Total Crystallinity Index Research Articles

Influence of chlorite treatment on the fine structure of alkali pretreated sugarcane bagasse

Bagasse, an industrial agro waste is treated with alkali initially to remove hemicelluloses fraction followed by treatment with sodium chlorite solution varying the treatment time. The novelty of the work lies in the bleaching with chlorite treatment in alkaline medium. The treated bagasse fiber was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), particle size analysis by dynamic light scattering technique (DLS), optical microscope, scanning electron microscope (SEM), atomic force microscope (AFM), UV spectroscope, and thermogravimetric analysis (TGA). It was found that during alkali treatment, a lattice transformation from cellulose I to cellulose II took place. Chlorite treatment removed lignin initially, and then with increasing time, the amorphous portion of cellulose is removed, rendering high crystallinity in the fiber. All the changes have been accounted by evaluation of LOI (lateral order of index), TCI (total crystallinity index), and HBI (hydrogen bond intensity) from FTIR study. XRD study also revealed the same fact. AFM study also supported the same fact indicating generation of sharp crystal and rough surface. Morphological study of treated and untreated bagasse fiber also exhibited fibrillation of fiber. Radius of hydration as estimated by DLS analysis followed a decreasing trend with increase in chlorite treatment time. The loss of transparency in cellulose fiber has been exposed by UV spectra analysis. TGA study showed that thermal stability has been increased with chlorite treatment. Such alkali treatment along with sodium chlorite for cellulose extraction from bagasse has not been performed by earlier investigators. Extracted cellulose fiber will be a very suitable reinforcing agent due to highly fibrillated morphology.

Rice straw saccharification using cellulolytic cocktail from Aspergillus tubingensis and structure alterations studies of the wall polymer

Optimization of saccharification of rice straw plays a crucial role in harnessing maximum fermentable sugars through enzymatic hydrolysis of this complex polymer. The present study was aimed to evaluate the applicability of A. tubingensis NKBP-55 cellulolytic cocktail for generation of fermentable sugars and to carry out parametric optimization of the saccharification process followed by batch ethanolic fermentation of the rice straw hydrolysate. Also, evaluation of the alterations (composition, crystallinity and structural morphology) occurring in the wall polymer structure after sequential treatments was studied. The cellulolytic cocktail, under the statistically optimized conditions (rice straw 4% w/v and pH 5.0) liberated 578 mg fermentable sugars (glucose 463 mg, xylose 114.35 and cellobiose 0.71 mg) per gram of pretreated rice straw showing 2.17-fold enhancement. Candida shehatae NCIM 3501 utilized both glucose and xylose and produced 16.15 g/L bioethanol along with yield (YP/S) 0.50 after 24 h of fermentation. Its bioethanol production was observed to be better than Saccharomyces cerevisiae (13.39 g/L) and their co-culture (15.57 g/L). Sequential changes brought about by the enzymatic treatment of the solid substrate revealed by X-ray diffraction and FTIR analyses showed decrease in the absolute crystallinity (CrI) (54.80 to 48.31%) and total crystallinity index (TCI) (1.002 to 0.991) and confirmed the degradation of the crystalline domain of cellulose by enzyme. The study demonstrated the potential of cellulolytic cocktail produced by A. tubingensis NKBP-55 in rice straw saccharification and its efficient fermentation by conventional and xylose-fermenting yeast in batch ethanolic fermentation.

Biological Characterization and Instrumental Analytical Comparison of Two Biorefining Pretreatments for Water Hyacinth (Eichhornia crassipes) Biomass Hydrolysis

