New article!!! Interplay between arsenic and selenium biomineralization in Shewanella sp. O23S

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.
AsS biominerals produced by Shewanella sp. O23S
AsS biominerals produced by Shewanella sp. O23S
Elemental map of AsS and Se(0) biominerals

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