Fungal Selenium(VI) Accumulation and Biotransformation—Filamentous Fungi in Selenate Contaminated Aqueous Media Remediation

Abstract

While selenium is an essential trace element, its excessive intake causes adverse effects to human health. Therefore, selenium control and removal from water and soil are crucial in limiting environmental and human health risk. Various microorganisms have recently been exploited for use in remediation processes, especially filamentous fungi, which are efficient metal(loid) bioaccumulators with unique metabolic pathway of metal(loid) transformation into volatile derivatives. This contribution investigates the filamentous fungus Aspergillus clavatus' efficient and environmentally friendly selenium(VI) bioaccumulation and volatilization in selenium contaminated substrates remediation. The static batch culture experiments investigated these phenomena with initial selenium(VI) concentrations up to 89 mg L−1. The biovolatilization and bioaccumulation efficiency was calculated from selenium concentration data determined by inductively coupled plasma optical emission spectrometry in biomass and culture medium after a 14‐day cultivation period. The maximum selenium bioaccumulation capacity was almost 2.3 mg g−1 dry fungal biomass, with significant 2.8 mg g−1 biovolatilization during the 14‐day fungal incubation. Although bioaccumulation dominates selenium removal in diluted solutions, biotransformation into non‐harmful volatile derivatives ensures efficient selenium removal from aqueous media with extreme selenium concentrations up to 89 mg L−1. In contrast to biosorption/bioaccumulation process, biovolatilization leaves no solid residues with high selenium loads, thus confirming biovolatilization is the most suitable biological method for selenium removal from contaminated waters and sediments. In addition, filamentous fungal biomass application is highly beneficial in treatment of selenium contaminated aqueous media.