Applied Microbiology and Biotechnology

, Volume 77, Issue 1, pp 61–68 | Cite as

Evaluation of continuous ethanol fermentation of dilute-acid corn stover hydrolysate using thermophilic anaerobic bacterium Thermoanaerobacter BG1L1

  • Tania I. Georgieva
  • Birgitte K. Ahring
Biotechnological Products and Process Engineering


Dilute sulfuric acid pretreated corn stover is potential feedstock of industrial interest for second generation fuel ethanol production. However, the toxicity of corn stover hydrolysate (PCS) has been a challenge for fermentation by recombinant xylose fermenting organisms. In this work, the thermophilic anaerobic bacterial strain Thermoanaerobacter BG1L1 was assessed for its ability to ferment undetoxified PCS hydrolysate in a continuous immobilized reactor system at 70°C. The tested strain showed significant resistance to PCS, and substrate concentrations up to 15% total solids (TS) were fermented yielding ethanol of 0.39–0.42 g/g-sugars consumed. Xylose was nearly completely utilized (89–98%) for PCS up to 10% TS, whereas at 15% TS, xylose conversion was lowered to 67%. The reactor was operated continuously for 135 days, and no contamination was seen without the use of any agent for preventing bacterial infections. This study demonstrated that the use of immobilized thermophilic anaerobic bacteria for continuous ethanol fermentation could be promising in a commercial ethanol process in terms of system stability to process hardiness and reactor contamination. The tested microorganism has considerable potential to be a novel candidate for lignocellulose bioconversion into ethanol.


Continuous fermentation Corn stover Fluidized-bed reactor Hemicellulose Thermophilic anaerobic bacteria Xylose 



We thank Quang Nguyen from Abengoa Bioenergy R&D, Chesterfield, MO and National Renewable Energy Laboratory (NREL), Golden, Colorado, for providing acid pretreated corn stover hydrolysate. We further thank Marie Just Mikkelsen from BioGasol ApS, Denmark for providing the strain and for performing the contamination tests.


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Copyright information

© Springer-Verlag 2007

Authors and Affiliations

  1. 1.BioScience and Technology Group, BioCentrum-DTUTechnical University of DenmarkLyngbyDenmark

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