Biotechnology Letters

, Volume 34, Issue 12, pp 2259–2263 | Cite as

Energy consumption and greenhouse gas emissions from enzyme and yeast manufacture for corn and cellulosic ethanol production

  • Jennifer B. DunnEmail author
  • Steffen Mueller
  • Michael Wang
  • Jeongwoo Han
Original Research Paper


Enzymes and yeast are important ingredients in the production of ethanol, yet the energy consumption and emissions associated with their production are often excluded from life-cycle analyses of ethanol. We provide new estimates for the energy consumed and greenhouse gases (GHGs) emitted during enzyme and yeast manufacture, including contributions from key ingredients such as starch, glucose, and molasses. We incorporated these data into Argonne National Laboratory’s Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation model and observed that enzymes and yeast together contribute 1.4 and 27 % of farm-to-pump GHG emissions for corn and cellulosic ethanol, respectively. Over the course of the entire corn ethanol life cycle, yeast and enzymes contribute a negligible amount of GHG emissions, but increase GHG emissions from the cellulosic ethanol life cycle by 5.6 g CO2e/MJ.


Enzymes Ethanol Life-cycle analysis Yeast 



This work was supported by the Biomass Program of the Office of Energy Efficiency and Renewable Energy of the United States Department of Energy, under contract DE-AC02-06CH11357. The authors acknowledge Andy Aden of NREL, Martha Schlicher of Monsanto, and Ignasi Palou-Rivera of LanzaTech for helpful discussions.

Supplementary material

10529_2012_1057_MOESM1_ESM.docx (329 kb)
Supplementary material 1 (DOCX 329 kb)


  1. Aden A, Ruth M, Ibsen K, Jechura J, Neeves K, Sheehan J, Wallace B, Montague L, Slayton A, Lukas J (2002) Lignocellulosic biomass to ethanol process design and economics utilizing co-current dilute acid prehydrolysis and enzymatic hydrolysis for corn stover. National Renewable Energy Laboratory Technical Report (NREL/TP-510-32438)Google Scholar
  2. Argonne National Laboratory GREET Model (2012) Accessed 30 April 2012
  3. Cherubini F, Strømman AH (2011) Life cycle assessment of bioenergy systems: state of the art and future challenges. Bioresour Technol. doi: 10.1016/j.bioretech.2010.08.010 PubMedGoogle Scholar
  4. Dhutta A, Dowe N, Ibsen K, Schell DJ, Aden A (2010) An economic comparison of different fermentation configurations to convert corn stover to ethanol using Z. mobilis and Saccharomyces. Biotechnol Prog 26:64–72Google Scholar
  5. Finnveden G, Lindfors L-G, Stripple H (1994) Livscykelanalys av etanol ur sorterat hushållsavfall med starksyrahydrolys. IVL-Rapport B1168. Institutet för Vatten och Luftvårdsforskning, StockholmGoogle Scholar
  6. Humbird D, Davis R, Tao L, Kinchin C, Hsu D, Aden A, Schoen P, Lukas J, Olthof B, Worley M, Sexton D, Dudgeon D (May 2011) Process design and economics for biochemical conversion of lignocellulosic biomass to ethanol. National Renewable Energy Laboratory Technical Report (NREL/TP-5100-47764)Google Scholar
  7. Ingledew WM, Austin GD, Kraus JK (2009) Commercial yeast production for the fuel ethanol and distilled beverage industries. In: Ingledew WM, Kelsall DR, Austin GD, Kluhspies C (eds) The alcohol textbook, 5th edn. Nottingham University Press, Nottingham, pp 127–144Google Scholar
  8. Knauf M, Kraus K (2006) Specific yeasts developed for modern ethanol production. Sugar Ind 131:753–758Google Scholar
  9. MacLean H, Spatari S (2009) The contribution of enzymes and process chemicals to the life cycle of ethanol. Environ Res Lett. doi: 10.1088/1748-9326/4/1/014001 Google Scholar
  10. Natural Resources Canada (2006) Wood to ethanol and synthetic natural gas pathways. Accessed 18 April 2012
  11. Nielsen PH, Oxenbøll KM, Wenzel H (2007) Cradle-to-gate environmental assessment of enzyme products produced industrially in Denmark by Novozymes A/S. Int J LCA. doi: 10.1065/lca2006.08.265.1 Google Scholar
  12. Qi B, Luo J, Chen G, Chen X, Wan Y (2012) Application of ultrafiltration and nanofiltration for recycling cellulase and concentrating glucose from enzymatic hydrolyzate of steam exploded wheat straw. Bioresour Technol. doi: 10.1016/j.biortech.2011.10.049 Google Scholar
  13. Sheehan J, Aden A, Paustian K, Killian K, Brenner J, Walsh M, Nelson R (2004) Energy and environmental aspects of using corn stover for fuel ethanol. J Ind Ecol 7:117–146CrossRefGoogle Scholar
  14. Wang M, Han J, Haq Z, Tyner W, Wu M, Elgowainy A (2011) Energy and greenhouse gas emission effects of corn and cellulosic ethanol with technology improvements and land use changes. Biomass Bioenergy. doi: 10.1016/j.biombioe.2011.01.028 Google Scholar
  15. Zhang Z, Donaldson AA, Ma X (2012) Advancements and future directions in enzyme technology for biomass conversion. Biotechnol Adv. doi: 10.1016/j.biotechadv.2012.01.020 Google Scholar

Copyright information

© Springer Science+Business Media Dordrecht (outside the USA) 2012

Authors and Affiliations

  • Jennifer B. Dunn
    • 1
    Email author
  • Steffen Mueller
    • 2
  • Michael Wang
    • 1
  • Jeongwoo Han
    • 1
  1. 1.Argonne National LaboratoryCenter for Transportation ResearchArgonneUSA
  2. 2.Energy Resources CenterUniversity of Illinois at ChicagoChicagoUSA

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