Lignin Research Papers - Academia.edu (original) (raw)

Advances in Biochemical Engineering/Biotechnology reviews actual trends in modern biotechnology. Its aim is to cover all aspects of this interdisciplinary technology where knowledge, methods and expertise are required for chemistry,... more

Advances in Biochemical Engineering/Biotechnology reviews actual trends in modern biotechnology. Its aim is to cover all aspects of this interdisciplinary technology where knowledge, methods and expertise are required for chemistry, biochemistry, micro-biology, genetics, chemical engineering and computer science. Special volumes are dedicated to selected topics which focus on new biotechnological products and new processes for their synthesis and purification. They give the state-of-the-art of a topic in a comprehensive way thus being a valuable source for the next 3-5 years.

Lignin is a major component of plant secondary cell walls. Here we describe caffeoyl shikimate esterase (CSE) as an enzyme central to the lignin biosynthetic pathway. Arabidopsis thaliana cse mutants deposit less lignin than do wild-type... more

Lignin is a major component of plant secondary cell walls. Here we describe caffeoyl shikimate esterase (CSE) as an enzyme central to the lignin biosynthetic pathway. Arabidopsis thaliana cse mutants deposit less lignin than do wild-type plants, and the remaining lignin is enriched in p-hydroxyphenyl units. Phenolic metabolite profiling identified accumulation of the lignin pathway intermediate caffeoyl shikimate in cse mutants as compared to caffeoyl shikimate levels in the wild type, suggesting caffeoyl shikimate as a substrate for CSE. Accordingly, recombinant CSE hydrolyzed caffeoyl shikimate into caffeate. Associated with the changes in lignin, the conversion of cellulose to glucose in cse mutants increased up to fourfold as compared to that in the wild type upon saccharification without pretreatment. Collectively, these data necessitate the revision of currently accepted models of the lignin biosynthetic pathway.

The objective of this study is to perform a comprehensive enzyme kinetics analysis in view of validating and consolidating a semimechanistic kinetic model consisting of homogeneous and heterogeneous reactions for enzymatic hydrolysis of... more

The objective of this study is to perform a comprehensive enzyme kinetics analysis in view of validating and consolidating a semimechanistic kinetic model consisting of homogeneous and heterogeneous reactions for enzymatic hydrolysis of lignocellulosic biomass proposed by the U.S. National Renewable Energy Laboratory (Kadam et al., Biotechnol Prog 20(3):698-705, 2004) and its variations proposed in this work. A number of dedicated experiments were carried out under a range of initial conditions (Avicel® versus pretreated barley straw as substrate, different enzyme loadings and different product inhibitors such as glucose, cellobiose and xylose) to test the hydrolysis and product inhibition mechanisms of the model. A nonlinear least squares method was used to identify the model and estimate kinetic parameters based on the experimental data. The suitable mathematical model for industrial application was selected among the proposed models based on statistical information (weighted sum of square errors). The analysis showed that transglycosylation plays a key role at high glucose levels. It also showed that the values of parameters depend on the selected experimental data used for parameter estimation. Therefore, the parameter values are not universal and should be used with caution. The model proposed by Kadam et al. (Biotechnol Prog 20(3):698-705, 2004) failed to predict the hydrolysis phenomena at high glucose levels, but when combined with transglycosylation reaction(s), the prediction of cellulose hydrolysis behaviour over a broad range of substrate concentrations (50-150 g/L) and enzyme loadings (15.8-31.6 and 1-5.9 mg protein/g cellulose for Celluclast and Novozyme 188, respectively) was possible. This is the first study introducing transglycosylation into the semimechanistic model. As long as these type of models are used within the boundary of their validity (substrate type, enzyme source and substrate concentration), they can support process design and technology improvement efforts at pilot and full-scale studies.

Plant cell walls containing suberin or lignin in the human diet are conjectured to protect against colon cancer. To confirm the existence of authentic lignin in cereal grain dietary fibers, the DFRC (derivatization followed by reductive... more

Plant cell walls containing suberin or lignin in the human diet are conjectured to protect against colon cancer. To confirm the existence of authentic lignin in cereal grain dietary fibers, the DFRC (derivatization followed by reductive cleavage) method was applied to different cereal grain dietary fibers. By cleavage of diagnostic arylglycerol--aryl ( -O-4) ether linkages and identification of the liberated monolignols, it was ascertained that lignins are truly present in cereal grains. From the ratios of the liberated monolignols coniferyl alcohol and sinapyl alcohol, it is suggested that lignin compositions vary among cereals. Furthermore, dimeric cross-coupling products, comprising ferulate and coniferyl alcohol, were identified in most cereal fibers investigated. These ferulate 4-O--and 8--coniferyl alcohol cross-coupled structures indicate radical cross-coupling of polysaccharides to lignin precursors via ferulate.

h i g h l i g h t s " Pre-hydrolysis liquor was prepared using commercial sugars, lignin and furfural. " Furfural and xylose had the highest and lowest adsorption levels on AC. " Experimental results were most fitted into Langmuir and... more

h i g h l i g h t s " Pre-hydrolysis liquor was prepared using commercial sugars, lignin and furfural. " Furfural and xylose had the highest and lowest adsorption levels on AC. " Experimental results were most fitted into Langmuir and pseudo-second order models. " Addition of PDADMAC to pre-hydrolysis liquor increased the adsorption on AC.

Lignocellulosic ethanol has been considered as an alternative transportation fuel. Utilization of hemicellulosic fraction in lignocelluloses is crucial in economical production of lignocellulosic ethanol. However, this fraction has not... more

Lignocellulosic ethanol has been considered as an alternative transportation fuel. Utilization of hemicellulosic fraction in lignocelluloses is crucial in economical production of lignocellulosic ethanol. However, this fraction has not efficiently been utilized by traditional yeast Saccharomyces cerevisiae. Genetically modified S. cerevisiae, which can utilize xylose, has several limitations including low ethanol yield, redox imbalance, and undesired metabolite formation similar to native xylose utilizing yeasts. Besides, xylose uptake is a major issue, where sugar transport system plays an important role. These genetically modified and wild-type yeast strains have further been engineered for improved xylose uptake. Various techniques have been employed to facilitate the xylose transportation in these strains. The present review is focused on the sugar transport machineries, mechanisms of xylose transport, limitations and how to deal with xylose transport for xylose assimilation in ...

