Metabolic activity and bioweathering properties of yeasts isolated from different supraglacial environments of Antarctica and Himalaya.

Abstract

Yeasts have been frequently isolated from cold habitats, but their contribution to essential ecological processes such as the mineralization of organic matter in these environments is less known. Here, the diversity, metabolic capability, and extracellular enzyme profiles of yeasts from snow, blue ice and cryoconite hole environments from East Antarctica and cryoconite holes from a glacier in Western Himalaya were determined. Eighty-six yeast strains isolated were affiliated to the genera Glaciozyma, Goffeauzyma, Mrakia, Phenoliferia, and Rhodotorula. Variations in the abundance, diversity, physiological properties, extracellular enzyme and carbon substrate utilization patterns of the isolated yeasts, reflect the specific environmental conditions from which they were isolated. Overall, 20-90% of the yeasts across all habitat types and geographical locations produced extracellular enzymes to degrade proteins, esters, carbohydrates, pectin, cellulose, lignin, and tannin. About 10 and 29% of the yeasts also exhibited ability to solubilize rock-minerals like phosphate and silicate, respectively. Additionally, selected isolates were able to metabolize 28-93% of the carbon substrates comprising different compound classes on Biolog YT plates. Overall, the ability of yeasts to use diverse organic compounds prevalent on the glacier surface, points to their ecological significance in the decomposition of organic matter, cycling of nutrients, and in the weathering of minerals in supraglacial environments. Moreover, their wide metabolic capabilities suggest that they can colonize new niches and environments when meltwater export during the summer that enables links with surrounding ecosystems.