对17株实验室保藏的标准乳酸杆菌进行了重金属镉耐受性(最低抑菌浓度MIC)测定,筛选出4株对镉具有高耐受性的乳酸杆菌(MIC≥4.0 g/L).通过原子吸收分光光度法测定4株高耐受乳酸菌具有较强的镉离子吸附能力(＞27％,100 mg/L Cd2+溶液).以l株在镉耐受性实验中MIC最低(10 mg/L)的植物乳杆菌LAB-54(Lactobacillus plantarum ATCC 8014)作为对照,采用傅氏转换红外光谱(Fourier transform infrared spectroscopy,FTIR)、扫描电镜(SEM)结合研究分析1株在镉耐受MIC较高的鼠李糖乳杆菌LAB-5(Lactobacillus rhamnosus ATCC 53103)与镉吸附前后的细胞微观结构及形态变化,证明了细胞组成成分参与了镉离子与乳酸菌的相互作用,参与官能团有羟基(O—H)、羧基(C=O)、磷酸基(P=0)、酰胺基(N—H)、烃基(C—H).镉离子使细胞的微观结构受到了严重破坏,镉吸附机制包括胞外的络合反应、离子交换、物理吸附(静电引力),微沉淀(胞外及胞内)和胞内扩散.%17 standard Lactobacillus strains were selected by MIC test against cadmium.Among them,4 strains showed high resistance to Cd (MIC ≥4.0 g/L).The selected bacteria were assessed in vitro for their ability to remove Cd (＞ 27％ in 100 mg/L Cd2 + solution).To clarify the removal mechanism of Lactobacillus rhamnosus ATCC 53103 (LAB-5 strain),fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were used to structurally and morphologically characterize the interaction of bacteria and Cd ion.LAB-54 (Lactobacillus plantarum ATCC 8014),a Cd-sensitive strain,was used as control.Results indicated that hydroxyl (O-H),carboxyl (C =O),phosphoryl (P =O),amide (N-H) and hydrocarbonyl (C-H) groups were involved in biosorption process.Cd removal mechanisms of LAB might include complexation,ion exchange,physical adsorption (electrostatic interaction),precipitation and diffusion.Cell microstructure was heavily damaged by treatment with Cd2 + ion.Distorted,sunken,rough,crumpled,cracked and perforated cells were observed.
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