Wheat Straw Lignin Research Articles

Anaerobic Biodegradation of Wheat Straw Lignin: The Influence of Wet Explosion Pretreatment

Large amounts of lignin residue is expected in the future when biorefineries for producing biofuels and bio-products will increase in numbers. It is, therefore, valuable to find solutions for using this resource for the sustained production of useful bioenergy or bio-products. Anaerobic digestion could potentially be an option for converting the biorefinery lignin into a valuable energy product. However, lignin is recalcitrant to biodegradation under anaerobic conditions unless the structure is modified. Wet oxidation followed by steam explosion (wet explosion) was previously found to make significant changes to the lignin structure allowing for biodegradation under anaerobic conditions. In this study, we examine the effect of wet explosion pretreatment for anaerobic digestion of wheat straw lignin under mesophilic (37 °C) conditions. Besides the biorefinery lignin produced from wheat straw, untreated lignin was further tested as feed material for anaerobic digestion. Our results showed that wet exploded lignin pretreated with 2% NaOH showed the highest lignin degradation (41.8%) as well as the highest methane potential of 157.3 ± 9.9 mL/g VS. The untreated lignin with no pretreatment showed the lowest methane yield of 65.8 ± 4.8 and only 3.5% of the lignin was degraded. Overall, increased severity of the pretreatment was found to enhance anaerobic degradation of lignin.

High-Performance Hydrogel Adsorbent Based on Cellulose, Hemicellulose, and Lignin for Copper(II) Ion Removal.

Cellulose, hemicellulose, and lignin are three kinds of biopolymer in lignocellulosic biomass, and the utilization of the three biopolymers to synthesize hydrogel adsorbent could protect the environment and enhance the economic value of the biomass. A novel hydrogel adsorbent was prepared using cellulose, lignin, and hemicellulose of wheat straw by a one-pot method, and the adsorbent showed excellent adsorption performance for copper(II) ions. Scanning electron microscopy and Fourier transform infrared spectroscopy analysis showed that the prepared straw-biopolymer-based hydrogel had porous structure, and cellulose fibrils had crosslinked with lignin and hemicellulose by poly(acrylic acid) chains. The effects of contact time, initial concentration, and temperature on the copper(II) ion removal using the prepared hydrogels were investigated, and the obtained results indicated that the adsorption kinetics conformed to the pseudo-second-order and Elovich equation models and the adsorption isotherm was in accord with the Freundlich model. The adsorption thermodynamics study indicated that the adsorption process was spontaneous and accompanied by heat. X-ray photoelectron spectroscopy analysis revealed that the adsorption behavior resulted from ion exchange. The prepared hydrogel based on cellulose, hemicellulose, and lignin could be used for water treatment and soil remediation because of its high performances of excellent heavy metal ion removal and water retention.

A comprehensive study of the promoting effect of manganese on white rot fungal treatment for enzymatic hydrolysis of woody and grass lignocellulose

