Characterization of pulp carbohydrates by enzymatic hydrolysis and determination of pulping yield with carbohydrate profile (original) (raw)
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CARBOHYDRATE ANALYSIS OF PULPS USING ENZYMATIC HYDROLYSIS AND HIGH PRESSURE LIQUID CHROMATO- GRAPHY
2000
A revised method for analysis of carbohydrates in pulps is presented. The method utilizes commercially available enzyme preparations for enzymatic hydroly- sis of the pulp, followed by acid hydrolysis for com- plete cleavage of oligomers that are still present. Quantification of monosaccharides in the hydrolysate was performed by HPLC using a Pb-sulphonate/poly- mer column and deionized water as the mobile
2019
The results of enzymatic hydrolysis of birch and beech kraft cellulosic pulps indicate that they may be promising feedstocks for fermentation processes including biofuel manufacturing. The aim of this study was to investigate whether birch and beech wood require the same degree of delignification by kraft pulping as pine wood. The differences observed in the efficiency of hydrolysis for the raw materials tested suggest that the differences in the anatomical structure of the examined wood in relation to pine wood is essential for the efficiency of the enzymatic hydrolysis process. The yields of glucose and other reducing sugars obtained from the birch and beech cellulosic pulps were similar (up to around 75% and 98.3% dry weight, and 76% and 98.6% dry weight, respectively). The highest glucose yields from cellulose contained in the birch and beech pulp were around 81.2% (at a Kappa number of 28.3) and 83.1% (at a Kappa number of 30.4), respectively. The maximum glucose yields and tot...
Energies, 2019
The results of enzymatic hydrolysis of birch and beech kraft cellulosic pulps indicate that they may be promising feedstocks for fermentation processes including biofuel manufacturing. The aim of this study was to investigate whether birch and beech wood require the same degree of delignification by kraft pulping as pine wood. The differences observed in the efficiency of hydrolysis for the raw materials tested suggest that the differences in the anatomical structure of the examined wood in relation to pine wood is essential for the efficiency of the enzymatic hydrolysis process. The yields of glucose and other reducing sugars obtained from the birch and beech cellulosic pulps were similar (up to around 75% and 98.3% dry weight, and 76% and 98.6% dry weight, respectively). The highest glucose yields from cellulose contained in the birch and beech pulp were around 81.2% (at a Kappa number of 28.3) and 83.1% (at a Kappa number of 30.4), respectively. The maximum glucose yields and total reducing sugars of birch wood on a dry weight basis (39.8% and 52.1%, respectively) were derived from the pulp at a Kappa number of 28.3, while the highest yields of glucose and total reducing sugars of beech wood on a dry weight basis (around 36.9% and 48.2%, respectively) were reached from the pulp at a Kappa number of 25.3. To obtain the highest glucose yields and total reducing sugars of a wood on a dry weight basis, total lignin elimination from the birch and beech pulps was not necessary. However more in-depth delignification of birch and beech wood is required than for pine wood.
THE RELATION BETWEEN CARBOHYDRATE COMPOSITION AND SOFTWOOD KRAFT PULP YIELD
2000
A large number of kraft pulps has been manufactured with or without additives like anthraquinone, polysulfide or H2S impregnation. Carbohydrate analysis of the pulps showed that the main mechanism for yield increase by additives is increased retention of glucomannan. On the other hand, the retention of cellulose was somewhat affected by the use of anthraquinone and higher kappa number. Xylan
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 were degraded through hemicelluloses pre-extraction, leading to a significant change in their structure. This in turn resulted in more cellulose being more accessible to pulping and enzymatic hydrolysis respectively. The study showed that alkaline pre-extracted biomass materials have a more amenable structure to processing, as a result of the disruption of the unreactive LCCs in the residual lignin. Further, alkaline hemicelluloses pre-extraction in combination with soda AQ holds more promise for VPP due to reduced LCCs. This could have a positive impact in downstream processes such as bleaching.
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...
