Results
Isolation of psychrophilic and psychrotolerant yeasts
The 34 soil and 14 water samples obtained from different
areas of King George Island were processed as
described in the Methods section. The suspensions
obtained from each soil samples were seeded onto nutritive
plates, and incubated in triplicate over a range
of temperatures (4, 10, 15 and 22°C). After 30–90 days
of incubation, approximately 30 to 60 yeast-like colonies
developed on each plate. In contrast, no colonies
or low colony numbers (4 to 8) appeared on plates from water samples. Because large numbers of isolates
were obtained, isolates were grouped according to their
isolation growth temperature and colony characteristics
such as pigmentation, texture, elevation and size.
Among the 64 groups, several differed only by isolation
growth temperature. These isolates were grown at different
temperatures and re-grouped according to
macromorphological characteristics at their optimal
growth temperature. In this way, 35 groups were ultimately
generated. Several isolates from each group (at
least one isolate per sampling site; a total of 78 isolates)
were selected for molecular and biochemical
analyses.