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  • 1
    Digitale Medien
    Digitale Medien
    Enzymatic hydrolysis of wood: an engineering assessment (1995)
    Springer
    Bioprocess and biosystems engineering 12 (1995), S. 253-261 
    Details
    ISSN: 1432-0797
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract Eucalyptus wood samples were delignified with HCl-catalysed acetic acid solutions under selected experimental conditions and treated with NaClO solutions. The solid residues obtained were employed as substrates for enzymatic hydrolysis. The NaClO concentration used in the pretreatment step, the liquor/solid ratio and the enzyme/substrate ratio were considered as operational variables. The experimental data allowed the development of generalized kinetic models which provided the necessary information for design calculations. The operational conditions were compared from an engineering viewpoint on the basis of economic estimates. Optimum conditions were established from these estimates.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00369499
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  • 2
    Digitale Medien
    Digitale Medien
    Production of xylitol from raw wood hydrolysates by Debaryomyces hansenii NRRL Y-7426 (1995)
    Springer
    Bioprocess and biosystems engineering 13 (1995), S. 125-131 
    Details
    ISSN: 1432-0797
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract Xylose solutions were obtained from the hemicellulosic fraction of Eucalyptus globulus by means of sulphuric acid treatments performed under selected operational conditions. The hydrolysates were neutralized, supplemented with nutrients, sterilized and utilised as fermentation media for xylitol production using the yeast Debaryomyces hansenii NRRL Y-7426. Preliminary experiments allowed the adaptation of the strain to the culture media. Further fermentation trials were performed with adapted cells according to an incomplete, factorial design of experiments. Empirical models describing the bioconversion were derived from the experimental results. The effects of three operational variables (nutrient concentration, initial pH and shaking speed) on both xylose consumption and xylitol production rates were described by significant mathematical equations. Additional aspects in relation to the process were also discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00369695
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  • 3
    Digitale Medien
    Digitale Medien
    Empirical modeling of eucalyptus wood processing (1992)
    Springer
    Bioprocess and biosystems engineering 8 (1992), S. 129-136 
    Details
    ISSN: 1432-0797
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract Eucalyptus globulus wood samples were treated with NaOH solutions in order to obtain substrates highly susceptible to enzymatic hydrolysis. The experiments performed in the extraction and hydrolysis stages followed an incomplete factorial design. Temperature, NaOH concentration and extraction time were considered as independent variables. Their influence on five dependent variables (defined to measure the extraction yield, the chemical composition of processed samples and the enzymatic conversion) was assessed using second order, empirical models. In addition to the experimental results, other aspects related to the extraction selectivity are discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01254228
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  • 4
    Digitale Medien
    Digitale Medien
    Studies on the utilization of Pinus pinaster bark (1987)
    Springer
    Wood science and technology 21 (1987), S. 65-74 
    Details
    ISSN: 1432-5225
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Maschinenbau
    Notizen: Summary The chemical constituents of Pinus pinaster bark are studied, as a first step of a study devoted to its benefit. The analyzed samples showed an average content of 0.5% ash, 2.5% waxes (measured as the hexane and benzene soluble fractions), 39.3% of soluble materials in polar organic solvents, water and NaOH solutions, 28.9% polysaccharides (roughly half corresponding to cellulose), 29.6% Klason lignin, 59.7% aromatic content and 1.0% suberin. The fraction with potential utility, formed by formaldehyde-condensable polyphenols and polysaccharides, is over 60 weight percent of bark. The results are compared with those determined for other pine species.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00349718
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  • 5
    Digitale Medien
    Digitale Medien
    Studies on the utilization of Pinus pinaster bark (1987)
    Springer
    Wood science and technology 21 (1987), S. 155-166 
    Details
    ISSN: 1432-5225
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Maschinenbau
