The presence of Saccharomyces cerevisiae DNA in various media used to propagate yeasts and its removal by ethidium monoazide

Aims:  In this study we demonstrate the interference of yeast extract in enumeration of Saccharomyces cerevisiae using real-time PCR and develop a method for its removal from the media using ethidium monoazide (EMA).
Methods and Results:  Using real-time PCR and primers to S. cerevisiae we demonstrate the presence of yeast DNA in various media as well as the media impact on S. cerevisiae real-time PCR standard curves. By pretreatment with EMA, we were able to remove this interference.
Conclusions:  Saccharomyces cerevisiae DNA can be found in a number of common laboratory media and may impact the enumeration of this yeast by real-time PCR. However, pretreatment with EMA eliminates this concern.
Significance and Impact of the Study:  We have developed a method for removal of contaminating DNA in yeast growth media.