The development of effective strategies for lignin valorization to valuable products is of high interest in various industries such as pulp and paper and the emerging bioenergy process. Indeed, the successful valorization of lignin could... more

The development of effective strategies for lignin valorization to valuable products is of high interest in various industries such as pulp and paper and the emerging bioenergy process. Indeed, the successful valorization of lignin could improve the profitability of these processes and their environmental performance. In this study, an original strategy involving the sequential application of enzymes and pyrolysis was explored for the conversion (i.e., valorization) of lignins to bio-oil rich in phenols. Methods Four technical lignins from different processes were pretreated for 24 h using the concerted depolymerization action of lignin peroxidase and quinone reductase enzymes. Pyrolysis was then performed on the pretreated and untreated (control) samples using a bench-scale tubular reactor at 550 ℃ for 30 min. Results Enzymatic pretreatment could contribute to a 17.5-82.3% increase in the bio-oil mass yield during subsequent pyrolysis. In some cases, enzymatic pretreatment also improved the production of total phenols in bio-oils by a maximum of 43%, with steam explosion (S-E) lignin showing the best performance. Of the four technical lignins, S-E and sodaanthraquinone lignins gave the highest production of monomeric phenols whereas the sulfite lignins were more challenging to valorize due to their high inorganic contents. Conclusion Enzymatic pretreatment could contribute to the valorization of some technical lignins to phenols during subsequent pyrolysis.

Rice straw was treated with a mixed solution of acetic acid and propionic acid to enhance its biodegradability. The effect of acid concentration, pretreatment time, and the ratio of solid to liquid on the delignification performance of... more

Rice straw was treated with a mixed solution of acetic acid and propionic acid to enhance its biodegradability. The effect of acid concentration, pretreatment time, and the ratio of solid to liquid on the delignification performance of rice straw were investigated. It was found that the optimal conditions for hydrolysis were 0.75 mol/L acid concentration, 2 h pretreatment time and 1:20 solid to liquid ratio. Batch methane fermentation of untreated rice straw, pretreated rice straw, and the hydrolysates (the liquid fraction) of pretreatment were conducted at 35°C for 30 days, and the results indicated that methane production of rice straw can be enhanced by dilute organic acid pretreatment. Moreover, most of the acid in hydrolysates can also be converted into methane gas.

h i g h l i g h t s " Maize stem was treated with alkali before and after endoglucanase hydrolysis. " Two soluble lignin-carbohydrate (LC) fractions were quantitatively recovered. " LC1 and LC2 contained 39% and 8% of total lignin and 24%... more

h i g h l i g h t s " Maize stem was treated with alkali before and after endoglucanase hydrolysis. " Two soluble lignin-carbohydrate (LC) fractions were quantitatively recovered. " LC1 and LC2 contained 39% and 8% of total lignin and 24% and 2.1% of ferulic acid. " Thioacidolysis, acid/alkaline hydrolysis, FTIR were used to study each fraction. " The procedure revealed important heterogeneity regarding structure of grass lignins. a b s t r a c t Sequential fractionation of extractive-free maize stems was carried out using two mild alkaline extractions (0.5 and 2 M NaOH, 20°C, 24 h) before and after endoglucanase treatment. This procedure provided two lignin-carbohydrate fractions (LC1 and LC2) recovered after each alkali treatment. LC1 and LC2 contained 39% and 8% of the total lignin amount, respectively. These two fractions contained structurally distinct lignin molecules. While the content of resistant interunit bonds in lignin was 77% in LC1, it was increased up to 98% in LC2. Not unexpectedly, both alkali-soluble fractions contained substantial amount of p-coumaric and ferulic acids ether-linked to lignins. These results outline heterogeneity of maize stem lignins related to fractionation of grass materials.

Plant cell walls are composed primarily of cellulose, hemicelluloses, lignins, and pectins. Of these components, lignins exhibit unique chemistry and physiological functions. Although lignins can be used as a product feedstock or as a... more

Plant cell walls are composed primarily of cellulose, hemicelluloses, lignins, and pectins. Of these components, lignins exhibit unique chemistry and physiological functions. Although lignins can be used as a product feedstock or as a fuel, lignins are also generally seen as a barrier to efficient enzymatic breakdown of biomass to sugars. Indeed, many pretreatment strategies focus on removing a significant fraction of lignin from biomass to better enable saccharification. In order to better understand the fate of biomass lignins that remain with the solids following dilute acid pretreatment, we undertook a structural investigation to track lignins on and in biomass cell walls. SEM and TEM imaging revealed a range of droplet morphologies that appear on and within cell walls of pretreated biomass; as well as the specific ultrastructural regions that accumulate the droplets. These droplets were shown to contain lignin by FTIR, NMR, antibody labeling, and cytochemical staining. We provide evidence supporting the idea that thermochemical pretreatments reaching temperatures above the range for lignin phase transition cause lignins to coalesce into larger molten bodies that migrate within and out of the cell wall, and can redeposit on the surface of plant cell walls. This decompartmentalization and relocalization of lignins is likely to be at least as important as lignin removal in the quest to improve the digestibility of biomass for sugars and fuels production.

Thermal sterilization is widely applied in fermentation to ensure a pure culture. In this study, a facile and energyefficient strategy by eliminating thermal sterilization (ETS) was unveiled for upgrading lignin bioconversion. Through... more

Thermal sterilization is widely applied in fermentation to ensure a pure culture. In this study, a facile and energyefficient strategy by eliminating thermal sterilization (ETS) was unveiled for upgrading lignin bioconversion. Through alkaline solubilization and neutralization, lignin dispersion in aqueous fermentation media was significantly enhanced by ETS. Small-angle X-ray scattering and dynamic light scattering analyses indicated that the lignin colloid size was dramatically reduced. Compared to 20.5 wt % lignin precipitation during the conventional thermal sterilization, precipitated lignin was not observed within the ETS medium. 31 P NMR characterization demonstrated an 11.7% increase of phenolic OH in ETS lignin. Ionization of phenolic OH presented more negatively charged groups, strengthening electrostatic repulsion, resulting in smaller colloidal particles. Interestingly, the pure culture of Rhodococcus opacus PD630 was achieved within the ETS medium due to the lack of lignin degradation ability with most natural microbes. R. opacus PD630 cell amount, lignin degradation, and lipid production by ETS increased by 330, 16.6, and 20.7%, respectively. Overall, an energy-efficient ETS strategy that promoted lignin dispersion and bioconversion significantly is reported in this study.

