Rare earth salts and rare earth complexes have strong and broad spectrum antibacterial effects, especially on Bacillus. This may correlate to the properties of the rare earth and the characteristics of Bacillus. In this paper, the spores of Bacillus are crashed and the small molecules in the spores are extracted with biological and chemical methods. By means of electronic microscopy, infrared spectrometry, fluorescence spectrometry and atomic absorption spectrometry, we have located the binding site of the rare earth ion in Bacillus at molecular level. Based on the above experiments, the bacteriostatic mechanism of the rare earth compounds is proposed. The rare earth bacteriostats not only destroy the special structure of the spores by the substitution of Ca~(2+) in DPA-Ca~(2+) with the rare earth ion, but also cause the loss of Ca~(2+). Therefore, the bacteriostatic or bactericidal action occurs.

Key words: RARE EARTH, BACILLUS, IR, ATOMIC ABSORPTION SPECTROPHOTOMETRY, PYRIDINE P