• Applied Chemistry for Engineering
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• v.33 no.6
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• pp.666-674
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• 2022

The removal efficiencies of nutrients (N and P) and heavy metals (Cu and Ni) by Rhodobacter blasticus and R. blasticus attached to polysulfone carriers, alginate carriers, PVA carriers, and PVA + zeolite carriers in synthetic wastewater were compared. In the comparison of the nutrient removal efficiency based on varying concentrations (100, 200, 500, and 1000 mg/L), R. blasticus + polysulfone carrier treatment showed removal efficiencies of 98.9~99.84% for N and 96.92~99.21% for P. The R. blasticus + alginate carrier treatment showed removal efficiencies of 88.04~97.1% for N and 90.33~97.13% for P. The R. blasticus + PVA carrier treatment showed removal efficiencies of 18.53~44.25% for N and 14.93~43.63% for P. The R. blasticus + PVA + zeolite carrier treatment showed removal efficiencies of 26.65~64.33% for N and 23.44~64.05% for P. In addition, at the minimum inhibitory concentration of heavy metals, R. blasticus (dead cells) + polysulfone carrier treatment showed removal efficiencies of 7.77% for Cu and 12.19% for Ni. Rhodobacter blasticus (dead cells) + alginate carrier treatment showed removal efficiencies of 25.83% for Cu and 31.12% for Ni.

• Applied Chemistry for Engineering
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• v.34 no.6
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• pp.640-648
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• 2023

The purpose of this study was to determine the inhibitory effect of heavy metals [Cd(II), Ni(II), and Zn(II)] on the growth of Rhodobacter species (Rhodobacter blasticus, Rhodobacter sphaeroides, and Rhodobacter capsulatus) and their potential use for Cd(II), Ni(II), and Zn(II) bioremoval from liquid media. The presence of toxic heavy metals prolonged the lag phase in growth and reduced biomass growth for all three Rhodobacter species at concentrations of Cd, Ni, and Zn above 10 mg/L. However, all three Rhodobacter species also had a relatively high specific growth rate against each toxic heavy metal stress test for concentrations below 20 mg/L and possessed a potential bioaccumulation ability. The removal efficiency by all strains was highest for Cd(II), followed by Ni(II), and lowest for Zn(II), with the removal efficiency of Cd(II) by Rhodobacter species being 66% or more. Among the three strains, R. blasticus showed a higher removal efficiency of Cd(II) and Ni(II) than R. capsulatus and R. sphaeroides. Results also suggest that the bio-removal processes of toxic heavy metal ions by Rhodobacter species involve both bioaccumulation (intracellular uptake) and biosorption (surface binding).