UV-B radiation (280-320 nm) is harmful to living organisms and has detrimental effects on plant growth, development and physiology. In this work we examined some mechanisms involved in plant responses to UV-B radiation. Seedlings of... more

UV-B radiation (280-320 nm) is harmful to living organisms and has detrimental effects on plant growth, development and physiology. In this work we examined some mechanisms involved in plant responses to UV-B radiation. Seedlings of quinoa (Chenopodiurn quinoa Willd.) were exposed to variable numbers of UV-B radiation doses, and the effect on cotyledons was studied. We analyzed (1) cotyledons anatomy and chloroplasts ultrastructure; (2) peroxidase activity involved in the lignification processes; and (3) content of photosynthetic pigments, phenolic compounds and carbohydrates. Exposure to two UV-B doses induced an increase in the wall thickness of epidermal cells, which was associated with lignin deposition and higher activity of the peroxidase. The chloroplast ultrastructure showed an appearance typical of plants under shade conditions, likely in response to reduced light penetration into the mesophyll cells due to the screening effect of epidermal lignin deposition. Exposure to UV-B radiation also led to (1) enhancement in the level of phenolics, which may serve a protective function; (2) strong increase in the fructose content, a fact that might be related to higher requirement of erythrose-4P as a substrate for the synthesis of lignin and phenolics; and (3) reduction in the chlorophyll concentration, evidencing alteration in the photosynthetic system. We propose that the observed lignin deposition in epidermal tissues of quinoa is a resistance mechanism against UV-B radiation, which allows growing of this species in Andean highlands.

A high throughput enzyme assay platform, called GENPLAT, was used to guide the development of an optimized mixture of individual purified enzymes from ten ''accessory" and six ''core" enzymes. Enzyme mixtures were optimized for release of... more

A high throughput enzyme assay platform, called GENPLAT, was used to guide the development of an optimized mixture of individual purified enzymes from ten ''accessory" and six ''core" enzymes. Enzyme mixtures were optimized for release of Glu, Xyl, or a combination of the two from corn stover pretreated by ammonia-fiber expansion (AFEX). Assay conditions were a fixed enzyme loading of 15 mg/g glucan, 48 h digestion, and 50°C. Five of the ten tested accessory proteins enhanced Glu or Xyl yield compared to the core set alone, and five did not. An 11-component mixture containing the core set and five accessory enzymes optimized for Glu released 52.1% of the available Glu, compared to 38.5% with the core set alone. A mixture optimized for Xyl released 39.9% of the Xyl, compared to 26.4% with the core set alone. We predict that there is still considerable opportunity for further improvement of synthetic mixtures. Furthermore, the strategy described here is applicable to the development of more efficient enzyme cocktails for any pretreatment/biomass combination and for detecting enzymes that make a heretofore unrecognized contribution to lignocellulose deconstruction.

Due to their recognised properties of biocompatibility, biodegradability and sustainability, chitosan nanocarriers have been successfully used as new delivery systems. In this work, nanoparticles combining chitosan and lignosulfonates... more

Due to their recognised properties of biocompatibility, biodegradability and sustainability, chitosan nanocarriers have been successfully used as new delivery systems. In this work, nanoparticles combining chitosan and lignosulfonates were developed for the first time for cosmetic and biomedical applications. The ability of lignosulfonates to act as a counter polyion for stabilisation of chitosan particles, generated using high intensity ultrasound, was investigated. Several conditions for particles preparation were tested and optimised and the resulting nanoparticles were comprehensively characterised by measuring particle size, zeta potential and polydispersity index. The pH of chitosan solution, sonication time and the presence of an adequate surfactant, poloxamer 407, were determinant factors on the development of smaller particles with low polydispersity index (an average particle size of 230 nm was obtained at pH 5 after 8 min of sonication). The beneficial effects of lignosulfonates complex on chitosan nanoparticles were further characterised. Greater stability to lysozyme degradation, biocompatibility with human cells and antimicrobial activity was found upon lignosulfonates incorporation into chitosan nanoparticles. Furthermore, these particles were able to incorporate a hydrophilic model protein -RNase A. A burst release was observed when nanoparticles were loaded with low amount of protein while with high protein content, a sustained release was found, suggesting that the protein cargo maybe loaded both at the surface as in the bulk of the particle, depending on the concentration of drug incorporated.

This paper describes the organosolv delignification of depithed bagasse using glycerol-water mixtures without a catalyst. The experiments were performed using two separate experimental designs. In the first experiment, two temperatures... more

This paper describes the organosolv delignification of depithed bagasse using glycerol-water mixtures without a catalyst. The experiments were performed using two separate experimental designs. In the first experiment, two temperatures (150 and 190°C), two time periods (60 and 240 min) and two glycerol contents (20% and 80%, v/v) were used. In the second experiment, which was a central composite design, the glycerol content was maintained at 80%, and a range of temperatures (141.7-198.3°C) and time (23-277 min) was used. The best result, obtained with a glycerol content of 80%, a reaction time of 150 min and a temperature of 198.3°C, produced pulps with 54.4% pulp yield, 7.75% residual lignin, 81.4% delignification and 13.7% polyose content. The results showed that high contents of glycerol tend to produce pulps with higher delignification and higher polyoses content in relation to the pulps obtained from low glycerol content reactions. In addition, the proposed method shows potential as a pretreatment for cellulose saccharification.

The oyster mushroom (Pleurotus ostreatus) is widely cultivated on wheat straw (Triticum aestivum); however, there is a need to better understand the relationship between the chemical composition of the compost and mushroom growth. Wheat... more

The oyster mushroom (Pleurotus ostreatus) is widely cultivated on wheat straw (Triticum aestivum); however, there is a need to better understand the relationship between the chemical composition of the compost and mushroom growth. Wheat straw was degraded over a period of 63 days by P. ostreatus during which time it was sampled at weekly intervals. Off-line thermochemolysis with tetramethylammonium hydroxide and solid-state 13 C NMR were then used in the molecular characterization of the undegraded wheat straw and the degraded samples. The degraded wheat straw samples had a lower proportion of syringyl-to guaiacyl-derived moieties and cinnamyl-to guaiacyl-derived moieties than the undegraded control. There were increases in both guaiacyl and syringyl acid to aldehyde ratios with composting time, which showed that side-chain oxidation has been mediated by P. ostreatus. The 13 C NMR spectra confirmed the increase in carboxyl content but indicated that the overall lignin and methoxyl contents remained relatively constant, although some nonsystematic variations were observed. The spectra also showed a decrease in amorphous noncellulosic polysaccharides in relation to the crystalline cellulose upon degradation.

