球形红细菌转化去除重金属镉及其机理研究

Study on transformation and removal of the heavy metal cadmium by Rhodobacter sphaeroides

研究了不同理化因素对光合细菌球形红细菌(Rhodobactersphaeroides)H菌株生长和镉去除能力的影响.结果表明,该菌株的最佳生长和对镉的最佳去除条件为:pH=7.0,温度为30℃,好氧黑暗,接种量9%.在最佳条件下,镉的去除率可达85%以上.通过X射线衍射光谱分析,H菌株对镉离子的转化产物为硫化镉.通过测定镉的去除与细菌生长曲线及半胱氨酸脱巯基酶的活性,表明镉的去除与菌体的生长稳定期相关.此外,通过分析菌体对硫酸盐的代谢过程,探讨了该菌株生长细胞去除重金属镉的机理.

The influences of several factors on the growth and removal for cadmium of Rhodobacter sphaeroidcs H stain were analyzed in this study. The results demonstrated that the optimum conditions for the growth of H stain and the removal rate for cadmium were pH7.0, temperature at 30℃ , aerobic dark and inoculation amount of 9%. The removal rate for cadmium of H stain reached 85% under the optimal conditions. Furthermore, the analysis of X- ray diffraction diagram indicated that cadmium ion was transformed into cadmium sulfides by H strain. Also, we found that the removal for cadmium was dependent on the growth stationary phase of H stain through determining the removal rate for cadmium, the growing curve of cell and the activity of cysteine desulfhydrase. Moreover, the mechanism of removal for cadmium was discussed via analyzing the sulfate metabolism in H stain.