【摘要】 研究不同条件下鞘细菌S9对Fe²⁺的转化作用及活性因子的转化机制.从培养时间、培养温度、初始pH、接种量等因素探讨鞘细菌对亚铁离子的转化特性;采用4因素3水平正交实验考察菌株对亚铁离子转化特性的影响,进一步优化鞘细菌对亚铁离子的转化条件;并从活性因子定位及温度、pH及抑制剂对活性因子转化机制进行研究.结果表明,鞘细菌对亚铁离子的最佳转化条件为:培养温度36 ℃,培养时间72 h,初始pH 7.0,接种量5%,在此条件下,鞘细菌对二价铁离子的转化作用最佳,其转化率可达96.31%.该活性因子是鞘细菌产生的一类胞外酶.该因子对温度较为敏感,在70℃下保温10 min后,基本上检测不到该因子对二价铁离子的转化作用;对pH具有一定的依赖性,当pH太低或太高,活性因子的转化效率都会受到影响;不同浓度的胰蛋白酶、SDS及氯化镉对活性因子具有一定程度的抑制作用.更多还原

【Abstract】 The transformation effect of strain S9 on Fe²⁺ and the transformation mechanism of active factors was studied under different conditions. The transformation characteristics of sheathe bacteria to ferrous ion were studied on the basis of the factors of cultivating time, cultivating temperature, initial pH, inoculation amount, etc. The effects of the strain on the transformation characteristics of ferrous ion were investigated by orthogonal experimental design with 4 factors and 3 levels, which further optimized the transformation of ferrous ions through sheathe bacteria. In addition, the mechanism of transformation was studied from the aspects including the localization and temperature of active factors pH and inhibitors. The results showed that sheath bacteria’s optimum transformation of ferrous ion are as follows: cultivating temperature is 36 ℃, cultivating time is 72 h, initial pH is 7.0, and inoculation amount is 5%. Under these conditions, the transformation rate of sheath bacteria to divalent iron ion was the highest, which could reach 96.31%. The active factor is one class of extracellular enzymes produced by sheath bacteria. The factor was sensitive to temperature. After holding 10 min at 70 ℃, it could not detect the transformation effect of this factor on divalent iron. Besides, it has certain dependence on pH. When the value of pH was too low or too high, the transformation efficiency of active factor would be affected. Different concentrations of trypsin, SDS and cadmium chloride could cause the inhibition of the active factors to some extent.更多还原