BioEnergy Research

, Volume 5, Issue 2, pp 372–379 | Cite as

Low Temperature and Long Residence Time AFEX Pretreatment of Corn Stover

  • Bryan D. BalsEmail author
  • Farzaneh Teymouri
  • Tim Campbell
  • Mingjie Jin
  • Bruce E. Dale


Low temperature and long residence time pretreatments have been proposed as an alternative to conventional pretreatments within a centralized biorefinery, allowing for a decentralized pretreatment without high energy costs. Ammonia fiber expansion (AFEX™) pretreatment may be uniquely suitable for decentralized pretreatment, and this study considers the possibility of decreasing the temperature in AFEX pretreatment of corn stover. AFEX pretreatment at 40°C and 8 h produced comparable sugar and ethanol yields as conventional AFEX pretreatment at high temperatures and short residence time during subsequent hydrolysis and fermentation. Increasing the ammonia loading at these temperatures tends to increase digestibility, although the moisture content of the reaction has little effect. This study suggests a greater flexibility in AFEX pretreatment conditions than previously thought, allowing for an alternative approach for decentralized facilities if the economic conditions are appropriate.


AFEX Biofuel Corn stover Pretreatment Ammonia Regional processing 



Ammonia fiber expansion


National Renewable Energy Laboratory


Low temperature/long residence time



This project was funded in part by the Michigan Agricultural Experiment Station. Additional funding was provided by DOE Great Lakes Bioenergy Research Center ( supported by the US Department of Energy, Office of Science, Office of Biological and Environmental Research, through Cooperative Agreement DEFC02-07ER64494. AFEX is a trademark of MBI International. The corn stover used in this project was provided by the National Renewable Energy Laboratory, and the Spezyme CP, Multifect Xylanase, and Multifect Pectinase were donated by Genencor International. We would like to thank Christa Gunawan and Heather Hodge for providing the HPLC analysis, as well as Janette Moore for her help in performing enzymatic hydrolysis.


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Copyright information

© Springer Science+Business Media, LLC. 2011

Authors and Affiliations

  • Bryan D. Bals
    • 1
    Email author
  • Farzaneh Teymouri
    • 2
  • Tim Campbell
    • 2
  • Mingjie Jin
    • 1
  • Bruce E. Dale
    • 1
  1. 1.Biomass Conversion Research Laboratory, Department of Chemical Engineering and Material Science, and Great Lakes Bioenergy Research CenterMichigan State UniversityLansingUSA
  2. 2.MBI InternationalLansingUSA

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