SEASONAL OCCURRENCE OF YEASTS AND YEAST-LIKE ORGANISMS IN THE RIVER DANUBE

One hundred and seventy yeast strains belonging to 14 genera and 29 sp ecies were isolated from 112 water samples of the river Danube in the area of Bratislava. The samples were collected through the year from A pril to March. Saccharomyces cerevisiae, Candida maltosa, Aureobasidiu m pullulans, Cystofilobasidium capitatum, Rhodotorula glutinis, Geotri chum candidum, and Candida krusei were the most frequent. The basidiom ycetous yeasts and yeast-like organisms with oxidative metabolism were present in approximately equal numbers to those with fermentative met abolism. Saccharomyces cerevisiae was the dominant yeast and was isola ted from 50% of all samples examined and represented approximately one quarter of the yeast community. Yeast densities ranged from 100 to 21 ,100 CFU per litre. The highest population density was observed in Oct ober. Cryptococcus albidus, Saccharomyces cerevisiae, Rhodotorula glut inis, and Aureobasidium pullulans formed the main part of the yeast po pulation in this month.