Difference Between Yeast and Mold

Main Difference – Yeast vs Mold

Yeast and mold are two growth types of fungi. Fungi are unicellular or multicellular eukaryotic microorganisms. They live as saprophytes, externally decomposing organic materials and absorbing nutrients through their cell wall. The main difference between yeast and mold is that yeast is a unicellular type of fungi whereas mold is multicellular filaments of the fungi. Mold consists of tubular branches with multicellular nuclei. The reproduction of yeast occurs by budding. Mold reproduces by the production of sexual or asexual spores. Yeast is used in baking industry and ethanol production. Mold is used in the production of cheese.

Key Areas Covered

1. What is Yeast
      – Definition, Structure, Function
2. What is Mold
      – Definition, Structure, Function
3. What are the Similarities Between Yeast and Mold
      – Outline of Common Features
4. What is the Difference Between Yeast and Mold
      – Comparison of Key Differences

Key Terms: Budding, Fermentation, Fungi, Mold, Multicellular, Spores, Unicellular, Yeast

What is Yeast

Yeast refers to a microscopic fungus, consisting of a single oval cell. It is a unicellular structure. Yeast is oval-shaped and is mostly colorless or white in color. The most significant feature of yeast is its asexual reproduction method. Yeast produces a daughter cell as a bud. Therefore, the asexual reproduction method is called budding. Budding yeast is shown in the following video.

Video 1: Budding yeast

Yeast requires organic materials for obtaining their nutrients. They secrete enzymes to the external food sources and digest them to obtain simple forms of nutrients. Therefore, yeast can be used to produce ethanol by fermentation. It is also used in the baking industry to make the dough rise.

What is Mold

Mold refers to a growth form of fungus, which grows in the form of multicellular filaments called hyphae. Colonies of molds are visible to the naked eye. The multiplication of fungi occurs through vegetative reproduction. Tubular hyphae may contain a large number of nuclei with the same genetic composition. Mold grows on organic matter. It produces both sexual and asexual spores. A mold on feces is shown in figure 2.

Figure 2: Mold

Like yeast, molds obtain their nutrients by external enzymatic digestion of organic matter. They absorb nutrients through their cell wall. Molds are also used in food processing such as cheese, tempeh and soy sauce production.

Similarities Between Yeast and Mold

Both yeast and mold are two types of fungi.
Both yeast and mold contain a chitin cell wall.
Both yeast and mold are saprophytes.

Definition

Yeast: Yeats refers to a microscopic fungus, consisting of a single, oval cell.

Mold: Mold refers to a growth form of fungus, which grows in the form of multicellular filaments called hyphae.

Habitat

Yeast: Yeast is very common in the environment.

Mold: Molds can be found in damp, dark or steam-filled areas.

Appearance

Yeast: Yeast is oval in shape, and is colorless and smooth.

Mold: Mold has a fuzzy appearance, and the colors can be green, orange, black, brown, purple, and pink.

Energy Production

Yeast: Yeast converts carbohydrates to alcohol during fermentation.

Mold: Mold secretes hydrolytic enzymes to external food sources and absorbs nutrients.

Reproduction

Yeast: Yeast reproduces through budding.

Mold: Mold reproduces through either sexual or asexual spores.

Uses

Yeast: Yeast is used in baking industry and in the production of ethanol.

Mold: Mold is used in the production of cheese.

Examples

Yeast: Saccharomyces cerevisiae (baking yeast) and Cryptococcus neoformans are the examples of yeast.

Mold: Mucor, Penicillium, Rhizopus, and Aspergillus are the examples of mold.

Conclusion

Yeast and mold are two forms of fungi. Both yeast and mold are saprophytes that secrete digestive enzymes on the external organic matter to digest them and absorb nutrients through their cell wall. Yeats is a unicellular, oval-shaped organism whereas mold is a filamentous organism. The main difference between yeast and mold is the structure of each type of organism.

Reference:

1. “What is Yeast?” Red Star Yeast, Available here.
2. “What is Mold? – Definition, Types & Causes.” Study.com, Available here.

Media Courtesy:

1. “Budding yeast” by Darren Wilkinson (CC BY-SA 2.0) via Flickr
2. “Mold (Spinellus fusiger) on feces with dew” By Andrea massagli – Own work (CC BY-SA 4.0) via Commons Wikimedia