Isolated indigenous yeasts from Antarctica with the ability to remove toxic hexavalent chromium

CRUZ, ELÍAS L.; PAJOT, HIPÓLITO F.; MARTORELL, MARÍA M.; MAC CORMACK, WALTER P.; DE FIGUEROA, LUCÍA I. C.; FERNÁNDEZ, PABLO M.

CHEMISTRY AND ECOLOGY

TAYLOR & FRANCIS LTD

Año: 2022 p. 1 - 18

0275-7540

Seven chromate-reducing yeasts isolated from Antarctic soils (with no history of Cr(VI) contamination) wereevaluated as promising candidates for alleviating Cr(VI)-contamination. These yeast species have not beenextensively studied regarding Cr(VI) tolerance and reduction abilities. Based on their tolerance (up to 2 mM)and ability to remove Cr(VI) from culture media, two representative isolates of Candida sake #14 andDebaryomyces hansenii #35 were chosen. The resistant yeasts were cultivated in YM medium plus 1 mMCr(VI) at 25°C, causing a removal of ∼90 and ∼70% hexavalent chromium before reaching 96 h of cultureaccording to growth curves of C. sake #14 and D. hansenii #35, respectively. Cr(VI) removal kinetic analysisindicated that both isolates removed Cr(VI) by reduction to Cr(III), and incorporated a small portion into thebiomass. Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (SEM-EDX) confirms thebiosorption process, indicating the existence of a complex remediation mechanism. In conclusion, Antarcticais an extreme environment with a potential to discover promising new candidates for the removal of Cr(VI).These results are interesting from a biotechnological point of view since psychrotolerant yeasts could beinvolved in the design of a profitable technology for the elimination of the toxic form of Cr.