Main Biomass Components Research Articles

Isolation and Identification of Alkaloid Genes from the Biomass of Fritillaria taipaiensis P.Y. Li

Background/Objectives: Fritillaria taipaiensis P.Y. Li is a valuable traditional Chinese medicinal herb that utilizes bulbs as medicine, which contain multiple alkaloids. Biomass, as a sustainable resource, has promising applications in energy, environmental, and biomedical fields. Recently, the biosynthesis and regulatory mechanisms of the main biomass components of biomass have become a prominent research topic. Methods: In this article, we explored the differences in the heterosteroidal alkaloid components of F. taipaiensis biomass using liquid chromatography–mass spectrometry and high-throughput transcriptome sequencing. Results: The experimental results demonstrated significant differences in the eight types of heterosteroidal alkaloid components among the biomass of F. taipaiensis, including peimisine, imperialine, peimine, peiminine, ebeinone, ebeiedine, ebeiedinone, and forticine. Transcriptomic analysis revealed substantial significant differences in gene expression patterns in the various samples. Three catalytic enzyme-coding genes, 3-hydroxy-3-methylglutaryl coenzyme A synthase (HMGS), 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR), and terpene synthase (TPS), were speculated to contribute to the regulation of the differential accumulation of alkaloid synthesis in F. taipaiensis bulbs. A strong positive correlation was observed between the transcriptional level of the TPS gene and the alkaloid content of F. taipaiensis biomass, suggesting that TPS may be a key gene in the biosynthesis pathway of alkaloids. This finding can be used for subsequent gene function verification and molecular regulatory network analysis. Conclusions: This work provides fundamental data and novel insights for the subsequent research on alkaloid biosynthesis in F. taipaiensis.

Efficient synthesis of lactic acid from cellulose through the synergistic effect of zinc chloride hydrate and metal salts

The chemocatalystic conversion of cellulose, the main component of lignocellulosic biomass, to building-block chemicals in water under mild conditions, is an ideal but highly challenging process due to the robust crystal structure of cellulose. It is also the key to establishing a sustainable biomass-based chemical process. Here, we present a highly efficient and selective chemocatalytic hydrolysis of cellulose using ZnCl2·3H2O hydrate as the pretreatment reagent and water-compatible metal salts - ErCl3 as the catalyst, into lactic acid (LA), which is an important chemical building-block widely utilized in the food industry and in the production of chemicals and biodegradable plastic. With 94.0 % conversion of cellulose, an impressive LA yield of 84.6 % was achieved at 170 °C after 4 h under ambient air pressure in water. High yields of LA were also obtained from other carbohydrates, such as fructose (68.3 %), glucose (52.7 %), starch (54.4 %), and inulin (67 %). A series of experiments demonstrated that Er(III) combination with water catalyzed cascading steps of soluble cellulose into LA after ZnCl2·3H2O hydrate disrupted the hydrogen bonds in the cellulose, Zn(II) played an indirect role by promoting LA formation through inhibition of side reactions. A plausible mechanism was proposed for the chemocatalytic conversion of cellulose to LA.

Interaction Effects between the Main Components of Protein-Rich Biomass during Microwave-Assisted Pyrolysis.

The interaction effects between the main components (proteins (P), carbohydrates (C), and lipids (L)) of protein-rich biomass during microwave-assisted pyrolysis were investigated in depth with an exploration of individual pyrolysis and copyrolysis (PC, PL, and CL) of model compounds. The average heating rate of P was higher than those of C and L, and the interactions in all copyrolysis groups reduced the max instant heating rate. The synergistic extent (S) of PC and PL for bio-oil yield was 16.78 and 18.24%, respectively, indicating that the interactions promoted the production of bio-oil. Besides, all of the copyrolysis groups exhibited a synergistic effect on biochar production (S = 19.43-28.24%), while inhibiting the gas generation, with S ranging from -20.17 to -6.09%. Regarding the gaseous products, apart from H2, P, C, and L primarily generated CO2, CO, and CH4, respectively. Regarding bio-oil composition, the interactions occurring within PC, PL, and CL exhibited a significantly synergistic effect (S = 47.81-412.96%) on the formation of N-heterocyclics/amides, amides/nitriles, and acids/esters, respectively. Finally, the favorable applicability of the proposed interaction effects was verified with microalgae. This study offers valuable insights for understanding the microwave-assisted pyrolysis of protein-rich biomass, laying the groundwork for further research and process optimization.

