Dilute-Sulfuric Acid Pretreatment of Corn Stover in Pilot-Scale Reactor: Investigation of Yields, Kinetics, and Enzymatic Digestibilities of Solids

Daniel J. Schell, Jody Farmer, Millie Newman, James D. McMillan

Research output: Contribution to journalArticlepeer-review

402 Scopus Citations

Abstract

Corn stover is a domestic feedstock that has potential to produce significant quantities of fuel ethanol and other bioenergy and biobased products. However, comprehensive yield and carbon mass balance information and validated kinetic models for dilute-sulfuric acid (H2SO4) pretreatment of corn stover have not been available. This has hindered the estimation of process economics and also limited the ability to perform technoeconomic modeling to guide research. To better characterize pretreatment and assess its kinetics, we pretreated corn stover in a continuous 1 t/d reactor. Corn stover was pretreated at 20% (w/w) solids concentration over a range of conditions encompassing residence times of 3-12 min, temperatures of 165-195°C, and H2SO4 concentrations of 0.5-1.4% (w/w). Xylan conversion yield and carbon mass balance data were collected at each run condition. Performance results were used to estimate kinetic model parameters assuming biphasic hemicellulose hydrolysis and a hydrolysis mechanism incorporating formation of intermediate xylo-oligomers. In addition, some of the pretreated solids were tested in a simultaneous saccharification and fermentation (SSF) process to measure the reactivity of their cellulose component to enzymatic digestion by cellulase enzymes. Monomeric xylose yields of 69-71% and total xylose yields (monomers and oligomers) of 70-77% were achieved with performance level depending on pretreatment severity. Cellulose conversion yields in SSF of 80-87% were obtained for some of the most digestible pretreated solids.

Original languageAmerican English
Pages (from-to)69-86
Number of pages18
JournalApplied Biochemistry and Biotechnology - Part A Enzyme Engineering and Biotechnology
Volume108
Issue number1-3
DOIs
StatePublished - 2003

Bibliographical note

Posted with permission

NREL Publication Number

  • NREL/JA-510-34471

Keywords

  • Corn stover
  • Dilute-sulfuric acid
  • Enzymatic conversion
  • Kinetics
  • Pilot scale
  • Pretreatment
  • Xylan conversion

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