氧化硫硫杆菌TS6的生长条件及其对重金属耐受性研究

Optimum growth condition of Acidithiobacillus thiooxidans TS6 and its resistance to heavy metals

采用纯培养的方法研究了温度和介质起始pH以及重金属对嗜酸性氧化硫硫杆菌（Acidithiobacillus thiooxidans TS6）菌株生长与活性的影响.研究表明,菌株TS6的最适生长温度为28℃,最适起始生长pH范围为2.0～6.0.在上述条件下,TS6旺盛生长,表现出氧化硫能力最强.通过检测TS6对几种重金属（Cr^3＋、Cu^2＋、Zn^2＋、Ni^2＋）的耐受性,结果发现TS6对上述重金属均有较强的耐受性,至少可耐受Cr^3＋、Cu^2＋、Zn^2＋、Ni^2＋的浓度分别达1500、400、1000和250mg·L^-1.在相同的浓度下,不同重金属对TS6生长产酸作用的影响由小到大依次为Cr^3＋、Zn^2＋、Cu^2＋、Ni^2＋.随着TS6菌株驯化时间的延长,它们对重金属的耐受性可望得到进一步的增强,完全满足对各种污水污泥进行生物淋滤处理的条件.

Acidithiobacillus thiooxidans TS6 isolated from sewage sludge was studied for its optimum growth conditions and resistance to Cr^3＋ , Cu^2＋ , Zn^2＋ , and Ni^2＋ by pure culture method. It was found that optimum temperature and initial pH in medium for strain TS6 growth were 28℃ and pH 2.0 - 6.0, respectively, as exhibiting that pH declined rapidly under these conditions. The sulfur-oxidizng activity of Acidithiobacillus thiooxidans TS6 was reduced obviously when cultural temperature was above 36℃ or below 24℃ and also initial pH in medium was more than pH 7. Furthermore, a higher resistance of Acidithiobacillus thiooxidans TS6 to Cr^3＋ , Cu^2＋ , Zn^2＋ , and Ni^2＋ in the medium was also observed in the study. Acidithiobacillus thiooxidans TS6 could resist the attack of at least 1500 mg·L^-1 of Cr3 ＋ ,400 mg·L^-1 of Cu^2＋ , 1000 mg·L^-1 of Zn^2＋ , and 250 mg·L^-1 of Ni^2＋ in medium. For the same metal concentration, the stress of different metal to strain TS6 was Ni^2＋ 〈 Cu^2＋ 〈 Zn^2＋ 〈 Cr^3＋ . In term of metal concentration in most of sewage sludge, strain TS6 could be used for bioleaching of heavy metals of sewage sludge.