the softwood cellulose in absence of the mannanase domain. Considering that LPMOs not bound to a substrate are sensitive to autocatalytic inactivation, this intramolecular synergy provides a perfect rationale for the evolution of modular enzymes such as CcLPMO10‐Man5. The intramolecular coupling of the LPMO with a mannanase and two CBMs ensures that the LPMO is directed to areas where mannans are removed and cellulose thus becomes available. [ABSTRACT FROM AUTHOR]

The valorization of lignin, a currently underutilized component of lignocellulosic biomass, has attracted attention to promote a stable and circular bioeconomy. Successful approaches including thermochemical, biological, and catalytic lignin depolymerization have been demonstrated, enabling opportunities for lignino‐refineries and lignocellulosic biorefineries. Although significant progress in lignin valorization has been made, this review describes unexplored opportunities in chemical and biological routes for lignin depolymerization and thereby contributes to economically and environmentally sustainable lignin‐utilizing biorefineries. This review also highlights the integration of chemical and biological lignin depolymerization and identifies research gaps while also recommending future directions for scaling processes to establish a lignino‐chemical industry. [ABSTRACT FROM AUTHOR]

This study introduces an alternative approach towards lignocellulosic biomass fractionation. For this purpose, reactive eutectic media (REM) based on ammonium formate and different organic acids are investigated, possible products are identified, and the REM are employed for lignin extraction and terminal isolation of cellulose pulp from beech wood. The method promises a considerable process intensification by simultaneous separation of high purity cellulose pulp, lignin isolation as a cationically modified species, and production of value‐added chemicals from reaction products of the REM. This study puts a further focus on the generated cellulose pulp and investigates it with respect to surface charge and fiber length. [ABSTRACT FROM AUTHOR]

Straw pollution and the increasing scarcity of phosphorus resources in many regions of China have had severe impacts on the growing conditions for crop plants. Using microbial methods to enhance straw decomposition rate and phosphorus utilization offers effective solutions to address these problems. In this study, a microbial consortium 6 + 1 (consisting of a straw-degrading bacterium and a phosphate-solubilizing bacterium) was formulated based on their performance in straw degradation and phosphorus solubilization. The degradation rate of straw by 6 + 1 microbial consortium reached 48.3% within 7 days (The degradation ability was 7% higher than that of single bacteria), and the phosphorus dissolution rate of insoluble phosphorus reached 117.54 mg·L− 1 (The phosphorus solubilization ability was 29.81% higher than that of single bacteria). In addition, the activity of lignocellulosic degrading enzyme system was significantly increased, the activities of endoglucanase, β-glucosidase and xylanase in the microbial consortium were significantly higher than those in the single strain (23.16%, 28.02% and 28.86%, respectively). Then the microbial consortium was processed into microbial agents and tested in rice pots. The results showed that the microbial agent significantly increased the content of organic matter, available phosphorus and available nitrogen in the soil. Ongoing research focuses on the determination of the effects and mechanisms of a functional hybrid system of straw degradation and phosphorus removal. The characteristics of the two strains are as follows: Straw-degrading bacteria can efficiently degrade straw to produce glucose-based carbon sources when only straw is used as a carbon source. Phosphate-solubilizing bacteria can efficiently use glucose as a carbon source, produce organic acids to dissolve insoluble phosphorus and consume glucose at an extremely fast rate. The analysis suggests that the microbial consortium 6 + 1 outperformed individual strains in terms of both performance and application effects. The two strains within the microbial consortium promote each other during their growth processes, resulting in a significantly higher rate of carbon source consumption compared to the individual strains in isolation. This increased demand for carbon sources within the growth system facilitates the degradation of straw by the strains. At the same time, the substantial carbon consumption during the metabolic process generated a large number of organic acids, leading to the solubilization of insoluble phosphorus. It also provides a basis for the construction of this type of microbial consortium. [ABSTRACT FROM AUTHOR]