Process simulation of flax straw pyrolysis with kinetic reaction Model: Experimental validation and exergy analysis

Pyrolysis, a viable method for converting organic material into value-added products, has significant potential to reduce environmental footprints. In this study, slow and fast pyrolysis of flax straw biomass was modeled in an Aspen Plus. This was followed by validation of the product yields (biochar, bio-oil, and gas) with our earlier experimental data with slow pyrolysis. The Aspen Plus model incorporated a kinetic reaction model based on the three main components of lignocellulosic biomass: cellulose, hemicellulose, and lignin. The kinetic reaction model includes 21 reactions representing the volatilization, degradation, and decomposition processes inherent in biomass pyrolysis. The Aspen Plus confirmed the consistency of the findings by validating the biogas yield (which ranged from 21.4 wt% to 38.6 wt%), biochar (29.5 wt% to 42.8 wt%), and bio-oil (35.8 wt% to 40.3 wt%). The robustness of the model was verified by experimental data using controlled pyrolysis tests of flax straw feedstock at different temperatures, showing strong agreement. The kinetic reaction model is adaptable for predicting pyrolysis yields for various lignocellulosic biomass feedstocks under typical pyrolysis conditions. Furthermore, energy and exergy analyses were briefly assessed using the product yields, pyrolysis temperature, and heating values of the products at slow and fast pyrolysis conditions. The conventional exergy analysis showed an exergy efficiency of 87–95 % with varying temperatures from 400 to 600 °C for slow pyrolysis, with the highest efficiency obtained at 500 °C. Fast pyrolysis has resulted in a higher exergy efficiency than slow pyrolysis, ranging from 89 % to 98 %.

Precursor screening of fruit shell derived hard carbons for low-potential sodium storage: A low lignin content supports the formation of closed pores

Biomass hard carbons are being explored for anode materials of sodium-ion batteries due to the wide availability. However, the precursor screening for optimal microstructure and sodium storage performance is tedious and time-consuming. Here, we selected three kinds of fruit shells to prepare hard carbons for sodium-ion batteries and investigated their structure characteristics and sodium storage performance. It is demonstrated that a low lignin content in fruit shells is favor to the formation of closed pores in the derived hard carbons, thus generating a high low-potential plateau capacity. Among the main component of biomass, lignin with rich aromatic ring structure possesses higher thermal stability than cellulose and hemicellulose. During the pyrolysis and carbonization, lignin may decompose to large-size crystalline domains, which hinders the random stacking of carbon layers. Therefore, as the lower lignin content than pine nut shell and macadamia nut shell (28.4% vs. 39.2% and 37.4%), the walnut shell derived hard carbon shows a largest interlayer distance of 0.397 nm and a highest closed pore area of 391 m2 g−1, contributing to the supreme specific capacity of 362.6 mAh g−1, with a plateau capacity of 195.8 mAh g−1 as well as a remarkable cycle stability. The assembled WNSC//NVP full-cell remains a discharge capacity of 53.1 mAh g−1 after 100 cycles at 0.1 A g−1. This work gives a deep insight of the relationship between biomass composition and microstructure of the derived hard carbons to explore its high sodium storage ability in low-potential region.

Independent metabolism of oligosaccharides is the keystone of synchronous utilization of cellulose and hemicellulose in Myceliophthora.