BackgroundThe efficiency of biological systems as an option for pretreating lignocellulosic biomass has to be improved to make the process practical. Fungal treatment with manganese (Mn) addition for improving lignocellulosic biomass fractionation and enzyme accessibility were investigated in this study. The broad-spectrum effect was tested on two different types of feedstocks with three fungal species. Since the physicochemical and structural properties of biomass were the main changes caused by fungal degradation, detailed characterization of biomass structural features was conducted to understand the mechanism of Mn-enhanced biomass saccharification.ResultsThe glucose yields of fungal-treated poplar and wheat straw increased by 2.97- and 5.71-fold, respectively, after Mn addition. Particularly, over 90% of glucose yield was achieved in Mn-assisted Pleurotus ostreatus-treated wheat straw. A comparison study using pyrolysis gas chromatography mass spectrometry (Py-GC/MS) and two-dimensional 1H–13C heteronuclear single quantum coherence (2D HSQC) nuclear magnetic resonance (NMR) spectroscopy was conducted to elucidate the role of Mn addition on fungal disruption of the cross-linked structure of whole plant cell wall. The increased Cα-oxidized products was consistent with the enhanced cleavage of the major β-O-4 ether linkages in poplar and wheat straw lignin or in the wheat straw lignin–carbohydrate complexes (LCCs), which led to the reduced condensation degree in lignin and decreased lignin content in Mn-assisted fungal-treated biomass. The correlation analysis and principal component analysis (PCA) further demonstrated that Mn addition to fungal treatment enhanced bond cleavage in lignin, especially the β-O-4 ether linkage cleavage played the dominant role in removing the biomass recalcitrance and contributing to the glucose yield enhancement. Meanwhile, enhanced deconstruction of LCCs was important in reducing wheat straw recalcitrance. The findings provided not only mechanistic insights into the Mn-enhanced biomass digestibility by fungus, but also a strategy for improving biological pretreatment efficiency of lignocellulose.ConclusionThe mechanism of enhanced saccharification of biomass by Mn-assisted fungal treatment mainly through Cα-oxidative cleavage of β-O-4 ether linkages further led to the decreased condensation degree in lignin, as a result, biomass recalcitrance was significantly reduced by Mn addition.Graphic abstract

Revealing migration discipline of lignin during producing fermentable sugars from wheat straw through autohydrolysis

Fermentable sugars have long been a research focus and are an important product of biorefining. Many researches have been dedicated to improving the yield of fermentable sugars from lignocellulose. However, an understanding of the residual lignin in pretreated and hydrolyzed residues remains lacking. In this work, wheat straw (WS) was autohydrolyzed under increasingly severe reaction conditions (temperature of 160–200 °C and reaction times of 20–60 min), and the anatomical characteristics of the resultant biomass were carefully analyzed to provide visual evidences of the fate of lignin. The results showed that 12.3 g/L of total xylose can be produced from autohydrolysis of WS. Further, the enzymatic hydrolysis efficiency of WS increased by 70.3% after autohydrolysis at 200 °C for 60 min. Under those conditions, the cell wall of WS were found to be significantly damaged, and the vascular bundles of lignin in the cell wall was firstly removed depending on the distribution of constituent compounds in the cell wall. The NMR analysis showed that the β-O-4 link bond and G-lignin units were affected the most during the autohydrolysis of WS, providing a route to understand the changes in WS lignin before and after autohydrolysis. It is our hope that these findings will lead to more targeted approaches for WS pretreatment and increase its applicability to biorefinery processes.

Effect of Biologically Treated Wheat Straw with White-Rot Fungi on Performance, Digestibility and Oxidative Status of Rabbits.

Raising growing rabbits is an ideal solution to confront animal protein deficiency, especially in developing countries. The presence of lignin in wheat straw causes limitation of the digestion overall process. The biological delignification is a practical and promising alternative due to improving the digestibility of wheat straw. This study aimed to enhance wheat straw digestibility and enriching it with protein and use it as a growing rabbit feedstuff. Enzymes production of white-rot fungi was assayed in myco-straw and the mean value was recorded. Wheat straw has been treated with the three most effective fungal species with Biological Treated Wheat Straw (BTWS). After that, the myco-straw was grounded and included in diet to evaluate the growth performance, digestibility and blood parameters of a growing V-line rabbit. The best three species for enzyme productions were P. sajor-caju, P. columbinus and P. floridanus. The optimum incubation period was 16 days. The fungal treatments showed significant enzymes activity of laccase, Mn-peroxidase, cellulase and xylanase. Body weight, body weight gain and feed conversion ratio of growing V-line rabbits had improved than those of the control. But, nutrients digestibility of the diet containing BTWS and Carcass traits of growing V-line rabbits were non-significant compared with the control one. In comparison with control, the lipid profile had no differences but the total protein was improved. White-rot fungal conversion of wheat straw is maybe one potential alternative providing a more practical, environmental-friendly and nutritionally enhancing as rabbits feedstuff. Rabbits fed BTWS-diets had significantly improved growth performance.

