期刊
COLLOIDS AND SURFACES B-BIOINTERFACES
卷 192, 期 -, 页码 -出版社
ELSEVIER
DOI: 10.1016/j.colsurfb.2020.111085
关键词
Bacterial adhesion; Thermodynamics analysis; Extended DLVO theory; Montmorillonite; Sphingomonas sp. GY2B
资金
- National Key Research and Development Program of China [2017YFD0801004]
- National Natural Science Foundation of China [41673092, 41972037]
- Basic and Applied Basic Research Foundation of Guangdong Province [2019B1515120015]
- Guangdong Special Support Program for Local Innovative and Research Teams Project [2019BT02L218]
- Guangdong Special Support Program for Millions of Leading Engineering Talents [201626011]
Bacterial adhesion on mineral surface are of fundamental importance in geochemical processes and biogeochemical cycling, such as mineral transformation and clay-mediated biodegradation. In this study, thermodynamics analysis combined with classical Derjaguin-Landau-Verwey-Overbeek (DLVO) theory as well as the extended DLVO (XDLVO) theory were employed to investigate the adhesion of the Gram-negative PAH-degrading bacteria Sphingomonas sp. GY2B on montmorillonite (Mt). Scanning electron microscopy (SEM), Fourier transform infrared spectra (FTIR) and X-ray photoelectron spectroscopy (XPS) indicated the affinity of GY2B for Mt, and the experimental results could be described well by pseudo-second-order (R-2 = 0.997) and Langmuir model (R-2 = 0.995). The thermodynamics analysis revealed the physical nature of bacterial adhesion onto Mt, which was confirmed by the XDLVO theory. The related surface properties (Zeta potential, hydrodynamic diameter and hydrophobicity) at different ionic strength were determined and the interaction energy between Mt and GY2B were also calculated using the DLVO and XDLVO theories in KCl or CaCl2 solution. At low ionic strength (<= 20 mM), GY2B adhesion onto Mt was primarily driven by long-range DLVO forces (e.g. electrostatic repulsion), while short-range (separation distance < 5 nm) Van der Waals and hydrophobic interactions played more important roles in the bacterial adhesion at higher ionic strength (50 -100 mM). In addition, Mt had a better adhesion capacity to bacteria in Ca2+ solution than that in K+ solution, owing to less negative charge and lower energy barrier in mineral-bacteria system in Ca2+ solution. Overall, the adhesion of bacteria onto Mt could be evaluated well on the basis of the XDLVO theory along with thermodynamics analysis. This study provides valuable insights into the clay-mediated microbial remediation of hydrophobic organic contaminants in the environment.
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