An overview of the different inhibitors formed by pre-treatment of lignocellulosic materials and their inhibition of ethanol production in yeast and bacteria is given. Different high temperature physical pre-treatment methods are... more

An overview of the different inhibitors formed by pre-treatment of lignocellulosic materials and their inhibition of ethanol production in yeast and bacteria is given. Different high temperature physical pre-treatment methods are available to render the carbohydrates in lignocellulose accessible for ethanol fermentation. The resulting hydrolyzsates contain substances inhibitory to fermentation-depending on both the raw material (biomass) and the pre-treatment applied. An overview of the inhibitory effect on ethanol production by yeast and bacteria is presented. Apart from furans formed by sugar degradation, phenol monomers from lignin degradation are important co-factors in hydrolysate inhibition, and inhibitory effects of these aromatic compounds on different ethanol producing microorganisms is reviewed. The furans and phenols generally inhibited growth and ethanol production rate (Q EtOH) but not the ethanol yields (Y EtOH) in Saccharomyces cerevisiae. Within the same phenol functional group (aldehyde, ketone, and acid) the inhibition of volumetric ethanol productivity was found to depend on the amount of methoxyl substituents and hence hydrophobicity (log P). Many pentose-utilizing strains Escherichia coli, Pichia stipititis, and Zymomonas mobilis produce ethanol in concentrated hemicellulose liquors but detoxification by overliming is needed. Thermoanaerobacter mathranii A3M3 can grow on pentoses and produce ethanol in hydrolysate without any need for detoxification.

Hydroxyapatite (HAP) is the most suitable biocompatible material for bone implant coatings; its brittleness, however, is a major obstacle, and the reason why research focuses on creating composites with biopolymers. Organosolv lignin... more

Hydroxyapatite (HAP) is the most suitable biocompatible material for bone implant coatings; its brittleness, however, is a major obstacle, and the reason why research focuses on creating composites with biopolymers. Organosolv lignin (Lig) is used for the production of composite coatings, and these composites were examined in this study. Titanium substrate is a key biomedical material due to its well-known properties, but infections of the implantation site still impose a serious threat. One approach to prevent infection is to improve antimicrobial properties of the coating material. Silver doped hydroxyapatite (Ag/HAP) and HAP coatings on titanium were obtained by an electrophoretic deposition method in order to control deposited coating mass and morphology by varying applied voltage and deposition time. The effect of lignin on microstructure, morphology and thermal behavior of biocomposite coatings was investigated. The results showed that higher lignin concentrations protect the HAP lattice during sintering, improving coating stability. The corrosion stability was evaluated in simulated body fluid (SBF) at 37 °C. Newly formed plate-shaped carbonate-HAP was

Mowing is commonly implemented to Artemisia tridentata ssp. wyomingensis (Beetle & A. Young) S.L. Welsh (Wyoming big sagebrush) plant communities to improve wildlife habitat, increase forage production for livestock, and create fuel... more

Mowing is commonly implemented to Artemisia tridentata ssp. wyomingensis (Beetle & A. Young) S.L. Welsh (Wyoming big sagebrush) plant communities to improve wildlife habitat, increase forage production for livestock, and create fuel breaks for fire suppression. However, information detailing the influence of mowing on winter habitat for wildlife is lacking. This information is crucial because many wildlife species depended on A. tridentata spp. wyomingensis plant communities for winter habitat and consume significant quantities of Artemisia during this time. Furthermore, information is generally limited describing the recovery of A. tridentata spp. wyomingensis to mowing and the impacts of mowing on stand structure. Stand characteristics and Artemisia leaf tissue crude protein (CP), acid detergent fiber (ADF), and neutral detergent fiber (NDF) concentrations were measured in midwinter on 0-, 2-, 4-, and 6-year-old fall-applied mechanical (mowed at 20 cm height) treatments and compared to adjacent untreated (control) areas. Mowing compared to the control decreased Artemisia cover, density, canopy volume, canopy elliptical area, and height (P \ 0.05), but all characteristics were recovering (P \ 0.05). Mowing A. tridentata spp. wyomingensis plant communities slightly increases the nutritional quality of Artemisia leaves (P \ 0.05), but it simultaneously results in up to 20 years of decrease in Artemisia structural characteristics. Because of the large reduction in A. tridentata spp. wyomingensis for potentially 20 years following mowing, mowing should not be applied in Artemisia facultative and obligate wildlife winter habitat. Considering the decline in A. tridentata spp. wyomingensisdominated landscapes, we caution against mowing these communities.

A multireaction kinetic model was developed for closed-system enzymatic hydrolysis of lignocellulosic biomass such as corn stover. Three hydrolysis reactions were modeled, two heterogeneous reactions for cellulose breakdown to cellobiose... more

A multireaction kinetic model was developed for closed-system enzymatic hydrolysis of lignocellulosic biomass such as corn stover. Three hydrolysis reactions were modeled, two heterogeneous reactions for cellulose breakdown to cellobiose and glucose and one homogeneous reaction for hydrolyzing cellobiose to glucose. Cellulase adsorption onto pretreated lignocellulose was modeled via a Langmuir-type isotherm. The sugar products of cellulose hydrolysis, cellobiose and glucose, as well as xylose, the dominant sugar prevalent in most hemicellulose hydrolyzates, were assumed to competitively inhibit the enzymatic hydrolysis reactions. Model parameters were estimated from experimental data generated using dilute acid pretreated corn stover as the substrate. The model performed well in predicting cellulose hydrolysis trends at experimental conditions both inside and outside the design space used for parameter estimation and can be used for in silico process optimization.

The genomic era facilitates the understanding of how transcriptional networks are interconnected to program seed development and filling. However, to date, little information is available regarding dicot seeds with a transient perisperm... more

The genomic era facilitates the understanding of how transcriptional networks are interconnected to program seed development and filling. However, to date, little information is available regarding dicot seeds with a transient perisperm and a persistent, copious endosperm. Coffea arabica is the subject of increasing genomic research and is a model for nonorthodox albuminous dicot seeds of tropical origin.The aim of this study was to reconstruct the metabolic pathways involved in the biosynthesis of the main coffee seed storage compounds, namely cell wall polysaccharides, triacylglycerols, sucrose, and chlorogenic acids. For this purpose, we integrated transcriptomic and metabolite analyses, combining real-time RT-PCR performed on 137 selected genes (of which 79 were uncharacterized in Coffea) and metabolite profiling.Our map-drawing approach derived from model plants enabled us to propose a rationale for the peculiar traits of the coffee endosperm, such as its unusual fatty acid composition, remarkable accumulation of chlorogenic acid and cell wall polysaccharides.Comparison with the developmental features of exalbuminous seeds described in the literature revealed that the two seed types share important regulatory mechanisms for reserve biosynthesis, independent of the origin and ploidy level of the storage tissue.

