Our article “Interplay between arsenic and selenium biomineralization in Shewanella sp. O23S” was published in Environmental Pollution (read). The paper explores the complex interaction between arsenic and selenium metabolism in a strain of Shewanella previously isolated from a gold mine. This work is the product of a successful collaboration with scientists from Poland (Paulina Wójtowicz), Hungary (Mihály Pósfai and Zsombor Molnár) and Spain (Encarnación Ruiz-Agudo; Diego Baragaño and José Luis Gallego).
The main findings are summerized below:
- Shewanella sp. O23S reduced As and Se oxyanions to AsS and Se0(-S) biominerals.
- AsS (realgar) and As2S3 (orpiment) were formed using cysteine as a source of H2S.
- SeO42− and SeO32− reduction led to red Se0 with variable sulfur (-S) content.
- All biominerals were extracellular, amorphous, polydispersed and negatively-charged.
- The reduction of the two elements seems to involve seperate enzymes.
Geomicrobiology 