| 1. |
- Alriksson, Björn, et al.
(author)
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Fish feed from wood
- 2014
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In: Cellulose Chemistry and Technology. - 0576-9787. ; 48, s. 843-848
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Journal article (peer-reviewed)abstract
- Increased demand of fish in combination with overexploitation of the fish stocks of the oceans has led to an increased production of fish through aquaculture. Today, fishmeal is the main protein source in fish feed for most aquaculture species. However, fishmeal is soon expected to fall short of demand as its production is associated with environmental problems. This shortage must therefore be met by sustainable alternative protein sources. Protein-rich microorganisms (i.e. Single cell protein) is an interesting option as a fishmeal substitute in fish feed which, in addition, can be produced as an important co-product in wood-based biorefineries. In the current study, four different microorganisms were cultivated on five different residual streams from Swedish wood-based biorefineries. Screening experiments were carried out in shake flasks, optimization experiments in benchtop bioreactors, and scale-up experiments were performed in a 50-litre pilot bioreactor. In addition, a demo-scale experiment was carried out in the Swedish Biorefinery Demo Plant. Microbial biomass from the scale-up experiments was collected and used for production of different fish feed formulations which, in turn, were used in feeding trials of the freshwater fish Tilapia. Fishes fed with feed, in which part of the fishmeal had been substituted with Single cell protein, showed similar or better growth than fishes fed with a fishmeal-based control feed.
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| 2. |
- Belkheiri, Tallal, 1985, et al.
(author)
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Kraft Lignin Depolymerization in Near-Critical Water: Effect of Changing Co-Solvent
- 2014
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In: Cellulose Chemistry and Technology. - 0576-9787. ; 48:9-10, s. 813-818
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Journal article (peer-reviewed)abstract
- As part of developing a process to valorize lignin in a pulp mill with lignin separation, the depolymerisation of lignin to valuable chemicals was investigated in near-critical water. This was done by using methanol as co-solvent and hydrogen donor, phenol to suppress repolymerization (e.g. formation of char), and ZrO2 as a heterogeneous catalyst, with potassium carbonate as a co-catalyst. The reaction was carried out in a continuous flow fixed-bed reactor (500 cm(3)), at 280-350 degrees C and 25MPa. An important aspect is to suppress char formation. Therefore, the char formation was studied by using different concentrations of methanol and phenol. The char yield varied between 14% and 26%. When using methanol as the only co-solvent, the char yield decreased with increasing methanol concentration. Adding phenol resulted in a further decrease. The reactor outlet consisted mainly of two liquid phases, an aqueous and an oil phase, mixed together. The chemical analysis of the aqueous phase showed the presence of mainly phenolic compounds, for instance guaiacol, catechol, phenol and cresol.
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| 3. |
- Bi, Ran, et al.
(author)
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Isolation and identification of microorganisms from soil able to ive on lignin as carbon source and produce enzymes that cleave beta-O-4mbond in lignin
- 2011
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In: Cellulose Chemistry and Technology. - 0576-9787.
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Journal article (peer-reviewed)abstract
- Twenty one strains of micro organism from Scandinavian soil had been isolated that could utilize lignin as only carbon source and 11 strains of them were identified. Different types of technical lignins were used.5 faster growing strains were cultivated in shaking flask cultures with ligninosulfonate as sole carbon source,and lignin appeared to be consumed after several days while mycelia was observed accumulated.Cell free filtrates of the 5 faster growing strains could lower the apparent molecular weights of lignosulphonates and the culture filtrate of one strain could cleave the lignin model compound with.The significances of the results are discussed.
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| 4. |
- Bi, Ran, et al.
(author)
-
Isolation and identification of microorganisms from soil able to live on lignin as a carbon source and to produce enzymes which cleave beta-O-4 bond in a lignin model compound
- 2012
-
In: Cellulose Chemistry and Technology. - 0576-9787. ; 46:3-4, s. 227-242
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Journal article (peer-reviewed)abstract
- Several strains of fungi were isolated and identified from Scandinavian soil using agar plates with lignin as a carbon source. The strains grew significantly faster on this medium than on control plates without lignin. Different types of technical lignins were used, some of which contained trace amounts of sugars, even if the increased growth rate seemed not related to the sugar content. Some strains were cultivated in shaking flask cultures with lignin as a carbon source, with lignin apparently consumed by microbes - while accumulation of the microorganism biomass occurred. The cell-free filtrates of these cultures could reduce the apparent molecular weights of lignosulphonates, while the culture filtrate of one strain could cleave the beta-O-4 bond in a lignin model compound.
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| 5. |
- Bi, Ran, 1985-, et al.
(author)
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Isolation and identification of microorganisms from soil able to live on lignin as acarbon source and to produce enzymes which cleave the β-o-4 bond in a lignin model compound
- 2012
-
In: Cellulose Chemistry and Technology. - : UBC. - 0576-9787. ; 46:3-4, s. 227-242
-
Journal article (peer-reviewed)abstract
- Several strains of fungi were isolated and identified from Scandinavian soil using agar plates with lignin as a carbon source. The strains grew significantly faster on this medium than on control plates without lignin. Different types of technical lignins were used, some of which contained trace amounts of sugars, even if the increased growth rate seemed not related to the sugar content. Some strains were cultivated in shaking flask cultures with lignin as a carbon source, with lignin apparently consumed by microbes - while accumulation of the microorganism biomass occurred. The cell-free filtrates of these cultures could reduce the apparent molecular weights of lignosulphonates, while the culture filtrate of one strain could cleave the beta-O-4 bond in a lignin model compound.
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| 6. |
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| 7. |
- Bi, Ran, et al.
