Cold-adapted yeasts from Austral Argentine Sea

DE GARCÍA VIRGINIA; VAN BROOCK MARÍA

Dublin

Conferencia; CAREX Conference on Life in Extreme Environments; 2011

CAREX

Yeasts are distributed in almost every part of aquatic environments. Marine yeasts are reported to be truly versatile agents of biodegradation; they participate in a range of ecologically significant processes in the sea, especially in estuarine and near-shore environments. Among such activities, decomposition of plants substrates, nutrient-recycling, biodegradation of oil/recalcitrant compounds and parasitism of marine animals are important. Eighty percent of the biosphere is at low temperatures (3 - 7 °C) and 90 % of marine habitats are at less than 5 °C. These extreme cold environments are frequently colonized by extremophilic yeasts known as psychrotolerant and psychrophiles; they have metabolic adaptations to survive at low temperatures. Occurrence of cold-adapted yeasts in sea water from Austral Argentinian Sea has been studied for the first time and is reported here. Six water samples were collected from Austral Argentinean Sea (3 from Beagle channel and 3 from Cape Horn meridian), in April of 2010, 100 mL were filtrated; filters were incubated at 10 ºC in MYP agar with and without NaCl 5 %, for up to 1 month. A total of 70 strains were isolated, highest yeasts viable counts (CFU L–1) were found in the second point of Cape Horn meridian, this point presented the maximum salinity (33,91 psu) and second lowest temperature (6,32 °C). Strains of Sakaguchia dacryoidea, Metschnikowia australis, Candida oleophila, Protomyces inouyei, Kondoa aeria, Udeniomyces puniceus, Sporobolomyces sp.nov., Debaryomyces hansenii, Bullera oryzae, Cryptococcus sp.nov., Rhodosporidium diobovatum, Candida deformans, Candida takamatsuzukensis were identified. These results are in agreement with reports on yeast diversity from other marine environments of the world, also new species have been found. This is the first report of cold-adapted yeasts on this unexplored extreme environment. Cold extreme environments are potential source of new taxa with desirable characteristics, which could be explored further for metabolic and biotechnological properties. It also contributes to understanding global warming consequences. Microorganisms present in sea environments may be released from glacial environments (polar areas) and complement/change existing microbial communities therein.