Accumulation of nickel ion (Ni2+) by immobilized cells ofEnterobacter species

Summary AnEnterobacter species, isolated from electroplating effluent, could remove significant amount of nickel ion (Ni²⁺) from growth medium and sewage effluent. In order to construct a bioreactor to remove Ni²⁺ from electroplating effluent, bacterial cells were immobilized in polyacrylamide beads. The highest removal capacity (RC, mg of Ni²⁺/g of dry cells) and removal efficiency (RE, % of added Ni²⁺ removed by bacterial cells) of Ni²⁺ of immobilized bacterial cells were obtained by optimizing the growth conditions for the bacterial cells such as the composition of the growth medium, incubation time and incubation temperature; and the operational parameters of the bioreactor such as retention time and pH of the Ni²⁺ containing solution, respectively.