| 1. |
- Bi, Ran, et al.
(författare)
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Isolation of exceedingly low oxygen consuming fungal strains able to utilize lignin as carbon source
- 2016
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Ingår i: Cellulose Chemistry and Technology. - 0576-9787. ; 50:7-8, s. 811-817
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Tidskriftsartikel (refereegranskat)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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| 2. |
- Deshpande, Raghe, et al.
(författare)
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Initial phase of sodium bisulphite pulping of spruce. Part I
- 2016
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Ingår i: Cellulose Chemistry and Technology. - : Editura Academiei Romane. - 0576-9787. ; 50:2, s. 293-300
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Tidskriftsartikel (refereegranskat)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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| 3. |
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| 4. |
- Garcia, Ariel, et al.
(författare)
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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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Ingår i: 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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Tidskriftsartikel (refereegranskat)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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| 5. |
- Garcia, Ariel, et al.
(författare)
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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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Ingår i: Cellulose Chemistry and Technology. - 0576-9787. ; 49:9-10, s. 737-744
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Tidskriftsartikel (refereegranskat)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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| 6. |
- Gulbrandsen, Torea A., et al.
(författare)
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Extracting hemicelluloses from softwood and bagasse as oligosaccharides using pure water and microwave heating
- 2015
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Ingår i: Cellulose Chemistry and Technology. - : Editura Academiei Romane. - 0576-9787. ; 49:2, s. 117-126
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Tidskriftsartikel (refereegranskat)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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| 7. |
- Klingberg, Maria, 1970, et al.
(författare)
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Mechanical properties of paperboard with a needled middle layer
- 2018
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Ingår i: Cellulose Chemistry and Technology. - 0576-9787. ; 52:1-2, s. 89-97
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Tidskriftsartikel (refereegranskat)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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| 8. |
- Klingberg, Maria, 1970, et al.
(författare)
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Processing and structure of paperboard with a needled middle layer
- 2019
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Ingår i: Cellulose Chemistry and Technology. - : Institutul de Chimie Macromoleculara Petru Poni. - 0576-9787 .- 2457-9459. ; 53:3-4, s. 315-323
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Tidskriftsartikel (refereegranskat)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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| 9. |
- Lima, David Albuquerque, et al.
(författare)
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Comparison of bioethanol production from acid hydrolyzates of waste office paper using saccharomyces cerevisiae and spathaspora passalidarum
- 2015
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Ingår i: Cellulose Chemistry and Technology. - Bucuresti, Romania : Editura acad Romane. - 0576-9787. ; 49:5-6, s. 463-469
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Tidskriftsartikel (refereegranskat)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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| 10. |
- Sundman, Ola, 1979-, et al.
(författare)
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Homogenous benzylation of cellulose : impact of different methods on product properties
- 2015
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Ingår i: Cellulose Chemistry and Technology. - 0576-9787. ; 49:9-10, s. 745-755
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Tidskriftsartikel (refereegranskat)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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