(author)
-
Isolation of exceedingly low oxygen consuming fungal strains able to utilize lignin as carbon source
- 2016
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In: Cellulose Chemistry and Technology. - 0576-9787. ; 50:7-8, s. 811-817
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Journal article (peer-reviewed)abstract
- Lignin biodegradation is normally related to aerobic microorganisms, and it is often claimed that microbes do not metabolize lignin as a carbon source. In this work, several fungal strains were isolated from the sediment of a small stream located in a forest and tested on agar plates with lignin as the only carbon source. All identified strains were Ascomycetes, Penicillium spinulosum, Pseudeurotium bakeri and Galactomyces geotrichum. When cultivated in shaking flasks with lignosulphonate as a carbon source, the lignin was consumed, and cell free culture filtrates appeared to depolymerize lignosulphonate to some extent. It is suggested that the strains detected are part of a symbiotic community and live in a microbiological niche in which they are able to utilize lignin residues left from brown rot and humus having extremely low oxygen content.
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| 8. |
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| 9. |
- Damlin, Pia, et al.
(author)
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Characterization of Hardwood-Derived Carboxymethylcellulose by High pH Anion Chromatography Using Pulsed Amperometric Detection
- 2010
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In: Cellulose Chemistry and Technology. - 0576-9787. ; 44:1-3, s. 65-69
-
Journal article (peer-reviewed)abstract
- An approach for the quantitative analysis of substituent distribution in carboxymethylcellulose (CMC) is presented. In short, the high-pH anion-exchange chromatography method, coupled to pulsed amperometric detection (PAD), is introduced. Each of the seven derivatives in CMC is presented by a single peak on the PAD trace, thus enabling an easy quantification. New inside information on monomer composition is obtained by this novel method, which is essential for understanding the structure versus property relationships in the CMC samples.
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| 10. |
- Danielsson, Sverker
(author)
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Sorption and desorption of black liquor xylan onto cellulose fibers
- 2014
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In: Cellulose Chemistry and Technology. - 0576-9787. ; 48:9-10, s. 819-823
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Journal article (peer-reviewed)abstract
- The potential of xylan as a polymer in different new materials is large and not yet utilized. The availability in kraft pulp mills is large as the polymeric xylan dissolved in process liquors corresponds to up to 160 kg/adt and is today burnt to recover energy. A pre-requisite for using black liquor xylan in high-value products is to purify it from inorganic material and lignin in a technically effective and economical feasible way. This study combines two known properties of xylan: its affinity to cellulose and its solubility in alkali. The aim is to design an efficient separation process to produce black liquor xylan of high purity. A very pure xylan was reached with as low lignin contents as 1%. The hydroxide ion concentration was varied in the sorption step and it was found that an increase in hydroxide ion concentration resulted in a decreased amount of isolated xylan, decreased degree of substitution of uronic acids, but no effect on the lignin content and ash content was seen.
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| 11. |
- Dehnavi, Gholamali Z., et al.
(author)
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Fractionation of the main components of barley spent grains from a microbrewery
- 2011
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In: Cellulose Chemistry and Technology. - 0576-9787. ; 45:5-6, s. 339-345
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Journal article (peer-reviewed)abstract
- The chemical composition of barley spent grains generated in a microbrewery and their fractionation by acid hydrolysis and delignification were investigated. The material contained high amount of carbohydrates (60%), while its lignin content was lower than that reported for other sorts of barley spent grains. Different dilute-acid hydrolysis methods were evaluated for separating the main components of the spent grains, without affecting the sugars generated by starch hydrolysis. The utilization of a two-step dilute-acid hydrolysis approach allowed to hydrolyse starch in a first step, at 100 ºC, and hemicelluloses in a second step, at 121 ºC. Acetosolv and alkaline delignification were used for solubilising the lignin fraction. A higher lignin solubilisation (95% of the lignin contained in the raw material) was achieved after alkaline delignification, whereas only 34% of the initial lignin was removed by direct acetosolv. When the acetosolv treatment was combined with acid hydrolysis, lignin solubilisation increased to 74%. Lignin was precipitated from the liquors at recovery rates from 40 to 93%, as depending on the hydrolysis/delignification method used.
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| 12. |
- Deshpande, Raghe, et al.
(author)
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Initial phase of sodium bisulphite pulping of spruce. Part I
- 2016
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In: Cellulose Chemistry and Technology. - : Editura Academiei Romane. - 0576-9787. ; 50:2, s. 293-300
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Journal article (peer-reviewed)abstract
- A sodium bisulphite cooking study has been performed on spruce chips with the aim of monitoring the impregnation and the initial phase of such a cook performed at pH 4.5. Both pulp and liquor analyses have been carried out and the experiments have been done with a laboratory-prepared cooking acid, in comparison with a mill cooking acid. The pulping experiments have been performed down to a total pulp yield of 60%. The objective was to verify and extend the current knowledge of bisulphite pulping with a focus on the initial phase of the cook. With the help of a kinetic model that has been developed in the project, the pulp composition during the cook with respect to cellulose, lignin, glucomannan and xylan can now be predicted. The side reactions with respect to thiosulphate formation were also analyzed in this study.
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| 13. |
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| 14. |
- Ek, Monica, et al.
(author)
-
WOBAMA : wood based materials and fuels
- 2014
-
In: Cellulose Chemistry and Technology. - 0576-9787. ; 48:9-10, s. 773-779
-
Journal article (peer-reviewed)abstract
- WOBAMA - Wood Based Materials and Fuels is a biorefinery oriented scientific research project supported by Wood Wisdom-Net Research Programme and ERA-NET Bioenergy. In this project, the wood based raw materials were converted to a range of value added products through unconventional techniques. So far, many demonstrators have been prepared, such as the dissolving pulps with high cellulose content, the regenerated cellulose films with high tenacity, the hydrophobic materials based on cellulose and birch bark suberin, as well as the adhesives based on polysaccharides.
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| 15. |
- Ekblad, C., et al.
(author)
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Enzymatic-mechanical pulping of bast fibers from flax and hemp
- 2005
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In: Cellulose Chemistry and Technology. - 0576-9787. ; 39:02-jan, s. 95-103
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Journal article (peer-reviewed)abstract
- A technique for pulping of bast fibers of flax (Linum usitatissimum) and hemp (Cannabis sativa), based on treatment with cellulolytic and pectinolytic enzymes has been developed. Initially the bast fibers were mechanically separated from shieves and subjected to washing with diluted acid, followed by enzyme treatment, an alkaline hydrogen peroxide bleaching step that also inactivated the enzymes, and finally beating in a laboratory beater. Brightness, dewatering and strength of handsheets were comparable with the traditionally-made pulps. Fibers not treated with enzymes could not be beaten. The main pulping effect is related to cellulases, but the presence of pectinases influenced both brightness and strength properties.
