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In order to detect the effects of simulated nitrogen deposition on litter decomposition and degradation of lignin and cellulose, a one-year field experiment of simulated nitrogen deposition has been conducted using litter bag method from November 2013 to November 2014 in an evergreen broad-leaved forest, Rainy Area of West China. Four levels of nitrogen deposition were set, i.e., control (0 g N·m -2 ·a -1 ), low (5 g N·m -2 ·a -1 ), medium (15 g N·m -2 ·a -1 ) and high (30 g N·m -2 ·a -1 ) nitrogen deposition. The results indicated that foliar litter decomposed faster in summer, obviously faster than in the other seasons. N deposition significantly inhibited the decomposition of foliar litter in this evergreen broad-leaved forest. As N deposition increased, the inhibition effect was enhanced. The time of 95% mass loss (T 95% ) of foliar litter due to simulated N deposition was increased by 0.53-1.88 years compared with T 95% of control (4.81 years). N deposition significantly inhibited the degradation of lignin and cellulose. The mass remaining after one year of decomposition of lignin and cellulose in the medium and high nitrogen deposition treatments were significantly higher than that in the control. There was a significant positive linear relationship among mass remaining rate and lignin and cellulose remaining rates. The inhibiting effects of inorga-nic N on degradation of lignin and cellulose explained the inhibitory effect of N on foliar litter decomposition.

The objective of the study was to evaluate the dynamics of recalcitrant components during foliar litter decomposition under edge effects of forest gap in Pinus massoniana plantations in the low hilly land, Sichuan basin. A field litterbag experiment was conducted in seven forest gaps with different sizes (100, 225, 400, 625, 900, 1225, 1600 m 2 ) which were generated by thinning P. massoniana plantations. The degradation rate of four recalcitrant components, i.e., condensed tannins, total phenol, lignin and cellulose in foliar litter of two native species (Cinnamomum camphora and Toona ciliata) at the gap edge and under the closed canopy were measured. The results showed that the degradation rate of recalcitrant components in T. ciliata litter except for cellulose at the gap edge were significantly higher than that under the closed canopy. For C. camphora litter, only the degradation of lignin at the gap edge was higher than that under the closed canopy. After one-year decomposition, four recalcitrant components in two types of foliar litter exhibited an increment of degradation rate, and the degradation rate of condensed tannin was the fastest, followed by total phenol and cellulose, but the lignin degradation rate was the slowest. With the increase of gap size, except for cellulose, the degradation rate ofthe other three recalcitrant components of the T. ciliata at the edge of medium sized gaps (400 and 625 m 2 ) were significantly higher than at the edge of other gaps. However, lignin in the C. camphora litter at the 625 m 2 gap edge showed the greatest degradation rate. Both temperature and litter initial content were significantly correlated with litter recalcitrant component degradation. Our results suggested that medium sized gaps (400-625 m 2 ) had a more significant edge effect on the degradation of litter recalcitrant components in the two native species in P. massoniana plantations, however, the effect also depended on species.

Acetic acid, as a main by-product generated in the pretreatment process of lignocellulose hydrolysis, significantly affects cell growth and lipid synthesis of oleaginous microorganisms. Therefore, we studied the tolerance of Rhodotorula glutinis to acetic acid and its lipid synthesis from substrate containing acetic acid. In the mixed sugar medium containing 6 g/L glucose and 44 g/L xylose, and supplemented with acetic acid, the cell growth was not:inhibited when the acetic acid concentration was below 10 g/L. Compared with the control, the biomass, lipid concentration and lipid content of R. glutinis increased 21.5%, 171% and 122% respectively when acetic acid concentration was 10 g/L. Furthermore, R. glutinis could accumulate lipid with acetate as the sole carbon source. Lipid concentration and lipid yield reached 3.20 g/L and 13% respectively with the initial acetic acid concentration of 25 g/L. The lipid composition was analyzed by gas chromatograph. The main composition of lipid produced with acetic acid was palmitic acid, stearic acid, oleic acid, linoleic acid and linolenic acid, including 40.9% saturated fatty acids and 59.1% unsaturated fatty acids. The lipid composition was similar to that of plant oil, indicating that lipid from oleaginous yeast R. glutinis had potential as the feedstock of biodiesel production. These results demonstrated that a certain concentration of acetic acid need not to be removed in the detoxification process when using lignocelluloses hydrolysate to produce microbial lipid by R. glutinis.

Lignin degradation products are toxic to microorganisms, which is one of the bottlenecks for fuel ethanol production. We studied the effects of phenolic ketones (4-hydroxyacetophenone, 4-hydroxy-3-methoxy-acetophenone and 4-hydroxy-3,5-dimethoxy-acetophenone) derived from lignin degradation on ethanol fermentation of xylose and cellular lipid composition of Pichia stipitis NLP31. Ethanol and the cellular fatty acid of yeast were analyzed by high performance liquid chromatography (HPLC) and gas chromatography/mass spectrometry (GC/MS). Results indicate that phenolic ketones negatively affected ethanol fermentation of yeast and the lower molecular weight phenolic ketone compound was more toxic. When the concentration of 4-hydroxyacetophenone was 1.5 g/L, at fermentation of 24 h, the xylose utilization ratio, ethanol yield and ethanol concentration decreased by 42.47%, 5.30% and 9.76 g/L, respectively, compared to the control. When phenolic ketones were in the medium, the ratio of unsaturated fatty acids to saturated fatty acids (UFA/SFA) of yeast cells was improved. When 1.5 g/L of three aforementioned phenolic ketones was added to the fermentation medium, the UFA/SFA ratio of yeast cells increased to 3.03, 3.06 and 3.61, respectively, compared to 2.58 of the control, which increased cell membrane fluidity and instability. Therefore, phenolic ketones can reduce the yeast growth, increase the UFA/SFA ratio of yeast and lower ethanol productivity. Effectively reduce or remove the content of lignin degradation products is the key to improve lignocellulose biorefinery.

Biomass energy is being industrialized rapidly in China in recent years, whereas, research on energy grass is still in primary stage. Only if near-infrared spectroscopy mode was constructed which was used to predict the lignin, cellulose and hemicellulose contents in energy crop, the varieties screening, performance evaluation and on-line control of industrialization would be facilitated. In this study, the prediction model for quality indices (cellulose, hemicellulose, lignin and ash) of four energy grass (Miscanthus) was built using Fourier transform near-infrared (FT-NIR) spectroscopy combined with partial least squares regression (PLSR), and the impacts exerted by particle size on the model were also revealed. The results showed that (1) the root mean error of cross validation (RMSECV) of cellulose, hemicelluloses and lignin contents were 1.35% (R = 0.88), 0.39% (R = 0.91) and 0.35 (R2 = 0.80), respectively in stalk and 0.72% (R = 0.88), 0.85% (R2 = 0.85) and 0.44 (R2 = 0.87), respectively in leaf. The model showed good performance in prediction of corresponding contents in unknown samples, however, no satisfying performance in ash content. (2) Both 2 mm and 0.5 mm grades of particle size can meet accuracy requirements of the model. But considering the time and labor cost, 2 mm grade was suggested for model building.