Investigation of the Formation of Coherent Ash Residues during Fluidized Bed Gasification of Wheat Straw Lignin

Thermal conversion of ash-rich fuels in fluidized bed systems is often associated with extensive operation problems caused by the high amount of reactive inorganics. This paper investigates the behavior of wheat straw lignin—a potential renewable fuel for dual fluidized bed gasification. The formation of coherent ash residues and its impact on the operation performance has been investigated and was supported by thermochemical equilibrium calculations in FactSage 7.3. The formation of those ash residues, and their subsequent accumulation on the surface of the fluidized bed, causes temperature and pressure fluctuations, which negatively influence the steady-state operation of the fluidized bed process. This paper presents a detailed characterization of the coherent ash residues, which consists mostly of silica and partially molten alkali silicates. Furthermore, the paper gives insights into the formation of these ash residues, dependent on the fuel pretreatment (pelletizing) of the wheat straw lignin, which increases their stability compared to the utilization of non-pelletized fuel.

Oxidative conversion of lignin isolated from wheat straw into aromatic compound catalyzed by NaOH/NaAlO2.

Lignin was isolated from wheat straw via organosolv process and further transferred to monophenolic compounds via oxidative conversion. Wheat straw lignin (WSL) with purity at 91.4 wt% was acquired in the presence of heterogeneous and recyclable catalyst of Amberlyst‐45. WSL was characterized by infrared spectrometer (IR), nuclear magnetic resonance spectroscopy (NMR) including 1H NMR and 13C NMR spectra. The results showed that WSL possesses typical syringyl (S), guaiacyl (G), and p‐hydroxyphenyl (H) units, and it is mainly composed of S and G units. The product distribution was dependent on the composition of WSL. Derivatives from S and G units were found to be the main products. The oxidative conversion of WSL was performed by varying oxidant and catalyst. Both the formation of monophenolic compounds and aromatic aldehydes were enhanced by combining oxidants and catalysts. The composite catalyst composed of NaOH/NaAlO2 was effective for the oxidation of WSL in the presence of nitrobenzene and atmospheric pressure air. The total yield of monophenolic compounds reached up 18.1%, and yields at 6.3 and 5.7% for syringaldehyde and vanillin were achieved, respectively.

Fractionation of herbaceous biomass using a recyclable hydrotropic p–toluenesulfonic acid (p–TsOH)/choline chloride (ChCl) solvent system at low temperatures

Lignin valorization is significantly influenced by the degrees of lignin condensation measured by the amount of cleaved βO4 ether linkages and interunit CC linkages formed during biomass fractionation. To minimize the cleavage of aryl ether and formation of CC linkages, a p–toluenesulfonic acid (p–TsOH)/choline chloride (ChCl) solvent system with hydrotropic properties was evaluated. The ChCl was chosen to control the H+ concentration of the p–TsOH/ChCl solvent system. Compared with p–TsOH/H2O, the degradation of βO4 was kept in a similar rate during p–TsOH/ChCl fractionation; however, the formation of CC linkage was slower. Under 75/25 p–TsOH/ChCl mass ratio at 80 °C for 20 min, 76.6 % of miscanthus lignin, with βO4 content of 30.9 %, and 88.9 % of wheat straw lignin, with βO4 content of 33.6 %, can be dissolved. In addition, the low polar and layered structure of hydrotropic p–TsOH/ChCl system has a strong ability to dissolve lignin, which resulted in lignin with larger particle size and lower surface charge. The results also indicated that lignin from p–TsOH/ChCl solvent system has great potential for lignin depolymerization to aromatics for valorization.