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| 16. |
- Fiskari, Juha, 1967-, et al.
(author)
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Quick non-destructive analysis of condensed lignin by ftir. part 2. pulp samples from acid sulfite cooking
- 2021
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In: Cellulose Chemistry and Technology. - 0576-9787. ; 55:3-4, s. 263-270
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Journal article (peer-reviewed)abstract
- In our previous work, we demonstrated how lignin condensation and precipitation taking place in kraft pulping can be detected and even quantified by Fourier Transform Infrared (FTIR) spectroscopy. Because lignin reactions in acid sulfite pulping are very different from those occurring during kraft cooking, a new analysis method is proposed to rapidly analyze the condensed lignin in acid sulfite pulp. This kind of analysis is useful for sulfite pulp mills to detect the elevated risk of black cook. This paper presents and discusses the novel method using FTIR spectroscopy to rapidly analyze lignin condensation in softwood pulp samples from acid sulfite processes. Several softwood pulp samples from acid sulfite pulping at varying levels of condensation were included in this research. According to the results, FTIR spectroscopy allows indirect quantification of lignin condensation in a difficult matrix of wood constituents, such as in incompletely delignified acid sulfite pulp.
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| 17. |
- Forsberg, Diana Carolina Reyes, et al.
(author)
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On the importance of variation of alkalisation conditions on cellulose ether synthesis
- 2022
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In: Cellulose Chemistry and Technology. - : Publishing House of the Romanian Academy. - 0576-9787. ; 56:3-4, s. 227-238
-
Journal article (peer-reviewed)abstract
- With a multivariate approach, we investigate and correlate the effect of mercerization conditions on the properties of a cellulose ether. We have chosen to work with carboxymethylcellulose (CMC) for analytical reasons. As expected, the DS was found to increase when the NaOH/AGU (anhydroglucose unit) stoichiometric ratio (r) was increased (range 1.0–1.3) and [NaOH] was decreased (range 50-30%). However, such changes also favoured the formation of unwanted side products. Decreased (r) and increased [NaOH] resulted in increased heterogeneity, and thus the quantities of insoluble particles and unreacted chemicals also increased. As another result, the prediction between mercerisation and synthesis weakens. Consequently, a DS of 0.18–0.7 was obtained; the measured solubility was much lower than expected. A non-statistical distribution of substituents was further found. Interestingly, the relative importance of substitution at increases with an increased [NaOH].
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| 18. |
- Garcia, Ariel, et al.
(author)
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Chemical and physical characterization and acid hydrolysis of a mixture of Jatropha curcas shells and husks
- 2015
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In: Cellulose Chemistry and Technology. - : Editura Academiei Romane,Publishing House of the Romanian Academy. - 0576-9787. ; 49:9-10, s. 737-744
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Journal article (peer-reviewed)abstract
- Jatropha curcas L. is a tropical plant with considerable potential for producing biodiesel and other products of high economic and social interest. During the biodiesel production process from J. curcas different residues, such as shells and husks are generated. In this work, the physical characterization of J. curcas fruits was performed, and the chemical composition of a mixture of shells and husks was determined. The physical characterization revealed that shells and husks account, respectively, for 25.0 and 27.8% of the fruit weight. The compositional analyses of the material showed a rather high content of glucans (32.8% w/w) and xylans (16.4% w/w), which indicates the potential of J. curcas shells and husks for production of ethanol, xylitol and other glucose- and xylose-derived products. Acid hydrolysis was applied to a mixture of shells and husks under different sulphuric acid concentrations (from 0.5 to 4.5%), temperatures (170 – 220ºC) and time (10 – 20 min), and the hydrolytic conversion of xylan was evaluated. A zone of experimental conditions giving maximal xylan conversion was identified at around 4% H2SO4, 180ºC and reaction time below 10 min.
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| 19. |
- Garcia, Ariel, et al.
(author)
-
Chemical and physical characterization and acid hydrolysis of a mixture of Jatropha Curcas shells and husks
- 2015
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In: Cellulose Chemistry and Technology. - 0576-9787. ; 49:9-10, s. 737-744
-
Journal article (peer-reviewed)abstract
- Jatropha curcas L. is a tropical plant with considerable potential for producing biodiesel and other products of high economic and social interest. During the biodiesel production process from J. curcas different residues, such as shells and husks are generated. In this work, the physical characterization of J. curcas fruits was performed, and the chemical composition of a mixture of shells and husks was determined. The physical characterization revealed that shells and husks account, respectively, for 25.0 and 27.8% of the fruit weight. The compositional analyses of the material showed a quite high content of glucans (32.8% w/w) and xylans (16.4% w/w), which indicates the potential of J. curcas shells and husks for production of ethanol, xylitol and other glucose- and xylose-derived products. Acid hydrolysis was applied to a mixture of shells and husks under different sulphuric acid concentrations (from 0.5 to 4.5%), temperatures (170-220 degrees C) and time (10-20 min), and the hydrolytic conversion of xylan was evaluated. A zone of experimental conditions giving maximal xylan conversion was identified at around 4% H2SO4, 180 degrees C and reaction time below 10 min.
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| 20. |
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| 21. |
- Gulbrandsen, Torea A., et al.
(author)
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Extracting hemicelluloses from softwood and bagasse as oligosaccharides using pure water and microwave heating
- 2015
-
In: Cellulose Chemistry and Technology. - : Editura Academiei Romane. - 0576-9787. ; 49:2, s. 117-126
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Journal article (peer-reviewed)abstract
- The objective of the study was to identify conditions for hemicelluloses extraction in oligomeric form. Using microwave assisted hot water extraction (HWE), the effects of both retention time and temperature on hemicelluloses yields, as well as the degree of polymerization (DP) as analyzed by SEC-MALLS, were investigated using both softwood (sawmill shavings) and sugarcane bagasse. The results are discussed in the light of the unavoidable yield-DP compromise resulting from the application of batch mode operations. Nevertheless, significant differences between the two raw materials could be observed, as expected. For softwood shavings, data interpolation indicated that about 50% of the hemicelluloses could be obtained as oligomers at an average DP of 30 when extracted at 183 °C for 5 minutes. For bagasse, longer extraction times seemed optimal. After hot water extraction at 183 °C for 12 minutes, about 62% of the bagasse hemicelluloses were extracted as oligomers at an average DP of about 100.