The development and utilization of lignocellulosic biomass resource becomes a major subject of widespread concern at home and abroad. To make better use of this resource and reduce cost, a thorough understanding of recalcitrance mechanism as well as chemical compositional and structural characteristics of lignocellulosic cell walls seems desiderated. With the property of fast testing, high sensitivity and simple sample preparation, FTIR microspectroscopy can provide microanalysis and nondestructive test. It has been proved to accurately present compositional and structural information of lignocellulosic cell walls and be suitable for the study of topochemistry of main components at the cellular level. After a brief introduction of the principle of FTIR microspectroscopy and its detailed experimental procedure, this review provides an overview on the feasibility of FTIR microspectroscopy in monitoring as well as evaluating the composition and structure of lignocellulosic cell walls from three aspects, including in situ distribution, changes after pretreatment and molecular orientation of the major components in cell walls. Some prospects, for example development of the magnification of the microscope and the spatial resolution of chemical imaging, combination with various analysis methods and instruments are also proposed. This technology can act as a new approach in characterizing lignocellulosic cell walls.

To understand the pyrolysis mechanism of lignin with α-O-4 linkage, 4-(3-hydroxy-1-phenoxypropyl)-phenol was selected as an α-O-4 type lignin dimer model compound, and its pyrolysis process was studied by density functional theory with M06-2X method at 6-31+G (d,p) level. Equilibrium geometries of the reactant, intermediates, transition states and products were fully optimized. The activation energies in each pyrolysis pathway were calculated. The dimer decomposed mainly through the homolytic cleavage and concerted decomposition of the C(α)-O linkage. Pyrolytic products mainly included various phenolic compounds such as phenol, 4-methylphenol, 4-vinylphenol and p-coumaryl alcohol, as well as light compounds such as ethanol, methanol and formaldehyde. Pyrolytic depolymerization process has its potential in biomass-based fuels.

In order to explore the possibility of Jerusalem artichoke stalk for bioenergy conversion, we analyzed the main composition of whole stalk, pitch, and core of the stalk. Meanwhile, these parts were pretreated with different NaOH concentrations at 121 degrees C. Afterwards, enzymatic hydrolysis was performed to evaluate the pretreatment efficiency. Jerusalem artichoke stalk was characterized by relatively high lignin content (32.0%) compared with traditional crop stalks. The total carbohydrate content was close to that of crop stalks, but with higher cellulose content (40.5%) and lower hemicellulose (19.6%) than those of traditional crop stalks. After pretreatment, the lignin content in the whole stalk, pitch, and core decreased by 13.1%-13.4%, 8.3%-13.5%, and 19.9%-27.2%, respectively, compared with the unpretreated substrates. The hemicellulose content in the whole stalk, pitch, and core decreased 87.8%-96.9%, 87.6%-95.0%, and 74.0%-90.2%, respectively. Correspondingly, the cellulose content in the pretreated whole stalk, pitch, and core increased by 56.5%-60.2%, 52.2%-55.4%, and 62.7%-73.2%, respectively. Moreover, increase of NaOH concentration for pretreatment could improve the enzymatic hydrolysis of the whole stalk and pitch by 2.3-2.6 folds and 10.3-18.5 folds, respectively. The hydrolysis of pretreated stalk core decreased significantly as 2.0 mol/L NaOH was employed, although the increased NaOH concentration can also improve its hydrolysis performance. Based on these results, hot-NaOH can be regarded as an option for Jerusalem artichoke stalk pretreatment. Increasing NaOH concentration was beneficial to hemicellulose and lignin removal, and consequently improved sugar conversion. However, the potential decrease of sugar conversion of the pretreated core by higher NaOH concentration suggested further optimization on the pretreatment conditions should be performed.

Confocal Raman microspectroscopy (CRM) represents a powerful technique that can provide insights into topochemistry in lignocellulosic biomass cell wall. In this work, CRM was used to explore the impact of dilute acid (DA) pretreatment on the topochemistry of lignin and hydroxycinnamic acid (HCA) in the-fiber cell walls of Miscanthus × giganteus internode. Raman spectra extracted from different morphological regions of untreated fiber cell walls indicated the heterogeneous concentration of lignin and HCA. There is a companied trend between them, that is, regions where there is the higher lignin concentration have the higher concentration of HCA. When treated with DA, it was found that the intensity of 1600 cm(-1) (lignin) and 1170 cm(-1) (HCA) were decreased, which could be contributed to the partially removal of lignin and HCA. The removal rate in different morphological areas followed the decreasing order: secondary cell wall (SW) > compound middle lamella (CML) > cell corner middle lamella (CCML). The increase of the Raman band intensity ratio (1170/1600) indicated the preferential removal of lignin in the SW and CML as a result of DA pretreatment, while the constant of the ratio meant there is no preference between lignin and HCA in the CCML. The research will provide the deep understanding of the topochemistry of lignin and HCA at sub-cellular level during DA pretreatment, meanwhile, it also expands the application of Raman spectra in the research area of plant cell wall.

The acid detergent fiber (ADF) from tobacco leaves was obtained by treating the sample with petroleum ether-ethanol (6:4, v/v), 30 g/L sodium dodecylsulfate and 0.5 mol/L sulphuric acid containing 20 g/L hexadecyl trimethyl ammonium bromide successively. The ADF was degraded by the alkaline CuO oxidation procedure. In this work, six samples of ADF degradation products from tobacco leaves were prepared. The samples were analyzed by using gradient liquid chromatography (LC) where an Ultimate XB C18 column was used as stationary phase, with a mixture of methanol and water as mobile phase, at a column temperature of 35 °C and a flow rate of 0.8 mL/min. Dual wavelengths of 280 nm and 320 nm were chosen for the detection. It was found that there were four characteristic peaks for the ADF degradation products. By taking these peaks as research object, the optimum time for the degradation was found to be 5 h and the sample solution could be kept stable within 7 days. The established method may provide a new approach for the studies of the differences between lignin composition in different tobacco leaves and the relationship between lignin content and the smoking quality of tobacco leaves.

