Preparation of immobilized sulfate reducing bacteria (SRB) granules for effective bioremediation of acid mine drainage and bacterial community analysis

•A novel immobilized SRB granule was prepared to treat AMD.•High removal of heavy metals and sulfate was achieved.•Resistance to high concentrations of multiple metal ions was revealed.•Microbial community mainly included SRB and fermentative bacteria.

Heavy metal-resistant immobilized sulfate-reducing bacteria (SRB) granules were prepared to treat acid mine drainage (AMD) containing high concentrations of multiple heavy metal ions using an up-flow anaerobic packed-bed bioreactor. The bioreactor demonstrated satisfactory performance at influent pH 2.8 and high concentrations of metals (Fe 463 mg/L, Mn 79 mg/L, Cu 76 mg/L, Cd 58 mg/L and Zn 118 mg/L). The effluent pH ranged from 7.8 to 8.3 and the removal efficiencies of Fe, Cu, Zn and Cd were over 99.9% except for Mn (42.1–99.3%). The bacterial community in the bioreactor was diverse and included fermentative bacteria and SRB (Desulfovibrio desulfiricans) involved in sulfate reduction. The co-existing anaerobic fermentative bacteria (Clostridia bacterium, etc.) with the ability to use lactate as electron donor could explain the differences between actual lactate consumption and what would be expected based solely on sulfate reduction.