Carbohydrate composition of eucalyptus, bagasse and bamboo by a combination of methods (original) (raw)
Related papers
Holzforschung, 2000
The residual wood meal left after milled wood lignin (MWL) isolation (MWR) was extracted with the cellulose solvent lithium chloride/N,N-dimethylacetamide (LiCl/DMAc) to obtain a soluble fraction (C-L) and an insoluble fraction (C-L-residue). The C-L-residue was further extracted with the hemicellulose solvent 3 M NaOH to give a soluble fraction named hemicellulose-lignin fraction (HC-L) with 21.3% yield based on MWR. It was found that HC-L was composed of xylan, cellulose and lignin with abundant S-type β-O-4 substructures. HC-L lignin was bonded to HC-L cellulose or HC-L hemicelluloses or both. The method, which comprised acetylation for hardwood xylan (by acetic anhydride/pyridine/formamide) and extraction with chloroform, was found to be effective for selective xylan acetate fractionation. HC-L was further fractionated by the same method and subsequent deacetylation to give a xylan-lignin fraction (X-L) in 11.3% yield based on HC-L. X-L was composed mainly of xylan and lignin wi...
Holzforschung, 2013
Background: Lignin is a promising source of building blocks for upgrading to valuable aromatic chemicals and materials. Endocarp biomass represents a non-edible crop residue in an existing agricultural setting which cannot be used as animal feed nor soil amendment. With significantly higher lignin content and bulk energy density, endocarps have significant advantages to be converted into both biofuel and bioproducts as compared to other biomass resources. Deep eutectic solvent (DES) is highly effective in fractionating lignin from a variety of biomass feedstocks with high yield and purity while at lower cost comparing to certain ionic liquids. Results: In the present study, the structural and compositional features of peach and walnut endocarp cells were characterized. Compared to typical woody and herbaceous biomass, endocarp biomass exhibits significantly higher bulk density and hardness due to its high cellular density. The sugar yields of DES (1:2 choline chloride: lactic acid) pretreated peach pit (Prunus persica) and walnut shell (Juglans nigra) were determined and the impacts of DES pretreatment on the physical and chemical properties of extracted lignin were characterized. Enzymatic saccharification of DES pretreated walnut and peach endocarps gave high glucose yields (over 90%); meanwhile, compared with dilute acid and alkaline pretreatment, DES pretreatment led to significantly higher lignin removal (64.3% and 70.2% for walnut and peach endocarps, respectively). The molecular weights of the extracted lignin from DES pretreated endocarp biomass were significantly reduced. 1 H-13 C HSQC NMR results demonstrate that the native endocarp lignins were SGH type lignins with dominant G-unit (86.7% and 80.5% for walnut and peach endocarps lignins, respectively). DES pretreatment decreased the S and H-unit while led to an increase in condensed G-units, which may contribute to a higher thermal stability of the isolated lignin. Nearly all β-O-4′ and a large portion of β-5′ linkages were removed during DES pretreatment. Conclusions: The high lignin content endocarps have unique cell wall characteristics when compared to the other lignocellulosic biomass feedstocks. DES pretreatment was highly effective in fractionating high lignin content endocarps to produce both sugar and lignin streams while the DES extracted lignins underwent significant changes in SGH ratio, interunit linkages, and molecular sizes.
Carbohydrate Polymers, 2014
Two fractions of sugarcane, namely bagasse and straw (or trash), were characterized in relation to their chemical composition. Bagasse presented values of glucans, hemicelluloses, lignin and ash of 37.74, 27.23, 20.57 and 6.53%, respectively, while straw had 33.77, 27.38, 21.28 and 6.23% of these same components. Ash content was relatively high in both cane biomass fractions. Bagasse showed higher levels of contaminating oxides while straw had a higher content of alkaline and alkaline-earth oxides. A comparison between the polysaccharide chemical compositions of these lignocellulosic materials suggests that similar amounts of fermentable sugars are expected to arise from their optimal pretreatment and enzymatic hydrolysis. Details about the chemical properties of cane biomass holocellulose, hemicelluloses A and B and -cellulose are provided, and these may offer a good opportunity for designing more efficient enzyme cocktails for substrate saccharification.
Covalent lignin-carbohydrate linkages between lignin and carbohydrates have been suggested to be a major obstacle to complete delignification of biomass feedstocks during chemical processing, e.g. pulping or enzymatic hydrolysis of the biomass to release sugars for ethanol production. The current study is aimed at developing an understanding of the structural composition and the behaviour of lignin carbohydrate complexes (LCCs) in sugarcane bagasse, a potential raw material for bio-ethanol production. Hemicelluloses were pre-extracted prior to soda AQ pulping with the aim of preserving it for further use instead of losing it in the black liquor (Value Prior Pulping or VPP). LCCs from the hemicelluloses pre-extracted soda AQ pulps as well, as non-extracted materials i.e. controls, were isolated and quantified. Mainly, two types of LCCs were identified: the xylan-lignin and glucan-lignin-xylan complexes. FTIR and GPC analyses of LCC fractions confirmed that the ester bonds of LCCs wer...
