The role of microbial mats in the removal of hexavalent chromium and associated shifts in their bacterial community composition

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 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. The mats were able to reduce 1 mg l-1 of Cr(VI) in 7 days under aerobic and anaerobic conditions. MiSeq sequencing of the mats showed distinct shifts in the bacterial community composition after Cr(VI) incubation suggesting a role of these bacteria in the removal of Cr(VI).