Effect of molecular configuration on flocculation of Zn2+by the extracellular polymeric substance,poly-γ-glutamic acid
The interaction of extracellular polymeric substance(EPS)secreted by microorganisms and heavy metals plays an important role in the survival of microorganism,wastewater treatment and bioremediation.However,the structural characteristics of EPS molecules and its relationship with the"solution-floc"transition and the corresponding mechanism are still unclear.This study characterized the content of secondary structure,adsorption capacity,Zeta potential and chemical bonding mode of the soluble complex formed between the EPS,poly-γ-glutamic acid(γ-PGA),and Zn2+.Combined with the"solution-floc"transition of γ-PGA-heavy metal ions(γ-PGA-M)in the presence of both Zn2+and Pb2+,the important role of molecular configuration change in flocculation was revealed.This study extends the flocculation mechanism of γ-PGA to the molecular configuration level,provides a theoretical basis for understanding the important role of γ-PGA in microbial survival,wastewater treatment,and bioremediation.Moreover,it offers theoretical guidance for the application of γ-PGA,its derivatives,and γ-PGA-producing microorganisms in the removal of heavy metal ions and bioremediation.
microbial extracellular polymerspoly-γ-glutamic acidmolecular configurationbinuclear bidentate bonding model
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