The effective utilization of cellulose and hemicellulose, the main components of plant biomass, is a key technical obstacle that needs to be overcome for the economic viability of lignocellulosic biorefineries. Here, we firstly demonstrated that the thermophilic cellulolytic fungus Myceliophthora thermophila can simultaneously utilize cellulose and hemicellulose, as evidenced by the independent uptake and intracellular metabolism of cellodextrin and xylodextrin. When plant biomass serviced as carbon source, we detected the cellodextrin and xylodextrin both in cells and in the culture medium, as well as high enzyme activities related to extracellular oligosaccharide formation and intracellular oligosaccharide hydrolysis. Sugar consumption assay revealed that in contrast to inhibitory effect of glucose on xylose and cellodextrin/xylodextrin consumption in mixed-carbon media, cellodextrin and xylodextrin were synchronously utilized in this fungus. Transcriptomic analysis also indicated simultaneous induction of the genes involved in cellodextrin and xylodextrin metabolic pathway, suggesting carbon catabolite repression (CCR) is triggered by extracellular glucose and can be eliminated by the intracellular hydrolysis and metabolism of oligosaccharides. The xylodextrin transporter MtCDT-2 was observed to preferentially transport xylobiose and tolerate high cellobiose concentrations, which helps to bypass the inhibition of xylobiose uptake. Furthermore, the expression of cellulase and hemicellulase genes was independently induced by their corresponding inducers, which enabled this strain to synchronously utilize cellulose and hemicellulose. Taken together, the data presented herein will further elucidate the degradation of plant biomass by fungi, with implications for the development of consolidated bioprocessing-based lignocellulosic biorefinery.

Interaction among lignocellulosic biomass components in thermochemical processes

This research aims to evaluate the thermal behavior of main components of biomass (hemicellulose, cellulose and lignin) in order to identify their synergistic effect in thermochemical processes. These components were isolated from sugarcane bagasse and straw using different chemical treatments and their chemical and physical-chemical characterizations were performed. Results showed that chemical treatments were adequate for cellulose and lignin isolation, although it was verified that more adequate methodologies must be sought for hemicellulose isolation. The thermogravimetric analysis of each sample and their mixtures in inert (N2) and oxidant (synthetic air) atmospheres allowed investigating the synergism among the components. It was observed that the synergistic effect was more pronounced in DTG curves in an oxidizing atmosphere. There was a weak interaction effect between cellulose and hemicellulose, but hemicellulose allowed reducing cellulose decomposition rate. Moreover, the mixture between hemicellulose and lignin showed a synergistic effect on lignin, which promoted an increase in hemicellulose decomposition rate, while hemicellulose anticipated the main event of lignin decomposition in an oxidizing atmosphere. It was found that lignin had a positive effect on cellulose decomposition in an oxidizing atmosphere, thus inhibiting its decomposition, while cellulose promoted an increase in lignin decomposition rate in its final event. Ultimately, results for the synergistic effect allowed detecting other components besides isolated elements in the biomass structure in smaller amounts, which nevertheless affect the behavior of its thermal decomposition.

Simultaneous Electrochemical Determination of Hydroquinone and Catechol by Lignocellulose Biopolymers Derived Porous Carbon

AbstractHemicellulose and lignin, which are main components of wood biomass with different structures, were carbonized and activated by KOH to prepare wood biomass‐derived porous carbons (WBM‐PCs). The resulting WBM‐PCs were characterized by SEM, XRD, Raman, FI‐IR, and N2‐adsorption/desorption isotherms, and successfully utilized as an effective modifier on the glassy carbon electrode surface (GCE) for simultaneous electrochemical determination of dihydroxybenzene isomers, i. e. hydroquinone (HQ) and catechol (CC), which are highly toxic and non‐degradable. The resulting WBM‐PCs‐modified GCEs allowed simultaneous determination of HQ and CC with cyclic voltammetry and constant‐potential amperometry. The linear range for determination of HQ by hemicellulose‐derived carbon (HC) was from 1.0 to 3000 μmol/L with the limit of detection (LOD) of 1.05 μmol/L, and that for CC was from 1.0 to 5000 μmol/L with LOD of 0.4 μmol/L. For lignin‐derived carbon (LC), the linear range for HQ was from 0.5 to 1000 μmol/L with LOD of 0.095 μmol/L, and that for CC was from 0.5 to 3000 μmol/L with LOD of 0.15 μmol/L. These results imply that wood biomass (hemicellulose and lignin), which is sustainable, renewable and environment‐friendly material, have potential as an effective precursor of electrochemically active porous carbon materials applicable to various electrochemical sensors.

Preparation of Biomass Biochar with Components of Similar Proportions and Its Methylene Blue Adsorption.

