微生物胞外聚合物对重金属镉的解毒作用及红外光谱分析

为探索微生物胞外物在微生物对重金属的抗性和去除过程中的作用，比较分析了对重金属镉具有不同抗性和去除率的菌株SCSE425-7和SCSE709-6胞外物的产生情况和菌株的红外光谱谱图。结果表明，在含镉条件培养时，菌株SCSE425-7表现了较高的镉抗性，分泌了相对较多的可溶性胞外多糖;而菌株SCSE709-6镉抗性较SCSE425-7低，但镉的生物去除性能较好，分泌了更多不可溶胞外聚合物。这说明，在重金属毒性胁迫下，微生物分泌的可溶性胞外多糖可能有助于提高微生物对重金属的抗性，而不可溶性胞外聚合物有助于重金属的微生物吸附。菌株红外光谱分析结果表明不可溶胞外聚合物上的酰胺基和羧基是其吸附镉离子的主要官能团。

FTIR Spectrum and Detoxication of Extracellular Polymeric Substances Secreted by Microorganism

In order to explore the effect of extracelluar polymeric substances (EPS) on resistance and removal of heavy metals, the production of EPS, secreted by cadmium-resistant strain (SCSE425-7) and cadmium-removal strain (SCSE709-6) was investigated combined with Fourier transform infrared spectroscopy (FTIR). The results showed that the high resistance to cadmium of strain SCSE425-7 was related to the high production of soluble EPS, whereas SCSE709-6 secreted more insoluble EPS resulting in better cadmium removal performance. It was indicated that soluble extracellular carbohydrates may help the bacteria to enhance resistance to Cd2+, and insoluble EPS could contribute to Cd2+ removal effectively. The FTIR spectra showed that the peaks of amide and carboxyl were main functional groups for Cd2+ adsorption.