Basic interactions of Aspergillus niger with Se(IV)

Filamentous fungus Aspergillus niger is commonly found on decaying vegetation or in indoor environment and has a number of uses, including application in bioremediation. Hence, the basic interactions of this common mould with selenite were studied, including biovolatilization, bioaccumulation and toxicity effects of selenite on fungal growth. The fungal strain, originally isolated from noncontaminated soil, was cultivated under aerobic conditions on liquid cultivation media with concentration of Se(IV) 19 or 27 mg.l-1 during 25 days. The fungal growth in the presence of selenite was not inhibited when compared to control, only the sporulation was reduced. The concentration of Se(IV) in liquid medium decreased rapidly within first ten days to 1 mg.l-1. However, according to results from the 25th day of cultivation, the concentration of total selenium in medium did not change significantly and only negligible amount of selenium (less then 1%) was bioaccumulated. That indicates some biotransformation of selenite into other selenium species. During the cultivation, up to 21% of total amount of selenium was transformed into volatile derivatives (biovolatilization) by filamentous fungus A. niger.