Kinetic study of detoxification of dilute-acid hydrolyzates by Ca(OH)2.

Detoxification of dilute-acid hydrolyzates by addition of Ca(OH)(2) (overliming) and cultivation of the detoxified hydrolyzates by Saccharomyces cerevisiae were examined. The examined overliming involves increasing the pH of the hydrolyzates to 9, 10, 11 or 12, keeping up to 90 min at different temperatures of 30, 45 and 60 degrees C, followed by readjustment of the pH to 5. Increasing the pH, time and/or temperature resulted in more effective degradation of furans and resulted in better fermentability for both of the tested hydrolyzates, but higher loss of the sugars was observed as well. Overliming of glucose and furfural solution at pH 12 showed a rapid decrease in concentration of these chemicals followed by a slow degradation process. Therefore, a kinetic model was proposed for the detoxification, where the sugars or furans make transient complexes with calcium ions and this complex will then be converted to the degradation product. The ANOVA analysis of the model resulted in an average R(2) of 0.99 for the model fitted to all the experimental data points.

[1]  Mohammad J. Taherzadeh,et al.  Conversion of dilute-acid hydrolyzates of spruce and birch to ethanol by fed-batch fermentation , 1999 .

[2]  Mohammad J. Taherzadeh,et al.  Acetic acid—friend or foe in anaerobic batch conversion of glucose to ethanol by Saccharomyces cerevisiae? , 1997 .

[3]  Bernard A. Prior,et al.  Production of ethanol from sugar cane bagasse hemicellulose hydrolyzate byPichia stipitis , 1988 .

[4]  Lo Gorton,et al.  Effect of different forms of alkali treatment on specific fermentation inhibitors and on the fermentability of lignocellulose hydrolysates for production of fuel ethanol. , 2002, Journal of agricultural and food chemistry.

[5]  Guido Zacchi,et al.  Ethanol from lignocellulosics: A review of the economy , 1996 .

[6]  L. Gustafsson,et al.  Inhibition effects of furfural on aerobic batch cultivation of Saccharomyces cerevisiae growing on ethanol and/or acetic acid. , 2000, Journal of bioscience and bioengineering.

[7]  M. Hidai,et al.  Substrate-dependent chemoselective aldose-aldose and aldose-ketose isomerizations of carbohydrates promoted by a combination of calcium ion and monoamines. , 2001, Carbohydrate research.

[8]  G. J. Hajny,et al.  Fermentation of wood sugars to ethyl alcohol , 1945 .

[9]  Mohammad J. Taherzadeh,et al.  Effect of pH, time and temperature of overliming on detoxification of dilute-acid hydrolyzates for fermentation by Saccharomyces cerevisiae , 2002 .

[10]  A Martinez,et al.  Effects of Ca(OH)(2) treatments ("overliming") on the composition and toxicity of bagasse hemicellulose hydrolysates. , 2000, Biotechnology and bioengineering.

[11]  L. Gustafsson,et al.  Characterization and fermentation of dilute-acid hydrolyzates from wood , 1997 .

[12]  L. Gustafsson,et al.  Physiological effects of 5-hydroxymethylfurfural on Saccharomyces cerevisiae , 2000, Applied Microbiology and Biotechnology.

[13]  V. Sunjic,et al.  Comparative study of C(2) epimerization of d-glucose and d-mannose catalyzed by water soluble organometallic complexes with nitrogen ligands , 1996 .

[14]  Bärbel Hahn-Hägerdal,et al.  Fermentation of lignocellulosic hydrolysates. II: inhibitors and mechanisms of inhibition. , 2000 .

[15]  J N Nigam,et al.  Bioconversion of water-hyacinth (Eichhornia crassipes) hemicellulose acid hydrolysate to motor fuel ethanol by xylose-fermenting yeast. , 2002, Journal of biotechnology.

[16]  A Martinez,et al.  Detoxification of Dilute Acid Hydrolysates of Lignocellulose with Lime , 2001, Biotechnology progress.

[17]  J N Nigam,et al.  Ethanol production from wheat straw hemicellulose hydrolysate by Pichia stipitis. , 2001, Journal of biotechnology.

[18]  Mohammad J. Taherzadeh,et al.  Effects of Furfural on the Respiratory Metabolism of Saccharomyces cerevisiae in Glucose-Limited Chemostats , 2003, Applied and Environmental Microbiology.

[19]  L. Gustafsson,et al.  The effects of pantothenate deficiency and acetate addition on anaerobic batch fermentation of glucose by Saccharomyces cerevisiae , 1996, Applied Microbiology and Biotechnology.

[20]  M. Galbe,et al.  Ethanol production from enzymatic hydrolysates of sugarcane bagasse using recombinant xylose-utilising Saccharomyces cerevisiae , 2002 .

[21]  S. Osanai,et al.  C-2 Epimerization of Aldoses by Calcium Ion in Basic Solutions. A Simple System to Transform D-Glucose and D-Xylose into D-Mannose and D-Lyxose , 1993 .

[22]  Leif J. Jönsson,et al.  Comparison of different methods for the detoxification of lignocellulose hydrolyzates of spruce , 1999 .

[23]  Jervis,et al.  The effect of overliming on the toxicity of dilute acid pretreated lignocellulosics: the role of inorganics, uronic acids and ether-soluble organics. , 2000, Enzyme and microbial technology.