Remediation of hexavalent chromium by consortia of indigenous bacteria from tannery waste-contaminated biotopes in Fez,Morocco

Bioremediation is a promising, safe and economical technology widely used to clean up both soils and wastewaters containing Cr(VI). Most work uses pure microbial cultures. Little research has been done with mixed microbial cultures. In this study, consortia of indigenous bacteria isolated from a polluted site have been used to study the effect of different conditions such as Cr(VI) concentration, metal ions, electron donors and pH on Cr(VI) reduction by the consortia. We also evaluate the microbial ability to detoxify repeatedly and continuously in a non-modified medium. Results show that consortia of indigenous bacteria are resistant to greater than 200 mg/L Cr(VI). However, mixed cultures exhibited decreasing diversity with increasing levels of chromate. The consortia show high Cr(VI) removal capacity under various conditions and exhibit an ability for continuous reduction of Cr(VI) up to three consecutive inputs. The consortia may be appropriate for environmental applications for Cr(VI) remediation.