1株嗜酸硫杆菌的分离鉴定及其对污染底泥中重金属的去除效果

采用常规细菌分离方法,从河流底泥中筛选到1株细菌FD97,通过序批式摇瓶培养考察了不同温度下(22~40℃)该菌株对污染底泥中Zn、Cu和Cr的去除效果.结果表明,形态学和16S rDNA序列同源性分析鉴定菌株FD97为嗜酸硫杆菌属(Acidithiobacillussp.).在22~40℃条件下,以Acidithiobacillussp.FD97为主要菌株的生物沥浸作用可有效去除污染底泥中Zn、Cu和Cr.沥浸处理16 d,Zn、Cu和Cr的去除率可分别达70%、90%和25%.从底泥pH值变化、SO42-产生以及重金属去除率角度衡量不同温度的底泥沥浸处理效果依次为:34℃28℃≈40℃22℃.控温28℃较适宜今后的实际应用.底泥重金属生物沥浸去除率的大小与底泥pH值变化密切相关,与温度无直接关系.当底泥pH值降至5.0、3.5和2.5时,底泥中Zn、Cu和Cr分别开始溶出,pH值降为2.0,重金属去除率达最大.

Isolation, Identification of Acidithiobacillus sp. and Its Role in the Removal of Heavy Metals from Contaminated Sediments

A sulfur-oxidizing bacterium FD97 was isolated from heavy metal-contaminated river sediments. According to the morphological characteristics and sequence analysis of 16S rDNA of FD97, the strain was identified as Acidithiobacillus sp. . The effects of temperature on heavy metals bioleaching efficiencies from contaminated sediments by using Acidithiobacillus sp. FD97 were investigated in shake flask experiments. The tests were performed at four different temperatures in the range of 22-40℃ . The results showed that after 16 days of bioleaching, almost 70% of Zn, 90% of Cu, and 25% of Cr could be removed from the sediments, respectively. From the variations of pH reduction, sulfate production, and metals removal, the order of bioleaching efficiency at different temperatures was 34℃ > 28℃≈40℃ > 22 ℃ . The preferable temperature used for the future larger-scale bioleaching process is 28 ℃ . It was found that during the bioleaching process, temperature did not directly affect the metal removal process; the final level of metal removal achieved was highly correlated to sediment pH. When the pH decreased to 5.0, 3.5, and 2.5, the removal of Zn, Cu, and Cr began to increase sharply, respectively, and the maximum metal removal could be achieved when the pH decreased to below 2.0.