罗尔斯通菌去除土壤重金属铅的效能及机制

Removal Efficiency and Mechanism of Heavy Metal Lead(Pb)by Ralstonia Bcul-1 in Soil

从矿区土壤分离得到的罗尔斯通菌(Ralstonia Bcul-1)对重金属离子具有广谱抗性,可在重金属铅含量为87.35 mg·kg^(-1)的酸性土壤生长(pH 5.62)。低浓度Pb^(2+)可诱导部分重金属抗性基因表达,但高浓度Pb^(2+)(>15 mg·L^(-1))则抑制这些基因的表达。在Pb^(2+)胁迫下,一些蛋白质的表达同样受到诱导或者抑制。重金属抗性基因和抗性蛋白的表达使Ralstonia Bcul-1能够适应重金属铅污染的生存环境。在含Pb^(2+)的液体培养基中(pH<6.50),Ralstonia Bcul-1菌体对Pb^(2+)的去除效率高达8.22%~29.09%。将Ralstonia Bcul-1接菌到受重金属铅污染的酸性菜园土壤中(pH 5.32,重金属铅总含量为94.37 mg·kg^(-1)),在没有添加任何营养物质的条件下,Ralstonia Bcul-1能持续生长达12 d,并且对土壤悬浮物(包括泥浆)重金属铅的去除效率达到12.71%~24.71%(土壤悬浮物的重金属铅含量为32.67 mg·kg^(-1))。研究结果表明,Ralstonia Bcul-1能在重金属铅污染的酸性菜园土壤中存活,并对土壤悬浮物的重金属铅有较强的去除效率,具有修复土壤重金属铅污染的潜力。

The Ralstonia Bcul-1 isolated from mining soil had a broad-spectrum resistance to heavy metal ions,and could grow in acidic soil with heavy metal lead content of 87.35 mg·kg^(-1)(pH 5.62).Low concentration of Pb^(2+) could induce the expression of some heavy metal resistance genes,but high concentration of Pb^(2+)(>15 mg·L^(-1))inhibited the expression of these genes.The expression level of some proteins were also induced or inhibited under Pb^(2+) stress.The expression of heavy metal resistance genes and resistant proteins enable Ralstonia Bcul-1 to adapt to survival environment contaminated with heavy metal lead.The removal efficiency of Ralstonia Bcul-1 to Pb^(2+) was up to 8.22%~29.09%in the liquid medium supplemented with Pb^(2+)(pH<6.50).Ralstonia Bcul-1 was inoculated into acid vegetable soil contaminated with heavy metal lead(pH 5.32,total content of heavy metal lead was 94.37 mg·kg^(-1))that could grow continuously for 12 days without adding any nutrients.In addition,the removal efficiency of heavy metal lead in soil suspended solids(including slurry)was as high as 12.71%~24.71%(the content of heavy metal lead in soil suspended solids was 32.67 mg·kg^(-1)).The results showed that Ralstonia Bcul-1 could survive in acid vegetable soil polluted by heavy metal lead and simultaneously had a strong removal efficiency for heavy metal lead in soil suspended solids,which had the potential to repair soil heavy metal lead pollution.