重金属Cu2+抗性菌的筛选与吸附性能研究

采用富集培养方法从污水处理厂污泥中分离筛选出3株对Cu2+吸附能力较强的菌株,考察pH值、温度和Cu2+初始质量浓度对3株菌吸附能力的影响。结果表明,Z-1-4在pH值为5.0,30℃,Cu2+质量浓度为140 mg/L时吸附效果最好;Z-1-5在pH值为6.0,28℃,Cu2+质量浓度为170 mg/L时吸附效果最好;Z-1-6在pH值为6.0,28℃,Cu2+质量浓度为140 mg/L时吸附效果最好。其中菌株Z-1-5吸附能力最强,吸附容量可达13.68 mg/g。对Z-1-5进行16S rDNA序列分析,初步确定为鞘胺醇单胞菌(Sphingomonas sp.)。

Isolation and biosorption performance of copper-resistant bacteria

The paper is aimed at analyzing the isolation and biosorption behavior of copper-resistant bacteria accumulated in the aquatic ecosystem,which would be likely to bring about direct or indirect threat to human health.Particularly speaking,our discussion would be focused on the copper absorption capacity of the three bacteria strains we have isolated from the activated sludge in a sewage treatment plant via concentration gradient screening.When proceeding with our research,we have investigated the effects of pH value,temperature and concentration of Cu2+ of the three strains on the adsorption behavior of Cu2+.As the result of our investigations and experiments,we have gained the following characteristic features of the strain: Z-1-4 indicates highest adsorptive efficiency of Cu2+ when its concentration reaches 140 mg/L with the pH 5.0 at 30 ℃,whereas Z-1-5 exhibits greatest adsorptive efficiency of Cu2+ on the condition that its concentration gets to 170 mg/L with the pH being 6.0 at 28 ℃.As to Z-1-6,its highest adsorptive efficiency of Cu2+ while its concentration is 140 mg/L with the pH being 6.0 at 28 ℃.All the above results prove that the optimal increasing value of pH is neutral,though the osmotic tolerance of the strain was not very strong.However,strain Z-15 tends to display its maximal biosorption efficiency among all the three strains.Its optimal growing conditions tend to be displaying at the initial concentration of 200 mg/L,with the rate of the shaker at 120 r/min,the cultured time being of 1 h,when the adsorption efficiency could reach 82.41%.The adsorption capacity would like to reach its maximum at 14.23 mg/g when the Cu2+ concentration is 170 mg/L,and the sequential analysis of 16S rDNA reveals that Z-1-5 belongs to the genus sphingomonas,whereas Strain Z-1-5 would like to reach its greatest potential for treating artificial Cu2+ in the sewage under a wide range of environmental conditions.