Mold Vs. Yeast

Mold Vs. Yeast

Mold and yeast belong to the fungi kingdom of eukaryotic organisms. Let's find out the differences with respect to both these groups of fungi.
We have all seen some or the other sort of mold, be it on stale loaves of bread, or on the walls and ceilings during prolonged rainy weather. Yeast is also something that most of us are aware of, many of us have even used it for culinary purposes. Well, since both of these fungi types are so familiar to us, albeit on a superficial level, let's dig a little deeper to find out more about them, including their individual characteristics, as well as the distinctive features that set them apart.


Molds belong to the fungus family. Mold colonies and growths are clearly visible to the naked eye, and are composed of multiple cells. This is one of the major differences between yeast and molds, as yeasts are unicellular organisms. Molds are structured as hyphae, which mean that they have the same branching structure of filaments that are found in most fungi, which multiply through vegetative reproduction. Molds usually occur as colonies of tubular hyphae, which contain a large number of nuclei that have the same genetic structure and composition. Each of these colonies is recognized as one single organism. Although biologically closer to plants than animals, molds cannot undergo the process of photosynthesis to derive nutrition. They have to rely upon organic matter for such purposes. This is the reason why we see mold growing on organic hosts, mostly dead or decaying. Molds produce spores, which can remain airborne or cling to other particles infinitely, till they chance upon a favorable breeding ground. They reproduce using both sexual and asexual reproduction methods. The ideal breeding environment for molds is moist, humid places that contain organic matter, away from strong lights and dry weather conditions. Some mold species are used for production and processing of various food items like Stilton cheese, soy sauce, tempeh, etc.


Yeasts also belong to the fungus family of eukaryotic organisms. As opposed to molds, they are unicellular structures. Most yeast species reproduce asexually, either by the formation of new organisms on the existing one by way of budding, or by undergoing the reproductive process of binary fission, where a single organism divides into two separate, identical entities. Both yeast and molds require organic hosts to derive nutrition. Yeasts find widespread use in food preparation and processing due to their ability to break down carbohydrates and cause fermentation. Breweries and distilleries, where alcoholic beverages are produced, use yeasts on a large scale. It is also used extensively in bakeries for preparation of bread, and for uplifting the dough. For more information on yeast and related matters, check out the following links:Difference Between Molds and Yeast

Although belonging to the fungus kingdom, there are a few points of differences in relation to mold and yeast species that set them apart from each other. Let's take a look at such differentiating factors.

Point of DistinctionMoldYeast
StructureMulticellular with tubular and filamentous hyphae (branches)Mostly unicellular, and existing either individually or with buds growing on them
Predominance of OccurrenceAny organic environment having a moist/humid atmosphere and not exposed to harsh weather conditionsMostly occur naturally in oceans
Method of ReproductionProduction of sexual or asexual airborne sporesBudding or binary fission
AppearanceThreadlike, and appear in a wide variety of colors and huesRound or oval-shaped, dull colored, and mostly monochromatic

Not all molds are harmful, and a few mold species have actually benefited mankind, like Penicillium chrysogenum, from which the antibiotic drug Penicillin was developed by Alexander Fleming. Likewise, yeast is widely used for the production of alcoholic beverages and many baked food items. However, the possibilities of fungal infections and allergic reactions from both of these fungi types are equally present. Knowing more about the various species of yeasts and molds are the best ways to avoid the harmful ones and nurturing the beneficial ones.