Soluble and insoluble solids contributions to high-solids enzymatic hydrolysis of lignocellulose

David B. Hodge, M. Nazmul Karim, Daniel J. Schell, James D. McMillan

Research output: Research - peer-reviewArticle

  • 162 Citations

Abstract

The rates and extents of enzymatic cellulose hydrolysis of dilute acid pretreated corn stover (PCS) decline with increasing slurry concentration. However, mass transfer limitations are not apparent until insoluble solids concentrations approach 20% w/w, indicating that inhibition of enzyme hydrolysis at lower solids concentrations is primarily due to soluble components. Consequently, the inhibitory effects of pH-adjusted pretreatment liquor on the enzymatic hydrolysis of PCS were investigated. A response surface methodology (RSM) was applied to empirically model how hydrolysis performance varied as a function of enzyme loading (12-40 mg protein/g cellulose) and insoluble solids concentration (5-13%) in full-slurry hydrolyzates. Factorial design and analysis of variance (ANOVA) were also used to assess the contribution of the major classes of soluble components (acetic acid, phenolics, furans, sugars) to total inhibition. High sugar concentrations (130 g/L total initial background sugars) were shown to be the primary cause of performance inhibition, with acetic acid (15 g/L) only slightly inhibiting enzymatic hydrolysis and phenolic compounds (9 g/L total including vanillin, syringaldehyde, and 4-hydroxycinnamic acid) and furans (8 g/L total of furfural and hydroxymethylfurfural, HMF) with only a minor effect on reaction kinetics. It was also demonstrated that this enzyme inhibition in high-solids PCS slurries can be approximated using a synthetic hydrolyzate composed of pure sugars supplemented with a mixture of acetic acid, furans, and phenolic compounds, which indicates that generally all of the reaction rate-determining soluble compounds for this system can be approximated synthetically.

LanguageEnglish (US)
Pages8940-8948
Number of pages9
JournalBioresource Technology
Volume99
Issue number18
DOIs
StatePublished - Dec 2008
Externally publishedYes

Profile

lignocellulose
enzymatic hydrolysis
sugars
Enzymatic hydrolysis
Sugars
hydrolysis
Hydrolysis
sugar
corn stover
furans
acetic acid
Furans
Acetic Acid
Acetic acid
furan
maize
enzyme
Zea mays
Enzymes
enzyme inhibition

Keywords

  • Cellulase
  • Corn stover
  • High-solids saccharification
  • Lignocellulosic hydrolyzates
  • Process integration

ASJC Scopus subject areas

  • Agronomy and Crop Science
  • Food Science
  • Process Chemistry and Technology
  • Applied Microbiology and Biotechnology

Cite this

Soluble and insoluble solids contributions to high-solids enzymatic hydrolysis of lignocellulose. / Hodge, David B.; Karim, M. Nazmul; Schell, Daniel J.; McMillan, James D.

In: Bioresource Technology, Vol. 99, No. 18, 12.2008, p. 8940-8948.

Research output: Research - peer-reviewArticle

Hodge, David B. ; Karim, M. Nazmul ; Schell, Daniel J. ; McMillan, James D./ Soluble and insoluble solids contributions to high-solids enzymatic hydrolysis of lignocellulose. In: Bioresource Technology. 2008 ; Vol. 99, No. 18. pp. 8940-8948
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