TIAN Zhi-yu, LI Fu-chun, LI Yong

College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China

Abstract: 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.

Keywords: clay minerals Bacillus mucilaginous mineral-bacterial complexes adsorption centrifugal speed

*Corresponding Author, E-Mail: fchli@njau.edu.cn

Bulletin of Mineralogy, Petrology and Geochemistry Vol. 33, No.6, 2014, page 778-783