    Notizen: Summary The influence of several variables (temperature, time, alkali type and concentration) on the yield of polyphenol from alkaline extractions is studied, using Pinus pinaster bark. For this purpose, the gravimetric Stiasny method and a spectrophotometric procedure based on molibdate ions are used. The influence of time on the extraction process was evaluated, and the results were correlated by semiempirical equations.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00376195
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  • 6
    Digitale Medien
    Digitale Medien
    Sugars from pine bark by enzymatic hydrolysis effect of sodium chlorite treatments (1987)
    Springer
    Wood science and technology 21 (1987), S. 167-178 
    Details
    ISSN: 1432-5225
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Maschinenbau
    Notizen: Summary For the utilization of polysaccharides from Pinus pinaster bark, both untreated and NaOH-treated samples were delignified to different stages using NaClO2 and submitted to enzymatic hydrolysis with Trichoderma reesei cellulase and Aspergillus niger beta-glucosidase. In the best conditions, samples treated with 1% NaOH for 15 min and NaClO2 for 7 hours the conversion of polysaccharides into sugars accounts for the 75% of the potential yield, and the glucose obtained amounts to 87% of the theoretical value.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00376196
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  • 7
    Digitale Medien
    Digitale Medien
    Effect of selected operational variables on the susceptibility of NaOH-pretreated pine wood to enzymatic hydrolysis: a mathematical approach (1994)
    Springer
    Wood science and technology 28 (1994), S. 297-300 
    Details
    ISSN: 1432-5225
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Maschinenbau
    Notizen: Summary Pinus pinaster wood samples were treated with NaOH solutions in order to improve their susceptibility to enzymatic hydrolysis. The variations caused by pretreatments on the chemical composition of treated samples and on the extent of enzymatic saccharification were correlated with the experimental variables studied (temperature, liquor/wood ratio and alkali concentration). Empirical models were used to assess the extraction and the hydrolysis steps. The reliability of the mathematical models was confirmed by further experimentation. Additional aspects affecting the studied process (such as selectivity of extraction and kinetics of enzymatic hydrolysis) are discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00204216
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  • 8
    Digitale Medien
    Digitale Medien
    Acid prehydrolysis of pinus pinaster bark with dilute sulfuric acid (1988)
    Springer
    Wood science and technology 22 (1988), S. 219-225 
    Details
    ISSN: 1432-5225
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Maschinenbau
    Notizen: Summary The influence of temperature (100–150°C) and acid concentration (0–5 wt%) on the prehydrolysis of pine bark and its alkaline-extracted residues was studied (the latter were obtained by vigorously stirring the bark for 15 min with a solid/liquid ratio of 1:10). Optimal prehydrolysis conditions were established by the sectioning method with a solid/liquid ratio of 1:10. For milled bark these conditions were: temperature 125°C, sulphuric acid concentration 2 wt%, duration of prehydrolysis 4.5 h; and for alkali-extracted residues, temperature 125°C, sulphuric acid concentration 3 wt%, duration of prehydrolysis 5 h. These treatments removed respectively 90% and 75% of non-glucose sugars in the hydrolysate while solubilizing less than 20% (respectively 10%) of the potential glucose yield. Enzymatic digestion of bark successively alkali-extracted and prehydrolysed under optimal conditions gave poor results, with yields similar to those obtained after other pretreatments.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00386016
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  • 9
    Digitale Medien
    Digitale Medien
    Preliminary evaluation of acetic acid-based processes for wood utilization (1995)
    Springer
    Holz als Roh- und Werkstoff 53 (1995), S. 347-353 
    Details
    ISSN: 1436-736X
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Maschinenbau
    Notizen: Eucalyptus globulus wood in acetic acid media was assessed by means of both technical and economic calculations. From a process diagram, material and energy balances were formulated on the basis of reported kinetic models in order to obtain the information necessary for preliminary economic estimates. The economic study included the evaluation of a base-case, optimization and analyses of sensitivity to the major economic variables.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s001070050105
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  • 10
    Digitale Medien
    Digitale Medien
    Hydrothermal processing of lignocellulosic materials (1999)
    Springer
    Holz als Roh- und Werkstoff 57 (1999), S. 191-202 
    Details
    ISSN: 1436-736X
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Maschinenbau
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s001070050039
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