胞外聚合物(EPS)在藻菌生物膜去除污水中Cd的作用

Role of EPS in Removing Cadmium in Waste Water by Algae-Bacteri a Biofilm

基于藻菌生物膜在自然水体和污水生物处理工艺中起到去除水体中重金属的重要作用 ,在室内模拟实验的基础上探讨了丝藻 (Ulothrix sp.) -细菌生物膜所分泌的胞外聚合物 (EPS)与藻菌生物膜去除毒性金属 Cd之间的关系 .研究结果表明 :EPS主要由丝藻产生 ,其含量与污水中 Cd的去除率及生物膜中 Cd的积累量之间相关性良好 .处理含 Cd污水生物膜和对照组的生物膜 ATP的含量比较表明 :Cd对藻菌生物膜整体上具有一定的毒性 ,并在一定程度上抑制了生物膜的活性和生物量的增长 .而且 ,丝藻所分泌的 EPS为与其共生的细菌及其本身提供了一个缓冲 Cd毒性的微环境 ,这使藻菌生物膜能在不利的环境中保持较高的活性并能持续有效地去除水体中的Cd.

On the basis of a series of tests, the relationship between EPS pr oduced by Ulothrix-bacteria biofilm and Cadmium removal efficiency in sewa ge is discussed. The result shows that the EPS is mainly produced by Ulothrix sp. and the amount of EPS has a good correlation with cadmium removal efficiency an d cadmium accumulated in biofilm. A comparison of ATP content between the hand led sewage biofilms containing Cd with the contrast group indicates Cd has certa in toxicity on the whole algae-bacteria biofilms, and has suppressed the activation of the biofilms and the growth of living beings quantity to a certain extent. Furthermo re, the EPS from Ulothrix sp. provides an improved microenvironment with has the ability to buffer the toxicity of cadmium for both symbiotic bacteria and Ulo thrix sp., which maintains higher activity of the biofilm and removes Cd in wa ter persistently and efficiently in unfavorable environment.