The wood (willow branch) and grass (rice straw) materials were pyrolyzed at different temperatures (300, 450 and 600 °C) to obtain the biochars used in the present study. The biochars were characterized using elementary analysis, X-ray photoelectron spectroscopy (XPS) and solid state 13C cross-polarization and magic angle spinning nuclear magnetic resonance spectroscopy (13C NMR) to illuminate the structure and composition of the biochars which were derived from the different thermal temperatures and biomass. The results showed that the H/C, O/C and (O+N)/C ratios of the biochars decreased with the increase in the pyrolysis temperatures. The surface polarity and ash content of the grass-derived biochars were higher than those of the wood-derived biochars. The minerals of the wood-derived biochars were mainly covered by the organic matter; in contrast, parts of the mineral surfaces of the grass-derived biochars were not covered by organic matter? The 13C NMR of the low temperature-derived biochars revealed a large contribution of aromatic carbon, aliphatic carbon, carboxyl and carbonyl carbon, while the high temperature-derived biochars contained a large amount of aromatic carbon. Moreover, the wood-derived biochars produced at low heat treatment temperatures contained more lignin residues than grass-derived ones, probably due to the existence of high lignin content in the feedstock soures of wood-derived biochars. The results of the study would be useful for environmental application of biochars.

The poplar powder was acetylated with different duration as sample, processed ray radiation by using ultraviolet test box, contrasting the influences to lightfastness of wood with different acetylation degree, analyzing changing rules of characteristic peaks' intensity which belonged to the chemistry components of samples based on FTIR spectra, and the relationship between duration of acetylation and changes of chemistry components was established, The results showed that: Before UV radiation, the characteristic peaks' intensity of acetylated poplar powder at 1 739 cm(-1) which belonged to C = O in saturated esters compounds and 1 385 cm(-1) which belonged to C-H in acetate were higher than untreated ones', the poplar powder with 40 min's acetylation has the highest characteristic peaks' intensity, highest weight gain rate, remarkable acetylation effect; After UV radiation, characteristic peaks' intensity of Benzene at 1 504 cm(-1) which belonged to lignin of poplar powder was obviously higher than untreated ones', and characteristic peaks' intensity of poplar powder with 40 min's acetylation was the highest, this showed that acetylation could effectively reduce the light degradation of wood chemistry components, in order to improve the lightfastness, especially the poplar powder with 40 min's acetylation; SEM photos showed that, the fibrous surface of acetylated poplar powder was more smooth and had more narrow particle size than untreated ones', so acetylation can effectively improve the stability of wood.

Using pig manure and corn straw as raw materials for high-temperature composting, setting three different treat- ments: C/N 15, C/N 25, and C/N 35. Composting period is 120 days, which contains 30 days for ventilation cycle by forced continuous ventilation. Sampled on 0, 22, 30, 60, 90, 120th days, they were analyzed by elemental analysis and IR spectroscopy to study effect of different lignin content on compost humic acid (HA) composition and molecular structure. The results showed that the change in composting humic acid C focused on the first 30 days, while after composting, the O/C of compost HA increased, H/C decreased, and N content increased. Low C/N (15) and higher C/N ratio (35) had higher degree of oxidation than the C/N 25 in compost HA. FTIR indicated that the infrared spectrum shapes with different lignin content treatment are similar during the composting process, but the peak intensity is obviously different. Research results proved that the composting stage is more conducive to enhanced aromatic in compost HA. After composting, C/N 15 had less polysaccharide and fat ingredients and more aromatic structural components in compost HA, compared with C/N 25 and 35. In addition, compost HA of C/N 15 had higher degree of humification and its structure was more stable.

Lignin is complex heteropolymer produced from hydroxycinnamyl alcohols through radical coupling. In nature, white-rot fungi are assumed initially to attack native lignin and release lignin-derived-low-molecular-weight compounds, and soil bacteria play an importent role for completely degradation of these compounds. Study on the soil bacteria degrading lignin-derived-low-molecular-weight compounds will give way to understand how aromatic compounds recycle in nature, and to utilize lignin compounds as the renewable materials for valuable materials production. Sphingobium sp. SYK-6 that grows on lignin biphenyl (5,5'-dehydrodivanillate) had been isolated from pulp effluent in 1987. We have researched this bacterium more than 25 years, a serious aromatic metabolic pathway has been determined, and related genes have been isolated. As the complete genome sequence of SYK-6 has been opened to the public in 2012, the entire aromatic compounds degradation mechanisms become more clear. Main contents in our review cover: (1) genome information; (2) aryl metabolism; (3) biphenyl metabolism; (4) ferulate metabolism; (5) tetrahydrofolate-dependent O-demethylation system for lignin compound degrdation; (6) protocatechuate 4,5-cleavage pathway; (7) multiple pathways for 3-O-methylgallate metabolism.

Arundo donax linn, as a perennial energy crop, has promising application prospect. In the present study, Fourier transform Raman (FT Raman) spectroscopy was applied to determine the structural information of materials, milled wood lignin (MWL), and alkaline lignins (AL, under different treated time) from A. donax stem nondestructively. The results indicated that, extractable compounds in A. donax had negative contribution to the Raman spectra without rising new Raman peaks. FT Raman spectrum of MWL indicated that MWL from A. donax was HGS type lignins. Compared with the spectra of MWL from wood materials, the peak at 1173 cm(-1) was much higher in intensity for the MWL from A. donax stem, which may be assigned to hydroxycinnamic acid by analyzing the standard. With respect to FT Raman spectra of ALs, the relatively highest intensity of 1173 cm(-1) was found in alkaline lignin (AL2), which was treated for 40 min by alkaline. Moreover, the peak of coniferaldehyde/sinapaldehyde (1630 cm(-1)) was lowest in intensity while the band attributed to coniferyl alcohol/sinapyl alcohol (1660 cm(-1)) was almost disappeared in AL2. It could be inferred that AL2 demonstrated a highest content of phenolic acid, which may improve its potential application, such as for antioxidant activity. Furthermore, the results obtained by FT Raman spectra were verified by two dimensional heteronuclear singlequantum coherence nuclear magnetic resonance analyses. Above all, FT Raman spectroscopy provided alternative safe, rapid, accurate, and nondestructive technology for lignin structure determination.

In order to investigate the changes of secondary metabolites content of alfalfa induced by thrips Odontothrips loti damaging, two alfalfa strains, one resistant to thrips (R-1) and the other susceptible to thrips (I-1) , were chosen to measure the phenols and lignin contents of alfalfa leaves under infestation with thrips at different densities (0, 1, 3, 5, 7 thrips x branch(-1), and 0 thrip x branch(-1) as control). After infestation 7 days, the polyphenols, tannin and condensed tannin contents increased in both leaves of R-l and I-i with the increasing thrips density, the simple phenols content had no significant difference, while the lignin content increased significantly compared with the control. After infestation 14 days, the polyphenols, tannin, condensed tannin and lignin contents in both leaves of R-1 and I-1 increased obviously with the increasing thrips density, while the simple phenols content had no significant difference. The lignin content increased significantly, and was significantly higher under 7 thrips x branch(-1) than under the control. After infestation 21 days, the polyphenols, tannin, and lignin contents in both leaves of R-1 and I-1 increased obviously with the increasing thrips density, and were the highest under 7 thrips x branch(-1). Simple phenols content of I-1 strain was increased significantly, but that of R-1 strain had no significant change. The condensed tannin content in both leaves of R-1 and I-1 was not obvious compared with the control. Phenols and lignin contents in R-1 and I-1 leaves increased obviously after thrips infestation, and the polyphenols, tannin and lignin contents increased faster in R-1 strain than in I-1 strain. Thrips infestation had inductive effects on phenols and lignin contents of alfalfa, which could be used to evaluate the resistance of alfalfa.

