Discussion
Approximately 70% of the isolated yeasts could grow at
temperatures above 20°C, and 16% of them were able to
grow at ≥30°C. The predominance of psychrotolerant
fungi in cold environments has been previously noted,
and is attributable to seasonal and local increases in soil
temperature due to solar radiation [2]. In our study, the
temperature measured in situ at the different sampling
sites ranged from 0 to 11.9°C, but temperatures up to
20°C have been reported in this region [15-17]. The
main obstacle to assessing the yeast communities in Antarctic regions is the scant knowledge regarding their
environmental and nutritional requirements. Because
the yeast populations/species inhabiting terrestrial and
aquatic environments can colonize specific niches, no
appropriate method exists for efficiently isolating all species
[18]. In this work the yeasts were isolated using rich
media supplemented with glucose, because almost all
known yeasts can assimilate this sugar [19]. However,
this culture condition could favor the proliferation of
yeasts with high metabolic rates, to the detriment of
slow-growing yeasts. Nevertheless, large numbers and
high species diversity were attained in this study (22 species
from 12 genera). Cold-loving yeasts have been isolated
mainly from the Antarctic and the Arctic, and
from European and South American glaciers [10]. In all
of these environments, the most ubiquitous species are
Rhodotorula laryngis and Cr. victoriae. On the other
hand, C. sake, D. fristingensis, G. antarctica and Sp. salmonicolor
have been isolated only in the Southern Cone
(South American glaciers and Antarctica). This work
reports for the first time the isolation of Cryptococcus
gastricus, Cryptococcus gilvescens, D. fristingensis and
Leucosporidiella creatinivora from an Antarctic region.
Also isolated was W. anomalus, which is not generally
found in cold regions.