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Keywords:

  • psychrophilic yeasts;
  • glacial environments;
  • Alpine glaciers

Abstract

The presence of psychrophilic yeasts in supra- and subglacial sediments, ice and meltwater collected from two glaciers of the Italian Alps (Forni and Sforzellina – Ortles-Cevedale group) was investigated. After incubation at 4 °C, subglacial sediments contained from 1.3 × 103 to 9.6 × 103 CFU of yeasts g−1. The number of yeast cells in supraglacial sediments was c. 10–100-fold lower. A significant proportion of isolated yeasts exhibited one or more extracellular enzymatic activities (starch-degrading, lipolytic, esterolytic, proteolytic and pectinolytic activity) at 4 °C. Selected isolates were able to grow at 2 °C under laboratory-simulated in situ conditions. In all, 106 isolated yeasts were identified by MSP-PCR fingerprinting and 26S rRNA gene sequencing of the D1/D2 region as belonging to 10 species: Aureobasidium pullulans, Cryptococcus gilvescens (over 50% of the total), Cryptococcus terricolus, Mrakia gelida, Naganishia globosa, Rhodotorula glacialis, Rhodotorula psychrophenolica, Rhodotorula bacarum, Rhodotorula creatinivora and Rhodotorula laryngis. Four strains, all belonging to a new yeast species, yet to be described, were also isolated.