具有砷(Ⅴ)还原能力的硫酸盐还原菌筛选及生长特性研究

Isolation and Characterization of Sulfate-reducing Bacteria with the Ability to Reduce Arsenate

采用亨盖特(Hungate)厌氧滚管技术从锦州湾受砷污染的底泥中分离纯化出3株具有砷(V)还原活性的硫酸盐还原菌,分别编号为S2、S3-11和S13.16S r RNA基因序列分析显示这3株菌分别与梭菌属(Clostridium)内的不同"种"之间亲缘关系最近.在As(V)初始浓度为1.0 mmol·L-1时,菌株S3-11可在10 h内还原23.4%的As(V),但当As(V)初始浓度增加到3.0或5.0 mmol·L-1时,菌株S2和S13则相对于S3-11展现出更强的砷还原能力,菌株S2甚至可以在7.0 mmol·L-1的砷环境中生长并在24 h内将14.2%的As(V)还原.菌株S2为严格厌氧菌,为直杆状革兰氏阳性菌,产芽孢,其细胞大小约为2.0μm×0.6μm,16S r RNA基因序列与梭菌属中Clostridium sporogenes strain JCM 7849同源性为99%.菌株S2可利用蔗糖、葡萄糖、甲酸钠、乳酸钠和乙酸钠为唯一碳源生长,生长适宜温度为30℃.

Three sulfate-reducing bacterial strains that can reduce arsenate to arsenite,designated as S2,S3-11,and S13,were isolated by Hungate anaerobic techniques from arsenic-contaminated estuarial sediment at Jinzhou bay,China. Analysis of 16 S r RNA gene sequences suggest that these strains are most similar to species from Clostridium.In presence of 1.0 mmol·L^-1As（V）,strain S3-11 could reduce 23.4% of arsenate within 10 hours;however,strainS2 and Strain S13 showed relatively higher arsenate reduction efficacy compared to strain S3-11 when 3.0 mmol·L^-1or 5.0 mmol·L^-1arsenate was present. Strain S2 could grow with 7.0 mmol·L^-1and reduced 14.2% of arsenate in a24 h incubation. Strain S2 was a rod-shape,Gram-positive,spore-forming,and strictly anaerobic bacterium. Thecells of S2 were 2.0×0.6 μm in size. Strain S2 shares a 99% sequence similarity in 16 S r RNA gene with Clostridium sporogens strain JCM 7849. Sucrose,glucose,sodium formate,sodium acetate,and sodium lactate could be used asthe sole carbon source by strain S2 and the optimum temperature for growth was 30 ℃.