Water hyacinth is a rapidly growing troublesome aquatic weed plant, which causes eutrophication in water bodies and irreversible damage to the ecological system. In this work, we have investigated the water hyacinth biomass (WHB) hydrolysis efficacy of dilute alkaline (DA) pretreatment followed by biological pretreatment with white-rot fungus Alternaria alternata strain AKJK-2. The effectiveness of the dilute alkaline (DA) and biological pretreatment process on WHB was confirmed by using X-ray Diffraction (XRD) and Fourier Transform Infrared Spectrophotometer (FTIR), and was further visualized by Scanning Electron Microscope (SEM) and Confocal Laser Scanning Microscopy (CLSM). XRD spectra showed the increase in the crystallinity of pretreated samples, attributed to the elimination of amorphous components as lignin and hemicellulose. FTIR peak analysis of pre-treated WHB showed substantial changes in the absorption of cellulose functional groups and the elimination of lignin signals. Scanning electron microscopy (SEM) images showed firm, compact, highly ordered, and rigid fibril structures without degradation in the untreated WHB sample, while the pretreated samples exhibited loose, dispersed, and distorted structures. XRD indices (Segal, Landis, and Faneite), and FTIR indices [Hydrogen bond intensity (HBI); Total crystallinity index (TCI); and Lateral order crystallinity (LOI)] results were similar to the aforementioned results, and also showed an increase in the crystallinity both in alkaline and biological pretreatments. Alkaline pretreated WHB, with these indices, also showed the highest crystallinity and a crystalline allomorphs mixture of cellulose I (native) and cellulose II. These results were further validated by the CLSM, wherein fluorescent signals were lost after the pretreatment of WHB over control. Overall, these findings showed the significant potential of integrated assessment tools with chemical and biological pretreatment for large-scale utilization and bioconversion of this potential aquatic weed for bioenergy production.

HYDROHYPROPYL CELLULOSE/POLYURETHANE BLENDS. THE BEHAVIOR AFTER ACCELERATED AGEING. A FTIR STUDY

A series of hydroxypropyl cellulose/polyurethane blends (PU_HPC 20/80, PU_HPC 50/50 and PU_HPC 80/20) were investigated by FT-IR spectroscopy after exposure to simulated ageing conditions (UV irradiation, 40 °C and 60% humidity) for 600 h. The degree of structural organization was analyzed through quantitative determination of the crystallinity indexes: total crystallinity index (TCI), lateral order index (LOI) and the hydrogen bond intensity (HBI), as well as by the evolution of the “ordered”, “disordered” and “free” areas in the carbonyl (1600-1800 cm-1) spectral region. The accelerated weathering conditions determined structural modification in the PU_HPC blends in correlation with their composition and the exposure time, both polymeric components being affected by the hydrolysis and oxidation processes.

Using infrared spectrum analyses to predict tensile strength of fibres in a group of closely related plant species: case of Mascarenes Pandanus spp.

Replacing synthetic fibres with natural ones is key for clean and sustainable manufacturing. Natural fibres require characterization to investigate their usefulness. However, current testing methodologies require a large sample size due to the strong variation of tensile strength (TS) among the fibre of the same plant species. The development of a simpler test method to predict fibre TS would help in the selection of the most appropriate plant species with desirable TS values while performing fewer tests; thus saving on time and cost. FT-IR results that determine fibre crystallinity through specific IR absorbance peak ratios may serve to predict the fibre TS. In this study, we tested the relationship between fibre TS and cellulose crystallinity for seven different species of Pandanus spp. Thus, empirical mathematical relationships between the fibre TS value and indices obtained by three specific IR absorbance peaks ratios, namely the total crystallinity index, lateral order index, and hydrogen bond index have been established with a good correlation coefficient (96, 98, and 95%, respectively).

Preparation and Characterization of an Amino-functionalized α-Cellulose from Pineapple [Ananas comosus (L.) Merr.] Crown Leaves

Amino-functionalized α-cellulose from pineapple [Ananas comosus (L.) Merr.] crown leaves (PCLs) was prepared using 3-(aminopropyl)triethoxysilane (APTES) to explore the diverse utilization of PCL. It was then characterized using optical microscopy, attenuated total reflectance Fourier-transform infrared spectroscopy (ATR FTIR), ninhydrin test, and differential scanning calorimetry (DSC). The amino-functionalization was confirmed by the appearance of disintegrated primary layers and balloons in the 400x and 1000x optical micrographs, higher lateral order index (LOI), higher total crystallinity index (TCI), higher energy of H-bonds (EH) at 3432 cm–1, longer radius of H-bonds (R) at 3432 cm–1, higher depolymerization temperature (Tm(DP)), and higher enthalpy of dehydration (ΔdehydrationH) of α-cellulose-APTES as compared to α-cellulose, and the positive reaction of α-cellulose-APTES with ninhydrin. The results showed that the prepared α-cellulose-APTES have notable properties to be used in a variety of adsorbent and enzyme-immobilization applications.

Biodegradation inducers to enhance wheat straw pretreatment by Gloeophyllum trabeum to second-generation ethanol production.