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| 22. |
- Gustavsson, Catrin, et al.
(author)
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On the nature of residual lignin
- 2004
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In: Cellulose chem. techmol.. - 0576-9787. ; 35, s. 321-331
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Journal article (peer-reviewed)abstract
- In a recent study, the results of oxygen delignification trials on kraft, prehydrolysis kraft and magnesium sulphite pulps were compared, thus providing the basis for a theory on the nature of the lignin residual lignin remaining in pulp after cooking, and particularly after oxygen delignification, the so-called residual lignin. It is suggested that, at least after oxygen delignification, the residual lignin effectively consists of LCC-bound monolignins, a theory relating to the efficiency of oxygen delignification and bleaching, and indicating possible strategies for improving the efficiency of such processes. An efficient means of breaking the LCC bonds would lead to a more efficient bleaching, known as requiring either a complete oxidation of the LCC-bound monolignins or a peeling off the carbohydrate binding to the LCC. In any case, a mere breaking of one unsaturated bond in an aromatic ring is not sufficient to achieve depolymerisation of the residual lignin or an efficient kappa reduction.
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| 23. |
- Harmini, Sri, et al.
(author)
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Fungal Pretreatment of Oil Palm Empty Fruit Bunch : Effect of Manganese and Nitrogen
- 2013
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In: Cellulose Chemistry and Technology. - : Editura Academiei Romane. - 0576-9787. ; 47:9-10, s. 751-757
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Journal article (peer-reviewed)abstract
- Oil palm empty fruit bunch (OPEFB) was biologically pretreated using Pleurotus floridanus LIPIMC996 supplemented with various concentrations of manganese and nitrogen and incubated for 35 days at 30°C, and enzyme activities of manganese peroxidase (MnP) and laccase were examined. When OPEFB was supplemented with manganese, the highest lignin reduction was achieved up to 25.0±5.6% at the addition of 200 μg Mn2+/g OPEFB.In addition, Pleurotus floridanus LIPIMC996 grew best on OPEFB supplemented with 800 μg Mn2+/g OPEFB. When OPEFB was supplemented with nitrogen, the highest lignin reduction was achieved up to 27.2± 3.5% at the addition of 20 mM nitrogen. The best growth of Pleurotus floridanus was also achieved with the addition of 20 mM nitrogen. The addition of nitrogen and manganese on OPEFB did not significantly affect the activity of MnP and laccase.
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| 24. |
- Harmini, S, et al.
(author)
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Fungal Pretreatment of Oil Palm Empty Fruit Bunch: Effect of Manganese and Nitrogen
- 2013
-
In: Cellulose Chemistry and Technology. - 0576-9787. ; 47:9-10, s. 751-757
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Journal article (peer-reviewed)abstract
- Oil palm empty fruit bunch (OPEFB) was biologicallypretreated usingPleurotus floridanusLIPIMC996 supplementedwith various concentrations of manganese and nitrogen and incubated for 35 days at 30°C, and enzyme activities ofmanganese peroxidase (MnP) and laccase were examined. When OPEFB was supplemented with manganese, thehighest lignin reduction was achieved up to 25.0±5.6% at the addition of 200 μg Mn2+/g OPEFB.In addition,PleurotusfloridanusLIPIMC996 grew best on OPEFB supplemented with 800μg Mn2+/g OPEFB. When OPEFB wassupplemented with nitrogen, the highest lignin reduction was achieved up to 27.2± 3.5% at the additionof 20 mMnitrogen. The best growth ofPleurotus floridanuswas also achieved with the addition of 20 mM nitrogen. The additionof nitrogen and manganese on OPEFB did not significantly affect the activity of MnP and laccase.
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| 25. |
- Henriksson, Gunnar, et al.
(author)
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Migrating electron holes in lignin during wood biosynthesis and biodegradation - A hypothesis
- 2005
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In: Cellulose Chemistry and Technology. - 0576-9787. ; 39:04-mar, s. 189-200
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Journal article (peer-reviewed)abstract
- An unsolved question in biodegradation is how ligninases can oxidize the lignin structures that are located so deep inside the compact woody cell walls, that they are inaccessible for the enzyme, due to sterical restrictions. One explanation may be that ligninases generate small diffusible agents, redox mediators, that in turn perform lignin oxidation. Parts of the cell wall structure may nevertheless be too compact even for these, and some enzymes seem to interact directly with the lignin. The present paper discusses the hypothesis that the enzymatically generated aromatic radicals in lignin can oxidize other aromatic structures within the polymer. A chain-reaction may be therefore created, that allows the electron-holes to migrate, probably facilitated by some flexibility of the lignin. Thus, the eventual depolymerization of lignin may possibly occur far apart from the initial oxidation site. The migrating electron hole theory might be also applied on lignin biosynthesis.
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| 26. |
- Hyvärinen, Sari, et al.
