REMOVAL OF SELENIUM FROM MINNESOTA INDUSTRIAL AND MUNICIPAL WASTEWATERS BY COMMON SOIL FUNGI

Selenium (Se) is essential in moderate doses to most organisms for the production of selenoproteins, but elevated levels in the environment can cause detrimental biological repercussions. Selenium bioavailability is highly linked to its oxidation state in the environment, and the Se forms common in oxic surface environments are Se(VI) and Se(IV), which are highly water soluble and bioavailable. Current strategies for removing Se from wastewaters are expensive and inefficient, but some environmentally ubiquitous fungi remove Se from solution by aerobic reduction of dissolved Se(+IV/VI) to form solid Se(0) and volatile Se(-II). To this end, culture experiments with Se-reducing fungi, Alternaria alternata and Alternaria strain “F7”, an isolate from Se-contaminated soil, were performed to quantify total Se removed from solution in two Se-contaminated Minnesota wastewaters. In parallel, a second set of cultures were assembled with nutrient-lean culture media (“AY”) and 2000 µg/L or 25 µg/L Se(IV or VI) to reflect the wastewaters’ Se content. Using a draw-and-fill method, samples were taken to monitor total Se in the aqueous phase at 0, 2, and 7 days. Solid-associated Se data was collected at the end of each experiment. As the industrial wastewater was lacking in N, P and C, a second and third set of experiments were designed with carbohydrate- or glycerin- based proprietary industry carbon additives and additional nutrients. The data presented here highlights the high potential for the mycoremediation of Se-contaminated wastewaters, and reveals that it is essential to understand the phase of selenium present in the contaminated water to achieve efficient bioremediation.