New Industrial Products from Starch

Koch, H.; Röper, H.

doi:10.1002/star.19880400402

Cited by 74 publications

(15 citation statements)

References 22 publications

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“…One method was to directly incorporate biomass, such as starch, lignocellulose, lignin, coffee grounds, bark, and so forth, in polyurethane formulations (Hostettler 1979;Koch and Roper 1988;Yoshida et al 1987). It was reported by Hatakeyama et al (1995) that rigid polyurethane foams that contained as much as 50% biomass can be obtained by mixing biomass materials with petro-based polyols before foaming.…”

Section: Introductionmentioning

confidence: 99%

Microwave-assisted liquefaction of wood with polyhydric alcohols and its application in preparation of polyurethane (PU) foams

2011

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Microwave radiation was used as the heating source in southern pine wood liquefaction with PEG/ glycerin binary solvent. It was found that microwave heating was more efficient than conventional oil bath heating for wood liquefaction. The wood residue content of the H 2 SO 4 catalyzed liquefied wood dropped to zero within 5 min with microwave heating. The resulting liquefied wood polyols have suitable hydroxyl values for the preparation of rigid PU foams. Both the compressive strength and apparent modulus of the liquefied-wood-based PU foams increased as the isocyanate index increased from 80 to 120. The foams from H 3 PO 4 catalyzed polyols had lower densities than those from H 2 SO 4 and the petroleum-based controls. They also showed lower strength and modulus than those from H 2 SO 4 . Liquefied-wood-based PU foams generally have lower compressive strength and apparent modulus than the petroleumbased controls. However, they showed better restorability from deformation than the petroleum-based controls. Zusammenfassung Mittels Mikrowellenstrahlung als Wär-mequelle wurde Southern Pine Holz mit PEG/Glycerin als binärem Lösungsmittelsystem verflüssigt. Es zeigt sich, dass Holz mittels Mikrowellenerhitzung effizienter verflüssigt werden kann als mittels konventioneller Erhitzung im Ölbad. Der Restholzanteil des mit Katalysator H 2 SO 4 verflüssigten Holzes fiel nach fünfminütiger Mikrowellenbeheizung auf Null. Die Hydroxylzahlen der so verflüssigten Holzpolyole sind für die Herstellung von PUHartschaumstoff geeignet. Sowohl die Druckfestigkeit als auch die Steifigkeit der PU-Schaumstoffe aus verflüssigtem Holz nahmen mit steigendem Isocyanatindex von 80 auf 120 zu. Die Schaumstoffe der mit Katalysator H 3 PO 4 erzeugten Polyole wiesen geringere Dichten auf als diejenigen mit Katalysator H 2 SO 4 und als Schaumstoffe auf Mineralölbasis. Die Festigkeit und der E-Modul waren ebenfall geringer. PU-Schaumstoffe auf Basis von verflüssigtem Holz wiesen generell eine niedrigere Druckfestigkeit und eine niedrigere Steifigkeit auf als die Kontrollproben auf Mineralölbasis. Allerdings zeigten sie ein besseres Rückverformungsverhal-ten als die Kontrollproben auf Mineralölbasis.

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Section: Introductionmentioning

confidence: 99%

Microwave-assisted liquefaction of wood with polyhydric alcohols and its application in preparation of polyurethane (PU) foams

2011

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“…They catalyze the hydrolysis of various polysaccharides to lower sugars or glucose. These hydrolyzates are used in the fermentative production of alcohols, amino acids, biopolymers, carboxylic acids and enzymes [2]. Therefore, they represent a valuable starting material for chemical and biochemical syntheses.…”

Section: Introductionmentioning

confidence: 99%

Mathematical modeling of maltose hydrolysis in different types of reactor

Findrik

Presečki

Vasić-Rački

2009

Bioprocess Biosyst Eng

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A commercial enzyme Dextrozyme was tested as catalyst for maltose hydrolysis at two different temperatures: 40 and 65°C at pH 5.5. Its operational stability was studied in different reactor types: batch, repetitive batch, fed-batch and continuously operated enzyme membrane reactor. Dextrozyme was more active at 65°C, but operational stability decay was observed during the prolonged use in the reactor at this temperature. The reactor efficiencies were compared according to the volumetric productivity, biocatalyst productivity and enzyme consumption. The best reactor type according to the volumetric productivity for maltose hydrolysis is batch and the best reactor type according to the biocatalyst productivity and enzyme consumption is continuously operated enzyme membrane reactor. The mathematical model developed for the maltose hydrolysis in the different reactors was validated by the experiments at both temperatures. The Michaelis-Menten kinetics describing maltose hydrolysis was used.List of symbols EC Enzyme consumption (kU g -1 ) K m Michaelis constant (g dm -3 ) k d Enzyme operational stability decay rate constant (min -1 ) q v Flow rate of the reaction solution (cm 3 min -1 ) Q BP Biocatalyst productivity (g kU -1 ) Q p Volumetric productivity (kg dm -3 d -1 )Maximal reaction rate (g dm -3 min -1 )Greek symbols c Concentration (g dm -3 ) u Enzyme concentration expressed as enzyme volume per volume of reaction mixture (cm 3 /cm 3 )