(author)
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Ionic liquid fractionation of woody biomass for fermentable monosaccharides
- 2011
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In: Cellulose Chemistry and Technology. - : Cellulose Chemistry and Technology. - 0576-9787. ; 45:7-8, s. 483-486
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Journal article (peer-reviewed)abstract
- The goal of the present study, devoted to wood fractionation, was to obtain monosaccharides, hexoses and pentoses by means of an ionic liquid (IL) based pre-treatment procedure. Softwood sawdust (maximum particle size of 2 mm) of Scots pine (Pinus sylvestris) and Norway spruce (Picea abies) were exposed to ionic liquids – 1-ethyl-3-methylimidazolium acetate (C2mimAce) and 1-ethyl-3-methylimidazolium chloride (C2mimCl) – and thermal treatment (80-150 °C), for various time intervals (0-72 h). Furthermore, cellulose of various origins (plants, wood pulps) was dissolved in C2mimAce and 1-butyl-3-methylimidazolium chloride (C4 mimCl) for the study of the dissolved fractions, stress being laid on monosaccharides and possible by-products, 5-hydroxymethylfurfural and furfural. Knowing the challenges in analysis techniques when ILs and sugars are involved, the present work focuses on the development of suitable analysis methods. To this end, a Hewlett Packard 1100 series HPLC equipped with a refractive index (RI), detector model HP1047 A and a diode array UV detector (DAD) fitted with a carbohydrate column HPX-87K was utilized. Challenges and improvements are discussed.
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| 27. |
- Hyvärinen, S, et al.
(author)
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Towards ionic liquid fractionation of lignocellulosics for fermentable sugars
- 2010
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In: Cellulose Chemistry and Technology. - 0576-9787. ; 44:4-6, s. 187-195
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Journal article (peer-reviewed)abstract
- The present study investigates wood fractionation through ionic liquid (IL) mediated pretreatment, for obtaining simple fermentable sugars, namely oligo- and monosaccharides, and in particular hexoses (andpentoses). The study focuses on softwood, Scots Pine (Pinus sylvestris) and Norway Spruce (Picea abies), exposed to ionic liquid 1-ethyl-3-methylimidazolium chloride (EmimCl). Since both EmimCl and the monosaccharides are water-soluble and dissolve readily in similar solvents, the separation of this hydrophilic IL from sugars is difficult. Moreover, the analytics of monosaccharides released from lignocellulosics with the help of EmimCl is challenging. Sufficiently diluted samples, with low enough EmimCl concentrations, tolerated by GC sugar columns, can be also analyzed by GC. The results obtained suggest that some IL-tolerating HPLC columns can be utilized for a quantitative determination of monosaccharides. However, frequently, these columns have low separation ability for monosaccharides and, consequently, the retention time values are very close to each other. So far, the best results on HPLC utilization were obtained with isocratic elution, using a refractive index detector and a diode array UV detector in series.
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| 28. |
- Jansson, Mikael, et al.
(author)
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Second generation ethanol through alkaline fractionation of pine and aspen wood
- 2010
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In: Cellulose Chemistry and Technology. - 0576-9787. ; 44:1-3, s. 47-52
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Journal article (peer-reviewed)abstract
- Pre-treatment studies on pine and aspen wood with alkaline fractionation were performed, the experimental results obtained being used as input for assessing the conversion of an existing pulp mill to ethanol and lignin production. By the LignoBoost process, the extracted lignin could be used in the lime kiln to replace fuel oil, while the lignin not needed in the lime kiln could be sold as a by-product. In addition to fuel applications, lignin could be used in a wide range of bio-based product applications, which would increase the value of the extracted lignin and increase the total revenues. A WinGEMS model was used to calculate mass and energy balances, and the results were used for an economic evaluation of the concept. The assessment indicated that the proposed alkaline concept would have reasonable production costs from both pine and aspen wood, comparable with the bioethanol produced from grain in Northern Europe today, i.e. about 0.45 ε/L ethanol (∌5 SEK/L). The production rate of a typical mill producing 1000 tonnes of pulp per day before conversion would be in the order of 140 000 m 3 of ethanol per year, as depending on the raw wood material. The corresponding lignin production would range from 25 000 to 63 000 tonnes per year. The use of alkaline delignification to produce a substrate with low lignin content for the enzymatic hydrolysis builds entirely on known and well-proven technology, yet it needs to be further developed. The process chain from enzymatic hydrolysis to ethanol is very similar to that used today for grain ethanol. Altogether, the technical risk should therefore be low.
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| 29. |
- Jaros, Adam, et al.
(author)
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Effect of acetate on fermentation production of butyrate
- 2012
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In: Cellulose Chemistry and Technology. - 0576-9787. ; 46:5-6, s. 341-347
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Journal article (peer-reviewed)abstract
- A carbon source for the fermentation production of butyrate is xylose extracted from ligno-cellulosic material by hot water extraction. Although this auto-hydrolysis of hemicellulose can provide a low-cost source of xylose, the process generates a high level of acetic acid that might inhibit subsequent fermentations. This study focuses on the effects of acetate on the production of butyrate from xylose by batch fermentations with a selected strain Clostridium tyrobutyricum.At initial acetate concentrations of 17.6 g L-1 and 26.3 g L-1 in the media, C. tyrobutyricum cultures exhibited a lag phase (45 and 118 hours, respectively) in terms of sugar consumption, butyrate production and cell biomass growth, lowering the overall production rate. Butyrate fermentations performed with high concentrations of acetate in the media demonstrated a re-uptake of acetate into the butyrate production pathway and after the lag phase, all cultures adapted to the inhibitory acetate, which increased the final butyrate yields by 12.6% (32.6 g L-1 compared to 28.5 g L-1).
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| 30. |
- Karlström, Katarina, et al.
(author)
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Sulphur-free cooking for value added cellulose
- 2014
-
In: Cellulose Chemistry and Technology. - 0576-9787. ; 48:9-10, s. 781-786
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Journal article (peer-reviewed)abstract
- To study sulphur- and chlorine-free processes to produce pulps for triacetylation and preparation of films for LCD screen application was one of the aims in the EU project AFORE. It was shown possible to produce pulp suitable for triacetylation from Eucalyptus globulus chips with pre-hydrolysis soda cooking and a single oxygen delignification step. Pre-hydrolysis with water at elevated temperatures extracts wood components, mainly hemicelluloses and the wood matrix is opened to facilitate alkaline pulping. After a severe pre-hydrolysis extracting some 25% of the wood raw material, a subsequent soda cook reduces the lignin content to about 1%. The oxygen delignification step produces a pulp with low lignin content, kappa no 1.4, and low hemicelluloses content, < 2 wt% xylose. The resulting cellulose had high molar mass and produced highly transparent triacetate solutions. It was also possible to produce a transparent cellulose triacetate film by solution casting with good physical properties without using plasticizer. The process also results in a sulphur-free black-liquor suitable for lignin separation by the LignoBoost process. The resulting lignin is of high purity with low hemicelluloses content.