Components separation is the key technology in biorefinery. Combination of steam explosion and laccase was used, and synergistic effect of the combined pretreatment was evaluated in terms of physical structure, chemical components and extraction of lignin. The results showed that steam explosion can destroy the rigid structure and increase the specific surface area of straw, which facilitated the laccase pretreatment. The laccase pretreatment can modify the lignin structure based on the Fourier transform infrared test, as a result the delignification of straw was enhanced. Nuclei Growth model with a time dependent rate constant can describe the delignification, and the kinetics parameters indicated that the combined pretreatment improved the reaction sites and made the delignification reaction more sensitive to temperature. The combined pretreatment enhanced delignification, and can be a promising technology as an alternative to the existing pretreatment.

To increase the integral economic effectiveness, biorefineries of lignocellulosic materials should not only utilize carbohydrates hydrolyzed from cellulose and hemicellulose but also use lignin. We used steam-exploded corn stalk as raw materials and optimized the temperature and alkali concentration in the lignin extraction process to obtain lignin liquor with higher yield and purity. Then the concentrated lignin liquor was used directly to substitute phenol for phenolic foam preparation and the performances of phenolic foam were characterized by microscopic structure analysis, FTIR, compression strength and thermal conductivity detection. The results indicated that, when steam-exploded corn stalk was extracted at 120 degrees C for 2 h by 1% NaOH with a solid to liquid ratio of 1:10, the extraction yield of lignin was 79.67%. The phenolic foam prepared from the concentrated lignin liquor showed higher apparent density and compression strength with the increasing substitution rate of lignin liquor. However, there were not significant differences of thermal conductivity and flame retardant properties by the addition of lignin, which meant that the phenolic foam substituted by lignin liquor was approved for commercial application. This study, which uses alkali-extracted lignin liquor directly for phenolic foam preparation, provides a relatively simple way for utilization of lignin and finally increases the overall commercial operability ofa lignocellulosic biorefinery derived by steam explosion.

Recent concerns about the gradual depletion of conventional fossil resources and the pressure from global climate change have accentuated the need for new alternative feedstock. As one of the main components in biomass, lignin is the second most abundant natural polymer after cellulose, and has the potential to serve as a sustainable source of energy and organic carbon to replace petroleum-based chemicals. Efficient conversion of lignin into high value-added chemicals is crucial to improve the economic feasibility of biomass refinery. In the present study, several pretreatment technologies on industrial lignin were carried out to enhance phenol production. A microwave irradiation assisted biphasic reaction system was used to convert pretreated industrial lignin into phenolic compounds. Lignin conversion, reaction temperature, time and pretreatment method, were optimized. The highest phenol yield was 8.14% obtained from lignin pretreated by 1-ethyl-3-methylimidazolium acetate at 400 W for 60 min in a biophasic system catalyze by 1-aminoethyl-3-methylimidazolium tetrafluoroborate.

Byproducts in lignocellulose hydrolysates, namely sodium formate (1 to 5 g/L), sodium acetic (2.5 to 8.0 g/L), furfural (0.2-2 g/L), 5-hydroxymethylfurfural (5-HMF, 1 to 1.0 g/L) or vanillin (0.5 to 2 g/L) were used to evaluate their effects on ethanol fermentation by Issatchenkia orientalis HN-1 using single factor test and the response surface central composite experiment. Results showed that most of the byproducts had no obvious inhibition on the production of ethanol, except for the addition of 2 g/L vanillin or 1 g/L of 5-HMF, which reduced the ethanol production by 20.38% and 11.2%, respectively. However, high concentration of some byproducts in lignocellulose hydrolysates, such as sodium formate (1 to 5 g/L), sodium acetic (2.5 to 8.0 g/L), furfural (0.2 to 2 g/L) and vanillin (0.5 to 2 g/L) inhibited the growth of I. orientalis HN-1 significantly. Compared with the control, the dry cell weight of I. orientalis HN-1 decreased by 25.04% to 37.02%, 28.83% to 43.82%, 20.06% to 37.60% and 26.39% to 52.64%, respectively, when the above components were added into the fermentation broth and the fermentation lasted for 36 h. No significant interaction effect of the various inhibitors (sodium formate, sodium acetic, furfural and vanillin) except for vanillin single factor on the ethanol production was observed based on the central composite experiments. The concentrations of byproducts in most lignocellulose hydrolysates were below the initial inhibition concentration on ethanol production by Issatchenkia orientalis HN-1, which indicated that Issatchenkia orientalis HN-1 can be used for ethanol production from lignocellulose hydrolysates.

Fermentation inhibitors are toxic to cells, which is one of the bottlenecks for lignocellulose bio-refinery process. How to remove those inhibitors serves a key role in the bioconversion of lignocellulose. This article reviews the sources and the types of the inhibitors, especially the updated removal strategies including physical methods, chemical methods, biological methods and inhibitor-tolerant strain construction strategies. Based on these, we introduce a new bio-refinery model named "fractional conversion", which reduces the production of inhibitors at pretreatment stage, and a novel in situ detoxification method named "fermentation promoter exploitation technology". This review could provide new research ideas on the removal of fermentation inhibitors.

Laccase is one of the most important oxidoreductase with industrialization potential. However, due to the high cost and catalytic toxicity of laccase synthetic mediator, the laccase-mediator-system still cannot achieve industrialization. Therefore, searching for high efficient, environment-friendly, and cheap natural mediator from small molecule precursors or intermediates and degradation products of lignin has been considered as a hot research topic. Therefore, we introduce the type and catalytic mechanism of laccase mediator, the composition and separation of natural laccase mediator from water washed solution of steam exploded straw, black liquor and lignocelluloses degradation products during the fermentation of white-rot fungi. We also provide the theoretical and technical direction for exploring of high reactive of laccase natural mediators and achieving the oriented high-value utilization of lignocellulose degradation products.

Deconstruction of lignocellulosic plant cell walls to fermentable sugars by biochemical means is impeded by several poorly understood ultrastructural and chemical barriers. Pretreatment is an essential step by altering the morphological and compositional characteristics of biomass to enhance the sugar release during enzymatic hydrolysis. Therefore, getting insight into this field is necessary to improve the conversion of biomass into biofuels. In this review, we highlight our recent understanding on the impact of various promising pretreatments on biomass, with emphasis on the topochemical and ultrastructural changes of plant cell walls that are related to the reduction of recalcitrance and the consequence of saccharification. It will lend support to the scientific research and development with respect to biomass conversion.

