Scaling up and benchmarking of ethanol production from pelletized pilot scale AFEX treated corn stover using Zymomonas mobilis 8b

ABSTRACT

This report outlines the recent scale-up of AFEX pretreatment from the laboratory to pilot scale. Sugar yields were improved by 19 and 15% for glucose and xylose, respectively. Further improvement was achieved when scaling up the hydrolysis and fermentation of AFEX-treated corn stover to 2500 L working volume. Benchmarking was performed using CTec 3 and HTec 3 enzymes along with Zymomonas mobilis 8b. Subsequently, the seed train was modified to use a hydrolysate-based medium as a replacement for pure sugars and nutrients. Fermentation performance was comparable following this change. Economic analysis showed a 19% reduction in MESP for the new process over the previous benchmark process.

KEYWORDS:

• Pelletization
• commercialization
• AFEX
• hydrolysis
• seed train

Acknowledgments

This work was supported by the 21st Century Jobs Fund received through the Michigan Strategic Fund from the State of Michigan [Grant Case-48166]; the US Department of Energy [Award no. DE-EE0005071]; and the Great Lakes Bioenergy Research Center [Grant DE-FC02-07ER64494].

MBI holds the exclusive license to distribute AFEX™ technology. AFEX™ is a trademark of MBI. The authors would like to thank Christa Gunawan for her guidance for performing enzymatic hydrolysis using AFEX pellets and HPLC analysis; Josh Videto, Chandra Nielson, and Tim Campbell for performing the AFEX pretreatment; and Tonya Tiedje, Joe Kirkpatrick, Nathan Klintworth, Kelly Fell, Ben Haller, and Alaina Pardonnet for assisting with the pilot scale hydrolysis and fermentation. We would like to thank Novozymes for supplying the commercial enzymes.

Disclaimer: This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that it use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

Office of Science [DE-FC02-07ER64494]; 21st Century Jobs Trust Fund [48166]; U.S. Department of Energy [DEEE0005071]