Alkalitolerant Yeasts from Natural Biotopes

Using a solid nutrient medium containing alkaline buffer (pH 10) and an antibiotic, alkalitolerant yeasts were isolated from samples of soda-rich saline soils (solonchaks) of Armenia (Arazdayan) and the Transbaikal region (the Kungur Steppe). The species diversity of the yeast populations of the tested soda-rich soils was relatively insignificant. They only contained alkalitolerant representatives of asporogenic capsulated yeasts belonging to the species Cryptococcus laurentii, C. albidus, Rhodotorula glutinis, R. mucilaginosa,and Sporobolomyces roseus.C. laurentii representatives clearly dominated the isolates obtained, their number exceeding that of the other species by two to three orders of magnitude. All of the isolates grew on acidic wort agar, suggesting that they did not include obligate alkaliphiles.