Acremonium sp.

Genus/species (aliases): Acremonium sp.(Cephalosporium)

Classification:
 Ascomycete

Morphology:

  • Cell: 500 to 2000 micrometers in size. Ovoid to spherical in shape. Staining with H&E densely packed, stained hyphal packs are observed. Conidia hyaline usually consist of a single cell collecting post-secession at the head of the conidiogenous cell. Chlamydospores and sclerotia are sometimes present. Telemorphs present only in certain species.
  • Colony: Malt agar: Slow-growing colonies that get to a diameter of less than 25mm in 10 days on malt agar at a temperature of 20 degrees Celsius. Colonies are compact and moist, and over time they grow loose, cottony hyphae which are white, gray, or rose in color.
  • Spore: Hyphae are thin-walled and hyaline. Mostly, erect conidiogenous cells are formed in singles, but sometimes conidiophores with simple or verticillate branching occur. Single-celled spores are usually produced in slime drops or in dry chains.
  • Zygote: Conidiogenous cells separated by a basal septum, which are at times continuous with the hypha that they are formed from.
  • Ascus: Spores are single-celled on the end of the hyphae. Ascus is on the end of the hyphae and holds these cells.
  • Liquid Growth:

Physiological Traits:
Conidia are unable to germinate without the necessary nutrients. Dormant spores will readily germinate in a medium containing glucose, ammonium sulfate, magnesium sulfate, and potassium phosphate. Sulfate is necessary, as taking this away will reduce germ tube formation by around 20%. Temperature optimum range from 25 to 37 degrees Celsius. 

Ecological Traits: 
Commonly found in plant debris and soil.


Distinguishing Features: 
Only grow in moist conditions.Both Fusarium sp. and Acremonium are both hyaline, septate molds that sometimes produce shades of red, blue, or purple pigments during sporulation. These two molds can be distinguished using DNA analyses.

Role in wine:
Spoiled wine. Acremonium sp. infection in wine can lead to the formation of TCA (2,4,6-trichloroanisole) and TBA (2,4,6-tribromoanisole). These compounds are implicated in the “corked” character of some wines.


Sensitivities:

SO2: Sensitive

Sorbate: Sensitive (Deacreses Amino acid transport)

DMDC: not sensitive

pH: best growth at ph of 6.5

Acids: sensitive

Ethanol: sensitive

Anaerobiosis: obligate aerobe

Heat: sensitive(optimal at 23 degrees Celsius)

References: 
Zoecklein, Bruce. Enology Notes # 144, October 2nd, 2008. Virginia Tech University. http://www.fst.vt.edu/extension/enology/EN/144.html