Rapeseed straw, bagasse, and walnut peel have a large amount of resource reserves, but there are few technologies for high value-added utilization. In the research of biochar, walnut green husk is rarely used as raw material. In addition, the three main components of biomass (lignin, cellulose, and hemicellulose) are present in similar proportions, and the differences between the physical and chemical properties of biochar prepared with similar amounts of biomass raw materials are not clear. Using three kinds of biomass of the same quality as raw materials, biochar was prepared via pyrolysis at 400 °C, and activated carbon was prepared via CO2 activation at 800 °C. The results showed that the pore numbers of the three kinds of biochar increased after activation, resulting in the increase of the specific surface area. The resulting numbers were 352.99 m2/g for sugarcane bagasse biochar (SBB)-CO2, 215.04 m2/g for rapeseed straw biochar (RSB)-CO2, and 15.53 m2/g for walnut green husk biochar (WGB)-CO2. Ash increased the amount of carbon formation, but a large amount of ash caused biochar to form a perforated structure and decreased the specific surface area (e.g., WGB), which affected adsorption ability. When the three main components were present in similar proportions, a high content of cellulose and lignin was beneficial to the preparation of biochar. The adsorption value of MB by biochar decreased with the increase of biomass ash content. After activation, the maximum adsorption value of MB for bagasse biochar was 178.17 mg/g, rapeseed straw biochar was 119.25 mg/g, and walnut peel biochar was 85.92 mg/g when the concentration of methene blue solution was 300 mg/L and the biochar input was 0.1 g/100 mL at room temperature. The adsorption of MB by biochar in solution occurs simultaneously with physical adsorption and chemical adsorption, with chemical adsorption being dominant. The optimal MB adsorption by SBB-CO2 was dominated by multimolecular-layer adsorption. This experiment provides a theoretical basis for the preparation of biochar and research on its applications in the future.

One-step conversion of corn stalk to glucose and furfural in molten salt hydrate/organic solvent biphasic system

An effective approach for glucose and furfural production by converting cellulose and hemicelluloses from corn stalk in a biphasic system of molten salt hydrate (MSH) and organic solvent using H2SO4 as catalyst was reported. Results showed that the system with LiBr·3H2O and dichloromethane (DCM) had excellent performance in cellulose and hemicelluloses conversion. Under the optimal reaction conditions (corn stalk:LiBr·3H2O:DCM ratio = 0.35:10:20 g/mL/mL, 0.05 mol/L H2SO4, 120 °C, 90 min), 58.9% glucose and 72.5% furfural were yielded. Meanwhile, lignin was obviously depolymerized by the cleavage of β-O-4′ linkages and fractionated with high purity and low molecular weight for potential coproducts. Fluorescence microscopy and confocal Raman microscope displayed that the LiBr·3H2O/DCM treatment caused decreasing intensities in carbohydrate and lignin, suggesting the degradation of the main components of biomass. This research provided a promising biorefinery technology for the comprehensive utilization of corn stalk.

Improvement of enzymatic saccharification by simultaneous pulping of sugarcane bagasse and washing of its cellulose fibers in a batch reactor.

A modification of the conventional batch organosolv process is proposed in a way where the solid biomass remains inside a basket, physically separated from the liquid phase, with the vapor promoting the fractionation of the biomass and the extracted compounds and fragments being washed down to the liquid phase. The modified organosolv process applied to sugarcane bagasse (SB-M) delivers a rich cellulosic solid phase that after enzymatic hydrolysis leads to a hydrolyzed with approximately 100gL-1 of glucose. At the same enzymatic hydrolysis conditions, the conventional organosolv process (SB-C) delivers a hydrolyzed with 80gL-1 of glucose, while the autohydrolysis process (SB-A) leads to 55gL-1 of glucose. These different results are related to the cellulose content: SB-M (70%), SB-C (57%), e SB-A (44%), as well the reduced lignin content in the SB-M. The novelty of this study is the confirmation that it is possible to degrade lignin from sugarcane bagasse and simultaneously remove its fragments from the cellulose fibers in a batch reactor containing an internal basket. This study describes a simple and rapid protocol for the isolation of the main components of lignocellulosic biomass (cellulose, hemicellulose, and lignin), which may lead to the study of new catalysts for the chemical transformation of these components separately or simultaneously to the step of pretreatment.