The native state of lignocellulosic biomass is highly resistant to enzymatic hydrolysis and the fermentation process of biofuel production. Brown-rot fungi use an extracellular Fenton system to degrade lignocellulosic biomass in the initial stages of decay. In this work, the combined effects of Mn2+, Fe2+, and NO3- inducers were evaluated based on the activities of hydrolytic enzymes and Fe3+ reduction as well as the catechol-type compound production during wheat straw pretreatment by the brown-rot fungus Gloeophyllum trabeum. Weight loss and chemical changes were evaluated to establish the culture conditions for stimulating wheat straw degradation using a central composite design. The results showed that weight loss and the Fe3+-reducing activity were promoted at the highest concentrations of Fe2+. A positive effect on catechol compound production by the addition of Mn2+ and NO3- was observed. Cellulase activity was increased at the highest concentration of NO3-. The multiple optimizations of G. trabeum culture conditions in wheat straw resulted in 11.3% weight loss and 0.47 total crystallinity index at 0.24M NO3-, 0.95mM Fe2+, and 0.85mM Mn2+ after 40days. The wheat straw pretreatment by G. trabeum for 10days increased glucose recovery. The results indicated that the wheat straw pretreatment using G. trabeum with biodegradation inducers could be a complementary step to physicochemical pretreatment of lignocellulosic biomass for production of second-generation ethanol.

Extraction of α-cellulose from Eleocharis dulcis Holocellulose using NaOH and KOH

Cellulose is the greatest abundant and renewable biopolymer resources in world, it has been widely used in many industrial applications because of its favorable characteristics. Various cellulose resources, especially those obtained from local resources and agriculture waste, are being exploited to reduce the impact of environmental damage. This study presents an environmental friendly methods to produce cellulose from local plant, Eleocharis dulcis. E. dulcis is an aquatics plant belonging to the Cyperaceae family, mainly abundant in swampy area in South Kalimantan, Indonesia. In this study, α-cellulose were isolated from E. dulcis as a new renewable industrial resources. The sample was dewaxed using ethanol-toluene, then the free extractive sample was bleached using NaClO2 to produce holocellulose. The influence of type of alkali (NaOH and KOH) and concentration (15%; 17.5% and 20%) on the properties of α-cellulose was investigated. The Total Crystallinity Index (CrI), Lateral Order Index (LOI), Hydrogen Bond Intensity (HBI) and whiteness of α-cellulose were analysis using FTIR and CIELab color system, respectively.

ISOLATION OF MICROCRYSTALLINE CELLULOSE FROM MEDANG WOOD (Neolitsea latifolia)

Abstract - Research on the effect of the use of HCl concentrations in the hydrolysis process of cellulose from medang wood (Neolitsea latifolia) on the characteristics of microcrystalline cellulose has been studied. The purpose of this study was to determine the effect of HCl concentration on the characteristics of microcrystalline cellulose. The analysis carried out included yield, pH, color, functional group characterization using FTIR and crystallinity index using XRD. The hydrolysis process was carried out at 105 °C for 15 minutes with variations in HCl concentrations of 1.5 N, 2.5 N and 3.5 N. Based on the results of the research conducted, the results showed that the use of variations in the concentration of HCl in the hydrolysis process affected the yield, color, TCI (Total Crystallinity Index) value of FTIR data and crystallinity index of XRD data. The yield of microcrystalline cellulose produced from each variation of concentration was 64.41, 61.94 and 53.99. The color of microcrystalline cellulose is getting darker as the concentration of HCl is used. Based on FTIR data, the TCl value of microcrystalline cellulose from each variation of concentration was 0.861%, 0.907% and 0.976%. XRD data shows an increase in crystallinity index produced from each variation in concentration on microcrystalline cellulose amounted to 80.52%, 82.17% and 83.49%.

Large scale manufacturing of puree-only edible films from onion bulb (Allium cepa L.): Probing production and structure–processing–property correlations

The demand for bioplastics from renewable sources for a range of emerging applications has been as extensive as the efforts to find greener routes for their isolation from nature. Surfing this wave, we report on the production of flexible, optically semi-transparent onion-only bioplastics through different all-aqueous film-forming procedures encompassing hydrothermal, grinding, washing, and/or sieving pre-solvent casting steps. The onion bioplastics were extensively characterized targeting correlations among chemical structure, film-forming protocol, and film properties. HPLC evidenced insoluble carbohydrates/polysaccharides in all samples, though at different contents (11–44%) depending on processing, but washing lixiviated all soluble carbohydrates – the presence of ca. 14% of the latter in unwashed samples provided their films with reduced glass transition temperature – from 73–83 to 13 °C, as indicated by DSC; elastic modulus and tensile strength – from 1.5–3.2 GPa to 47 MPa and from 7–21 to 3 MPa, respectively; increased elongation at break – from 0.7–1.6% to 22%; and decreased contact angle with water – from 39-70° to 22° (in comparison with washed samples). Additionally, SEM provided morphological aspects; thermogravimetry indicated thermal stability profile; FTIR led to hydrogen bond energy [kJ] and distance [Å] as well as total crystallinity index (0.43–0.96), lateral order index (0.8–3.2), and hydrogen bonding intensity (13–4.7); and XRD determined the index of crystallinity (21–49%). Finally, the hydrophilic/hydrophobic nature, water barrier, and moisture sorption of the bioplastics were determined. Altogether, we herein depict the production of novel bioplastics made up exclusively of onion and used a range of characterization techniques to come up with relevant structure-processing-property correlations.

