MOLD OF THE MONTH

VE Science believes education is essential in providing a safe, clean environment. We've provided some insight into the different types of mold commonly found in this area.

In honor of Superbowl Month: YEAST

 Ecology:

Yeast are unicellular fungi. One of the more well known characteristics (and most important for the purposes of this month’s mold) is the ability to ferment sugars for the production of ethanol. Budding yeast are true fungi of the phylum Ascomycetes, class Saccharomycetes (also called Hemiascomycetes). The true yeast is separated into one main order Saccharomycetales.  

And now, the important stuff:  

Beer:   In brewing, Saccharomyces carlsbergensis, named after the Carlsberg Brewery in Copenhagen, where it was first isolated in pure culture by Dr. Emil Christian Hansen (1842-1909) in 1883, is used in the production of several types of beers including lagers. S. carlsbergensis is used for bottom fermentation. S. cerevisiae used for the production of ales and conducts top fermentation, in which the yeast rise to the surface of the brewing vessel.  

Bread and Rolls:   The yeast's function in baking is to ferment sugars present in the flour or added to the dough. This fermentation gives off carbon dioxide and ethanol. The carbon dioxide is trapped within tiny bubbles and results in the dough expanding, or rising.

Kingdom:     Fungi                                              Phylum:       Ascomycota

Subphylum: Saccharomycotine                       Order:          Saccharomycetes

Family:         Saccharomycetaceae                  Genus:         Saccharomyces

 

GENUS: ACREMONIUM

 Ecology:

Acremonium is a fungal genus with a number of species, which are often found living in structures, frequently in insulation. These fungi are also widely distributed in the soil and in plant debris, and they can be found all over the world, in a variety of environments. There are several species of note within this genus, ranging from fungi, which can cause serious infections to fungi used in the production of pharmaceuticals.

Kingdom:     Fungi                                                  Phylum:         Ascomycota Order:            Hypocreales                                    Family:        Hypocreaceae    Genus:          Acremonium                                   Subphylum: Ascomycotina  

 Description:

Colonies of Acremonium are moderately rapid growing, maturing within five days. The texture of the colony is compact, flat or folded and occasionally raised in the center. It is velvety and membrane-like at the beginning, but may become cottony with age due to the overgrowth of loose hyphae. The color of the colony is white, pale gray or pale pink on the surface. 

Species: 

GENUS: FUSARIUM

 Ecology:

Fusarium is a large genus of filamentous fungi widely distributed in soil and in association with plants. Most species are harmless saprobes and are relatively abundant members of the soil microbial community. Some species produce mycotoxins in cereal crops that can affect human and animal health if they enter the food chain.

Pathogenicity:   Fusarium species are among the fungi causing infections referred to as phaeohyphomycosis. Fatal deep mycoses due to Fusarium ………have been reported in immunocompromised patients. Brain abscess, peritonitis, cutaneous

GENUS: CLADOSPORIUM

 Ecology:

Cladosporium spores are easily made airborne and as such are a common cause of respiratory problems; allergic reactions and can be an agent for hypersensitivity diseases. Cladosporium is most common in late summer and early autumn. It is one of the primary invaders in nature common to the degradation of dead plant material. Obviously one of the largest sources of dead plant material at this time of year is falling leaves. Thanks to Cladosporium, we are not knee deep in old leaves.  

 Kingdom:     Fungi

Phylum:         Ascomycota

Subphylum: Ascomycotina

Genus:          Cladosporium

 Description:

Cladosporium species are widely found in air, rotten organic material and frequently isolated as a contaminant on foods. In interiors, Cladosporium species are found in water damaged environments. Some species may be resistant to certain types of treated lumber. Cladosporium species are generally the most frequently encountered fungi in both outdoor and indoor air.

Colonies of Cladosporium appear gray to black or very dark green and can have a powdery appearance. Most Cladosporium species do not grow at temperatures above 35º C. 

 Species:

Cladosporium Cladosporioides
Cladosporium elatum
Cladosporium herbarum 

GENUS: STACHYBOTRYS

STACHYBOTRYS on wall surface

Ecology:

Stachybotrys is a dark greenish black mold that grows on material with a high cellulose content such as hay, straw, wicker and wood chips, as well as building materials including ceiling tile, drywall, paper vapor barriers, wallpaper, insulation backing, cardboard boxes, paper files, fiberboard, particleboard, jute, dust and wood. This mold requires very wet and humid conditions to establish colony growth and to maintain this growth. A healthy colony will have an oily appearance on the surface.

Stachybotrys has been implicated in causing a wide variety of reactions and severe lung complications. Exposed groups have exhibited increased lower respiratory symptoms, dermatological, eye and constitutional symptoms, chronic fatigue and allergy history. Longer duration exposure was associated with upper respiratory, skin and central nervous system disorders. Higher and longer duration exposure has been linked to immune modulation and even slight immune suppression. 

