Model-based fed-batch for high-solids enzymatic cellulose hydrolysis

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

Research output: Research - peer-reviewArticle

  • 106 Citations

Abstract

While many kinetic models have been developed for the enzymatic hydrolysis of cellulose, few have been extensively applied for process design, optimization, or control. High-solids operation of the enzymatic hydrolysis of lignocellulose is motivated by both its operation decreasing capital costs and increasing product concentration and hence separation costs. This work utilizes both insights obtained from experimental work and kinetic modeling to develop an optimization strategy for cellulose saccharification at insoluble solids levels greater than 15% (w/w), where mixing in stirred tank reactors (STRs) becomes problematic. A previously developed model for batch enzymatic hydrolysis of cellulose was modified to consider the effects of feeding in the context of fed-batch operation. By solving the set of model differential equations, a feeding profile was developed to maintain the insoluble solids concentration at a constant or manageable level throughout the course of the reaction. Using this approach, a stream of relatively concentrated solids (and cellulase enzymes) can be used to increase the final sugar concentration within the reactor without requiring the high initial levels of insoluble solids that would be required if the operation were performed in batch mode. Experimental application in bench-scale STRs using a feed stream of dilute acid-pretreated corn stover solids and cellulase enzymes resulted in similar cellulose conversion profiles to those achieved in batch shake-flask reactors where temperature control issues are mitigated. Final cellulose conversions reached approximately 80% of theoretical for fed-batch STRs fed to reach a cumulative solids level of 25% (w/w) initial insoluble solids.

LanguageEnglish (US)
Pages88-107
Number of pages20
JournalApplied Biochemistry and Biotechnology
Volume152
Issue number1
DOIs
StatePublished - Jan 2009
Externally publishedYes

Profile

Cellulose
Hydrolysis
Cellulase
Costs and Cost Analysis
Enzymes
Enzymatic hydrolysis
Costs
Zea mays
Economics
Temperature
Acids
lignocellulose
Saccharification
Enzyme kinetics
Temperature control
Sugars
Process design
Differential equations
Kinetics
Design optimization

Keywords

  • Biomass
  • Cellulase
  • Corn stover
  • Fed-batch
  • High-solids saccharification
  • Optimal control

ASJC Scopus subject areas

  • Biochemistry
  • Biotechnology
  • Bioengineering
  • Applied Microbiology and Biotechnology
  • Molecular Biology
  • Environmental Engineering

Cite this

Model-based fed-batch for high-solids enzymatic cellulose hydrolysis. / Hodge, David B.; Karim, M. Nazmul; Schell, Daniel J.; McMillan, James D.

In: Applied Biochemistry and Biotechnology, Vol. 152, No. 1, 01.2009, p. 88-107.

Research output: Research - peer-reviewArticle

Hodge, David B. ; Karim, M. Nazmul ; Schell, Daniel J. ; McMillan, James D./ Model-based fed-batch for high-solids enzymatic cellulose hydrolysis. In: Applied Biochemistry and Biotechnology. 2009 ; Vol. 152, No. 1. pp. 88-107
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