Chemical changes within solids during liquid hot water pretreatment of wood

The chemical properties of willow were studied following liquid hot water pretreatment. Three different temperatures of liquid hot water pretreatment were used (160, 180, and 200 °C) for periods of 30, 60, 120, and 240 min. The contents of extractives, lignin, holocellulose, glucose, and xylose was determined. Compared with the original sample, the results indicated that lignin and extractives content increased after pretreatment. Further, the content of xylose decreased significantly with increasing pretreatment time for all three temperatures. The highest glucose content was obtained under the conditions of 180 °C for 240 min. In addition, a significant correlation was found between the content of xylose in the solid fraction and the severity factor of treatment. To determine the changes in cellulose crystallinity, the total crystallinity index (TCI) and the lateral order index (LOI) were calculated from the Fourier-transform infrared spectroscopy spectra of cellulose. An increase in both of these structural characteristics was observed at all experimental temperatures.

Exploring the lignolytic potential of a new laccase producing strain Kocuria sp. PBS-1 and its application in bamboo pulp bleaching

The pulp and paper industry is one of the largest polluting industries in the world employing chlorine-based bleaching processes. The hazardous impact on the environment can be mitigated by either removal of chlorine or minimizing its use by developing alternative bleaching methods. This study was undertaken to explore the applicability of a new laccase isolated from Kocuria sp. PBS-1 for bamboo pulp bleaching. The enzyme was optimally active at 50 °C and pH 7 and the Km, Vmax and Kcat were 39.45 ± 5.47 mM, 407.40 ± 4.9 μmol min−1 and 124.5 s−1 respectively. Further, the t1/2 was found to be 13 h at 30 °C. This laccase produced a significant increase in the ISO brightness to 80.03 ± 1.68% after LMPZ (Laccase, Mediator, Peroxide and Ozone) bleaching. A significant reduction in the kappa number was recorded for L, LM, LMP and LMPZ treated pulp samples. The FTIR peak at ~1118 cm−1 attributed to lignin present in spectra of the control pulp sample was not observed in spectra of the treated pulps. A new band at 1162 cm−1 in treated pulps indicated degradation of syringyl groups along with an increase in the total crystallinity index, empirical crystallinity index and apparent crystallite size of the cellulose. XRD data of treated pulp samples revealed an increase in the cellulose crystallinity index as per A1430/897 ratio. The SEM of treated pulps showed a change in morphology of pulps like the appearance of cracks, crevices, grooves and peeling of fibrils due to lignolytic activity. These findings may provide leads for the development of new cleaner and alternative methods for pulp bleaching.

Bacterial cellulose as a support for yeast immobilization – Correlation between carrier properties and process efficiency

The aim of the current study was to analyze physicochemical properties of bacterial cellulose (BC) produced by Komagataeibacter xylinus for various periods of time in stationary conditions with regard to its potential as a carrier for yeast (Saccharomyces cerevisiae and Yarrowia lipolytica) immobilization, and subsequently to correlate the relationship between these properties and the efficiency of the immobilization process. Physicochemical properties of BC, depending on the time of its biosynthesis, were as follows: surface area 7.21–11.04 m2/g, pore volume 3.11–3.96 cm3/g, pore diameter 0.011–0.109 nm, water holding capacity 32–64%, water relies capacity 10600–33400%, swelling ratio 132–389%, polymerization degree 2260–4780 and total crystallinity index 1.22–1.96 (3–30 days, respectively). The linear regression analysis showed that number of immobilized yeasts increased with values of surface area, pore size, pore diameter, swelling ratio, water release capacity and polymerization degree. The opposite trend was observed in case of water holding capacity and total crystallinity index. The analysis of physicochemical properties of BC performed in the current study have significant translational implications for understanding the relationships between BC-based carriers and the efficiency of yeast immobilization.

