Effect of Overliming on the Toxicity of Dilute Acid Pretreated Lignocellulosics: The Role of Inorganics, Uronic Acids, and Ether-Soluble Organics

Thilini D. Ranatunga, Judith Jervis, Richard F. Helm, James D. McMillan, Robert J. Wooley

Research output: Contribution to journalArticlepeer-review

95 Scopus Citations

Abstract

Although the treatment of dilute acid pretreated lignocellulosics with calcium hydroxide or carbonate (overliming) is known to improve the fermentability of carbohydrate-rich hydrolyzate streams, a firm understanding of the chemistry behind the process is lacking. Quantitative evaluation of inorganics, uronic acids, and non-polar organics indicates that only a portion of the improvement can be ascribed to these materials. Upon overliming the concentrations of inorganics either increase (Ca, Mg), decrease (Fe, P, Zn, K) or remain relatively the same (Al, Na). Furthermore, organic compounds that are not extractable with tert-butyl methyl ether (MTBE) are toxic to Zymomonas mobilis CP4(pZB5). Overliming and direct neutralization are somewhat effective in removing sulfate anions, although sulfate toxicity is considerably less than that of acetic acid. Uronic acids were found to be non-toxic under pH controlled conditions. Copyright (C) 2000 Elsevier Science Inc.

Original languageAmerican English
Pages (from-to)240-247
Number of pages8
JournalEnzyme and Microbial Technology
Volume27
Issue number3-5
DOIs
StatePublished - Aug 2000

NREL Publication Number

  • NREL/JA-580-26431

Keywords

  • Ethanol
  • Ether-soluble organics
  • Lignocellulosics
  • Overliming
  • Uronic acids
  • Zymomonas

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