Evidence for ligninolytic activity of the ascomycete fungus Podospora anserina

BackgroundThe ascomycete fungus Podospora anserina has been appreciated for its targeted carbohydrate-active enzymatic arsenal. As a late colonizer of herbivorous dung, the fungus acts specifically on the more recalcitrant fraction of lignocellulose and this lignin-rich biotope might have resulted in the evolution of ligninolytic activities. However, the lignin-degrading abilities of the fungus have not been demonstrated by chemical analyses at the molecular level and are, thus far, solely based on genome and secretome predictions. To evaluate whether P. anserina might provide a novel source of lignin-active enzymes to tap into for potential biotechnological applications, we comprehensively mapped wheat straw lignin during fungal growth and characterized the fungal secretome.ResultsQuantitative 13C lignin internal standard py-GC–MS analysis showed substantial lignin removal during the 7 days of fungal growth (24% w/w), though carbohydrates were preferably targeted (58% w/w removal). Structural characterization of residual lignin by using py-GC–MS and HSQC NMR analyses demonstrated that Cα-oxidized substructures significantly increased through fungal action, while intact β-O-4′ aryl ether linkages, p-coumarate and ferulate moieties decreased, albeit to lesser extents than observed for the action of basidiomycetes. Proteomic analysis indicated that the presence of lignin induced considerable changes in the secretome of P. anserina. This was particularly reflected in a strong reduction of cellulases and galactomannanases, while H2O2-producing enzymes clearly increased. The latter enzymes, together with laccases, were likely involved in the observed ligninolysis.ConclusionsFor the first time, we provide unambiguous evidence for the ligninolytic activity of the ascomycete fungus P. anserina and expand the view on its enzymatic repertoire beyond carbohydrate degradation. Our results can be of significance for the development of biological lignin conversion technologies by contributing to the quest for novel lignin-active enzymes and organisms.

Chemical Composition of High Organic Carbon Soil Amendments Affects Fertilizer-Derived N2O Emission and Nitrogen Immobilization in an Oxic Sandy Loam

Nitrous oxide (N2O) emission is a negative side effect of modern agriculture and a serious issue for global climate change. The combined application of nitrogen (N) fertilizer and high organic carbon soil amendments (HCA) has been regarded as an alternative to promote fertilizer-related N immobilization and enhance nitrogen use efficiency. The effect of HCA on N2O emission and N immobilization highly depends on its chemical composition, as it controls carbon (C) supply to soil microbes and reactivity of lignin-derived phenols to fertilizer-derived N species. Here we present a 127-d laboratory incubation study to explore the N2O emission and N immobilization after combined application of N fertilizer and HCA (wheat straw, spruce sawdust, and commercial alkali lignin) differing in their chemical composition. The 15N labelling technique was used to trace the transformation of fertilizer-N in ammonium (NH4+), NO3-, soil organic nitrogen (SON), and N2O. The amendment of wheat straw and spruce sawdust greatly promoted N immobilization and N2O emission, while lignin amendment enhanced the immobilization of fertilizer N. The chemical composition of HCA explained 26% of the total variance of fertilizer-derived N2O emission and N retention via soil microbial biomass, composition of lignin-derived phenols, and nitrification. The holocellulose/lignin ratio of HCA could be used as an indicator for predicting HCA decomposition, microbial N immobilization and N2O emission. In addition, the composition of lignin-derived phenols was affected by HCA amendment and significantly related to N2O emission and N retention. The varying chemical composition of HCA could thus be a promising tool for controlling N2O emission and N immobilization in environment-friendly and climate-smart agriculture.

Vanadium-Substituted Phosphomolybdic Acids for the Aerobic Cleavage of Lignin Models—Mechanistic Aspect and Extension to Lignin

This work deals with the aerobic oxidative cleavage of C-C and C-O bonds catalyzed by the Keggin-type phosphovanadomolybdic acid (H6[PMo9V3O40], noted H6PV3). The latter was synthesized by an adapted hydrothermal procedure classically used for lower vanadium content and was tested as a catalyst for the aerobic cleavage of 2-phenoxyacetophenone (noted K1HH) and 1-phenyl-2-phenoxyethanol (A1HH) used as two lignin models. The operative conditions (solvent, catalytic loading, etc.) were adjusted on K1HH and extrapolated to A1HH. The cleavage of the alcohol model required more drastic conditions and therefore further optimization. Preliminary attempts on an Organosolv wheat straw lignin were performed too. From the kinetic study, high performance liquid chromatography (HPLC) and gas chromatography–mass spectrometry (GC-MS) data, a mechanism of the cleavage of both models was proposed.

