Differences between Yeasts and Molds
Both yeast and moulds are eukaryotes – organisms with cell nuclei and membrane-bound organelles in the kingdom Fungi.
The major differences between the two groups include:
|1.||Definition||A yeast is a unicellular, budding fungus.||A mold is a multicellular, threadlike fungus.|
|2.||Form||Grow as large single cells.||Grow as multiple tubular branches.|
|4.||Habitat||Very common. Can be found on fruit and berries, in the stomachs of mammals and on skin, among other places.||Typically found in damp, dark or humid areas.|
|5.||Appearance||White and thready. Usually oval in shape.||Mold has a fuzzy appearance and can be found in several shapes.|
|6.||Hyphae||Yeasts do not have true hyphae. Instead they form
|Molds have microscopic filaments called hyphae.|
|7.||Spore||Yeast is a not a sporing species of fungi.||Mold is a sporing fungi|
|8.||Colony morphology||Yeast colonies are soft, opaque and cream-colored.||Filamentous type colony with vegetative hyphae and aerial hyphae.|
|9.||Color||Yeasts are less colorful compared to molds (colorless).||Molds are very colorful and may be orange, green, black, brown, pink or purple.|
|10.||Incubation Temperature||Routine incubation temperature is usually 25oC to 30oC (room temperature).||Routine incubation temperature is usually 25o to 30o C, although 35o C incubation can be used
to differentiate some molds based on temperature tolerance or to determine whether organisms are diphasic.
|11.||Cultivation time||These organisms usually grow within 24 to 36 hours after inoculation on media.||These organisms usually grow more slowly than yeasts after
inoculation to media.
|12.||Aerobic/Anaerobic||Yeast can grow in aerobic as well as in anaerobic conditions.||Molds grow only in aerobic conditions.|
|13.||pH range for growth||Growth limited to a pH range of 4.0 to 4.5.||Mold can grow in a wider range of acidity (pH) levels than yeasts.|
|Identification bases on physiologic test and a few key morphologic differences.||Most clinical molds can be determined by microscopic examination of the ontogeny and morphology of their asexual spores.|
|15.||Reproduction||Most reproduce asexually through mitosis. Most common form called “budding.” A smaller number of yeasts reproduce by binary fission.||Reproduce through small spores, which can be either sexual or asexual.|
|16.||Asexual Spores||Blastospore||Sporangiospores and Conidia|
|17.||Sexual Spores||No Sexual Spores.||Zygospores, Ascospores, and Basidiospores|
|18.||Energy Production||Convert carbohydrates to alcohol and carbon dioxide in anaerobic through fermentation. Also obtain carbon from hexose sugars.||Secrete hydrolytic enzymes that degrade biopolymers such as starch, cellulose and lignin into simpler substances that can be absorbed.|
|19.||Health risks||Can cause infection in individuals with compromised immune systems.||Can cause allergic reactions and respiratory problems.|
|20.||Other risks||Comparatively less involved in spoilage.||Moulds cause a greater threat in terms of food spoilage and sanitation concerns, particularly in fresh produce.|
|21.||Uses||Ethanol production, baking, vitamin supplements, study of cell cycle.||Some molds are used in food production, for example, Penicillium is used in the production of cheese, Neurospora in the production of oncom, which is made from the by-product of tofu. Mold is also a crucial saprophyte.|
|22.||Species||1500 known species – 1% of all fungi.||There are 400,000 types of molds.|
|23.||Examples||Saccharomyces cerevisiae, Cryptococcus neoformans, etc.||Alternaria, Aspergillus, Fusarium, Mucor, Penicillium, Rhizopus, Trichophyton, etc.|
- Parija S.C. (2012). Textbook of Microbiology & Immunology.(2 ed.). India: Elsevier India.
- Sastry A.S. & Bhat S.K. (2016). Essentials of Medical Microbiology. New Delhi : Jaypee Brothers Medical Publishers.