Sequential white-rot and brown-rot fungal pretreatment of wheat straw as a promising alternative for complementary mild treatments

White-rot and brown-rot fungi have complementary mechanisms to selectively degrade lignin and holocellullose, respectively. Thereby, a fungal co-culture of a white-rot and a brown-rot fungal could result in efficient strategy for a mild lignocellulosic biomass pretreatment. In this work, single, sequential and co-inoculation of the selective-lignin degrading white-rot fungus Ganoderma lobatum and the brown-rot fungus Gloeophyllum trabeum were evaluated as biological pretreatments of wheat straw to enhance enzymatic hydrolysis of cellulose. The single cultures of G. lobatum and G. trabeum exhibited preferential degradation of lignin and hemicellulose, respectively. The total crystallinity index decreased in samples pretreated with G. trabeum but not with G. lobatum. The pretreatment with single cultures of G. lobatum or G. trabeum increased glucose yields by 43.6% and 26.1% respectively compared to untreated straw. Although co-inoculation resulted in higher yields of glucose when compared with single cultures, only a slight synergistic effect between fungi was observed. Contrary, the sequential inoculation of G. lobatum incubated for 10 days followed by G. trabeum incubated for 10 days more showed a strong synergic effect on enzymatic hydrolysis. This sequential culture showed the highest glucose yield (191.5 mg g−1 wheat straw), 2.8-fold higher than untreated wheat straw, and 140–150% higher than the single-cultures of G. lobatum and G. trabeum, respectively.

Utilization of Saline Solutions in the Modification of Lignocellulose from Champaca Wood

Objective of this work is to study the effects of a saline solution used to pretreat lignocellulosic material derived from champak timber. The native lignocellulosic solids, in powder form, were mixed with saline water solutions of three different concentrations and maintained for 2 weeks without stirring. The treated solids were washed, recovered, and then dried under sunlight. The substrates were characterized using X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM). The crystallinity (CrI), lateral order index (LOI), total crystallinity index (TCI), and surface morphologies of all the samples were determined. The treated biomass structures were compared with controls. The data show that the structures of all the treated substrates changed, as indicated by CrI. CrI of the treated substrates decreased significantly compared with that of the original wood, as did LOI and TCI quantities, whereas the HBI parameter increased. The results indicate that the saline water pretreatment modified the wood samples.

Characterization of ionic liquid pretreated plant cell wall for improved enzymatic digestibility

An insight into the properties of cell wall of mustard stalk (MS) pretreated by five ionic liquids (ILs) revealed ILs interaction with cellulose, hemicellulose and lignin components. Differential Scanning Calorimetry (DSC) showed increased pore size coupled with increased population of pores evoked by certain ILs in better facilitating enzymatic accessibility. Interestingly, all the five ILs predominantly increased the propensity of two pore sizes formation; 19 and 198 nm, but remarkable difference in the pore volumes of pretreated MS suggested the supremacy of [OAc]− based ILs, resulting in higher glucose yields. Cellulose I to II transition in pretreated MS was supported by the reduced total crystallinity index (TCI), lateral order index (LOI) values. Strong inverse correlation existed between the said parameters and residual acetyl content with enzymatic hydrolysis (R2 > 0.8). An inverse relationship between hydrogen bond basicity, LOI and TCI suggested it to be a good indicator of IL pretreatment efficiency.

In-depth study of agave fiber structure using Fourier transform infrared spectroscopy

FTIR spectroscopy is a powerful method to analyse materials and especially fiber structure. This technique is largely used to obtain quick information on the fiber composition and to detect possible transformations after physical and chemical treatments. Unlike other techniques, FTIR is a quick method which demands a reduced amount of fibers. Furthermore, it is a non destructive method especially for Attenuated Total Reflectance (ATR), and Near Infrared (NIR) spectroscopy which are nowadays widely used.In this work, FTIR spectrum of agave fiber has been thoroughly investigated. Because of its complexity, the spectrum was separated into two regions: CH and hydrogen bond stretching (>2500cm−1) and “fingerprint” region (<2000cm−1). A detailed study of intermolecular and intramolecular chains was made.Infrared ratios (Lateral Order Index, Total Crystallinity Index, and Hydrogen Bond Intensity) were used to study the crystallinity and the degree of regularity of agave fiber.