In order to improve the reaction activity of bioethanol lignin, we investigated the activation of bioethanol lignin by a hydrothermal treatment method. Catalytic hydrothermal treatment of bioethanol lignin was performed at 180 degrees C for 3 h in the presence of alkaline solutions (NaOH, Na2 CO3, KOH and K2 CO3), the change in bioethanol lignin structures was studied comparatively by FTIR, 1H NMR,GPC and elemental analysis. FTIR spectra showed that after alkali hydrothermal treatment, the band at 1 375 cm(-1) attributed to the phenolic hydroxyl groups increased, and the band intensity at 1 116 cm(-1) attributed to the ether bond decreased. On the other hand, the band at 1 597 and 1 511 cm(-1) attributed to aromatic skeletal vibration remained almost unchanged. 1H NMR spectra showed that after alkali hydrothermal treatment, the number of aromatic methoxyl is increased, and based on the increment of the content of phenolic hydroxyl, the catalytic activity can be ranked as follows: KOH > NaOH > K2 CO3 > Na2 CO3. Especially for KOH, the increment of the content of phenolic hydroxyl was 170%, because the ion radius of potassium cation is bigger than sodium cation, so the potassium cations more easily formed cation adducts with lignin. GPC results showed that the molecular weight of alkali hydrothermal treatment lignin decreased and the molecular distribution got wider. Elemental analysis showed that hydrothermal treatment could break the interlinkage between lignin and protein, which can reduce the protein content and increase the purity of lignin, meanwhile, the content of O and H both decreased,while C fell, indicating that the bioethanol lignin had suffered a decarbonylation reaction. This is the most benefit of the lignin as a substitute for phenol.

The present paper described a triple-wavelength visible spectroscopic method for the determination of iron content in lignocellulosic materials. After the sample was pretreated with acidic hydrolysis method under selected conditions, the color agent, 1, 10-phenanthroline monohydrate, was added in the filtrate and then measured by a triple-wavelength spectroscopic method at wavelengths of 416, 510 and 700 nm, from which the iron contents of the sample can be calculated. The results showed that this method can efficiently deduct the influences of acidic soluble lignin and furfural compounds generated during the sample pretreatment and baseline drift caused by the tiny particles in the filtrates. It not only has a good measurement precision but also is accurate, in which the relative differences of the results obtained by the present method and ICP-OES method is less than 5%. The method is simple and practical, and suitable for industrial applications.

Due to the deficiency of energy supply and negative environmental impacts. Much attentions have been paid to agnicultural these lignocellulosic the replacement of fossil resources with and forestry biomass for the production of bio-fuels, chemicals and biomaterials on a global scale. Highly effective utilization of biomass is dependent on full understanding of their chemical composition and structural characteristics. A state-of-the-art Raman spectroscopy has evolved an important and nondestructive technique for plant research as information concerning histochemistry and structural characteristics of plant cell walls can be investigated in a nearly native state. In this paper, the principle of Raman imaging was introduced briefly. Meanwhile, the research progress in structural analysis of major components, micro-area distribution and molecular organization of the cellulose and lignin in the plant cell walls by Raman spectroscopy was summarized. The aim of the review is to promote the application of Raman spectroscopy to the study of plant cell walls.

In the study, we used oil palm residues (empty fruit bunch, EFB) as raw material to produce cellulosic ethanol by pretreatment, enzymatic hydrolysis and fermentation. Firstly, the pretreatment of EFB with alkali, alkali/hydrogen peroxide and the effects on the components and enzymatic hydrolysis of cellulose were studied. The results show that dilute alkali was the suitable pretreatment method and the conditions were first to soak the substrate with 1% sodium hydroxide with a solid-liquid ratio of 1:10 at 40 degrees C for 24 h, and then subjected to 121 degrees C for 30 min. Under the conditions, EFB solid recovery was 74.09%, and glucan, xylan and lignin content were 44.08%, 25.74% and 13.89%, respectively. After separated with alkali solution, the pretreated EFB was washed and hydrolyzed for 72 h with 5% substrate concentration and 30 FPU/g dry mass (DM) enzyme loading, and the conversion of glucan and xylan reached 84.44% and 89.28%, respectively. We further investigated the effects of substrate concentration and enzyme loading on enzymatic hydrolysis and ethanol batch simultaneous saccharification and fermentation (SSF). The results show that when enzyme loading was 30 FPU/g DM and substrate concentration was increased from 5% to 25%, ethanol concentration were 9.76 g/L and 35.25 g/L after 72 h fermentation with Saccharomyces cerevisiae (inoculum size 5%, V/V), which was 79.09% and 56.96% of ethanol theory yield.

To get the tolerability and consumption of Klebsiella oxytoca on major inhibitors in lignocelluloses hydrolysate, we studied the effect of acetic acid, furfural and 5-hydroxymethylfurfural on production of 2,3-butanediol by Klebsiella oxytoca. The metabolites of furfural and 5-hydroxymethylfurfural were measured. The results show that when acetic acid, furfural and 5-hydroxymethylfurfural was individually added, tolerance threshold for Klebsiella oxytoca was 30 g/L, 4 g/L and 5 g/L, respectively. Acetic acid was likely used as substrate to produce 2,3-butanediol. The yield of 2,3-butanediol increased when acetic acid concentration was lower than 30 g/L. In the fermentation, more than 70% 5-hydroxymethylfurfural was converted to 2,5-furandimethanol. All furfural and the rest of 5-hydroxymethylfurfural were metabolized by Klebsiella oxytoca. It showed that in the detoxification process of 2,3-butanediol production using lignocelluloses hydrolysate, furfural should be given priority to remove and a certain concentration of acetic acid is not need to removal.

To study chemical constituents contained in ethanol extracts from roots of Machilus yaoshansis. Fifteen compounds were separated from the roots of M. yaoshansis by using various chromatographic techniques. Their structures were identified on the basis of their physicochemical properties and spectral data as twelve lignans(+)-guaiacin (1), kadsuralignan C (2), (+)-isolariciresinol (3), 5'-methoxy-(+)-isolariciresinol (4), (7'S, 8R, 8'R)-lyoniresinol (5), meso-secoisolariciresinol (6), isolariciresinol-9'-O-beta-D-xylopyranoside (7), 5'-methoxy-isolariciresinol-9'-O-beta-D-xylopyranoside (8), lyoniresinol-9'-O-beta-D-xylopyranoside (9), (2R, 3R) -2, 3-dihydro-2-(4-hydroxy-3-methoxyphenyl)-7-methoxy-3-methyl-5-(E)-propenylbenzofuran (10), 3, 5'-dimethoxy-4', 7-epoxy-8, 3'-neolignan-4, 9, 9'-triol (11), nectandrin B (12), and three flavanes(+)-catechin (13), (-)-epicatechin (14), and bis-8, 8'-catechinylmethane (15). All of the compounds 1-15 were separated from M. yaoshansis for the first time.

