Coloured scanning electron micrograph (SEM) of brewer's yeast (Saccharomyces cerevisiae). Saccharomyces cerevisiae, also known as Baker's yeast, is a species of budding yeast. It is perhaps the most widely used yeast and has been used since ancient times in baking and brewing. It is used in beer production, bread making and alcohol fermentation processes. Shown here is a budding yeast along with other non-budding yeasts that contain bud scars on the ends of the yeast cells. S. cerevisiae is an important model organism in cell biology research and is the most thoroughly researched eukaryotic microorganism. Magnification: x2, 155 when shortest axis printed at 25 millimetres.