Screening yeast cells for absorption of selenium oxyanions

Certain yeast cells on solid nutrient medium produced colonies surrounded by a light zone of selenite absorption. This screening procedure resulted in the selection of 22 strains out of 200 isolates with different Se4+-absorbing capacity ranging from 16 to 98.8 μg Se4+ g−1 l−1 h−1. The highest rate of Se4+ elimination from the Na2SeO3 solution was observed with an oval shaped, cream pigmented fermentative yeast, tentatively called Candida sp. strain MS4. This strain was isolated from wastewater and found to accumulate selenium oxyanions. Se4+ uptake involved both inactive and active phenomena. The amounts of selenium (initial concentration 2 mg Se4+ l−1) removed from aqueous solution by inactive and active phenomena were 667 μg Se4+ g−1 l−1, and 1580 μg Se4+ g−1 l−1, respectively. The strain also removed selenate inactively (135 μg Se6+ g−1 l−1).