Saccobolus truncatus . [Descriptions of Fungi and Bacteria

Abstract A description is provided for Saccobolus truncatus . Almost all records of this species are on dung of herbivorous mammals, but the type material was stated to be on raven droppings, and there are also records on mushroom compost and a mushroom-growing bed and pig dung. Some information on its habitat, dispersal and transmission, and conservation status is given, along with details of its geographical distribution (Africa (Kenya, Morocco), North America (Canada (Manitoba, Ontario), USA (Colorado, Florida, New York, Virginia)), South America (Argentina, Brazil (Mato Grosso do Sul, Pernambuco), Chile, Peru), Asia (Armenia, China (Beijing, Yunnan), India (Himachal Pradesh, Uttarakhand), Israel, Japan, Nepal, Pakistan, Taiwan, Tajikistan, Thailand), Atlantic Ocean (Spain (Canary Islands)), Caribbean (Dominica, Guadeloupe, Puerto Rico, Saba (Caribbean Netherlands), St Lucia), Europe (Austria, Belgium, Bulgaria, Czech Republic, Denmark, Estonia, France, Italy, Germany, Moldova, Netherlands, Poland, Russia (Kursk Oblast, Leningrad Oblast, Republic of Mordovia), Ukraine, UK)). The present species has been included in studies of wheat straw lignin and cellulose modification by fungal colonists of herbivore dung, to explore the possibility that their anticipated ability to decompose lignocellulosic residues could be used to upgrade the nutritional value of animal feed.

Structural Motifs of Wheat Straw Lignin Differ in Susceptibility to Degradation by the White-Rot Fungus Ceriporiopsis subvermispora.

The white-rot fungus Ceriporiopsis subvermispora delignifies plant biomass extensively and selectively and, therefore, has great biotechnological potential. We previously demonstrated that after 7 weeks of fungal growth on wheat straw 70% w/w of lignin was removed and established the underlying degradation mechanisms via selectively extracted diagnostic substructures. In this work, we fractionated the residual (more intact) lignin and comprehensively characterized the obtained isolates to determine the susceptibility of wheat straw lignin’s structural motifs to fungal degradation. Using 13C IS pyrolysis gas chromatography–mass spectrometry (py-GC-MS), heteronuclear single quantum coherence (HSQC) and 31P NMR spectroscopy, and size-exclusion chromatography (SEC) analyses, it was shown that β-O-4′ ethers and the more condensed phenylcoumarans and resinols were equally susceptible to fungal breakdown. Interestingly, for β-O-4′ ether substructures, marked cleavage preferences could be observed: β-O-4′-syringyl substructures were degraded more frequently than their β-O-4′-guaiacyl and β-O-4′-tricin analogues. Furthermore, diastereochemistry (threo > erythro) and γ-acylation (γ-OH > γ-acyl) influenced cleavage susceptibility. These results indicate that electron density of the 4′-O-coupled ring and local steric hindrance are important determinants of oxidative β-O-4′ ether degradation. Our findings provide novel insight into the delignification mechanisms of C. subvermispora and contribute to improving the valorization of lignocellulosic biomass.