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| 31. |
- Klingberg, Maria, 1970, et al.
(author)
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Mechanical properties of paperboard with a needled middle layer
- 2018
-
In: Cellulose Chemistry and Technology. - 0576-9787. ; 52:1-2, s. 89-97
-
Journal article (peer-reviewed)abstract
- Needling of formed kraft pulp at a dry content of 20 % was previously shown to result in a redistribution of the fibres in the plane, resulting in local regions with a higher fibre structure density. The bending properties of a three-ply paperboard with a needled middle layer have here been studied, and it is shown that a needled middle layer can increase the bending resistance of a layered board by 8 % and that the peak bending angle can be increased by up to 20 %, although the bending stiffness may not be changed significantly. The needled middle layers had a higher compressive stiffness in the out-of-plane direction, but the effect of the needling on the tensile strength in the out-of-plane direction was insignificant.
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| 32. |
- Klingberg, Maria, 1970, et al.
(author)
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Processing and structure of paperboard with a needled middle layer
- 2019
-
In: Cellulose Chemistry and Technology. - : Institutul de Chimie Macromoleculara Petru Poni. - 0576-9787 .- 2457-9459. ; 53:3-4, s. 315-323
-
Journal article (peer-reviewed)abstract
- The possibility to change the fibre network structure of paperboard by using the needle punching method was studied. Needling was performed on the middle layer made from unbleached softwood kraft pulp at a dry content of 20%. The needled structure was studied by several microscopy methods, which showed that the fibres were redistributed mainly in-plane. Denser regions of the fibre network structure were observed close to the needle penetration sites. The local density was estimated to be 25% higher than that of the surrounding unaffected structure.
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| 33. |
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| 34. |
- Krusa, Martin, et al.
(author)
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Pre-treatment of cellulose by cellobiose dehydrogenase increases the degradation rate by hydrolytic cellulases
- 2007
-
In: Cellulose Chemistry and Technology. - 0576-9787. ; 41:2-3, s. 105-111
-
Journal article (peer-reviewed)abstract
- Cellobiose dehydrogenase (CDH) is an extra-cellular flavocytochrome with unknown biological function, produced by various wood degrading fungi. In the presence of Fe(III) and cellobiose, CDH produces hydroxyl radicals through a Fenton-type reaction. Treatment of cellulose with CDH, cellobiose, hydrogen peroxide and ferriacetate decreased cellulose's polymerization degree and increased its degradability for different functional types of hydrolytic cellulases, except for an exo-enzyme working from the reducing end. This suggests a biological role for CDH in fungal cellulose degradation, possibly by activating the cellulose for hydrolytic cellulases by depolymerization and disturbance of the hydrogen bonding pattern in cellulose.
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| 35. |
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| 36. |
- Lima, David Albuquerque, et al.
(author)
-
Comparison of bioethanol production from acid hydrolyzates of waste office paper using saccharomyces cerevisiae and spathaspora passalidarum
- 2015
-
In: Cellulose Chemistry and Technology. - Bucuresti, Romania : Editura acad Romane. - 0576-9787. ; 49:5-6, s. 463-469
-
Journal article (peer-reviewed)abstract
- The aim of this work was to evaluate waste office paper as raw material for bioethanol productionusing four strains of Saccharomyces cerevisiae and Spathasporapassalidarum HMD 14.2.Waste paper was hydrolyzed with 1-5% V/V sulfuric acid to 2-10% w/Vbiomass load for 60-120 min. The most significant variable for the total reduced sugar (TRS) was the biomass load, followed by the acid concentration. The pretreatment time did not exert any significant effect on TRS. The hydrolysate obtained with 5% V/V sulfuric acid, 10% w/V biomass load and 1 hour, containing8.45 g/L glucose and 9.27 g/L xylose, was chosen for the fermentations. The fermentation with S. passalidarum resulted in higher ethanol formation (3.54 g/L) than the fermentation with S. cerevisiae, which corresponds to a hypothetical yield of 0.708 g/g glucose. This indicates that S. passalidarum produces ethanol not only from glucose, but also from xylose.
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| 37. |
- Ondaral, Sedat, et al.
(author)
-
FIXATION OF DISSOLVED AND COLLOIDAL SUBSTANCES ON FIBERS AND SILICON OXIDE SURFACES USING WATER SOLUBLE CROSSLINKED CATIONIC POLYMERS
- 2008
-
In: Cellulose Chemistry and Technology. - 0576-9787. ; 42:1-3, s. 61-69
-
Journal article (peer-reviewed)abstract
- The efficiency of water soluble crosslinked cationic polymers (CCP) in the fixation of dissolved and colloidal substances (DCS) onto fibers was investigated. Two different types of CCP were synthesized by dispersion polymerization of acrylamide (AAm) and diallyldimethylammonium chloride (DADMAC), with N,N'-methylene-bis-acrylamide (MBA) as a crosslinker. Relative turbidity, zeta potential and average diameter of the colloidal particles were determined to monitor their performance in DCS fixation. The results indicated that both polymers were able to fix a maximum amount of DCS particles onto fibers around a zero zeta potential, most probably clue to a patch-type flocculation mechanism. The conclusion reached was that flocculation was significant while the particles still had a negative zeta potential. The aggregation mechanism of a fiber-free DCS suspension occurred as Charge neutralisation, changed, by the addition of 10 mM NaCl to a patch-type mechanism. The CCPI consumption necessary to attain a maximum DCS removal was lower than the CCP2 consumption, as ascribed to the higher charge density and higher molecular mass of this polymer. The experiments performed on a quartz crystal microbalance equipment with dissipation (QCM-D) showed that the adsorbed charge and layer thickness of the polymers significantly affected fixation of the DCS particles onto the pre-adsorbed polymer layers on the SiO2 surface.
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| 38. |
- Pezoa, R., et al.
