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Copper biosorption by Serratia plymuthica: crucial role of tightly bound extracellular polymeric substances in planktonic and biofilm systems

Summary

Researchers discovered that a bacterium called Serratia plymuthica can effectively remove copper from contaminated water using special protective layers of polymers it produces. These polymer layers, especially the protein components, act like tiny magnets that capture copper ions from solution. The study found that when these bacteria form biofilms on porous surfaces, they become even more effective at removing copper from industrial wastewater, achieving up to 97% removal efficiency even under harsh acidic conditions.

Background

Heavy metals in aquatic environments pose significant environmental and human health risks. Bacterial extracellular polymeric substances (EPS) play a crucial role in biosorption by providing active binding sites for metal cations through functional groups. This study explores the role of EPS in copper biosorption using Serratia plymuthica strain As3-5a(5).

Objective

This study investigates the role of bacterial EPS as active binding surfaces for copper in both planktonic cells and biofilm-based adsorption systems using Serratia plymuthica strain As3-5a(5). The research aims to identify specific EPS fractions involved in metal binding and evaluate the potential of this strain for copper removal from industrial electroplating wastewater.

Results

Serratia plymuthica achieved 92% Cu(II) biosorption in planktonic systems and 98% in biofilm systems on sintered glass. Maximum biosorption occurred with late stationary phase cells (72 h), attributed to increased protein fraction in tightly bound EPS. In electroplating wastewater containing 40 mM Cu(II) at pH 1.9, the system achieved 97% Cu(II) biosorption.

Conclusion

Tightly bound EPS proteins, particularly those containing carboxyl groups, are crucial for Cu(II) biosorption. Serratia plymuthica strain As3-5a(5) shows strong potential for developing efficient biological systems for heavy metal removal from industrial wastewater, with biofilm-based systems demonstrating superior performance compared to planktonic systems.
  • Published in:Biodegradation,
  • Study Type:Experimental Study,
  • Source: PMID: 41545695, DOI: 10.1007/s10532-026-10245-6
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