The thermokinetic properties of the action of two kinds of complexes RE(Hsal)2•(tch)•2H2O (RE＝La, Sm, Hsal＝salicylate C7H5O3, tch＝thiaproline C4H6NO2S) on growth metabolism of Escherichia coli were studied by means of a TAM air isothermal calorimeter at 37.00 ℃. The maximum heat output power Pmax, growth rate constant k, generation time tG, inhibitive ratio I (%) and half inhibition concentration cI,50 were obtained, respectively. Experimental results show that the two kinds of complexes RE(Hsal)2•(tch)•2H2O possess the biphacial biological effect and Hormesis effect, which stimulate the growth of Escherichia coli at lower concentrations, but inhibit the growth at higher concentrations. Inhibitory effect of Sm(Hsal)2•(tch)•2H2O (cI,50＝1.62 mg•L－1) is stronger than that of La(Hsal)2•(tch)•2H2O (cI,50＝7.60 mg•L－1).

Key words: rare earth complex, Escherichia coli (E. coli), microcalorimetry, thermokinetic parameter, hormesis