Different S.cerevisiae strains produce more carbon dioxide (useful in bread making) or more alcohol (for brewing or wine-making). It is believed to have been originally found on the skin of grapes, although it was, for the first time, isolated 1938, from rotten figs in Merced, California.
There have been documented cases of Gut Fermentation Syndrome in humans with causative agent Saccharomyces cerevisiae in their intestines (measured in stool culture). The symptoms usually resolve after treatment with antifungals and a low carbohydrate diet.
Saccharomyces boulardii was isolated from lychee and mangosteen fruit. It is used to treat bacterial and rotaviral diarrhea but may cause fatal infection in immunocompromised individuals. S. boulardii is also used for for general digestion problems, irritable bowel syndrome (IBS), inflammatory bowel disease (IBD, Crohn's, Ulcerative Colitis), Lyme disease, relapsing Clostridium difficilecolitis, and bacterial overgrowth, lactose intolerance, urinary tract infections (UTIs), vaginal yeast infections, high cholesterol levels, hives, fever blisters, canker sores, and teen-age acne. S.boulardii can be found in Ultra-Levure, Syntol AMD, Jarrow formulas: Saccharomyces Boulardii+MOS, Nexabiotic probiotics.
Strain GSY2239 was derived from the industrial brewing strain Wyeast1388 used to ferment ale-style beer.
Probiotic strain of Saccharomyces cerevisiae CNCM I-3856 (ibSium®) was isolated by French researchers at Lesaffre and was found to benefit the gut microflora. Taking it as a supplement significantly shifts the composition of gut microbes from the predominance of proteolytic (Clostridium, Fusobacterium) to glucidolytic (Bifidobacterium, Bacteroides) bacteria after 8 weeks of CNCM I-3856 administration at 4x109 CFU/day. It might be best for irritable bowel syndrome with constipation.
Other probiotic strains include CNCM I-1077, CNCM I-1079, MUCL 39885 and NCYC Sc47 ⁄ NCYC 1026/