Improved method of analysis of biomass sugars using high-performance liquid chromatography
Biotechnology Letters, 2000
The precise quantitative analysis of biomass derived sugars is a very important step in the conversion of biomass feedstocks to fuels and chemicals. However, the most accurate method of biomass sugar analysis is based on the gas chromatography analysis of derivatized sugars either as alditol acetates or trimethylsilanes. The derivatization method is time-consuming but the alternative HPLC method cannot resolve most sugars found in biomass hydrolysates. We have demonstrated for the first time that by careful manipulation of the HPLC mobile phase, biomass monomeric sugars (arabinose, xylose, fructose, glucose, mannose, and galactose) can be analyzed quantitatively and there is excellent baseline resolution of all the sugars. This was demonstrated for both standard sugars and corn stover hydrolysates. Our method can also be used to analyze dimmeric sugars (cellobiose and sucrose).
Industrial Crops and Products, 2009
Acid hydrolysis Enzymatic hydrolysis GC-FID GC-MS HPAEC-PAD HPAEC-Borate a b s t r a c t Acid hydrolysis, acid methanolysis, and enzymatic hydrolysis were compared for depolymerization of five different plant materials containing uronic acids. The analyzed plant materials were oat spelt, wheat straw, spruce thermomechanical pulp, aspen stemwood, and totally chlorine-free (TCF) bleached hardwood kraft pulp. Furthermore, GC (using both HP-1 and HP-5 capillary columns and FID and MSD detectors), HPAEC-PAD, and HPAEC-Borate techniques were compared for subsequent analysis of the released monosaccharides.
METHODS FOR DETERMINATION OF CHEMICAL COMPOSITION OF PLANT BIOMASS
Improved methods for the quantitative analysis of polysaccharides and lignin in biomass samples were developed by Designer Energy Ltd (DE). The DE method for determination of polysaccharides in biomass samples is based on the isolation of holocellulose, i.e. total polysaccharides containing both cellulose and hemicelluloses. After acid hydrolysis of holocellulose under mild conditions hemicelluloses were removed, and as a result the content of cellulose can be determined. The content of acid-insoluble lignin was measured by improved method after two-stage acidic hydrolysis of the biomass. In order to prevent loss of the components, a centrifugation technique was used for isolation of final products. The developed methods were used for analysis of chemical composition of crude and pretreated samples of switchgrass and sugarcane bagasse. It has been shown that DE methods provide more reliable results than conventional methods of chemical analysis.
The impact of hydrothermal, dilute acid, and alkaline pretreatments on the chemical structure of euca-lyptus, sugarcane bagasse, and straw were compared with a view to their subsequent bioconversion into ethanol. Sugarcane bagasse and straw contain high amounts of extractives (15.0% and 12.2%, respectively), ash (2.3% and 7.9%, respectively), and silica (1.4% and 5.8%, respectively). If not properly corrected, the presence of silica would lead to the overestimation of the lignin, while high amounts of extractives would cause the overestimation of the content of sugars in biomass. Applying a novel approach through the use of complete mass balance, bagasse and straw were proven to contain lower amounts of lignin (18.0 % and 13.9%, respectively) than previously reported for these raw materials, and certainly a much lower amount of lignin than eucalyptus (27.4%). The syringyl to guaiacyl units ratio (S/G) for lignin in bagasse and straw (1.1 and 0.5, respectively) was lower than that for eucalyptus (2.7), indicating a different reactivity during chemical pretreatments. The xylan content in sugarcane bagasse and straw was much higher than that in eucalyptus, with a significantly lower degree of substitution for uronic acids and acetyl groups. The sugarcane straw showed the highest mass loss during the investigated pretreatments, especially under alkaline conditions, with a total biomass yield of only 37.3%. During the hydrothermal and dilute acid treatments, mostly hemicelluloses were removed, followed by the formation a significant amount of pseudo-lignin structures, while the alkaline pretreatment affected the lignin content. With eucalyptus, the formation of structures similar in their behavior to extractives (i.e., soluble in toluene and ethanol, subsequently referred to as " pseudo-extractives ") was observed during all three pretreatments, with 12.4% for hydrothermal, 18.9% for dilute acid, and 8.7% for alkaline pretreatment. This information, combined with actual yields, should be taken into account when assessing the impact of pretreatments on the chemical composition and structure of biomass.
Talanta, 2011
We adapted and optimized a method to quantify the cellulose, hemicellulose, xylan, arabinan, mannan, galactan contents in lignocellulosic biomass. This method is based on a neutral detergent extraction (NDE) of the interfering biomass components, followed by a sulfuric acid hydrolysis (SAH) of the structural polysaccharides, and a liquid chromatography with charged aerosol detection (LC-CAD) to analyze the released monosaccharides. The first step of this NDE-SAH-LC-CAD method aims at removing all compounds that interfere with the subsequent sulphuric acid hydrolysis or with the subsequent chromatographic quantification of the cellulosic and hemicellulosic monosaccharides. This step includes starch hydrolysis with an analytical thermostable α-amylase followed by an extraction of soluble compounds by a Van Soest neutral detergent solution (NDE). The aim of this paper was to assess the precision of this method when choosing fiber sorghum (Sorghum bicolor (L.) Moench), tall fescue (Fest...