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 ethanolicus Ethanol Continuous fermentation Mutant selection Xylose fermentation 

Copyright information

© Springer-Verlag 1988

Authors and Affiliations

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

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