& The present study describes the usage of dried leafy biomass of mango (Mangifera indica) containing 26.3% (w=w) cellulose, 54.4% (w=w) hemicellulose, and 16.9% (w=w) lignin, as a substrate for bioethanol production from Zymomonas... more

& The present study describes the usage of dried leafy biomass of mango (Mangifera indica) containing 26.3% (w=w) cellulose, 54.4% (w=w) hemicellulose, and 16.9% (w=w) lignin, as a substrate for bioethanol production from Zymomonas mobilis and Candida shehatae. The substrate was subjected to two different pretreatment strategies, namely, wet oxidation and an organosolv process. An ethanol concentration (1.21 g=L) was obtained with Z. mobilis in a shake-flask simultaneous saccharification and fermentation (SSF) trial using 1% (w=v) wet oxidation pretreated mango leaves along with mixed enzymatic consortium of Bacillus subtilis cellulase and recombinant hemicellulase (GH43), whereas C. shehatae gave a slightly higher (8%) ethanol titer of 1.31 g=L. Employing 1% (w=v) organosolv pretreated mango leaves and using Z. mobilis and C. shehatae separately in the SSF, the ethanol titers of 1.33 g=L and 1.52 g=L, respectively, were obtained. The SSF experiments performed with 5% (w=v) organosolv-pretreated substrate along with C. shehatae as fermentative organism gave a significantly enhanced ethanol titer value of 8.11 g=L using the shake flask and 12.33 g=L at the bioreactor level. From the bioreactor, 94.4% (v=v) ethanol was recovered by rotary evaporator with 21% purification efficiency.

We report cloning and sequencing of gene ps1 encoding a versatile peroxidase combining catalytic properties of lignin peroxidase (LiP) and manganese peroxidase (MnP) isolated from lignocellulose cultures of the white-rot fungus Pleurotus... more

We report cloning and sequencing of gene ps1 encoding a versatile peroxidase combining catalytic properties of lignin peroxidase (LiP) and manganese peroxidase (MnP) isolated from lignocellulose cultures of the white-rot fungus Pleurotus eryngii. The gene contains 15 putative introns, and the deduced amino acid sequence consists of a 339-residue mature protein with a 31-residue signal peptide. Several putative response elements were identified in the promoter region. Amino acid residues involved in oxidation of Mn 2 and aromatic substrates by direct electron transfer to heme and long-range electron transfer from superficial residues as predicted by analogy with Phanerochaete chrysosporium MnP and LiP, respectively. A dendrogram is presented illustrating sequence relationships between 29 fungal peroxidases.

Novel lignin modified carbon nanotube (L-CNT) were prepared as reinforcement of nylon 6 composites. The carbon nanotube was coated with lignin using dioxane solvent. The filler was loaded in polyamide-6 composites through in-situ... more

Novel lignin modified carbon nanotube (L-CNT) were prepared as reinforcement of nylon 6 composites. The carbon nanotube was coated with lignin using dioxane solvent. The filler was loaded in polyamide-6 composites through in-situ polymerization. Two parameters were varied i.e. (i) sonication time during in-situ reaction and (ii) L-CNT content. The effect of L-CNT on molecular weight (Mn and Mw), glass transition temperature (Tg) and tensile modulus of the composites was studied. The molecular weight of in-situ polymerized PA6 was decreased with the addition of L-CNT content. The same effect was observed with the increase in sonication time due to hindrance in chain growth by L-CNT. Significant increase in the mechanical properties was observed up to the sonication time of 0.5 h. The tensile modulus of the composites was increased to 5.9 GPa in PA 6/L-CNT 10 nanocomposite. However there was 61% increase in the tensile modulus with 10 wt. % nanofiller addition compared with 1 wt. % L-CNT. The glass transition temperature for PA 6/L-CNT 1, PA 6/L-CNT 3, PA 6/L-CNT 5, and PA 6/L-CNT 10 was found as 80, 82, 84, and 101°C at 0.5 h sonication time. Hence there was 21% increase in the Tg upon the addition of 10 wt. % filler compared with 1 wt. % L-CNT addition.

The bio-oil used in this study was produced from the feed stock such as wheat hemlock. Therefore, in order to investigate the composition of bio-oil and its feedstock, initially the physical and chemical characterisation of wheat-hemlock... more

The bio-oil used in this study was produced from the feed stock such as wheat hemlock. Therefore, in order to investigate the composition of bio-oil and its feedstock, initially the physical and chemical characterisation of wheat-hemlock biomass was carried out using bomb calorimeter, XRD, TGA, ICP-MS, CHNSO, FT-IR and HPLC. The biomass was then subjected to fast pyrolysis process to obtained bio-oil, which is used both as an energy source and a feedstock for chemical production. The physical and chemical characterisation of bio-oil was carried out using bomb calorimeter, CHNSO, FT-IR, GC-FID and GC/MS to check for its composition. During the analysis it was observed that the bio-oil under study contained 59 % water with mixtures of hydrocarbons, fatty acids, phenols and its derivatives. Due to this high percentage of water in biooil, it forms azeotrope with phenolic and acidic compounds. Therefore the major objective of the present study was to isolate the valuable organic fraction of the bio-oil using supercritical CO 2 technique. Three fractions were separated at pressure of 10, 25 and 30 MPa at 40 o C for 2 hours and the yield of the extracts was found to be 3.3%, 13.2% and 15.2% respectively. The remaining waxy residue left after extraction mostly contained water. The bio-oil fractions obtained after extraction were characterised for its composition. The fractions collected at 10-25 MPa pressure were enriched with phenol derivatives and fraction obtained at 30 MPa contained improved percentage of fatty acid. These results indicate that the supercritical CO 2 is a suitable process for selective separation of valuable chemicals from azeotrope.

Mowing is commonly implemented to Artemisia tridentata ssp. wyomingensis (Beetle & A. Young) S.L. Welsh (Wyoming big sagebrush) plant communities to improve wildlife habitat, increase forage production for livestock, and create fuel... more

Mowing is commonly implemented to Artemisia tridentata ssp. wyomingensis (Beetle & A. Young) S.L. Welsh (Wyoming big sagebrush) plant communities to improve wildlife habitat, increase forage production for livestock, and create fuel breaks for fire suppression. However, information detailing the influence of mowing on winter habitat for wildlife is lacking. This information is crucial because many wildlife species depended on A. tridentata spp. wyomingensis plant communities for winter habitat and consume significant quantities of Artemisia during this time. Furthermore, information is generally limited describing the recovery of A. tridentata spp. wyomingensis to mowing and the impacts of mowing on stand structure. Stand characteristics and Artemisia leaf tissue crude protein (CP), acid detergent fiber (ADF), and neutral detergent fiber (NDF) concentrations were measured in midwinter on 0-, 2-, 4-, and 6-year-old fall-applied mechanical (mowed at 20 cm height) treatments and compared to adjacent untreated (control) areas. Mowing compared to the control decreased Artemisia cover, density, canopy volume, canopy elliptical area, and height (P \ 0.05), but all characteristics were recovering (P \ 0.05). Mowing A. tridentata spp. wyomingensis plant communities slightly increases the nutritional quality of Artemisia leaves (P \ 0.05), but it simultaneously results in up to 20 years of decrease in Artemisia structural characteristics. Because of the large reduction in A. tridentata spp. wyomingensis for potentially 20 years following mowing, mowing should not be applied in Artemisia facultative and obligate wildlife winter habitat. Considering the decline in A. tridentata spp. wyomingensisdominated landscapes, we caution against mowing these communities.

