Well, they are almost the same thing. Both the commercial and wild yeast is nothing but Saccharomyces cerevisiae, the sugar-eating fungus. The only difference is that they occur differently and mostly they are different strains of the same species. The baker's yeast, nutritional yeast, brewer’s yeast, or wild yeast, have almost the same genetic makeup. There is very little difference genetically, but it does make a whole lot of difference in terms of flavor in the resultant product. There are more than 8000 strains of yeast as it is found almost everywhere worldwide. The Baker’s yeast is cultured strains that have been monitored for their performance and activity. They have more controlled activity and are more reliable than wild yeast.