Applied Biochemistry and Biotechnology

, Volume 124, Issue 1, pp 911–922

Ammonium hydroxide detoxification of spruce acid hydrolysates


  • Björn Alriksson
    • Biochemistry, Division for ChemistryKarlstad University
  • Ilona Sárvári Horváth
    • Biochemistry, Division for ChemistryKarlstad University
    • Institute of Chemical Engineering and Environmental Sciences, Department of Chemical Reaction EngineeringChalmers University of Technology
  • Anders Sjöde
    • Biochemistry, Division for ChemistryKarlstad University
    • STFI-Packforsk AB, Swedish Pulp and Paper Research Institute
  • Nils-Olof Nilvebrant
    • STFI-Packforsk AB, Swedish Pulp and Paper Research Institute
    • Biochemistry, Division for ChemistryKarlstad University

DOI: 10.1385/ABAB:124:1-3:0911

Cite this article as:
Alriksson, B., Horváth, I.S., Sjöde, A. et al. Appl Biochem Biotechnol (2005) 124: 911. doi:10.1385/ABAB:124:1-3:0911


When dilute-acid hydrolysates from spruce are fermented to produce ethanol, detoxification is required to make the hydrolysates fermentable at reasonable rates. Treatment with alkali, usually by overliming, is one of the most efficient approaches. Several nutrients, such as ammonium and phosphate, are added to the hydrolysates prior to fermentation. We investigated the use of NH4OH for simultaneous detoxification and addition of nitrogen source. Treatment with NH4OH compared favorably with Ca(OH)2, Mg(OH)2, Ba(OH)2, and NaOH to improve fermentability using Saccharomyces cerevisiae. Analysis of monosaccharides, furan aldehydes, phenols, and aliphatic acids was performed after the different treatments. The NH4OH treatments, performed at pH 10.0, resulted in a substantial decrease in the concentrations of furfural and hydroxymethylfurfural. Under the conditions studied, NH4OH treatments gave better results than Ca(OH)2 treatments. The addition of an extra nitrogen source in the form of NH4Cl at pH 5.5 did not result in any improvement in fermentability that was comparable to NH4OH treatments at alkaline conditions. The addition of CaCl2 or NH4Cl at pH 5.5 after treatment with NH4OH or Ca(OH)2 resulted in poorer fermentability, and the negative effects were attributed to salt stress. The results strongly suggest that the highly positive effects of NH4OH treatments are owing to chemical conversions rather than stimulation of the yeast cells by ammonium ions during the fermentation.

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© Humana Press Inc. 2005