Importance and Significance of Molds and Yeast
The Basic Features, Habits, and Characteristics of Mold and Yeast
Apr 5, 2009
Unlike algae, which photosynthesize and make their own food, fungi have happy lives in dark or light places as they digest simple organic foods like paper, cardboard, glues and starch. They are helpful when they digest logs, twigs and leaves, produce antibiotics or help make cheeses. They are problematic when they grow in and on houses and people and damage them. The fungi are important to know.
Penicillium is the mold that many know as a producer of penicillin. It is a mold that literally has saved lives because of the useful antibiotic produced. A number of species of Penicillium, P. roquefortii and P. camembertii, are familiar to cheese lovers. Click on the pictures below in this article to get a better view of molds and yeasts.
Aspergillus is a less familiar name, but this genus of mold is responsible for allergy and pulmonary conditions in both humans and animals. Contaminated grain with Aspergillus mold and spores has wiped out entire flocks of birds and chickens in the pulmonary form of the disease known as aspergillosis. Aflatoxins, produced by some species of Aspergillus, are dangerous carcinogenic (cancer-causing) biochemicals released into contaminated batches of corn, peanuts and other nut and grain products.
Saccharomyces is the genus name for a common yeast used for leavened and baked bread, beers, wines and whiskeys. People all over the earth celebrate the good yeasts on a daily basis. Yeasts are fermenters and produce alcohol and carbon dioxide from the starch or sugars they inhabit by accident or intent. If there are no yeasts in the dough, then flat bread is produced: matzo, pita or pizza. If lots of yeast are present, the dough turns into a rising loaf with a nice fresh-baked odor. A combination of carbon dioxide gas and some alcohol vapor elevates the loaf and both quickly escapes from the baked bread.
Candida albicans is a yeast found in humans that may exist without causing harm (commensalism), or may cause irritating infections of the mouth, gastrointestinal tract and other mucosal areas of the body. In some instances, C. albicans may become blood-borne (septicemic) and cause damage to the kidneys and other internal organs. The yeast may become particularly aggressive in individuals on steroids (prednisone, corticosteroids), broad-spectrum antibiotics, or hormone therapy.
Agaricus campestris is the common edible mushroom of the supermarket or grocery. There are many other edible and delicious fungi.
Some fungi are poisonous and toxic, they are to be avoided at all costs. Never eat unknown fungi, unless certified and approved by a food company or expert mycologist.
Comparison of Molds and Yeasts
The molds and yeasts are easy to tell apart, one from the other, most of the time.
- Molds grow by extension of hyphae, yeasts by budding (some by dividing in half= binary fission)
- Molds produce asexual spores, yeasts typically make buds that break off and start new cells
- Molds and yeasts each have sexual phases, but the asexual cells and buds are more common
- Mold wall stucture is chemically dfferent from yeast wall stucture
- Molds tend to be more destructive to natural and man-made materials, yeasts are less so.
Fungal Culture and Identification in Mycology
Molds have characteristic sporulating characteristics that can help place them in certain phyla or special groups. For example, gilled fungi are Basidiomycota. Sporangial fungi like Rhizopus, the common black- bread mold, are Zygomycota. The Ascomycota class included all fungi that form sexual ascospores. Many fungi do not show a sexual phase, these fungi are called Deuteromycota.
Mycologists are specialists in microbiology who can isolate, culture and characterize and name the fungi that are isolated. Fungi are identified and named to indicate their relationship, one to another, and to enable an understanding of their ecology and physiology. This permits microbiologists to further know , understand and investigate fungi in a logical scientific way. For more information on molds and mold features and control click on these links 1. mold features 2. mold control
That is it for now. Time for some basidiomycete, pardon, mushroom soup! Cheers for the fungi!
Sources
Tortora,G.J., B.R. Funke, and C.L. Case. 2001. Microbiology An Introduction.7th ed., Benjamin Cummings / Addison Wesley Longman, Inc. San Francisco 887pp
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