Why does Kluyveromyces lactis not grow anaerobically?
Ishtar Snoek (1), Yde Steensma (2)
(1) Wassenaarseweg 64, 2333 AL Leiden, Netherlands; (2) IBL, yeastgenetics, Leiden university, Wassenaarseweg 64, Leiden, 2333 AL, Netherlands
While some other yeast strains can grow under anaerobic conditions, Kluyveromyces lactis can not. In this paper we investigate the requirements for yeast to grow without oxygen through Saccharomyces cerevisiae. Surprisingly, the genes that are experimentally essential for anaerobic growth in S. cerevisiae are generally not the ones a literature search indicated. Comparison of the K. lactis genome with the genes found to be anaerobically important in S. cerevisiae, both experimentally determined or indicated in literature, yields 20 genes that are missing in K. lactis. The identity of these genes leads to the hypothesis that one of the more important problems K. lactis might have when growing in an anaerobic environment, is the import of sterols, which is essential when no oxygen is present.