Saccharomyces kudriavzevii

Saccharomyces kudriavzevii
Scientific classification
Kingdom:	Fungi
Division:	Ascomycota
Class:	Saccharomycetes
Order:	Saccharomycetales
Family:	Saccharomycetaceae
Genus:	Saccharomyces
Species:	S. kudriavzevii
Binomial name
Saccharomyces kudriavzevii Naumov et al. 2000

Saccharomyces kudriavzevii, a type of yeast in the Saccharomyces sensu stricto complex. Its type strain is NCYC 2889T. It is used in production of alcoholic beverages, including lager beers and pinot noir wine. It is isolated widely from the bark of Oak trees (Quercus family).

"Saccharomyces" derives from Latinized Greek and means "sugar-mold" or "sugar-fungus", saccharo (σάκχαρις) being the combining form "sugar" and myces (μύκης, genitive μύκητος) being "fungus".

“Kudriavzevii” was named in honor of VI Kudriavzev, a Russian scientist who worked with yeast taxonomy and ecology, and also played a large role in introducing the wild strain of S. paradoxus into science (Naumov et al., 2000).

Other names include:

· S. kudriavzevii is the common scientific name

· Lager yeast

· Pinot Noir yeast

Saccharomyces kudriavzevii was initially isolated from decayed leaf (Kaneko & Banno, 1991) but is often isolated from bark of oak trees (Sampaio & Gonçalves, 2008).

This species of yeast is within the Saccharomyces clade and can be isolated from a variety of substrates and is unique in that it cannot live on galactose and is cryotolerant. Shown in Figure 2 is a summary of activity when grown on a variety of substrates. S. kudriavzevii, compared to S. cerevisiae.

Biology

Yeast cells can be isolated from a variety of natural substrates – virtually anything that contains sugars – such as decaying fruit, bark, and soil. Optimal growth for many yeasts occurs at 30 – 35 °C, but S. kudriavzevii is adapted to grow at much colder temperatures (Hittinger, 2013).

There are two forms at which yeast cells exist in – haploid and diploid – each of which are a part of the reproductive cycle of the organism. These labels have to do with the number of copies of chromosomes the cell hold, diploids having 2n, haploids having 1n. Haploid cells are those that have the ability to mate to haploids of the opposite mating type to form diploids. They have also been found to be hardier when exposed to varying and extreme conditions, so diploid yeast can go through meiosis, a cellular reproduction process, when exposed to these conditions to produce four haploid spores.

Many species within the Saccharomyces sensu stricto clade have been found to hybridize with other species, S. kudriavzevii included. In particular, it hybridizes with S. cerevisiae (Belloch et al., 2009). This hybridization is unique in that it likely resulted from a single hybridization even involving creation of chimeric chromosomes holding some S. kudriavzevii genes and some S. cerevisiae genes (Belloch et al., 2009).

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