Penelitian ini bertujuan untuk mengkaji pengaruh perlakuan perbedaan lama fermentasi menggunakan Aspergillus niger setelah dilakukan proses amoniasi pada kulit kacang terhadap kandungan selulosa, hemiselulosa dan lignin. Metode penelitian... more

Penelitian ini bertujuan untuk mengkaji pengaruh perlakuan perbedaan lama fermentasi menggunakan Aspergillus niger setelah dilakukan proses amoniasi pada kulit kacang terhadap kandungan selulosa, hemiselulosa dan lignin. Metode penelitian menggunakan rancangan acak lengkap dengan 4 ulangan. Perlakuan yang diberikan adalah perbedaan lama peram proses fermentasi 0 hari (T0), 5 hari (T1), 10 hari (T2) dan 15 hari (T3). Hasil penelitian menunjukkan terdapat pengaruh (P<0,05) lama fermentasi terhadap kandungan selulosa dan lignin dan tidak berpengaruh terhadap kandungan hemiselulosa. Kandungan selulosa dan hemiselulosa menurun sampai lama peram 15 hari (33,93%) dan (8,96%). Kandungan lignin meningkat sampai lama peram 15 hari (30,85%). Berdasarkan hasil penelitian dapat disimpulkan bahwa perlakuan lama fermentasi dapat meningkatkan kualitas kulit kacang tanah amoniasi. Perlakuan terbaik terjadi pada lama fermentasi 15 hari.

In vitro production of cellulase and xylanase was common among diverse freshwater ascomycetes and their hyphomycetous anamorphs. Production of enzymes involved in lignin degradation was rare. Most isolates were capable of causing mass... more

In vitro production of cellulase and xylanase was common among diverse freshwater ascomycetes and their hyphomycetous anamorphs. Production of enzymes involved in lignin degradation was rare. Most isolates were capable of causing mass loss in angiosperm wood, although values were low, at 10% during a 24-week period. A few isolates caused higher mass loss of up to 26.5%, and five of these were shown to solubilize significant amounts of lignin. This is the first report of lignin solubilization by freshwater fungi. Torula herbarum (hyphomycete) and Ophioceras dolichostomum (ascomycete) produced indices of lignin solubilization equivalent to those of terrestrial white-rot basidiomycetes. In all cases wood decay was 2.2-to 3-fold higher in exposed rather than submerged conditions.

The modern-day paper industry is highly capital-intensive industries in the core sector. Though there are several uses of paper for currency, packaging, education, information, communication, trade and hygiene, the flip side of this... more

The modern-day paper industry is highly capital-intensive industries in the core sector. Though there are several uses of paper for currency, packaging, education, information, communication, trade and hygiene, the flip side of this industry is the impact on the forest resources and other ecosystems which leads to increasing pollution in water and air, influencing several local communities. In the present paper, the authors have tried to explore potential and alternate source of industrial pulp through ruminant animal dung, which is widely available as a rural resource in India. Three types of undigested animal dung fibers from Indigenous cow (IDF), Jersey cow (JDF), and Buffalo (BDF) were taken. Wheat straw (WS) was the main diet of all animals. The cellulose, hemicellulose and lignin content for all animal dung samples were found in a range of (29–31.50%), (21–23.50%), and (11–13%), respectively. The abundant holocellulose and low lignin contents are suitable for handmade pulp and...

NMR fingerprinting of the components of finely divided plant cell walls swelled in DMSO has been recently described. Cell wall gels, produced directly in the NMR tube with perdeutero-dimethylsulfoxide, allowed the acquisition of well... more

NMR fingerprinting of the components of finely divided plant cell walls swelled in DMSO has been recently described. Cell wall gels, produced directly in the NMR tube with perdeutero-dimethylsulfoxide, allowed the acquisition of well resolved/dispersed 2D (13)C-(1)H correlated solution-state NMR spectra of the entire array of wall polymers, without the need for component fractionation. That is, without actual solubilization, and without apparent structural modification beyond that inflicted by the ball milling and ultrasonication steps, satisfactorily interpretable spectra can be acquired that reveal compositional and structural details regarding the polysaccharide and lignin components in the wall. Here, the profiling method has been improved by using a mixture of perdeuterated DMSO and pyridine (4 : 1, v/v). Adding pyridine provided not only easier sample handling because of the better mobility compared to the DMSO-d(6)-only system but also considerably elevated intensities and improved resolution of the NMR spectra due to the enhanced swelling of the cell walls. This modification therefore provides a more rapid method for comparative structural evaluation of plant cell walls than is currently available. We examined loblolly pine (Pinus taeda, a gymnosperm), aspen (Populus tremuloides, an angiosperm), kenaf (Hibiscus cannabinus, an herbaceous plant), and corn (Zea mays L., a grass, i.e., from the Poaceae family). In principle, lignin composition (notably, the syringyl : guaiacyl : p-hydroxyphenyl ratio) can be quantified without the need for lignin isolation. Correlations for p-coumarate units in the corn sample are readily seen, and a variety of the ferulate correlations are also well resolved; ferulates are important components responsible for cell wall cross-linking in grasses. Polysaccharide anomeric correlations were tentatively assigned for each plant sample based on standard samples and various literature data. With the new potential for chemometric analysis using the 2D NMR fingerprint, this gel-state method may provide the basis for an attractive approach to providing a secondary screen for selecting biomass lines and for optimizing biomass processing and conversion efficiencies.