(author)
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Use of ionic liquids in the pretreatment of forest and agricultural residues for the production of bioethanol
- 2010
-
In: Cellulose Chemistry and Technology. - : Publishing House of the Romanian Academy. - 0576-9787. ; 44:4-6, s. 165-172
-
Journal article (peer-reviewed)abstract
- Pretreatment of lignocellulosic materials is an important step to achieve higher amounts of simple sugars, mono- and disaccharides, for obtaining ethanol as a biofuel, via enzymatic hydrolysis. The study introduces a concept that utilizes ionic liquids (ILs) as solvents in the pretreatment step, before enzymatic saccharification, for both forest residues (Eucalyptus (Eucalyptus globulus Labill.) and Lenga (Nothofagus pumilio (POEPP. EX. ENDL.) KRASSER) and for agricultural residues (wheat and corn). The procedure was evaluated at four different temperatures (80, 121, 150 and 170 °C) for 30 and 60 min, respectively, with 1-ethyl-3-methylimidazolium chloride ([EMIM+][Cl-]). Subsequent enzymatic hydrolysis of these materials was carried out at 47 °C, for 72 h, with commercial cellulases. The results demonstrated that the best experimental conditions found for wheat, corn and Eucalyptus residues were the following: 150 °C, for 60 min, yielding a total of 46, 48 and 30% sugars, respectively; in the case of Lenga residues, the optimum conditions were: 150 °C for 30 min, yielding a total of 40% sugars after saccharification. Temperatures exceeding 170 °C are not recommended for this type of pretreatment with [EMIM+][Cl-], because significant portions of cellulose could be dissolved in this IL. Finally, an analysis of the solid material after ionic liquid pretreatment is required, to determine the changes related to lignin, cellulose and hemicellulose composition.
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| 39. |
- Rognes, H., et al.
(author)
-
Optimization of flax fiber separation by leaching
- 2000
-
In: Cellulose Chemistry and Technology. - 0576-9787. ; 34:04-mar, s. 331-340
-
Journal article (peer-reviewed)abstract
- The abilities of four chelators to separate bast fibers of non-retted oilseed flax from each other and the core and cuticle have been investigated at different pH level. EDTAand DTPA separate fibers efficiency at pH 10. Addition of a strong detergent (Sodium dodecyl sulphate, SDS) or sodium chloride further increased the fiber separation and so delignifying compounds hydrogen peroxide and sodium sulfite. A mixture of EDTA, SDS and hydrogen peroxide gave a complete fiber separation within 2 h at 70 degrees and pH 10. The fibers in the woody core of the flax straw did not separate under these conditions. The mechanistic background to fiber separation is discussed.
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| 40. |
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| 41. |
- Stevanic Srndovic, Jasna, et al.
(author)
-
The primary cell wall studied by dynamic 2D FT-IR : Interaction among components in Norway spruce (Picea abies)
- 2006
-
In: Cellulose Chemistry and Technology. - 0576-9787. ; 40:9-10, s. 761-767
-
Journal article (peer-reviewed)abstract
- Knowledge on the interactions among the wood polymers, viz. cellulose, hemicellulose, pectin, lignin and protein, in the outer fibre wall layers is essential for understanding fibre separation in thermomechanical and chemithermomechanical pulping processes. For this reason, dynamic two-dimensional Fourier Transform Infra-Red (2D FT-IR) spectroscopy was applied to examine the interaction of these components in the primary cell wall of spruce fibres. Sheets made of an enriched primary cell wall material were used for studying the viscoelastic response to loading. The dynamic 2D correlation FT-IR spectra indicated the existence of strong interactions between lignin and protein, as well as among pectin, xyloglucan and cellulose, in the primary cell wall. This is in contrast to the picture for the secondary cell wall, in which cellulose-glucomannan and xylan-lignin interactions are prevailing.
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| 42. |
- Strunk, Peter, et al.
(author)
-
Chemical changes of cellulose pulps in the processing to viscose dope
- 2012
-
In: Cellulose Chemistry and Technology. - 0576-9787. ; 46:9-10, s. 559-569
-
Journal article (peer-reviewed)abstract
- A selection of cellulose pulps was investigated for their chemical changes during the required process steps to viscose dope. The selection of the pulps was based on pulping process, original wood type and intrinsic viscosity. In total, five sulfite pulps and four sulfate pulps were chosen, of which all but one sulfate pulp were of dissolving grades. The physical and chemical properties of the pulps were analyzed as well as important qualitative parameters of the cellulose intermediates during mercerization, pre-aging and in the final viscose dope. Pre-aging curves were reported as a measure of each pulp's reactivity with respect to oxidative degradation, where high hemicellulose content and small pore area and pore diameter were found to hamper cellulose degradation. The correlations in pre-aged pulps of intrinsic viscosity to Mz, Mv and Mw were found to be ambiguous and show the need for a description of total molecular weight distribution of the alkali celluloses to better understand the degradation behavior of each pulp, instead of only intrinsic viscosity. It was also shown that R18 and R10 are insufficient analyses to determine pulp, and to predict viscose quality. Further, many pulps, independently of initial hemicellulose content, reached the same level of hemicellulose content after mercerization. The presence of crystalline hemicelluloses could be a possible cause for this level-off behavior, combined with hemicelluloses resistant to caustic lye treatment. The change of both low-molecular-weight celluloses and PD in the process to viscose dope was investigated due to the importance of these variables on dope spinnability and viscose fiber strength. Caustic resistance of cellulose and hemicelluloses and a more rigid fiber structure in some pulps are suggested to contribute to the different degradation behavior.
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| 43. |
- Sundman, Ola, 1979-, et al.
