The Role of Microbial Mats in the Removal of Hexavalent Chromium and Associated Shifts in Their Bacterial Community Composition

Raeid M.M. Abed*, Mary Shanti, Thirumahal Muthukrishnan, Zayana Al-Riyami, Bernhard Pracejus, Daniel Moraetis

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


Microbial mats are rarely reported for chromium-polluted ecosystems, hence information on their bacterial diversity and role in chromium removal are very scarce. We investigated the role of nine microbial mats, collected from three quarry sumps of chromium mining sites, in the removal of hexavalent chromium [Cr(VI)]. Bacterial diversity in these mats and community shifts after incubation with Cr(VI) have been investigated using MiSeq sequencing. In nature, a chromium content of 1,911 ± 100 mg kg–1 was measured in the microbial mats, constituting the third highest source of environmentally available chromium. The mats were able to remove 1 mg l–1 of Cr(VI) in 7 days under aerobic conditions. MiSeq sequencing of the original mats yielded 46–99% of the sequences affiliated to Proteobacteria, Firmicutes and Actinobacteria. When the mats were incubated with Cr(VI), the bacterial community shifted in the favor of Alphaproteobacteria and Verrucomicrobiae. We conclude that microbial mats in the quarry sumps harbor diverse microorganisms with the ability to remove toxic Cr(VI), hence these mats can be potentially used to remove chromium from polluted waters.

Original languageEnglish
Article number12
JournalFrontiers in Microbiology
Publication statusPublished - Jan 29 2020
Externally publishedYes


  • bacterial communities
  • hexavalent chromium
  • microbial mats
  • MiSeq
  • quarry sumps

ASJC Scopus subject areas

  • Microbiology
  • Microbiology (medical)

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