Journal of Industrial Microbiology and Biotechnology

, Volume 21, Issue 4, pp 247–253

Initiation of anaerobic growth of Saccharomyces cerevisiae by amino acids or nucleic acid bases: ergosterol and unsaturated fatty acids cannot replace oxygen in minimal media

  • K C Thomas
  • S H Hynes
  • W M Ingledew

DOI: 10.1038/sj.jim.2900584

Cite this article as:
Thomas, K., Hynes, S. & Ingledew, W. J Ind Microbiol Biotech (1998) 21: 247. doi:10.1038/sj.jim.2900584

Nine out of ten industrially important strains of Saccharomyces cerevisiae did not grow in minimal media under anaerobic conditions even when ergosterol and unsaturated fatty acids were provided. Anaerobiosis was maintained either by flushing the culture flasks with prepurified nitrogen or by incubating the flasks in an anaerobic chamber. Traces of oxygen present in ‘prepurified nitrogen gas’ were sufficient to initiate yeast growth and on removal of the oxygen by catalytic means the yeasts failed to grow. The yeast grew very well anaerobically if the medium was supplemented with a mixture of amino acids or with a mixture of purines and pyrimidines. The growth initiated by including a mixture of amino acids was further enhanced when the medium was supplemented with ergosterol and an unsaturated fatty acid. Since no oxygen requirement for the synthesis of amino acids or purines and pyrimidines has been demonstrated, growth promotion by these compounds under anaerobic conditions is most likely not by eliminating the need for oxygen for their synthesis. We suggest that the amino acids and the nucleic acid bases yielded, through some hitherto unknown reactions, small amounts of a molecular or usable form of oxygen which allowed key reactions essential for ‘anaerobic’ growth to proceed.

Keywords: yeast growth; sterols; unsaturated fatty acids; oxygen; anaerobiosis; amino acids; purine and pyrimidine bases; Saccharomyces cerevisiae

Copyright information

© Society for Industrial Microbiology 1997

Authors and Affiliations

  • K C Thomas
    • 1
  • S H Hynes
    • 1
  • W M Ingledew
    • 1
  1. 1.Department of Applied Microbiology and Food Science, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5A8CA