Dekkera/Brettanomyces yeasts for ethanol production from renewable sources under oxygen-limited and low-pH conditions

J Ind Microbiol Biotechnol. 2011 Aug;38(8):1079-88. doi: 10.1007/s10295-010-0885-4. Epub 2010 Oct 10.

Abstract

Industrial fermentation of lignocellulosic hydrolysates to ethanol requires microorganisms able to utilise a broad range of carbon sources and generate ethanol at high yield and productivity. D. bruxellensis has recently been reported to contaminate commercial ethanol processes, where it competes with Saccharomyces cerevisiae [4, 26]. In this work Brettanomyces/Dekkera yeasts were studied to explore their potential to produce ethanol from renewable sources under conditions suitable for industrial processes, such as oxygen-limited and low-pH conditions. Over 50 strains were analysed for their ability to utilise a variety of carbon sources, and some strains grew on cellobiose and pentoses. Two strains of D. bruxellensis were able to produce ethanol at high yield (0.44 g g(-1) glucose), comparable to those reported for S. cerevisiae. B. naardenensis was shown to be able to produce ethanol from xylose. To obtain ethanol from synthetic lignocellulosic hydrolysates we developed a two-step fermentation strategy: the first step under aerobic conditions for fast production of biomass from mixtures of hexoses and pentoses, followed by a second step under oxygen limitation to promote ethanol production. Under these conditions we obtained biomass and ethanol production on synthetic lignocellulosic hydrolysates, with ethanol yields ranging from 0.2 to 0.3 g g(-1) sugar. Hexoses, xylose and arabinose were consumed at the end of the process, resulting in 13 g l(-1) of ethanol, even in the presence of furfural. Our studies showed that Brettanomyces/Dekkera yeasts have clear potential for further development for industrial processes aimed at production of ethanol from renewable sources.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabinose / metabolism
  • Biomass
  • Biotechnology
  • Brettanomyces / genetics
  • Brettanomyces / metabolism*
  • Cellobiose / metabolism
  • Conservation of Natural Resources
  • Dekkera / genetics
  • Dekkera / metabolism*
  • Ethanol / economics
  • Ethanol / metabolism*
  • Fermentation
  • Glucose / metabolism
  • Hexoses / metabolism
  • Hydrogen-Ion Concentration
  • Oxygen / metabolism*
  • Pentoses / metabolism
  • Xylose / metabolism

Substances

  • Hexoses
  • Pentoses
  • Cellobiose
  • Ethanol
  • Xylose
  • Arabinose
  • Glucose
  • Oxygen