Copper Removal by Enterobacter cloacae strain IrSuk1, Enterobacter cloacae strain IrSuk4a, and Serratia nematodiphila strain IrSuk13 Isolated from Sukolilo River-Indonesia

Abstract

Copper is one of the pollutants found in Sukolilo river due to industrial activities surrounding this area. The concentration of copper in this river has exceeded the threshold causing the death of organisms in the sea and various diseases. The presence of copper in the environment continually causes bacteria to develop copper removal mechanism by accumulation and biosorption so that copper removal occurs. Waste treatment by using indigenous bacteria is an effective and economical way to remove copper from the environment. This study aims to isolate and characterize bacteria from the Sukolilo River. Selected bacterial isolates were tested for copper accumulation and biosorption potential. The growth medium used was Luria Bertani with the addition of CuSO4. Bacterial identification was carried out based on the 16S rDNA gene. Bacterial resistance was tested by determining the Minimum Inhibitory Concentration (MIC) value. The ability of copper accumulation and biosorption is measured using atomic absorption spectrophotometer. The results of bacterial isolation from Sukolilo River have obtained three bacterial isolates with the MIC values of 9 mM CuSO4 and coded by strains IrSuk1, IrSuk4a, and IrSuk13. Each bacterial strain has high similarities with Enterobacter cloacae, Enterobacter cloacae strain subsp. dissolvens, and Serratia nematodiphila strain LMG 2683 respectively with a value of 96.68%, 98.31%, and 99.03%. Copper quantities accumulated by that three bacterial strain are of 0.96 mg, 0.85 mg,1.89 mg per gram dry weight of cells, respectively. The efficiency of copper biosorption by strains IrSuk1, IrSuk4a, and IrSuk13 was 68.78%, 68.34%, and 68.47%, respectively.