Fractionation of Aspen Wood to Produce Microcrystalline, Microfibrillated and Nanofibrillated Celluloses, Xylan and Ethanollignin.

A new method for extractive-catalytic fractionation of aspen wood to produce microcrystalline (MCC), microfibrillated (MFC), nanofibrilllated (NFC) celluloses, xylan, and ethanollignin is suggested in order to utilize all of the main components of wood biomass. Xylan is obtained with a yield of 10.2 wt.% via aqueous alkali extraction at room temperature. Ethanollignin was obtained with a yield of 11.2 wt.% via extraction with 60% ethanol from the xylan-free wood at 190 °C. The lignocellulose residue formed after the extraction of xylan and ethanollignin was subjected to catalytic peroxide delignification in the acetic acid-water medium at 100 °C in order to obtain microcrystalline cellulose. MCC is hydrolyzed with 56% sulfuric acid and treated with ultrasound to produce microfibrillated cellulose and nanofibrillated cellulose. The yields of MFC and NFC were 14.4 and 19.0 wt.%, respectively. The average hydrodynamic diameter of NFC particles was 36.6 nm, the crystallinity index was 0.86, and the average zeta-potential was 41.5 mV. The composition and structure of xylan, ethanollignin, cellulose product, MCC, MFC, and NFC obtained from aspen wood were characterized using elemental and chemical analysis, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) analyses, Gas chromatography (GC), Gel permeation-chromatography (GPC), Scanning electron microscopy (SEM), Atomic force microscopy (AFM), Dynamic light scattering (DLS), Thermal gravimetric analysis (TGA).

Determination of Lignin, Cellulose, and Hemicellulose in Plant Materials by FTIR Spectroscopy

A procedure for determining concentrations of lignin, cellulose, and hemicellulose in plant materials using Fourier-transform IR spectroscopy in the middle spectral region was developed and tested. The procedure is based on the use of calibration functions reflecting the dependence of the intensity of analytical absorption bands on the concentration of lignin (1512 cm–1) and cellulose (1450 cm–1) in model samples; for hemicellulose, indirect correlations were used. The model samples were ternary mixtures consisting of lignin, bacterial cellulose, and hemicellulose in various proportions. The proposed method was tested on a wide range of plant biomass samples; it demonstrated adequate precision (RSD no more than 4%). The accuracy of the procedure for determining the main components of plant biomass (lignin, cellulose, and hemicellulose) was demonstrated using the standard addition method.

The formation mechanism of furfural in xylan pyrolysis: A machine learning study based on neural network potential

Biomass fast pyrolysis has attracted extensive attention to sustainably producing energy, fuels, and chemicals. Xylan as a typical hemicellulose is one of the main components of biomass, and it can produce the value-added platform product furfural (FF) by fast pyrolysis. However, the formation mechanism of FF is still unclear. Herein, the stochastic surface walking reaction sampling (SSW-RS) method based on neural network (NN) potential, together with density functional theory (DFT) calculation, were employed to explore the FF formation mechanism in xylan pyrolysis. Xylobiose and xylopyranose were used as the model compounds for investigation, with the aim to find out new FF formation pathways and to reveal the effects of the glycosidic bond. It is found that the existence of glycosidic bonds promotes dehydration and inhibits ring-opening reactions, and depolymerization becomes easier after dehydration. d-Xylose is an important precursor for FF formation, and a new pathway from d-xylose decomposition to generate FF has been found, involving 2-ene-3-deoxyxylose and 1,2-dicarbonyl-3-ene-5-pentanol as key intermediates. Due to the glycosidic bonds, the anhydro xylopyranoses (AXPs) as the dehydration and depolymerization products play an important role in FF formation. Another new pathway involving 4-ene-4-deoxyxylose (a cyclic AXP with C4C5 bond) is confirmed favorable for FF generation.

