Hong Zhi-Neng, Li Jiu-Yu, Jiang Jun, Li Zhao-Li, Xu Ren-Kou
State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
College of Resources and Environment, Yunnan Agricultural University, Yunnan 650201, China.
Colloids Surf B Biointerfaces. 2016 Dec 1;148:496-502. doi: 10.1016/j.colsurfb.2016.09.026. Epub 2016 Sep 22.
Sorption and desorption of phosphate (P) on Fe and Al (hydr)oxides may be affected by bacteria in soils because their ubiquitous and strong interactions. The role of Bacillus subtilis and Pseudomonas fluorescens in adsorption of P on gibbsite (γ-AlOOH) was systematically investigated under a wide range of conditions by combining in-situ attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy with batch macroscopic experiments. In-situ ATR-FTIR observations of the ternary systems (bacteria, P, and gibbsite) showed simultaneous desorption of P from, and adhesion of the bacteria to, gibbsite, indicating a competition between the two for surface sites. Batch desorption experiments showed that bacteria could mobilize the P from gibbsite into solution, and macroscopic adsorption data showed that the amount of P adsorbed on the bacteria-gibbsite complex was less than that on gibbsite alone over durations from 0h to 26h, concentrations of P from 0.1mM to 2.0mM, pH from 5 to 8, and ionic strength from 0M to 0.5M, suggesting that bacteria inhibit the adsorption of P on gibbsite. The degree of inhibition increased with the number of bacteria in the system and was significantly but non-linearly correlated with the decline in the positive charge on gibbsite induced by the bacteria. Therefore, competition for suitable sites on the surface of gibbsite between P and the bacteria and reduction in the positive charge on the surface of gibbsite induced by bacteria are proposed as two important mechanisms that inhibit P adsorption. These findings highlight the role of bacteria in regulating the availability of P to plants and its mobility in natural environments.
土壤中磷酸盐（P）在铁和铝（氢）氧化物上的吸附和解吸可能会受到细菌的影响，因为它们之间存在普遍且强烈的相互作用。通过将原位衰减全反射傅里叶变换红外光谱（ATR-FTIR）与批量宏观实验相结合，系统研究了枯草芽孢杆菌和荧光假单胞菌在三水铝石（γ-AlOOH）上对磷吸附的作用。对三元体系（细菌、磷和三水铝石）的原位ATR-FTIR观察表明，磷从三水铝石上同时解吸，且细菌附着在三水铝石上，这表明二者对表面位点存在竞争。批量解吸实验表明，细菌可将三水铝石中的磷转移到溶液中，宏观吸附数据表明，在0小时至26小时的时间范围内、磷浓度从0.1mM至2.0mM、pH值从5至8以及离子强度从0M至0.5M的条件下，细菌-三水铝石复合物上吸附的磷量少于单独三水铝石上吸附的磷量，这表明细菌抑制了磷在三水铝石上的吸附。抑制程度随体系中细菌数量的增加而增加，且与细菌诱导的三水铝石表面正电荷的减少显著但非线性相关。因此，磷与细菌在三水铝石表面对合适位点的竞争以及细菌诱导的三水铝石表面正电荷的减少被认为是抑制磷吸附的两个重要机制。这些发现突出了细菌在调节植物对磷的有效性及其在自然环境中的迁移性方面的作用。