Objective: To separate and identify chemical constituents from Coptis chinensis., Method: The compounds were separated and purified by various chromatographic techniques. Their structures were identified on the basis of their physicochemical properties using spectral techniques such as NMR and MS., Result: Thirteen compounds were separated from ethanol extracts of C. chinensis, including seven lignans, three simple phenylpropanoids, two flavones and one phenolic acid, and identified as erythro-guaiacylglycerol-8-O-4'-(coniferyl alcohol) ether (1), threo-guaiacylglycerol-8-O-4'-(coniferyl alcohol) ether (2), (+)-pinoresinol (3), (+)-medioresinol (4), (+)-lariciresinol (5), (+)-5'-methoxylariciresinol (6), (+)-isolariciresinol (7), chlorogenic acid (8), ferulic acid (9), Z-octadecyl caffeate (10), rhamnetin (11), wogonin (12), and vanillic acid (13)., Conclusion: Compounds 1, 2, 4, 6, 10-13 were separated from the genus Coptis for the first time.

The structures and qualities of main chemical compositions in cell wall of bamboo treated with gamma rays were tested by nuclear magnetic resonance spectrometer (NMR) and X-ray Diffraction (XRD). The result indicated that the bamboo crystallinity increased at the beginning of irradiation process, while the crystallinity reduced when the irradiation dose was raised to about 100 kGy. During the whole irradiation process, hemicellulose degraded, and with the irradiation doses increased the non-phenolic lignin changed to the phenolic.

In order to study the chemical constituents of the leaves of Tripterygium wilfordii and provide references for the bio-active study, we isolated nine compounds from the dried leaves of Tripterygium wilfordii. Their structures were determined by application of spectroscopic (NMR, MS) and chemical methods. These compounds were isolated and identified as (+)-lyoniresinol (1), (+)-isolariciresinol (2), burselignan (3), dibutyl phthalate (4), cyclo-(S-Pro-R-Phe) (5), cyclo-(S-Pro-R-Leu) (6), cyclo-(S-Pro-S-Ile) (7), 3-hydroxy-1-(4-hydroxy-3,5-dimethoxyphenyl)-1-propanone (8) and daucosterol (9). Compounds 1-3, 5-8 were isolated from this plant for the first time.

During the bioconversion of lignocellulose to ethanol, the biomass always undergoes pretreatment in order to increase the enzymatic digestibility of cellulose. In present work, we conducted the pretreatment of sugarcane bagasse with aqueous acetic acid for delignification and alkali for deacetylation respectively (Acetoline process) to increase cellulose accessibility for enzymatic hydrolysis. The effects of several factors on the pretreatment effectiveness were investigated. The enzymatic digestibility of pretreated bagasse was further studied. The enzymatic glycan conversion of pretreated solid reached about 80% when it was digested under 7.5% solid consistency with cellulase of 15 FPU/g solid and beta-glucosidase of 10 CBU/g solid for 48 h. Compared with dilute acid pretreatment, Acetoline pretreatment could obtain higher enzymatic glycan conversion. The experimental results indicate that Acetoline is an effective pretreatment method to increase the enzymatic digestibility of sugarcane bagasse.

An analytical method using reversed-phase high performance liquid chromatography (RP-HPLC) was developed for the separation and quantitative determination of main degradation products of lignin (4-hydroxybenzoic acid, vanillic acid, syringic acid, 4-hydroxybenzaldehyde, vanillin and syringaldehyde) during the steam exploded pretreatment for corn stovers. The separation was carried out on a C18 column with the mobile phase of acetonitrile-water (containing 1.5% acetic acid) at 30 degrees C at a flow rate of 0.8 mL/min and the detection wavelengths of 254 and 280 nm. Under the optimized conditions, the correlation coefficients of the 6 compounds were between 0.999 9 and 1.000 0. The recoveries of the 6 compounds were all above 96% and the relative standard deviations (n = 6) were less than 2.5%. This method is suitable for the determination of the main degradation products of lignin during the steam exploded pretreatment of lignocellulosics.

Biofuels and bio-based chemicals from lignocellulosic biomass are sustainable, making them alternatives to petroleum-derived fuels and chemicals to address the challenges of the shortage of crude oil supply and climate change resulted from the overconsumption of petroleum-based products, particularly in China. However, high cost in liberating sugars from lignocellulosic biomass is still the bottleneck of the commercialization of biofuels and bio-based chemicals. In this article, the major components of cellulases and their synergistic role in the hydrolysis of pre-treated biomass is reviewed, followed by how to evaluate the enzymatic hydrolysis. With the elucidation of the underlying mechanism of the conformations of the enzyme molecules and their effectiveness in attacking cellulose substrate, more efficient enzymes are expected to be developed. Using the high production strain Penicillium decumbens, the on-site production of cellulases for cellulose ethanol production is discussed.

The FTIR, UV-Visible, 1H NMR and GPC were used to study structural changes of brown-rotted lignin after sodium borohydride reduction. FTIR spectra showed that, after reduction, the band at 1,677 cm(-1) attributed to the conjugated carbonyl groups disappeared, and the band intensity at 1,715 cm(-1) attributed to the nonconjugated carbonyl groups decreased. On the other hand, the band at 1,509 and 1,603 cm(-1) attributed to aromatic skeletal vibration remained almost unchanged. UV spectra showed the decreased absorptions at 288 nm and 300-400 nm after reduction. 1H NMR spectra showed that, after reduction, the number of aromatic methoxyl and aromatic hydroxyls decreased, the number of aliphatic hydroxyls and the proton number attributed to many linkage structures connecting the phenylpropane units increased. GPC results showed that the molecular weight of reduced brown-rotted lignin increased and the molecular distribution got wider, as a consequence of the large molecular weight molecules generated during the reduction reaction. Our results suggest that the conjugated carbonyl groups can be totally reduced to the hydroxyl groups, but only some nonconjugated carbonyl groups can be reduced to the hydroxyl groups. The chemical structure of the brown-rotted lignin changed, but the benzyl ring kept stable. The condensation reaction took place during the sodium borohydride reduction process.

The enzymatic modification mechanism of lignin small molecular lignin guaiacyl coniferyl alcohol existing in softwood and hardwood treated by laccase was studied. Gas chromatography-mass spectrometry (GC-MS), gel permeation chromatography (GPC), FTIR spectrum and PCD(particle charge detector) etc were used for the measurement. GC-MS could not detect the coniferyl alcohol monomer after treated by laccase, so it was speculated that coniferyl alcohol participated in the reaction totally, and the structure of coniferyl alcohol was changed. GPC demonstrated that the molecular weight of coniferyl alcohol increased when it was treated by laccase, and coniferyl alcohol was polymerized. FTIR spectrum determined the reaction point of coniferyl alcohol when treated by laccase, and it is mainly phenolic hydroxyl, aromatic ring side chain substituent such as methoxy, double bound in side chain, beta-carbonyl groups, and gamma-carbonyl groups. PCD gave a result that the cationic demandv(CD) decreased by 88.38%.