Eugenol (2-methoxy-4-allyl-phenol) was used as a reducing agent for one-pot synthesis of gold nanoparticles in a mild alkaline aqueous/organic solution at room temperature. In this reaction, eugenol acts also as a stabilizing agent, since... more

Eugenol (2-methoxy-4-allyl-phenol) was used as a reducing agent for one-pot synthesis of gold nanoparticles in a mild alkaline aqueous/organic solution at room temperature. In this reaction, eugenol acts also as a stabilizing agent, since it undergoes polymerization upon oxidation. As a result, stable colloids of polyeugenol (PE)-capped gold nanoparticles are formed during the reaction with the average particle size of 44 nm. Moreover, conducting supports, such as ITO glass, are covered by Au/PE composite film when immersed in the reaction medium. The modified ITO shows redox activity assignable to residual quinone moieties of PE with redox couples at a potential range of −0.2 to 0.4 V (vs. Ag/AgCl at pH 7.4). Redox properties of Au/PE nanoparticulate films can be exploited for the electrocatalytic oxidation of NADH with over 0.5 V reduction of the reaction overpotential vs. unmodified ITO. Nanoparticulate composite films were characterized by UV-vis spectroscopy, XPS and FT-IR spectroscopy. The characterization revealed structural similarity of the formed PE to lignin.

Lignocellulosic agricultural byproducts are a copious and cheap source for cellulose fibers. Agro-based biofibers have the composition, properties and structure that make them suitable for uses such as composite, textile, pulp and paper... more

Lignocellulosic agricultural byproducts are a copious and cheap source for cellulose fibers. Agro-based biofibers have the composition, properties and structure that make them suitable for uses such as composite, textile, pulp and paper manufacture. In addition, biofibers can also be used to produce fuel, chemicals, enzymes and food. Byproducts produced from the cultivation of corn, wheat, rice, sorghum, barley, sugarcane, pineapple, banana and coconut are the major sources of agro-based biofibers. This review analyses the production processes, structure, properties and suitability of these biofibers for various industrial applications.

Pretreatment technology is a prerequisite to facilitate the release of sugars from a lignocellulosic biomass prior to fermentation. Recently, some pretreatment methods have been tried with ionic liquids, but they were still expensive and... more

Pretreatment technology is a prerequisite to facilitate the release of sugars from a lignocellulosic biomass prior to fermentation. Recently, some pretreatment methods have been tried with ionic liquids, but they were still expensive and unpractical. In this study, an efficient pretreatment method using ammonia and ionic liquid was developed for the recovery of bio-digestible cellulose from a lignocellulosic byproduct, rice straw, and the increase of ionic liquid utilization. The combined use of ammonia and ionic liquid ([Emim]Ac) treatment exhibited a synergy effect for rice straw with 82% of the cellulose recovery and 97% of the enzymatic glucose conversion. This cooperative effect showed over 90% of the glucose conversion even with a reduced enzyme usage and incubation time. The ionic liquid was successfully recycled more than 20 times. The 20th-recycled ([Emim]Ac) showed 74% of the cellulose recovery and 78% of the glucose conversion to rice straw. Compared with the conventional pretreatment, our combined method for lignocellulosic biomass pretreatment was an economical and eco-friendly.

Over the past two decades, the use of biomass as a resource for biofuels and bioenergy has garnered much interest. The reduction in green house gas emissions of renewable fuels as compared to conventional fossil fuels, coupled with the... more

Over the past two decades, the use of biomass as a resource for biofuels and bioenergy has garnered much interest. The reduction in green house gas emissions of renewable fuels as compared to conventional fossil fuels, coupled with the sustainability of these technological approaches, has fostered increased research into this field. Switchgrass is a perennial grass native to North America, and as a feedstock for biofuels it has garnered much interest because of its high productivity, adaptability and potential ease of integration into existing agricultural operations. In order to maximize the use of switchgrass as an energy crop, the chemical constituents as well as the chemical processes involved in its conversion to biofuels need to be understood. The goal of this paper is to review the published work on the chemistry of switchgrass as it pertains to biofuel production including elemental composition, chemical composition, biopolymer constituents and their structure. In addition, the impacts of these chemical constituents on the biological conversion to ethanol and pyrolysis oils are summarized.

Cassava starch foam (CSF) trays blended with zein, gluten, soy protein, kraft fiber, and palm oil at various concentrations: 0, 5, 10 and 15% by weight of starch, were characterized. The addition of zein and gluten into CSF resulted in... more

Cassava starch foam (CSF) trays blended with zein, gluten, soy protein, kraft fiber, and palm oil at various concentrations: 0, 5, 10 and 15% by weight of starch, were characterized. The addition of zein and gluten into CSF resulted in consolidated and homogeneous structural foams compared to its controls. Moreover, the flexural and compressive strength increased with increasing kraft, zein and gluten. CSF containing 15% kraft gave the highest flexural and compressive strength. However, the addition of palm oil into CSF gave the lowest flexural strength and compressive strength. The observed water absorption and water solubility index of CSFs blended with 15% zein and 15% gluten protein was lowest. Although kraft, zein and gluten could improve mechanical properties, water absorption and water solubility were greater than the expanded polystyrene foam (EPS). The CSF trays in this study might be an alternative for packing low water content foods.

We propose a new process using a vapor phase bioreactor (VPB) to simultaneously (i) delignify sugar-cane bagasse, a residue of sugar production that can be recycled in paper industry, and (ii) produce laccase, an enzyme usable to bleach... more

We propose a new process using a vapor phase bioreactor (VPB) to simultaneously (i) delignify sugar-cane bagasse, a residue of sugar production that can be recycled in paper industry, and (ii) produce laccase, an enzyme usable to bleach paper pulp. Ethanol vapor, used as laccase inducer, was blown up through a VPB packed with bagasse and inoculated with Pycnoporus cinnabarinus ss3, a laccase-hyperproducing fungal strain. After 28 days, the laccase activity in the ethanol-treated bagasse was 80-fold higher (80 U g ds -1 ) and the bagasse delignification percentage was 12-fold (12%) higher than in the reference samples produced in the absence of ethanol, corresponding to a high overall pulp yield of 96.1%. In the presence of ethanol, the total soluble phenols amount was 2.5-fold (3 mg FA g ds -1 ) higher than that without ethanol. Six monomeric phenols were detected: p-coumaric (4-hydroxyphenyl-2-propenoic), ferulic (4-hydroxy-3-methoxyphenyl-2-propenoic), syringic (4-hydroxy-3,5-dimethoxybenzoic), vanillic (4-hydroxy-3-methoxybenzoic) and 4-hydroxybenzoic acids, and 2-methoxyhydroquinone. Higher concentrations of phenolic compounds were observed when ethanol vapor was added, confirming a more efficient bagasse delignification. After 28 days, the fungal-treated bagasse (with ethanol addition) was pulped and refined. For a freeness of 81 mL CSF, this processing required 50% less energy than with untreated bagasse (without inoculation and ethanol addition), which indicated a significant potential economy for the pulp and paper industry. Handsheets were made from pulp obtained after fungal-treated and untreated bagasse. Comparison of bagassepulp characteristics for freeness of 35 and 181 mL CSF showed an average increment by 35% for tensile index and breaking strength and length. VPB allowed a simultaneous production of laccase (90 U g ds -1 , after pressing of the bagasse) that improved the overall profitability of the process.