Quantifying the intrinsic value of algal biomass based on a multi-product biorefining strategy

Microalgal biomass is poised to become an important feedstock in the quest to decarbonize the fuels and chemical industries. In this way, it is imperative that researchers prioritize efforts for increased chances of economic viability of the microalgae biomass supply chain. This work applies a sequential techno-economic assessment (TEA) methodology to compare the economic trade-offs between microalgae growth and compositional shift while solving for an alternative economic metric: intrinsic algal biomass value, i.e., the revenue obtained from processing and converting the main components of algae biomass - carbohydrates, lipids, and protein - to a portfolio of products. The framework relies on data derived from small-scale cultivations to initially determine the maximum economic potential of different product portfolios as obtained in multiple biorefining setups. The approach further downselects the number of possible strains to undergo an in-depth TEA in order to quantify the value of transitioning from nutrient-replete to nutrient-deplete cultivations. Among the 13 permutations of strains and cultivation strategies analyzed, this study demonstrated an increase in intrinsic biomass value for four strains after the compositional shift: Chlorella sorokiniana DOE1412, Chlorella sorokiniana DOE1116, Scenedesmus obliquus UTEX393, and Scenedesmus obliquus DOE0152.Z. While product selection is critical in the exploitation of microalgal biomass, the four mentioned strains at least double their intrinsic biomass values, reaching up to $264/ton in net margins above minimum biomass selling prices. This is attainable without considering the production of small market size specialty chemicals, instead targeting markets with scalability potential and/or with currently large sizes. Two other strains, namely Picochlorum celeri WT-CSM/EMRE and Tetraselmis striata LANL1001, should have their biomass productivities increased by around 5 g/m2/day in nutrient-deplete cultivations to achieve economic viability. The concept of implementing an objective comparison between different portfolio configurations detailed herein is an innovative approach towards the economic assessment of microalgae valorization strategies.

Multi-Omics and Genome Editing Studies on Plant Cell Walls to Improve Biomass Quality

Biomass is one of the most important sources of renewable energy and plays an important role in reducing our reliance on fossil fuels. Efficient biomass production is essential to obtain large amounts of sustainable energy with minimal environmental cost. However, the biochemical and molecular processes behind the synthesis of the main components of biomass are still not fully understood. This review provides a comprehensive summary of the most relevant studies on cell wall biosynthesis and degradation mechanisms, focusing on the lignocellulosic component, in which the conversion process to fermentable sugars is expensive, due to its recalcitrant nature. A focus is placed on multi-omics research involving genomics, transcriptomics, proteomics, metabolomics, and phenomics, since multi-omics approaches offer a unique opportunity to investigate the biological pathways underlying the genotype traits characterizing cell wall energy crops. Furthermore, our study highlights the advances in genome editing approaches and proposes the modification of the genes that are involved in the complex cell wall structure as a feasible solution to an efficient biomass production. Several key points for future research activities based on these emerging technologies are also discussed, focusing on the combination of multi-omics and gene editing approaches, which offer potential for improved biomass valorization and the development of tangible bioproducts.

Research Progress in Hemicellulose-Based Nanocomposite Film as Food Packaging

As the main component of agricultural and forestry biomass, hemicellulose has the advantages of having an abundant source, biodegradability, nontoxicity and good biocompatibility. Its application in food packaging has thus become the focus of efficient utilization of biomass resources. However, due to its special molecular structure and physical and chemical characteristics, the mechanical properties and barrier properties of hemicellulose films are not sufficient, and modification for performance enhancement is still a challenge. In the field of food packaging materials preparation, modification of hemicellulose through blending with nanofibers or nanoparticles, both inorganic and organic, has attracted research attention because this approach offers the advantages of efficient improvement in the expected properties and better cost efficiency. In this paper, the composition of hemicellulose, the classification of nanofillers and the research status of hemicellulose-based nanocomposite films are reviewed. The research progress in modification of hemicellulose by using layered silicate, inorganic nanoparticles and organic nanoparticles in food packaging is described. Challenges and outlook of research in hemicellulose-based nanocomposite film in food packaging is discussed.

