细菌在黏土矿物表面吸附量测定方法的优化

Optimization of Measuration Method for Bacterial Number Absorbed on the Surface of Clay Minerals

土壤微生物与矿物的吸附作用在矿物风化过程中具有重要的意义。为了优化细菌在矿物表面吸附量的测定方法,本文以胶质芽孢杆菌和蒙脱石、伊利石、高岭石为实验材料,对吸附在矿物表面的细菌数量的测定方法进行了研究。结果表明,利用茚三酮作为显色剂测定细菌蛋白质含量的方法可以获得可靠的细菌数量;以2000rpm转数离心10min可以有效地将矿物-细菌复合体与游离态细菌、矿物分开;3种矿物对胶质芽孢杆菌的吸附能力大小顺序为:蒙脱石>伊利石>高岭石;矿物的比表面积、沉淀速率和表面所带电荷数量以及细菌细胞活性是影响吸附量的主要因素;黏土矿物与细菌之间的吸附作用力主要来自阳离子桥。

The adsorptions of soil microbes and minerals play important roles in the mineral weathering process.This paper measured adsorbed quantities of Bacillus mucilaginous on the surfaces of clay minerals,montmorillonite,illite and kaolinite,and estimated the optimized measuring method.It showed that the bacterial number can be determined according to the measured content of bacterial protein by using ninhydrin as the chromogenic reagent.Centrifugation at 2000 rpm for 10 min can effectively separate minerals-bacteria complexes from free bacteria and minerals.The adsorption capacities of Bacillus mucilaginous on the three minerals are of following sequence：montmorillonite 〉 illite 〉 kaolinite.The specific surface area,the precipitation rate,the charge quantity on the surface of mineral and the bacterial activity are the main factors affecting the adsorption capacity.The cation bridge and electrostatic attraction might have lead the adsorption of bacteria on the surfaces of clay minerals.