【Abstract】 The biosorptive interaction of Ag++ with resting cell of %Lactobacillus sp.% strain A09 has been further studied on a molecular level by means of XPS, EDX, UV-Vis and FTIR techniques. The X-ray photoelectron spectroscopy(XPS) shows that the reductive ratio of the Ag++ to Ag+0 by the A09 biomass reaches to about 54^5% for 3 d. The contain of amino acid residues in dry powder of the biomass such as cysteine, methionine, arginine and lysine, being capable of reducing the Ag++ to Ag+0, are very small in quantity both cysteine and methionine are far less than 0^18%, and both arginine and lysine far less than 0^336%, %via% the analysis with quantitative energy-dispersive X-ray(EDX). The amount of the reducing sugars in the biomass is far larger than 2^71% analyzed by ultraviolet-visible spectrophotometry(UV-Vis). The chemical functional group on cell wass of the biomass such as the carboxylate anion of amino-acid residues seems to be the site for the Ag++ binding and the free aldehyde group of the hemiacetalic hydroxyl from reducing sugars, %i.e.% the hydrolysates of the polysaccharides from the cell wass, plays a protagonist in serving as the electron donor for reducing the Ag++ to Ag+0, characterized by fourier transform infrared(FTIR) spectrophotometry.更多还原