Fungus activity promoted transformation of REEs during bio-oxidation of Mn(II)

Yu, Q.; Onuki, Toshihiko; Tanaka, Kazuya*  ; Kozai, Naofumi   ; Sakamoto, Fuminori  ; Tani, Yukinori*

It is well known that microorganisms possess high sorption capability for REEs. However, the biological effect of metabolically active fungus on the transformation of REEs in aquatic environment is unclear. This study compared the biotransformation of REEs during biooxidation of Mn(II) in the absence of trisodium citrate versus that in the presence of trisodium citrate. In the absence of trisodium citrate, one of the biomolecules released from the fungus associated only with Ce and not with the other REEs or Fe, suggesting that this biomolecule specifically associates with Ce(IV) and is different from siderophore like substances. In contrast, in the presence of trisodium citrate, release of the specific Ce(IV) binding biomolecule was not observed. The present findings highlight that microbe adaptation and defense mechanisms could convert Ce to a more mobile form at the water Mn oxide interface.