| 酿酒酵母与Ag+的相互作用机制研究 |
| 摘要点击 2575 全文点击 1970 投稿时间：2007-12-13 修订日期：2008-01-15 |
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| 中文关键词 酿酒酵母 生物吸附 Ag+ 相互作用 机制 |
| 英文关键词 Saccharomyces cerevisiae biosorption Ag+ interaction mechanism |
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| 中文摘要 |
| 为探讨酿酒酵母与Ag+的相互作用机制，分析了酵母吸附Ag+过程中细胞阳离子的释放状况，并利用红外光谱（FTIR）、带能谱仪的扫描电镜（SEM-EDX）、带能谱仪的透射电镜（TEM-EDX）等手段表征了酵母细胞在吸附Ag+前后表面官能团的变化以及Ag+在酵母细胞中的存在位置和状态.结果表明，酵母细胞吸附Ag+伴随着大量细胞阳离子K+、Na+、Mg2+、Ca2+的释放.Ag+的存在会抑制体系pH值增加，并促进Mg2+、Ca2+的释放.与Ag+的吸附类似，K+、Na+、Mg2+、Ca2+的释放也很快，并且符合准二级动力学方程.酵母对Ag+的吸附，可被认为是离子交换机制和共价结合机制共同发挥作用.FTIR证明酵母表面羧基对Ag+的吸附发挥重要作用.电镜分析结果表明，酵母细胞表面不仅吸附了Ag+，同时产生更高浓度的含Ag沉淀物，使Ag+从溶液中去除，这些含Ag沉淀不均匀地分布于细胞表面，含Ag沉淀的性质以及形成过程还需要借助其他分析手段进行进一步确认. |
| 英文摘要 |
| To understand the characteristics of Ag+ biosorption by the waste biomass of Saccharomyces cerevisiae ，the release phenomena of the cell physiological cations，such as K+，Mg2+，Ca2+，Na+，and pH value change during Ag+ uptake were investigated.The presence of Ag+ promoted the release of the cations，and decreased the absorption of H+.Ion exchange was one of the mechanisms involved in metal-microbe interaction.Ag+ also exhibited a degree covalent binding with the biomass.Both Ag+ uptake and cation release (K+，Mg2+，Ca2+ or Na+) followed the pseudo-second order kinetics.Fourier transform infrared spectroscopy (FTIR) indicated that the carboxyl group on the surface of the cells could play important role in metal-microbe interaction.The scanning electron microscopy with energy-dispersive X-ray analysis (SEM-EDX) and transmission electron microscopy with energy-dispersive X-ray analysis (TEM-EDX) were used to directly observe the change of the component elements and surface configuration of the cells before and after the interaction of the microbe with Ag+，and the results proved that Ag+ was adsorbed by the cell surface.Simultaneously，the precipitate containing Ag with higher concentration than the surface-adsorbed Ag was formed on the cell surface also resulted in the removal of Ag+ from the aqueous solution. |