The effect of pH on the ability of different lignins to stabilize the oil-in-water emulsion

The ability of aspen soda and wheat straw soda lignin to stabilize the “rapeseed oilin-water” (O/W) emulsion, depending on the pH value and concentration of the applied water solutions as well as on the lignin chemical composition and molecular mass, and the sizes and zeta potential of lignin particles was studied. It was shown that the O/W emulsion stabilized with the alkaline water solutions of wheat straw lignin demonstrated the highest stability in alkaline medium, while the ability of aspen soda lignin to prevent the coalescence of oil droplets manifested itself in a whole range of the studied pH values. With decreasing pH values of the wheat straw lignin water solution, the drop in the separation volume of the O/W emulsion was insignificant with the exception for the lignin enhanced concentrations in acidic medium. The aggregative stability of the O/W emulsion, which was stabilized with aspen soda lignin, increased with decreasing pH values and increasing lignin content in the emulsion. The findings indicated that the stabilization of the O/W emulsion with the alkaline lignin solutions proceeded via the electrostatic stabilization mechanism, while in the neutral and acidic medium, this mechanism was more complicated, with a growing role of the ability of lignin to form interfacial polymeric films at the liquid/liquid interface. The comparison of the stability of the O/W emulsion showed that aspen soda lignin was a better stabilizer of the O/W emulsion than wheat straw lignin.

Effect of hydrothermal pretreatment severity on lignin inhibition in enzymatic hydrolysis

Hydrothermal pretreatment is commonly used for enhancing enzymatic hydrolysis of lignocellulosics. Spruce and wheat straw were pretreated with increasing severity and lignin characteristics were analysed. The effect of enzymatically isolated lignin on the hydrolysis of Avicel and the adsorption of a cellobiohydrolase onto lignin was measured. Non-pretreated lignins had only a minor effect on Avicel hydrolysis. The structural changes in lignin accompanying hydrothermal pretreatment were associated with increased binding and inactivation of the cellulase on the lignin surface. The inhibitory effect was more pronounced in spruce than in wheat straw lignin. However, similar pretreatment severities caused similar levels of inhibition in Avicel hydrolysis for both biomass sources. The combined severity factor of the pretreatment correlated well with the inhibitory effect of lignin.

Synergistic effects of surfactant-assisted biodegradation of wheat straw and production of polysaccharides by Inonotus obliquus under submerged fermentation

Current work proposes an innovative wheat straw biomass utilization strategy that connects efficient lignocellulose biodegradation with exo-polysaccharide (EPS) production in I. obliquus under submerged fermentation. The addition of Tween 80 increased the activities of ligninolytic enzymes MnP, LiP and Lac by 1200%, 125% and 39.9%, respectively. When wheat straw lignin recalcitrance was substantially reduced with the aid of Tween 80, I. obliquus was capable of utilizing the substrates and in turn accumulated EPS. The degradation of cellulose, hemicellulose and lignin reached 46.1%, 46.4% and 44.1% on Day 9 of growth, respectively. Meanwhile, the maximum mycelial biomass and EPS production increased by 23.3% and 142.9%, respectively. The EPS had higher contents of sugar, protein, uronic acid, and mannose ratio, and higher antioxidant activity against 2, 2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS•+) and hydroxyl radicals.

Reactivity improvement by phenolation of wheat straw lignin isolated from a biorefinery process

This work describes an effective phenolation process to improve wheat straw biorefinery lignin reactivity.

Electrochemical Decomposition of Wheat Straw Lignin into Guaiacyl‐, Syringyl‐, and Phenol‐Type Compounds Using Pb/PbO2 Anode and Alloyed Steel Cathode in Alkaline Solution

