Copper biosorption and ions release by Stenotrophomonas maltophilia in the presence of benzo[a]pyrene

To investigate metal biosorption in polluted environments where organic and inorganic pollutants coexisted, this study has focused on the removal of Cu(NO3)2 by Stenotrophomonas maltophilia in the presence of benzo[a]pyrene (BaP). Initial pH, biosorbent dosage, contact time and BaP concentration were the significant factors for Cu biosorption. The uptake capacities of 2 and 10 mg L−1 Cu(II) by 0.25 g L−1S. maltophilia were 7 and 26 mg g−1 at 0.5 h, respectively. Cu(II) biosorption included bioaccumulation, ions and macromolecules release, Ca2+ and Mg2+ exchange, functional groups attraction, and Cu(II) and NO3- bioreduction. During the biosorption process, S. maltophilia metabolically released K+, and metabolically independently exchanged Mg2+ and Ca2+ for Cu(II) bioaccumulation. When the initial concentration of Cu(II) was 2 or 10 mg L−1, the coexisted 1 mg L−1 BaP showed no significant influence on Cu(II) biosorption, ions release and cellular morphology.

► Effect of BaP on Cu(II) biosorption by Stenotrophomonas maltophilia   was studied.
► Cu(II) and NO3- were reduced to Cu(I) and NO2- by S. maltophilia.
► S. maltophilia released K+, and exchanged Mg2+ and Ca2+ for Cu(II) accumulation.
► Macromolecules were excreted to chelate Cu(II).
► Macromolecules could protect S. maltophilia from destruction by BaP.