Journal of the Chilean Chemical Society, 2015
Eucalyptus globulus wood chips were subjected to autohydrolysis pretreatment at 175ºC at three different residence times. Part of the recovered solids were submitted to alkaline extraction with NaOH solution to remove leachable lignin. The chemical composition of the fibrous material was analyzed by HPLC, Py-GCMS and 2D-NMR HSQC, while morphological changes were evaluated by SEM and LSCM. The pretreated materials were hydrolyzed with cellulases at a substrate loading of 10% (w/v) for up to 72 h. Glucose yields (based on dry wood) obtained in the enzymatic hydrolysis ranged between 38% and 65%, depending on reaction time in the autohydrolysis pretreatment. After the alkaline extraction, no significant change was observed in the yields in the enzymatic hydrolysis at 72 h, but at the lower severities, the initial rates of saccharification increased. The main effect of the hydrothermal pretreatment was removal of hemicelluloses, resulting in enriched cellulose pulps. SEM and LSCM images of the hydrothermal pretreated samples showed a disruption of the fiber surface, mainly in those samples obtained at the higher severity. Py-GC/MS and HSQC analysis showed that no major changes in the lignin structure occurred in the samples obtained by autohydrolysis and further alkaline extraction. By autohydrolysis at the higher severity (So=4.02), the lateral chains in lignin were cleaved and the formation of lignin droplets was observed. Hemicelluloses removal and lignin redeposition as droplets in certain regions of the fiber surface was associated with the higher accessibility of cellulose and the yield increase of the enzymatic hydrolysis.
Cellulose, 2013
Three different commercial b-1,4-endoxylanase preparations were used to hydrolyze bleached kraft pulp. Xylo-oligosaccharides in the produced filtrates were separated and quantified using both high performance liquid chromatography (HPLC) and capillary electrophoresis (CE). All the determinations were performed without sample derivatization. The analytical methods were used to highlight the differences between the enzymes behaviour in terms of hydrolysates, but also to estimate the productivity of xylo-oligosaccharides from kraft pulp when the bleached material would be used in biorefining industry. The research showed that the glycosyl hydrolase family 10 enzyme produced by Aspergillus oryzae released xylobiose and xylotriose from the pulp material. The major oligosaccharides released by the family 11 enzyme produced by Bacillus sp. were xylotriose, xylobiose and xylotetraose. On the contrary, another family 11 enzyme produced by A. oryzae produced also xylose. The HPLC results agreed well with the xylose concentrations obtained after acid hydrolysis. The CE data showed the same trend, but much lower concentrations were identified than with HPLC. At the same time the HPLC method was able to separate only small oligosaccharides, whereas CE could be used for separation of all the xylo-oligosaccharides from xylobiose to xylohexaose. The highest xylo-oligosaccharide yield was achieved with Shearzyme at pH 5 corresponding to 22 % of total xylan from bleached birch kraft pulp. Keywords Bleached kraft pulp Á Enzymatic hydrolysis Á Oligosaccharides Á Xylan Á Xylanases
Analytical and Bioanalytical Chemistry, 2013
Carbohydrate analysis is an important source of the information required for understanding and control of pulp and paper processes. The behavior of cellulose and hemicelluloses in the process, carbohydrate-lignin interactions, and the enzymatic treatment of fibers are examples of situations for which reliable, fast, qualitative, and quantitative methods are required. New uses of lignocellulosic material have further increased the need for carbohydrate analysis. This review collates and summarizes the most important findings and approaches in the analysis of wood-based carbohydrates by use of capillary zone electrophoresis and provides an analysis of the effect of different conditions on the separation, showing the advantages and limitations of the methods used. It provides guidelines for achieving higher quality and improved separation efficiency in carbohydrate analysis. Keywords Capillary zone electrophoresis. Carbohydrates. Hydrolysis. Derivatization Abbreviations 4-ABN 4-Aminobenzonitrile ABEE Aminobenzoic acid ethyl ester BGE Background electrolyte CE Capillary electrophoresis CTAB Cetyltrimethylammonium bromide CZE Capillary zone electrophoresis DP Degree of polymerization EOF Electroosmotic flow GC Gas chromatography HDB Hexadimethrine bromide HPLC High-performance liquid chromatography i.d.