Rong Xingmin, Huang Qiaoyun, He Xiaomin, Chen Hao, Cai Peng, Liang Wei
Key Laboratory of Subtropical Agriculture and Environment of Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China.
Colloids Surf B Biointerfaces. 2008 Jun 15;64(1):49-55. doi: 10.1016/j.colsurfb.2008.01.008. Epub 2008 Jan 19.
Equilibrium adsorption along with isothermal titration calorimetry (ITC), Fourier transform infrared spectra (FTIR) and scanning electron microscopy (SEM) techniques were employed to investigate the adsorption of Pseudomonas putida on kaolinite and montmorillonite. A higher affinity as well as larger amounts of adsorption of P. putida was found on kaolinite. The majority of sorbed bacterial cells (88.7%) could be released by water from montmorillonite, while only a small proportion (9.3%) of bacteria desorbed from kaolinite surface. More bacterial cells were observed to form aggregates with kaolinite, while fewer cells were within the larger bacteria-montmorillonite particles. The sorption of bacteria on kaolinite was enthalpically more favorable than that on montmorillonite. Based on our findings, it is proposed that the non-electrostatic forces other than electrostatic force play a more important role in bacterial adsorption by kaolinite and montmorillonite. Adsorption of bacteria on clay minerals resulted in obvious shifts of infrared absorption bands of water molecules, showing the importance of hydrogen bonding in bacteria-clay mineral adsorption. The enthalpies of -4.1+/-2.1 x 10(-8) and -2.5+/-1.4 x 10(-8)mJ cell(-1) for the adsorption of bacteria on kaolinite and montmorillonite, respectively, at 25 degrees C and pH 7.0 were firstly reported in this paper. The enthalpy of bacteria-mineral adsorption was higher than that reported previously for bacteria-biomolecule interaction but lower than that of bacterial coaggregation. The bacteria-mineral adsorption enthalpies increased at higher temperature, suggesting that the enthalpy-entropy compensation mechanism could be involved in the adsorption of P. putida on clay minerals. Data obtained in this study would provide valuable information for a better understanding of the mechanisms of mineral-microorganism interactions in soil and associated environments.
采用平衡吸附结合等温滴定量热法（ITC）、傅里叶变换红外光谱（FTIR）和扫描电子显微镜（SEM）技术，研究了恶臭假单胞菌在高岭土和蒙脱石上的吸附情况。发现恶臭假单胞菌在高岭土上具有更高的亲和力和更大的吸附量。蒙脱石上吸附的大部分细菌细胞（88.7%）可被水释放，而从高岭土表面解吸的细菌仅占小部分（9.3%）。观察到更多细菌细胞与高岭土形成聚集体，而在较大的细菌 - 蒙脱石颗粒中的细胞较少。细菌在高岭土上的吸附在焓变方面比在蒙脱石上更有利。基于我们的研究结果，提出除静电力外的非静电力在细菌被高岭土和蒙脱石吸附过程中起更重要的作用。细菌在粘土矿物上的吸附导致水分子红外吸收带明显位移，表明氢键在细菌 - 粘土矿物吸附中具有重要作用。本文首次报道了在25℃和pH 7.0条件下，细菌在高岭土和蒙脱石上吸附的焓变分别为 -4.1±2.1×10⁻⁸和 -2.5±1.4×10⁻⁸mJ细胞⁻¹。细菌 - 矿物吸附的焓变高于先前报道的细菌 - 生物分子相互作用的焓变，但低于细菌共聚集的焓变。细菌 - 矿物吸附焓变在较高温度下增加，表明焓 - 熵补偿机制可能参与了恶臭假单胞菌在粘土矿物上的吸附。本研究获得的数据将为更好地理解土壤及相关环境中矿物 - 微生物相互作用的机制提供有价值的信息。
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