In order to make clear the changes in the micro crystal structures of celluloses and the functional group of main components including cellulose, hemicelluloses and lignin in wood decayed by fungi, the crystallinity, layer spacing d in crystalline unit cell, width of crystallite and functional group of main components of Populus tomentosa Carr wood, which was decayed by Phanerochaete Chysosporium (white-rot) and Postia Placenta (brown-rot) with various durations, for two weeks, four weeks, six weeks, eight weeks and ten weeks, respectively, were investigated by means of X-ray diffraction and FTIR spectroscopy methods. It was concluded that the lattice structures of crystallite in wood cellulose were not destroyed by PC and PP, and the two theta angles and layer spacing d in crystallite were constant, although the decaying treatment times were different for each other when decayed by the same fungi. However, the crystallinity and width of crystallite decreased with the decaying treatment times increasing, and the decaying effects by PP were more significantly than those by PC, which showed that the damage extent of celluloses decayed by PP was greater than that by PC. It was estimated that the xylan in hemicelluloses had been degraded to various extents with the process of decaying in wood, resulting in the carbonyl content increasing, and the effects of degradation on hemicelluloses and celluloses by PC and PP were almost the same. Furthermore, benzene rings in lignin, which had no remarkable changes by PP, were oxidized into chain hydrocarbon after decaying by PC.

Main constituents (lignin, cellulose and hemicelullose) were extracted from rice straw, and characterized by elemental analysis and Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFT). Sorption of pyrene on rice straw and its main constituents was studied. The results showed that there are great differences in the properties of the three constituents, with lignin of higher aromaticity and lower polarity, while cellulose and hemicellulose of greater polarity and aliphaticity. Sorption of pyrene also differed a lot due to the varied characteristics of the sorbents. All isotherms were fitted well with Freundlich equation. Lignin showed the greatest sorption capacity for pyrene, with K(F) being 5.04 x 10(4), approximately 100 times greater than that of cellulose. Sorption of pyrene on hemicellulose was even a little smaller than that on cellulose. At low solute aqueous concentration (c(e) = 0.01 S(w)), the sorption of pyrene on rice straw was controlled by lignin, and sorption coefficient (K(d)) was a little smaller than that predicted by the K(d) value on lignin and its mass fraction. This suggested that some sorption sites such as alkyl and aromatic centers were covered when the lignin existed mixed in the rice straw. But at high concentration (c(e) = 0.5 S(w)), the K(d) value of pyrene on rice straw was markedly greater than the sum of those on three constituents, suggesting that partition on other constituents could not be neglected. Moreover, pyrene sorption isotherm on lignin was nonlinear (Freundlich exponent, n = 0.89), while sorption on the other three sorbents was more linear (n > 0.96). A negative relationship between n and aromaticity was observed, which illustrates that specific effect related with aromaticity is the main reason for nonlinearity. Organic carbon normalized sorption coefficients (K(oc)) increased with increasing aromaticity and decreased with increasing polarity of the sorbents.

Objective: To study the chemical constituents of the extract with water from Forsythia suspensa., Methods: The compounds were isolated and repeatedly purified on TLC, silica gel column chromatograph, gel column chromatography, and preparative HPLC, and the structures were elucidated by physico-chemical properties and NMR., Results: Eight compounds were obtained and elucidated as stearic acid(I), ursolic acid(II),p-hydroxyphenyl acetic acid(III),3-(4-ehtoxoy-3-hydroxyphenyl)acrylic acid(IV),isolariciresinol(V), epipinoresinol-4-O-beta-D-glucoside(VI),(+)-epipinoresionl(VII),(+)-pinoresinol(VIII)., Conclusion: Compound III is isolated from this genus for the first time.

The present paper reports a rapid method for the determination of furfural (F) and 5-hydroxymethyl furfural (HMF) in pre-extraction liquors of lignocellulosic biomass based on UV spectroscopy. In a concentrated acetic acid medium, F and HMF have an isosbestic point at 276 nm. It was found that the acidic soluble lignin in the pre-extraction sample is the major interference species in the F and HMF spectroscopic quantification However, only acidic soluble lignins have the absorption at the wavelengths above 325 nm. Based on the absorption of the acidic soluble lignins at 325 nm, their absorptions at either F or HMF absorbed wavelengths can be determined. Thus, with a simple triple-wavelength technique, both F and HMF in the pre-extraction liquors of lignocellulosic biomass can be quantified based on the spectroscopic measurement at the isosbestic point wavelength (276 nm), maximum absorption wavelength of F (272 nm) and the acid soluble lignin absorbed wavelength (325 nm). The present method does not require the hazardous organic compounds (such as phenolic compounds etc.) acting as a color reagent in the experiment. It is not only simple and rapid, but also has a good measurement precision and accuracy, with the relative standard deviations of 3.02% and 2.72%, and recoveries of 95%-107% and 96%-101%, respectively, in the F and HMF quantification. The present method is suitable for use in the research on pre-extraction hemicellulose of the lignocellulosic biomass in bio-refinery area in order to achieve a high selective sugar conversion.

Objective: To study the chemical constitutents of the 60% ethanol extract of the stems of Sambucus williamsii., Method: Compounds were isolated and purified by Diaion D101, silica gel,Sephadex LH-20, ODS column chromatography and preparative HPLC. Their structures were identified by spectroscopic methods., Result: Seven lignans were isolated and identified as erythro-guaiacylglycerol-beta-O-4'-sinapyl ether (1), 1-( 4'-hydroxy-3'-methoxyphenyl) -2- [4"-( 3-hydroxypropyl) -2", 6"-dimethoxyphenoxy] propane-1,3-diol (2), isolariciresinol (3), burselignan (4), lyoniresinol (5), 5-methoxy-isolariciresinol (6), cycloolivil (7)., Conclusion: All these compounds were obtained from this genus for the first time.

Objective: To investigate the chemical constituents from the leaves of Vaccinium bracteatum., Method: Many column chromatographic techniques were used for the isolation and separation of chemical constituents. Their structures were elucidated on the basis of spectral analysis and chemical evidences., Result: Twelve compounds were isolated from the plant, and they were identified as chrysoeriol (1), scopoletin (2), trans-p-hydroxycinnamic acid (3), trans-p-hydroxycinnamic acid ethyl ester (4), cafeic acid ethyl ester (5), beta-sitosterol (6), iuteolin (7), quercetin (8), esculetin (9), cafeic acid (10), isolariciresinol-9-O-beta-D-xyloside (11), 10-O-trans-p-coumaroylsandoside (12)., Conclusion: Compounds 4, 5, 11, 12 were isolated from the genus Vaccinium for the first time, and compounds 1, 2, 9, 10 were isolated from this plant for the first time.