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“…1 In the present study, the sacchari®cation of wheat starch to glucose was investigated with the intention of fermenting the glucose to lactic acid. 2,3 The sacchari®cation and fermentation steps are often integrated to reduce the effect of glucose inhibition in the two process steps and a kinetic model is useful in evaluating whether the sacchari®cation and the fermentation steps should be performed simultaneously or separately.…”

Section: Introductionmentioning

confidence: 99%

“…Initial glucose concentration (g glucose (100 g of solution) À1 ) C 1 Glucose concentration (g glucose (100 g of solution) a-amylase (g starch) À1 ) (eqn (10)) k es Parameter in velocity expression (g dm À3 ) (eqns (2) and (11))…”

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confidence: 99%

A kinetic model for enzymatic wheat starch saccharification

Åkerberg

Zacchi

Torto

et al. 2000

J. Chem. Technol. Biotechnol.

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A kinetic model describing the enzymatic sacchari®cation of wheat starch by a mixture of a-amylase and amyloglucosidase has been developed. The model describes the in¯uence of pH, glucose inhibition and starch and enzyme concentration. The results of experimental sacchari®cation under different physical conditions, eg pH and temperature, were used to determine the parameters in the model. The dominant enzyme in the mixture was amyloglucosidase and the maximum rate of sacchari®cation due to this enzyme was found to be optimal at pH 5, and increased Five-Fold when the temperature was increased from 30 to 55°C. Sacchari®cation due to the action of amyloglucosidase was inhibited by the glucose produced and simulation showed that the maximum rate of sacchari®cation decreased by 58% at a starch concentration of 140 g dm À3 compared with a starch concentration much less than 110 g dm À3 where the effect of glucose inhibition was negligible. # 2000 Society of Chemical Industry Keywords: kinetics; model; sacchari®cation; starch; wheat; enzyme catalysisGlucose concentration (g glucose (100 g of solution)Maximum glucose concentration (g glucose (100 g of solution)Concentration of an oligosaccharide with n glucose units (g dmTotal concentration of oligosaccharides and polysaccharides consisting of more than seven glucose units (g dmParameter in velocity expression (g dm À3 ) (eqns (2) and (11))Michaelis±Menten constant for an n-mer oligosaccharide (g oligosaccharide dmMaximal velocity for digestion rate of an n-mer oligosaccharide (h À1 ) (eqn (2)) k n Proportional parameter for the formation of glucose or an n-mer oligosaccharide from larger oligosaccharides (h À1 ) (eqns (10) and (12) INTRODUCTIONStarch hydrolysates are often used as substrates in the fermentative production of alcohols, amino acids, biopolymers, carboxylic acids and enzymes. 1 In the present study, the sacchari®cation of wheat starch to glucose was investigated with the intention of fermenting the glucose to lactic acid.2,3 The sacchari®cation and fermentation steps are often integrated to reduce the effect of glucose inhibition in the two process steps and a kinetic model is useful in evaluating whether the sacchari®cation and the fermentation steps should be performed simultaneously or separately. It is important to determine the model parameters for each step individually, and in this study an empirical kinetic model was developed which described enzymatic wheat starch sacchari®cation. The model will be used for simulation and optimisation of the total process of fermentative production of lactic acid from wheat starch.In the present study, starch was hydrolysed in two separate steps: liquefaction and sacchari®cation. In the liquefaction step the starch was hydrolysed to soluble oligosaccharides using a thermostable a-amylase. This enzyme is an endoamylase which randomly attacks the a(1→4) glucosidic linkages of starch to reduce the length of the starch chains. In the subsequent sacchari®cation step, the oligosaccharides were further hydroly...

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New Industrial Products from Starch

Cited by 74 publications

References 22 publications

Microwave-assisted liquefaction of wood with polyhydric alcohols and its application in preparation of polyurethane (PU) foams

Microwave-assisted liquefaction of wood with polyhydric alcohols and its application in preparation of polyurethane (PU) foams

Mathematical modeling of maltose hydrolysis in different types of reactor

A kinetic model for enzymatic wheat starch saccharification

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