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Chelation of zinc(II) with poly(γ-glutamic acid) in aqueous solution: kinetics, binding constant, and its antimicrobial activity.
- Source :
-
Polymer Bulletin . 2021, Vol. 78 Issue 3, p1353-1377. 25p. - Publication Year :
- 2021
-
Abstract
- The binding of zinc(II) ions onto γ-pga was studied in aqueous solution as a function of contact time, solution pH, initial concentration of metal ion, and solution temperature, respectively. IR and 13C NMR spectra of γ-pga and Zn(γ-pga) complex revealed binding of zinc(II) with carboxylate and amide groups on γ-pga. The strong interaction between zinc(II) ions and γ-pga occurred at pH 5. The binding kinetic data followed a pseudo-second-order kinetic model. The equilibrium binding data were fitted well by Langmuir isotherm model. The maximum amount of zinc(II) ions bound to γ-pga was estimated to be 13.97 mmol/g at 30 °C and 20.58 mmol/g at 45 °C. The values of activation energy (Ea 18.23 kJ/mol), changes in free energy (∆G°), enthalpy (∆H°), and entropy (∆S°) indicate that the formation of Zn(γ-pga) complex is an endothermic spontaneous physisorption process. The antimicrobial activity of Zn(γ-pga) complex was examined against a gram-negative bacteria (i.e., Escherichia coli) and a gram-positive bacteria (i.e., Bacillus subtilis). The IC50 values of Zn(γ-pga) complex were estimated to be (0.76 ± 0.03) mmol/L for E. coli and (0.94 ± 0.02) mmol/L for B. subtilis, respectively. Therefore, Zn(γ-pga) complex can be used as an antimicrobial agent against gram-positive and gram-negative microorganisms. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 01700839
- Volume :
- 78
- Issue :
- 3
- Database :
- Academic Search Index
- Journal :
- Polymer Bulletin
- Publication Type :
- Academic Journal
- Accession number :
- 148566423
- Full Text :
- https://doi.org/10.1007/s00289-020-03165-9