Adsorption of Tween 80 on sand was investigated, and the effect of inorganic salts (CaCl2), anionic surfactant (SDS) and lignosulphonates (sodium lignosulphonate or ammonium lignosulphonate) on the adsorption of Tween 80 on sand were evaluated at 25 degrees C. The results show that saturated adsorption amount of Tween 80 on sand enhance when CaCl2 or SDS is added into flushing solution of Tween 80. And the adsorption of Tween 80 on sand increase with the increase of molar fraction of CaCl2 or SDS in mixed flushing solution. And adsorption amount of Tween 80 on sand also enhance when SDS is added into sand firstly. The effects of mixing ratios and addition order of lignosulphonates on adsorption of Tween 80 were considered. The results show that with the increase of molar fraction of lignosulphonates in mixing flushing solution, adsorption amount of Tween 80 on sand decrease. The adsorption amount of Tween 80 reduce 20%-75% due to the exist of ammonium lignosulphonate is superior to sodium lignosulphonate (10%-60%) when mix the lignosulphonates-Tween 80 at the total mass ratios of 1:10, while the adsorption amount of Tween 80 reduce 70%-90% at the total mass ratios of 1:2. Lignosulphonates added into sand firstly is more efficient than that together. Therefore,use of lignosulphonates as a preflush can reduce the adsorption of surfactants on sand and is a better method to applied in in situ flushing.

In company with the development of nonaqueous enzymology, the enzymatic modification of lignin has gained increasing interests, especially in the synthesis of high molecular material. In the present article, the enzymatic modification of spruce alkali lignin in cetyltrimethylammonium bromide (CTAB) reversed micelles (100 mmol x L(-1) 1, pH 6.0, W/O = 40), alcohol lignin in ethanol solution (50%), lignin sulphonate in sodium phosphate buffer (pH 5.8, 20 mmol x L(-1)) and steam-explosion wheat straw alkali lignin in alkaline solution (pH 10.0, 20 mmol x L(-1) NaOH) by mycelia sterilia YY-5 laccase was studied. Laccase was isolated from Mycelia Sterilia YY-5 (CGMCC-1462) which was an entophytic fungus of Rhus Chinensis Mill. FTIR spectrum was used to assay the structure of lignins and gel permeation chromatography (GPC) was used to determine the molecular weight and molecular weight polydispersity of lignins. Bands of lignin in FTIR spectra of all lignins changed obviously after treated with YY-5 laccase, which indicated that some bond breakage or rearrangement occurred to lignin. The shift of non-conjugated C=O and conjugated carbonyl groups (alpha-carbonyl groups) stretching vibration, the decrease of phenol hydroxyl stretching vibration and the increase of C--O--C stretching vibration of ester bond proved that phenolic hydroxyl, carbonyl group and side chain substituent all might participate in the laccase modification reactions of lignin. Meanwhile, the results of GPC indicated that the molecular of lignins all have certain increase and molecular polydispersity decreased. From the point of the molecular mass polydispersity, the modification effect of YY-5 laccase on steam-exploded wheat straw alkali lignin and spruce alkali lignin was more significantly than other two lignins. The molecular mass polydispersity for steam-exploded wheat straw alkali lignin and spruce alkali lignin was 1.211 and 1.375 respectively, which might contribute to the alkali-stable enzyme for YY-5 laccase. Correspondingly, alkali solution was chosen as the optimum medium for YY-5 laccase to modify lignins.

Objective: To study the chemical constituents of Litsea lancifolia., Methods: AU compounds were isolated from the diethyl ether extract of the title herb by sillica gel column chromatogrphy, and their structures were identified by physical and chemical evidences and spectral methods., Results: Seven compounds were isolated and identified as (-)-aristortetralone (1), dehydrodiisoeugenol ( 2), dihydrodehydrodiconifery alcohol ( 3) , 5,7-dimethoxy-3', 4'-methylenedioxyflavan-3-ol (4), p-hydroxy-benzoic acid (5), vanillin(6), p-sitosterol (7), respectively., Conclusion: All compounds are isolated from this plant for the first time.

The Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-Visible), nuclear magnetic resonance spectroscopy (1H NMR) and TG analysis were used to study the oxidation of corn stover lignin by chloride dioxide and subsequently modified by furfuryl alcohol. The results were as following: The selective oxidation of lignin by chlorine dioxide was obtained by spectroscopy study. FTIR showed that the characteristic absorbance peaks of aromatic units were decreased after chloride dioxide oxidation. The increased absorbance for the band around 1720 cm(-1) corresponding to carbonyl stretching was achieved in the oxidized lignin and the lignin modified with furfuryl alcohol. The ultraviolet-visible spectroscopy showed that the absorbance around 280 nm was largely reduced after the lignin was oxidized. The 1H NMR spectroscopy also showed the decrease of aromatic units and methoxyl group in the oxidized lignin. All these indicated the formation of muconic acid and ester, or quinone derivatives when the lignin was selectively oxidized by chloride dioxide. The modification by furfuryl alcohol made the oxidized lignin more thermally stable.

Objective: To study chemical constituents from Ilex pubescens., Method: The constituents were isolated by chromatographic method and the structures were identified on the basis of spectral alanlysis., Result: Six lignin glycosides were identified as (7S, 8R) dihydrodehydrodiconiferyl alcohol 4-O-beta-D-glucopyranoside (1), (-)-olivil-4'-O-beta-D-glucopyranoside (2), (7S, 8R) dehydrodiconiferyl alcohol 4-O-beta-D-gluco-pyranosid (3), (+)-cyclo-olivil 6-O-p-D-glucopyranoside (4), (+)-medioresinol di-O-beta-D-glucopyranoside (5), (+)-pinoresinol-4, 4'-O-bisglucopyranoside (6)., Conclusion: All of them were isolated from this plant for the first time.

Objective: To study the chemical constituents in the root of Isatis indigotica., Method: The constituents root were separated through various chromatographic techniques and their structures were elucidated by means of physicochemical properties and the analysis of their spectral data., Result: Eleven compounds were isolated and identified as (+) -isolariciresinol (1), lariciresinol (2), lariciresinol-9-O-beta-D-glucopyranoside (3), lariciresinol-4'-O-beta-D-glucopyranoside (4), lariciresinol-4,4'-bis-O-beta-D-glucopyranoside (5), 3-formylindole (6), 1-methoxy-3-indolecarbaldehyde (7), 1-methoxy-3-indoleacetonitrile (8), deoxyvasicinone (9), epigoitrin (10), adenosine (11)., Conclusion: Compounds 4-8 were isolated from I. indigotica for the first time.