Oyster mushrooms are a type of lignocellulolytic fungus that is used for both culinary and medicinal purposes. The purpose of this study was to assess the nutritional value, biological efficiency, and yields of P. ostreatus M2191 and P. sajor-caju M2145 grown on spent grain from breweries that have been supplemented with various agricultural wastes. The primary substrates at varying compositions included sawdust, wheat straw, cottonseed, teff straw, bean straw, and brewer's spent grain. Two percent gypsum and eight percent wheat bran were added as supplements to the primary substrates. A daily assessment of the growth and development of the Pleurotus species was conducted during their aseptic cultivation. A combination of 25% brewer's spent grain and 75% cottonseed produced the highest biological efficiency and nutritional attributes. The lowest nutritional compositions, yields, and biological efficiency were found when eucalyptus sawdust was used alone or in combination with other agroindustrial residues. Under the weather conditions of Debre Berhan, P. ostreatus M2191 and P. sajor-caju M2145 could be grown using agricultural residues and leftover grains from the brewery. [ABSTRACT FROM AUTHOR]

Summary Our study utilized genome‐wide association studies (GWAS) to link nucleotide variants to traits in Populus trichocarpa, a species with rapid linkage disequilibrium decay. The aim was to overcome the challenge of interpreting statistical associations at individual loci without sufficient biological context, which often leads to reliance solely on gene annotations from unrelated model organisms. We employed an integrative approach that included GWAS targeting multiple traits using three individual techniques for lignocellulose phenotyping, expression quantitative trait loci (eQTL) analysis to construct transcriptional regulatory networks around each candidate locus and co‐expression analysis to provide biological context for these networks, using lignocellulose biosynthesis in Populus trichocarpa as a case study. The research identified three candidate genes potentially involved in lignocellulose formation, including one previously recognized gene (Potri.005G116800/VND1, a critical regulator of secondary cell wall formation) and two genes (Potri.012G130000/AtSAP9 and Potri.004G202900/BIC1) with newly identified putative roles in lignocellulose biosynthesis. Our integrative approach offers a framework for providing biological context to loci associated with trait variation, facilitating the discovery of new genes and regulatory networks. [ABSTRACT FROM AUTHOR]

Pretreatment facilitates cost-effective operations on lignocellulosic biomass ranging from densification to deconstruction and bioproduct development. However, determining molecular-level mechanisms behind pretreatment and their effects has remained elusive. Here, we combine computational simulation and experiment to investigate the effects on wheat straw agricultural residue densification of an emerging pretreatment solvent, namely, a deep eutectic solvent (DES) consisting of choline chloride (ChCl) and oxalic acid (OA). Ab initio molecular dynamics indicates that dissociation of lignin from cellulose in lignin–carbohydrate complexes, which does not occur to a significant extent in aqueous solution, is favorable in the DES and occurs via cleavage of the guaiacyl : xylose ether bond linkage by OA. The ensuing hemicellulose removal exposes lignin to the DES which, molecular dynamics simulation indicates, leads to lignin expansion. The resulting changes in wheat straw fiber structure, lignin distribution, and functional group modifications upon DES treatment by scanning electron and fluorescence microscopy along with Fourier-transform infrared spectroscopy. The molecular expansion of lignin enhances inter-particle binding in wheat straw, leading to denser structures under pelletization. The resulting high mechanical stability and combustion properties make the wheat straw a suitable precursor of high-quality densified solids (e.g., solid biofuel). Overall, we shed light on the molecular-level mechanisms involved in DES pretreatment for biomass densification, demonstrated here in the development of a solid biofuel. The approach here illuminates the rational design from first chemical principles of methods to convert lignocellulosic resources into advanced materials. [ABSTRACT FROM AUTHOR]

The processes of hemp bast fiber retting, forming, and drying offer the opportunity for value-added products such as natural fiber-reinforced composites. A new process for the retting of raw bast fibers through enzyme-triggered self-cultured bacterial retting was developed in the lab-scale setup. This study focused on comparing the energy consumption and environmental impacts of this bacterial retting process with the thermochemical retting process currently widely used to obtain lignocellulosic fibers for composites. The gate-to-gate life cycle assessment (LCA) models of the two retting processes were constructed to run a comparison analysis using the TRACI (the tool for the reduction and assessment of chemical and other environmental impacts) method for environmental impacts and the cumulative energy demand (CED) method for energy consumptions. This work has demonstrated the advantages of the bacterial retting method from an environmental standpoint. The result of our research shows about a 24% gate-to-gate reduction in CED for bacterial retting and 20–25% lower environmental impacts relating to global warming, smog formation, acidification, carcinogenics, non-carcinogenics, respiratory effects, ecotoxicity, and fossil fuel depletion when compared to that of thermochemical retting. [ABSTRACT FROM AUTHOR]