Direct Conversion of Cellulose into 5-HMF by Transition-Metal Doped Montmorillonite Catalyst in Water

AbstractCatalysts are very important in the use of cellulose, the main component of biomass, as a raw material for the large-scale production of liquid fuels and chemicals. 5-Hydroxymethylfurfural (HMF) is an extremely important intermediate in the fine chemical industry. HMF can be synthesized by acid-catalyzed dehydration of fructose, glucose, cellulose, or sucrose. The conversion of cellulose to HMF is challenging due to its chemical structure. The objective of the present study was to devise a more facile synthesis method using transition metal-doped montmorillonite catalysts (10Cr-Mnt, 10Cu-Mnt, 10Fe-Mnt, and 10Zn-Mnt) by wet impregnation. Samples were characterized by X-ray powder diffraction, specific surface area, and NH3-TPD analyses. The synthesized catalysts were used for the conversion of cellulose to 5-HMF in an aqueous medium. Among the metals studied, Cr showed the greatest catalytic activity. With the use of this catalyst, efficient conversion of cellulose to 5-HMF was achieved, affording a conversion yield of 93.47% and 5-HMF yield of 9.07% within 6 h at 200°C. The study described here could be useful for the efficient conversion of cellulose into 5-HMF, as well as into other biomass-derived chemicals.

Pyrolysis kinetics and thermodynamic parameters of bamboo residues and its three main components using thermogravimetric analysis

Detailed kinetic triplets and thermodynamic studies of the three main components are important in the efficient design of the pyrolysis process. In this work, the three main components (cellulose, hemicellulose and lignin) of lignocellulosic biomass were extracted from bamboo residues (BR). The kinetic triplets and thermodynamic parameters of BR and its three components were then interpreted using thermogravimetric analysis. Three iso-conversional methods (Friedman, Flynn-Wall-Ozawa and Kissinger-Akahira-Sunose models) estimated the average activation energy of BR and the extracted cellulose, hemicellulose and lignin to be 164.5, 145.3, 186.0 and 182.7 kJ mol−1, respectively. The frequency factors of BR ranged from 1013 to 1018 min−1 according to the Kissinger method, and the average frequency factors of the three main components were cellulose < hemicellulose < lignin. The master plots reveal the dominance of the diffusion mechanism in the pyrolysis process. The change in enthalpy (109.5–297.1 kJ mol−1) and Gibb free energy (138.7–156.3 kJ mol−1) indicated the endothermic and non-spontaneous nature of the pyrolysis of BR and the three main components. Kinetic and thermodynamic analyses confirmed the feasibility of BR as a potential candidate for bioenergy.

Synthesis and Characterization of Poly(lactic acid) Composites with Organosolv Lignin

Lignin, being one of the main structural components of lignocellulosic biomass, is considered the most abundant natural source of phenolics and aromatics. Efforts for its valorisation were recently explored as it is mostly treated as waste from heat/energy production via combustion. Among them, polymer-based lignin composites are a promising approach to both valorise lignin and to fine tune the properties of polymers. In this work, organosolv lignin, from beech wood, was used as fillers in a poly (lactic acid) (PLA) matrix. The PLA/lignin composites were prepared using melt mixing of masterbatches with neat PLA in three different lignin contents: 0.5, 1.0 and 2.5 wt%. Lignin was used as-isolated, via the organosolv biomass pretreatment/fractionation process and after 8 h of ball milling. The composites were characterised with Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR) spectroscopy, X-ray Diffraction (XRD), and Differential Scanning Calorimetry (DSC). Additionally, their antioxidant activity was assessed with the 2,2-Diphenyil-1-picrylhydrazyl (DPPH) method, the colour was measured with a colorimeter and the mechanical properties were evaluated with tensile testing. Ball milling, at least under the conditions applied in this study, did not induce a further substantial decrease in the already relatively small organosolv lignin primary particles of ~1 μm. All the produced PLA/lignin composites had a uniform dispersion of lignin. Compression-moulded films were successfully prepared, and they were coloured brown, with ball-milled lignin, giving a slightly lighter colour in comparison with the as-received lignin. Hydrogen bonding was detected between the components of the composites, and crystallization of the PLA was suppressed by both lignin, with the suppression being less pronounced by the ball-milled lignin. All composites showed a significantly improved antioxidant activity, and their mechanical properties were maintained for filler content 1 wt%.