(author)
-
Homogenous benzylation of cellulose : impact of different methods on product properties
- 2015
-
In: Cellulose Chemistry and Technology. - 0576-9787. ; 49:9-10, s. 745-755
-
Journal article (peer-reviewed)abstract
- This paper offers an evaluation of different methods for synthesizing benzyl cellulose and of how they affect characteristics such as solubility, degree of substitution, thermal stability and molecular weight of the products. Benzyl celluloses with degrees of substitution between 0.1 and 2.5 were synthesised from microcrystalline cellulose in (1) aqueous NaOH/Urea and (2) dimethyl sulfoxide/tert-butyl ammonium fluoride (DMSO/TBAF) systems in order to evaluate the different properties of the benzyl celluloses of low degree of substitution. In contrast to previous findings in the literature, both systems yielded soluble benzyl celluloses at degrees of substitution <0.5. Also in contrast to the literature, the low degree of substitution benzyl celluloses from both systems showed similar thermal properties. The filtration of the benzyl celluloses in DMSO/TBAF solutions before precipitation gave significantly higher solubility of the products and increased their thermal stability. The molecular weights of the benzyl celluloses of low degree of substitution (0.4 < DS < 1.25) were similar between the systems and differed in the range of one order of magnitude from the molecular weights of the higher degree of substitution benzyl celluloses. 13C-NMR data indicated differences in the substitution pattern between the two systems.
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| 44. |
- Sundqvist, Bror, et al.
(author)
-
Cellulose degradation during hydrothermal treatment of birch wood (Betula pubescens Ehrh.)
- 2006
-
In: Cellulose Chemistry and Technology. - 0576-9787. ; 40:3-4, s. 217-221
-
Journal article (peer-reviewed)abstract
- Study of cellulose degradation during wood's heat treatment showed a considerable degradation in both commercially and laboratory heat-treated wood samples, probably due to the low pH induced by the heat treatment. Experimental series were performed for investigating cellulose degradation in birch wood, at different pH levels and times, during heat treatments performed at pH values of 4, 7 and 10, for 3 and 6 hours at 180°C. The results show that the selected span of pH and time of treatment clearly affects the size of the cellulose molecules. Study of cellulose degradation involved intrinsic viscosity measurements on α-cellulose from the samples. As a result of heat treatment, viscosity drops from 1430 mL/g (untreated wood) to less than or equal 700 mL/g and less than or equal 350 mL/g, for durations of 3 and 6 hours, respectively. The wood buffered in an aqueous solution at pH 4 showed a drop in intrinsic viscosity around 880 mL/g, while a sample of commercial "thermowood" yielded an intrinsic viscosity of 732 mL/g. For neutral and alkaline pH values, the drop in viscosity is considerably lower. At pH values of 7 and 10, a 3 hr treatment had almost no effect on the degree of polymerisation, while a 6 hr treatment gave intrinsic viscosities around 1000 mL/g and 1216 mL/g, respectively. There is a distinct relation between cellulose's molecular size and wood's strength properties. The decrease in cellulose length in unbuffered systems may affect the strength properties of the treated wood. The experiments show that pH is an important factor to consider.
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| 45. |
- Tavast, Daniel, et al.
(author)
-
Selectiveness and efficiency of combined peracetic acid and chlorine dioxide bleaching stage for kraft pulp in removing hexeuronic acid
- 2011
-
In: Cellulose Chemistry and Technology. - 0576-9787. ; 45:1-2, s. 89-95
-
Journal article (peer-reviewed)abstract
- Combined peracetic acid and chlorine dioxide bleaching stages of unbleached and oxygen delignified hardwood and softwood kraft pulps were compared with conventional chlorine dioxide and peracetic acid stages as to kappa number and viscosity reduction, selectivity and reduction of hexenuronic acid content. The combined stages were more efficient in kappa number reduction than those with only chlorine dioxide. Part of the increased kappa number reduction was due to an improved degradation of hexenuronic acid. The stages where chlorine dioxide was added before the peracetic acid (DT) showed a higher selectivity than those in which the chemicals were added simultaneously (D+T); in turn, the latter were more efficient than the "pure" chlorine dioxide (D, D-0) and peracetic acid stages (T). However, peracetic acid and chlorine dioxide seemed to react with each other, leading to the degradation of both bleaching chemicals. The mechanisms and practical implementation of these bleaching sequences are discussed.
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| 46. |
- Ziesig, R., et al.
(author)
-
Production of a pure lignin product part 2: Separation of lignin from membrane filtration permeates of black liquor
- 2014
-
In: Cellulose Chemistry and Technology. - 0576-9787. ; 48:9-10, s. 80 -811
-
Journal article (peer-reviewed)abstract
- Future high value lignin-based products, such as carbon fibers, require a lignin raw material with a high purity level. Lignin with low inorganic content can be separated from kraft black liquor by the LignoBoost process. This laboratory scale study focuses on the effect of micro- and ultrafiltration of black liquor on the content of impurities in the LignoBoost lignin. Two black liquors, obtained from pulping of eucalyptus and softwood, were used in this study. The black liquors were micro- and ultrafiltered and thereafter lignin was separated from these permeates according to the LignoBoost process. It was found that micro- and ultrafiltration significantly reduced the amounts of carbohydrate residuals in the separated lignin. Eucalyptus lignin separated from permeates contained similar amounts of Al, Mn, Mg, Fe and Si, but significantly less Ca than the reference sample separated from unfiltered black liquor, resulting in 50% lower ash content. Softwood lignin separated from permeates contained lower amounts of Al, Mn, Mg, Fe, Ca and Si than the reference. In both cases, the Na and K content were unaffected by the introduction of micro- and ultrafiltration.
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| 47. |
- Östberg, Linda, et al.
(author)
-
Some aspects on the activation of dissolving pulps and the influence on the reactivity in a following viscose stage
- 2013
-
In: Cellulose Chemistry and Technology. - 0576-9787. ; 47:3-4, s. 165-169
-
Journal article (peer-reviewed)abstract
- It was found that, for a dissolving pulp, an enzymatic pre-treatment with an endoglucanase prior to viscose preparation did not change the correlation between the gamma number of the viscose dope and the carbon disulphide charge. Thus, the pulp stoichiometry, or reactivity, was not changed by an endoglucanase pre-treatment. It has nevertheless previously been found that the pulp reactivity, measured either by Fock's test or as the filter clogging value (Kw), increased for the same type of enzyme pre-treatment. Thus, the pulp reactivity seems to be influenced by the analysis method employed.
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