The deconstruction of lignin to enhance the release of fermentable sugars from plant cell walls presents a challenge for biofuels production from lignocellulosic biomass. The discovery of novel lignin-degrading enzymes from bacteria could... more

The deconstruction of lignin to enhance the release of fermentable sugars from plant cell walls presents a challenge for biofuels production from lignocellulosic biomass. The discovery of novel lignin-degrading enzymes from bacteria could provide advantages over fungal enzymes in terms of their production and relative ease of protein engineering. In this study, 140 bacterial strains isolated from soils of a biodiversity-rich rainforest in Peru were screened based on their oxidative activity on ABTS, a laccase substrate. Strain C6 (Bacillus pumilus) and strain B7 (Bacillus atrophaeus) were selected for their high laccase activity and identified by 16S rDNA analysis. Strains B7 and C6 degraded fragments of Kraft lignin and the lignin model dimer guaiacylglycerol-b-guaiacyl ether, the most abundant linkage in lignin. Finally, LC-MS analysis of incubations of strains B7 and C6 with poplar biomass in rich and minimal media revealed that a higher number of compounds were released in the minimal medium than in the rich one. These findings provide important evidence that bacterial enzymes can degrade and/or modify lignin and contribute to the release of fermentable sugars from lignocellulose.

Switchgrass is currently being developed as a sustainable bio-energy crop due to its broad adaptability, high mass yield and low agricultural input. Its current conversion to biofuels is detrimentally impacted by its native recalcitrance... more

Switchgrass is currently being developed as a sustainable bio-energy crop due to its broad adaptability, high mass yield and low agricultural input. Its current conversion to biofuels is detrimentally impacted
by its native recalcitrance which is typically addressed using chemical and/or biological pretreatments. In this study, extractives free switchgrass was pretreated with steam, dilute H2SO4 and lime at 160 C for 1 h. The degradation and impact of pretreatment was estimated semi-quantitatively by 13Ce1H HSQC (heteronuclear single quantum coherence) NMR analysis of ball milled untreated and pretreated
switchgrass samples in perdeuterated pyridinium chlorideeDMSO-d6 solvent system. As a result of steam pretreatment the resulting switchgrass was depleted of xylan and a slight degradation of lignin
were observed. This was confirmed by the relative decrease of cross peak intensity for b-aryl ether, phenylcoumaran, resinol and dibenzodioxocin units. Significant structural changes observed due to the
lime pretreatment of switchgrass was deacetylation/dissolution of hemicellulose and the extent of delignification was less however, a preferential removal p-hydroxy of benzoyl ester, ferulate and coumarate type linkages were notified from the HSQC studies. Finally the most significant degradation resulted in acid pretreatment involving w90% loss of hemicellulose and a substantial degradation of various lignin sub-units. These results are further supported by the composition analysis of the respective switchgrass samples.

Glucuronoxylans represent a significant fraction of woody biomass, and its decomposition is complicated by presence of lignin‐carbohydrate complexes (LCCs). Herein, LCCs from birchwood were used to investigate the potential coordinated... more

Glucuronoxylans represent a significant fraction of woody biomass, and its decomposition is complicated by presence of lignin‐carbohydrate complexes (LCCs). Herein, LCCs from birchwood were used to investigate the potential coordinated action of a glucuronoyl esterase (TtCE15A) and two α‐glucuronidases, (SdeAgu115A and AxyAgu115A). When supplementing α‐glucuronidase with equimolar quantities of TtCE15A, total MeGlcpA released after 72 h by SdeAgu115A and AxyAgu115A increased from 52% to 67%, and 61% to 95%, respectively. Based on the combined TtCE15A and AxyAgu115A activities, ~34% of MeGlcpA in the extracted birchwood glucuronoxylan was occupied as LCCs. Notably, insoluble LCC fractions reduced soluble α‐glucuronidase concentrations by up to 70%, whereas reduction in soluble TtCE15A was less than 30%, indicating different tendencies to adsorb onto the LCC substrate.

CITATIONS 94 READS 304 6 authors, including: Some of the authors of this publication are also working on these related projects: An integrated green process for biological carbon sequestration coupled with domestic sewage remediation by... more

CITATIONS 94 READS 304 6 authors, including: Some of the authors of this publication are also working on these related projects: An integrated green process for biological carbon sequestration coupled with domestic sewage remediation by algae in closed photo bioreactor and subsequent utilization of biomass as biofertilizer (IGG) View project Nanobiomaterials for water purification View project Prosenjit Saha a b s t r a c t

Synthetic structural materials with exceptional mechanical performance suffer from either large weight and adverse environmental impact (for example, steels and alloys) or complex manufacturing processes and thus high cost (for example,... more

Synthetic structural materials with exceptional mechanical performance suffer from either large weight and adverse environmental impact (for example, steels and alloys) or complex manufacturing processes and thus high cost (for example, polymer-based and biomimetic composites). Natural wood is a low-cost and abundant material and has been used for millennia as a structural material for building and furniture construction. However, the mechanical performance of natural wood (its strength and toughness) is unsatisfactory for many advanced engineering structures and applications. Pre-treatment with steam, heat, ammonia or cold rolling followed by densification has led to the enhanced mechanical performance of natural wood. However, the existing methods result in incomplete densification and lack dimensional stability, particularly in response to humid environments, and wood treated in these ways can expand and weaken. Here we report a simple and effective strategy to transform bulk nat...

In this paper, we proposed a new modification for an ethanol-based pulping process, which would consist of the pre-hydrolysis (pre-extraction) of wood chips for removing hemicelluloses; the ethanol extraction of pre-hydrolyzed wood chips... more

In this paper, we proposed a new modification for an ethanol-based pulping process, which would consist of the pre-hydrolysis (pre-extraction) of wood chips for removing hemicelluloses; the ethanol extraction of pre-hydrolyzed wood chips for removing lignin; and the post purification of cellulose, leading to the production of pure cellulose. We also experimentally evaluated the separation of hemicelluloses from the pre-hydrolysis liquor (PHL) obtained from a pulp mill. To remove lignin from the PHL, it was acidified to a pH of 2, which resulted in 47% lignin precipitation. The lignin separation from the acidified PHL was further improved via adding polyethylene oxide and poly aluminum chloride or adding ethyl acetate. To recover the hemicelluloses from the acidified PHL, ethanol was added to the acidified PHL with a volumetric ratio of 4 to 1. The isolated lignin and hemicelluloses were characterized by a Fourier transform infrared spectroscopy (FTIR) and a gas permeation chromatography (GPC).