The accelerated weathering of flax and miscanthus fibers possessing distinct chemical compositions was investigated. The chosen fibers included raw, extractive-free (EF) and delignified samples (x3), alone and used as fillers in a stabilized polypropylene blue matrix (PP). Modifications in both color and the chemical composition of the fibers throughout the weathering process under ultraviolet (UV) light were meticulously tracked and analyzed by spectrophotometry and attenuated total reflectance with Fourier-transform infrared spectroscopy (ATR-FTIR). The inherent nature and composition of the selected fibers led to varied color-change tendencies. Raw and EF flax fibers exhibited lightening effects, while raw and EF miscanthus fibers demonstrated darkening effects. Extractives exhibited negligible influence on the color alteration of both flax and miscanthus fibers. This disparity between the fibers correlates with their respective lignin content and type, and the significant formation of carbonyl (C=O) groups in miscanthus. Better stability was noted for delignified flax fibers. A comparative study was achieved by weathering the PP matrix containing these various fibers. Contrary to the weathering observations on individual fibers, it was noted that composites containing raw and EF flax fibers exhibited significant color degradation. The other fiber-containing formulations showed enhanced color stability when compared to the pure PP matrix. The study highlights that the UV stability of composites depends on their thermal history. As confirmed by thermogravimetric analysis (TGA), fiber degradation during extrusion may affect UV stability, a factor that is not apparent when fibers alone are subjected to UV aging. [ABSTRACT FROM AUTHOR]

Over the past decade, the production of biofuels from lignocellulosic biomass has steadily increased to offset the use of fuels from petroleum. To make biofuels cost-competitive, however, it is necessary to add value to the "ligno-" components (up to 30% by mass) of the biomass. The properties of lignin, in terms of molecular weight (MW), chemical functionality, and mineral impurities often vary from biomass source and biorefinery process, resulting in a challenging precursor for product development. Activated carbon (AC) is a feasible target for the lignin-rich byproduct streams because it can be made from nearly any biomass, and it has a market capacity large enough to use much of the lignin generated from the biorefineries. However, it is not known how the variability in the lignin affects the key properties of AC, because, until now, they could not be well controlled. In this work, various fractions of ultraclean (<0.6% ash) lignin are created with refined MW distributions using Aqueous Lignin Purification using Hot Agents (ALPHA) and used as precursors for AC. AC is synthesized via zinc chloride activation and characterized for pore structure and adsorption capacity. We show that AC surface area and the adsorption capacity increase when using lignin with increasing MW, and, furthermore, that reducing the mineral content of lignin can significantly enhance the AC properties. The surface area of the AC from the highest MW lignin can reach ~1830 m2/g (absorption capacity). Furthermore, single step activation carbonization using zinc chloride allows for minimal carbon burn off (<30%), capturing most of the lignin carbon compared to traditional burn off methods in biorefineries for heat generation. [ABSTRACT FROM AUTHOR]

Depolymerization of the cellulose part in lignocellulose to glucose is a significant step for lignocellulose valorization. As one of the main by‐products of agricultural biomass in crop‐producing filed, valorization of corn straw has attracted considerable attention. In this study, a two‐step depolymerizing strategy of high‐pressure CO2−H2O pretreatment and oxidation‐hydrolysis was applied for selective depolymerization of the cellulose component of corn straw to glucose production. Most part of the hemicellulose component could be removed through high‐pressure CO2−H2O pretreatment in the presence of low concentration of acetic acid, and then as high as 32.2 % yield of glucose was achieved in water at 170 °C for 6 h without additional catalyst. The active acid sites generated during the partial oxidation of hydroxymethyl groups to carboxyl groups on glucose units of cellulose was shown to be crucial for the efficient valorization of corn straw for glucose production. [ABSTRACT FROM AUTHOR]

Copyright of Environmental & Social Management Journal / Revista de Gestão Social e Ambiental is the property of Environmental & Social Management Journal and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)