GENUS: CHAETOMIUM

CHAETOMIUM  on wall surface

 Ecology:

Chaetomium is a fungal genus that includes approximately 80 different species.  The species that is reported to be growing in building interiors and present in air samples is C. globosum. It does produce a variety of mycotoxins called chaetoglobsins whose health effects in humans is for the most part unknown. Because it is a toxigenic fungus, it is one of species sometimes identified as requiring special precautions in its remediation

 Description:

Chaetomium species are typically found in soil, decaying vegetation and the air. In interiors, Chaetomium can exist in building materials, soil, cellulose substrates, wood and straw. Several species have been reported to play a major role in the decomposition of cellulose made materials. These fungi are able to dissolve the fibers in cotton and paper, causing the materials to break down. Colonies of Chaetomium are rapid growing, cottony and white in color initially. As colonies age, the color becomes grey to olive. 

Chaetomium species are among the fungi causing infections referred to as phaeohyphomycosis. Fatal deep mycoses due to Chaetomium atrobrunneum have been reported in immunocompromised patients. Brain abscess, peritonitis, cutaneous lesions and onychomycosis may also develop through exposure to Chaetomium species. 

GENUS: ASPERGILLUS

ASPERGILLUS on corn kernels

 Ecology:

Aspergillus is a very common mold and for those of you that enjoy gardening, a regular guest on your clothing and skin. This mold will grow readily indoors on various construction substrates and has been linked to various maladies. There is also a good side to this mold. There are many uses in food production and the medical industry.  A. oryzae is used to ferment soybeans to soy sauce. A. terreus produces mevinolin, which is able to reduce blood cholesterol; A. niger is used in the bread and beer making industries (enzyme production) and also is able to decompose plastic. A. niger and A. ochraceus are used in cortisone production.

 Description:

Aspergillus species are commonly found worldwide in soil, living and decaying vegetation, compost piles and the air, especially in the autumn and winter months in the northern hemisphere. There are over 185 species identified, with approximately 20 species reported as causative agents of opportunistic infections in man. The fungi that produce aflatoxins (Aspergillus flavus and parasiticus), can infect important food and feed crops before, during and after harvest. 

In interiors, Aspergillus is found in household dust, building materials, ornamental plants, items of food and water.

Aspergillus clavatus                                     Aspergillus flavus    

Aspergillus fumigatus                                  Aspergillus glaucus group

Aspergillus nidulans                                     Aspergillus niger

Aspergillus oryzae                                       Aspergillus sydowii

Aspergillus terreus                                       Aspergillus ustus     

Aspergillus versicolor

Mycotoxin production is noted here because of the production of a particular mycotoxin: aflatoxin. Aflatoxins are a group of structurally related toxic compounds produced by certain strains of the fungi Aspergillus flavus and Aspergillus parasiticus. Aflatoxins produce acute necrosis, cirrhosis and carcinoma of the liver in a number of animal species. No animal species is resistant to the acute toxic effects of aflatoxins, so it is logical to assume humans may be similarly affected. Aflatoxins have been linked to studies of weapons of mass destruction as well.

GENUS: PENICILLIUM

 Ecology:

Penicillium are ubiquitous soil fungi preferring cool and moderate climates. They live mainly on organic biodegradable substances. They are commonly known as moulds and are among the main causes of food spoilage. Several species of Penicillium play a central role in the production of cheese and of various meat products. Penicillium nalgiovense is used to improve the taste of sausages and hams and to prevent colonization by other moulds and bacteria.

Most importantly, they are the source of major antibiotics, particularly penicillin and griseofulvin.

 Description:

Penicillium species are found in soil, decaying vegetation, compost piles and the air. In interiors, Penicillium species are found in food, cellulose and grains. In addition, common locations will include carpet, wallpaper and organic substances inside interior fiberglass duct insulation. Penicillium species other than Penicillium marneffei are commonly considered as contaminants, but may cause infections, particularly in immunocompromised hosts. Penicillium species are known to produce mycotoxins.

Colonies of Penicillium other than Penicillium marneffei are rapid growing, flat, filamentous and velvety, wooly or cottony in texture. The colonies are initially white and then become blue green, gray green, olive gray, yellow or pinkish in time. It commonly produces a strong musty odor. The over riding microscopic feature is that they form brush like clusters at the tips that are referred to as penicilli.   Penicillium is one of the first fungi to grow on water-damaged materials. It is an indicator organism for dampness.

Penicillium chrysogenum                           Penicillium citrinum            

Penicillium janthinellum                             Penicillium marneffei

Penicillium purpurogenum                         Penicillium verrucosum