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Presence of bacteria reduced phosphate adsorption on goethite
Author(s) -
Hong Z. N.,
Li J. Y.,
Jiang J.,
Liu Z. D.,
Xu R. K.
Publication year - 2015
Publication title -
european journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 1351-0754
DOI - 10.1111/ejss.12247
Subject(s) - goethite , bacteria , phosphate , adsorption , chemistry , phosphate solubilizing bacteria , pseudomonas fluorescens , surface charge , inorganic chemistry , nuclear chemistry , biochemistry , rhizosphere , organic chemistry , biology , rhizobacteria , genetics
Summary Despite extensive studies, the information obtained from pure iron and aluminum (hydr)oxides cannot fully explain phosphate fixation in natural soils because of the ubiquitous interactions between (hydr)oxides and bacteria in soil. The effect of bacteria ( Bacillus subtilis subsp. and Pseudomonas fluorescens ) on phosphate adsorption on goethite (α‐ FeOOH ) was systematically examined under varying reaction times, phosphate concentrations, pH , ionic strength and bacteria dosage. Batch experiments in all cases showed significantly less adsorption on bacteria–goethite complexes than on pure goethite, demonstrating an inhibitory effect of bacteria. The inhibition of phosphate adsorption increased with bacterial loading, and showed a significant, non‐linear correlation with the decrease in the goethite positive charge induced by the bacteria. Moreover, in both the desorption experiment and in situ, the attenuated total reflectance F ourier‐transform infrared ( ATR‐FTIR ) spectra suggested a competition of bacteria surface groups (phosphate and carboxyl) with solution phosphate for hydroxyl on goethite. Therefore, the negative influences of bacteria on phosphate adsorption on goethite were probably caused by the surface charge modification and the competitive adsorption induced by the bacteria. Under most conditions, the effects of B. subtilis subsp. were conspicuous, while only slight influences were found for P. fluorescens . This difference between the two bacteria species was explained by differences in their surface charge, group content and chemical interaction with goethite. These findings uncover an important role of bacteria in phosphate phyto‐availability and mobility in natural environments.