An electrocatalytic method was applied to decompose unit structures of wheat straw lignin (WSL) through oxidation on Pb/PbO2 and reduction on alloyed materials cathode with different catalytic activity in alkaline solution. Six of guaiacyl‐type (G) compounds were chosen as target products for evaluating their properties and efficiencies of all selected cathodes in WSL decomposition. A series of alloyed materials were examined as catalysts for the electrocatalytic decomposition, thereinto, the selected catalysts were characterized and evaluated by a systematic study for hydrogenation of WSL in NaOH solution. The effects of reaction parameters, such as pH, current density, lignin concentration and temperature, on product yields were investigated. Gas chromatography (GC) monitored maximum yields of 1.134 and 1.248 g/kg‐lignin of guaiacol and acetovanillone using FeW9Cr4V5Co3 as cathode, 0.364, 3.797, and 1.147 g/kg‐lignin of 4‐ethylguaiacol, vanillin, and vanillyl acetone using 304 alloyed steel as cathode, 1.040 g/kg‐lignin of 4‐propyl guaiacol using FeW9Cr4Mo3V as cathode, respectively. Based on the maximum yield of guaiacyl‐type compounds, 304 alloyed steel gave the best results with respect of lignin decomposition at the optimum conditions. In addition, gel permeation chromatography (GPC) demonstrated that the average molecular weights (Mw) of the lignin decreased in the process of all reactions and the unit structures cut down from lignin were electro‐catalytically hydrogenated to guaiacyl‐, syringyl‐, and phenol‐type compounds. © 2018 American Institute of Chemical Engineers Environ Prog, 38:e13117, 2019

Process optimization, purification and characterization of alkaline stable white laccase from Myrothecium verrucaria ITCC-8447 and its application in delignification of agroresidues

The white laccase was produced from Myrothecium verrucaria ITCC-8447 under submerged fermentation. The media components were optimized by response surface methodology (CCD-RSM). The nutritional components (glucose and peptone) and physical parameters (pH and temperature) were optimized by response surface methodology for enhanced laccase production by Myrothecium verrucaria ITCC-8447. The enzyme activity under optimum condition exhibited 1.45 fold increases in laccase activity. The white laccase was subjected to ion exchange chromatography with 6 fold purification. The molecular weight of white laccase was ~63–75kDa as estimated by SDS-PAGE followed by the activity staining with ABTS where green bands confirmed the presence of laccase. The enzyme was stable over an alkaline pH range of 7–9 and the temperature range of 30–40°C. The characterization of white laccase was done by CD spectra, UV–visible absorption, FTIR and XRD. The Km and Vmax values of the purified laccase were 2.5mM and1818.2μmol/min/L. The delignification capability of the white laccase was determined by reduction in Kappa number (58.8%) and Klason lignin (64.7%) of wheat straw after 12h of incubation. Further the delignification was confirmed FTIR and XRD.

A waste-minimized biorefinery scenario for the hierarchical conversion of agricultural straw into prebiotic xylooligosaccharides, fermentable sugars and lithium-sulfur batteries

How to exert the value-added superiority was a key link in the development of biomass valorization that heightens an appeal for a waste-minimized protocol. The fractional use of three building blocks in biomass became an urgent challenge to be faced. Herein, we report an autohydrolysis-aided biorefinery for the sequential conversion of wheat straw hemicelluloses, cellulose and lignin into xylooligosaccharides (XOS), fermentable glucose and lithium-sulfur cathode at the end of the process, respectively. The yield of XOS (DP of 2–6) reached up to 24.06% (w/w) of xylan and 6.19% (w/w) of the initial biomass. The hydrothermal treatment removed the amorphous portion and disrupted the rigid structure, thereby improving the cellulose digestibility from 14.1 to 88.9%. The molecular weights, functional groups and structural features of residual lignin after enzymatic hydrolysis were thoroughly explored for the cathode of lithium-sulfur batteries via the carbonizing process. Because of the considerable surface area, the covalent linkage between the lignin-derived carbon (LC) and sulfur, and the uniform dispersion of sulfur particles, the developed LC@S cathode exhibited excellent rate capability, and the specific capacity of 1238, 1085 and 1035 mA h g−1 at 0.1, 0.2 and 0.5 C, respectively. The LC@S cathode retained 596 mA h g−1 after 200 cycles at 0.5 C with a coulombic efficiency of 92%. The present study provides a systematic strategy that bears the primary responsibility for exploiting biomass into a potential feedstock with worthwhile functions in the thriving domains of chemicals, biofuels and energy storage devices.