Characterization of a New Lignocellulosic Fiber from Brazil: Imperata brasiliensis (Brazilian Satintail) as an Alternative Source for Nanocellulose Extraction

ABSTRACTThe chemical, physical and thermal properties of a new lignocellulosic fiber from Brazil (Imperata brasiliensis) were examined by SEM, chemical composition, XRD, FTIR, and TGA. Fibers were analyzed aiming to compare the properties of its new natural resource with other lignocellulosic fibers used as a source of nanocellulose extraction. Microscopy analysis demonstrated that the bundle of fibers presented a variety of size and shapes, ranging between 25 and 500 µm, while a single fiber has a diameter of 5 µm. The chemical composition showed the presence of 37.7% of cellulose, 35% of hemicellulose and 14.3% of lignin. The total crystallinity index (CI) calculated using Segal method was of 36.6%. By TGA, it was possible to identify the degradation step of each primary component of lignocellulosic fiber and to observe that the onset degradation temperature was 157°C. With the results of ATR-FTIR technique, it was possible to estimate the CI, and the results exhibited good agreement with that calculated by XRD. Finally it was possible to conclude that fibers obtained from Imperata brasiliensis are suitable to be used as a resource for nanocellulose obtainment since presents almost the same properties of other lignocellulosic fibers successfully used in literature for nanocellulose extraction.

Comparison of steam-assisted versus microwave-assisted treatments for the fractionation of sweet sorghum bagasse

The fractionation of lignocellulosic materials can be applied to get each of the components (cellulose, hemicellulose and lignin) of biomass in its maximum purity and yield. The individual component can be further processed to high-value products such as fuels and biomaterials at existing or newly developing biorefineries. The steam-assisted and microwave (MW)-assisted processes were used to fractionate sweet sorghum bagasse into hemicellulosic sugars, cellulose-rich and high-density residue and solid lignin. The treatment temperature evaluated for the fractionation process was 121 °C for 30 to 120 min. The substrate was autohydrolysed to extract the hemicellulose, and the residue was delignified using lime solution to obtain cellulose-rich residue. The lignin and lime from the liquor obtained after the lime treatment of the autohydrolysed sweet sorghum bagasse (SSB) was precipitated using carbon dioxide gas. Under optimum conditions, the steam-assisted autohydrolysis extracted 72.69 (±0.08) % by weight of the hemicelluloses while the MW-assisted autohydrolysis extracted 70.83 (±0.49) % of the hemicelluloses from the sweet sorghum bagasse. The steam-assisted lime treatment resulted in 69.67 (±1.26) % of the lignin extraction the MW-assisted lime treatment resulted in 68.27 (±1.19) % of the lignin extraction from the corresponding autohydrolysed sweet sorghum bagasse samples. The CO2 treatment precipitated 58.85 (±3.2) % of the lignin dissolved in the yellow liquor of the steam-assisted process while 60.26 (±2.11) % of the dissolved lignin was recovered from the yellow liquor of the MW-assisted process. The two methods have not exhibited significant differences in overall recovery of the solids, hemicellulose extraction, delignification, residual concentration of cellulose and ash or in the recovery of lignin and lime. The difference was significant (p value <0.05) only in the concentration of total reducing sugars in the hydrolysate and the yellow liquor. The MW-assisted process increased the total crystallinity index (TCI) of the cellulose in the treated SSB and also increased the concentration of guaiacyl lignin content in the recovered lignin which was thermally more stable than the lignin produced in the steam-assisted process.

Chemical alterations of pine wood saccharides during heat sterilisation.

Alterations in saccharides during heat sterilisation of pine wood (Pinus sylvestris L.) were investigated. The mass loss, extractives, lignin, cellulose, holocellulose and hemicelluloses were determined. Changes in saccharides were evaluated by the determination of monosaccharides in wood, size exclusion chromatography (SEC) as well as Fourier transform infrared (FTIR) spectroscopy. During heat sterilisation of pine wood the slight mass loss, an increase in extractives and a decrease in lignin and polysaccharides were observed. Hemicelluloses are degraded approximately twice as fast as cellulose. The degree of polymerisation of cellulose decreases approximately by 10% and it increases in holocellulose (by approx. 8%) as a result of a faster degradation of shorter hemicellulose chains. FTIR spectroscopy shows that sterilisation results in the deacetylation of cellulose and the formation of new carbonyl groups, an increase in the total crystallinity index (TCI) and a decrease in the lateral order index (LOI) and the hydrogen-bond intensity (HBI).