Archives of Microbiology

, Volume 150, Issue 1, pp 48–55

Ethanol production from xylose by Thermoanaerobacter ethanolicus in batch and continuous culture

  • Lynda S. Lacis
  • Hugh G. Lawford
Original Papers

DOI: 10.1007/BF00409717

Cite this article as:
Lacis, L.S. & Lawford, H.G. Arch. Microbiol. (1988) 150: 48. doi:10.1007/BF00409717

Abstract

The fermentation of xylose by Thermoanaerobacter ethanolicus ATCC 31938 was studied in pH-controlled batch and continuous cultures. In batch culture, a dependency of growth rate, product yield, and product distribution upon xylose concentration was observed. With 27 mM xylose media, an ethanol yield of 1.3 mol ethanol/mol xylose (78% of maximum theoretical yield) was typically obtained. With the same media, xylose-limited growth in continuous culture could be achieved with a volumetric productivity of 0.50 g ethanol/liter h and a yield of 0.42 g ethanol/g xylose (1.37 mol ethanol/mol xylose). With extended operation of the chemostat, variation in xylose uptake and a decline in ethanol yield was seen. Instability with respect to fermentation performance was attributed to a selection for mutant populations with different metabolic characteristics. Ethanol production in these T. ethanolicus systems was compared with xylose-to-ethanol conversions of other organisms. Relative to the other systems, T. ethanolicus offers the advantages of a high ethanol yield at low xylose concentrations in batch culture and of a rapid growth rate. Its disadvantages include a lower ethanol yield at higher xylose concentrations in batch culture and an instability of fermentation characteristics in continuous culture.

Key words

Thermoanaerobacter ethanolicusEthanolContinuous fermentationMutant selectionXylose fermentation

Copyright information

© Springer-Verlag 1988

Authors and Affiliations

  • Lynda S. Lacis
    • 1
  • Hugh G. Lawford
    • 1
  1. 1.University of TorontoTorontoCanada