| 1. |
- Eklund, R, et al.
(author)
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Optimization of temperature and enzyme concentration in the enzymatic saccharification of steam-pretreated willow
- 1990
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In: Enzyme and Microbial Technology. - 0141-0229. ; 12:3, s. 225-228
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Journal article (peer-reviewed)abstract
- The effect of temperature and enzyme concentration on the enzymatic hydrolysis of steam-pretreated willow was investigated to obtain the optimal hydrolysis conditions. The willow was pretreated at 220°C for 10 min according to the results of earlier optimization studies of the steam-pretreatment conditions for high glucose yields. The concentrations of two commercial enzymes, Celluclast 2L and Novozyme 188, were varied in the range 0–20% (based on oven-dry substrate). A maximum in the conversion of cellulose to glucose was obtained using a mixture of 15% Celluclast and 3% Novozyme, corresponding to an activity of 11.4 FPU g−1 substrate. Higher enzyme concentrations did not increase the initial hydrolysis rate nor affect the final glucose yield. The effects of temperature in the range 40°C to 60°C were investigated. The temperature affects both the initial hydrolysis rate and the final glucose yield. The highest glucose yield was obtained at 40°C. The yield decreased with increasing temperature, due to increased enzyme deactivation at higher temperatures, while the initial reaction rate increased with increasing temperatures.
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| 2. |
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| 3. |
- Galbe, Mats, et al.
(author)
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Adsorption of cellulases on steam-pretreated willow
- 1990
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In: Applied Biochemistry and Biotechnology. - 1559-0291. ; 24-5, s. 87-101
-
Journal article (peer-reviewed)abstract
- The adsorption of cellulases on steam-pretreated willow has been measured for2, 4, and 8 wt% willow and with varying enzyme concentrations (2–100 wt% based on substrate). The enzyme concentration was measured as soluble protein, filter paper activity (FPA), CMC-ase activity, and activity toward willow. The adsorption data were modeled with a Langmuir isotherm. The maximum adsorption capability depends on the method for measurement of the enzyme concentration. The lowest value, 470 mg enzyme/g willow, was obtained for the soluble protein and the highest value, 650 mg/g, for the FPA. For technical applications, a single isotherm can be used for calculation of the adsorption capability of steam-treated willow.
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| 4. |
- Galbe, Mats, et al.
(author)
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Simulation of ethanol production processes based on enzymatic hydrolysis of lignocellulosic materials using ASPEN PLUS
- 1992
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In: Applied Biochemistry and Biotechnology. - 1559-0291. ; 34-5, s. 93-104
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Journal article (peer-reviewed)abstract
- The process simulator ASPEN PLUS was used for simulation of an ethanol production process based on enzymatic hydrolysis of lignocellulosic materials. The effect of water recycling, necessary to reduce the amount of waste water and to increase the ethanol concentration in the feed to the distillation, was investigated. For a process based on 20 t/h raw material, the amount of waste water can be reduced from 70.7 t/h, without recycling, to 7.1 t/h. Furthermore, the ethanol concentration in the distillation feed increased from 2.5 to 10%. The concentration of byproducts and possible inhibitors increased by a factor of 20-40 in the hydrolysis and fermentation steps. This gives new conditions for future hydrolysis and fermentation experiments.
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| 5. |
- Galbe, Mats, et al.
(author)
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Simulation of ethanol production processes based on enzymatic hydrolysis of woody biomass
- 1994
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In: Computers & Chemical Engineering. - : Elsevier BV. - 1873-4375 .- 0098-1354. ; 18:Suppl. 1, s. 687-691
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Journal article (peer-reviewed)abstract
- The process simulator ASPEN PLUS was used for simulation of an ethanol production process based on enzymatic hydrolysis of lignocellulosic materials. Various process configurations were studied to increase the overall yield of ethanol and to reduce the energy consumption in the process. An increased utilization of the pentosan fraction was achieved by a complex recycling of streams in the process. This increased the total overall yield from 56% to 70%. Internal recycling of an ethamol containing stream increased the ethanol concentration in the distillation feed from 2.6 to 7.1 wt% which decreased the energy consumption in the distillation from 8 to 2 MW. The recycling will however result in increased concentrations of byproducts and inhibitors which requires future investigation of how these new conditions will affect the performance in the hydrolysis and fermentation steps.
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