Simultaneous sulfate reduction and copper removal by a PVA-immobilized sulfate reducing bacterial culture

The effect of a sulfate reducing bacteria immobilized in polyvinyl alcohol (PVA) on simultaneous sulfate reduction and copper removal was investigated. Batch experiments were designed using central composite design (CCD) with two parameters, i.e. the copper concentration (10-100 mg/L), and the quantity of immobilized SRB in culture solution (19-235 mg of VSS/L). Response surface methodology (RSM) was used to model the experimental data, and to identify optimal conditions for the maximum sulfate reduction and copper removal. Under optimum condition, i.e. ∼138.5 mg VSS/L of sulfate reducing bacteria immobilized in PVA, and ∼51.5 mg/L of copper, the maximum sulfate reduction rate was 1.57 d^-1 as based on the first-order kinetic equation. The data demonstrate that immobilizing sulfate reducing bacteria in PVA can enhance copper removal and the resistance of the bacteria towards copper toxicity.