一株兼具砷氧化还原功能微杆菌的筛选和鉴定

Isolation and Identification of a Microbacterium Strain with Arsenite-Oxidizing and Arsenate-Reducing Abilities

[目的]为获取兼具砷氧化还原功能的多功能菌株。[方法]通过多次分离、纯化,先从广西河池砷污染地区的水源洞水样中筛选出砷耐受菌,再从砷耐受菌中筛选出在好氧条件下既能还原As(Ⅴ)又能氧化As(Ⅲ)的多功能菌株CLL-B7。[结果]经测定16SrDNA的序列,鉴定菌株属于Microbacterium sp.,GenBank中的注册号是JF975617。该菌株能耐受高达115mmol/LAs(Ⅴ)和40mmol/LAs(Ⅲ),不能利用除营养肉汤外的多种有机碳源,在pH6条件下生长情况最好。该菌株在3d内几乎能完全还原10mmol/LAs(Ⅴ),并从第7天开始表现出砷氧化功能。[结论]该菌株能在好氧环境下进行砷还原,可能利用有机碳源作为电子供体。

[Objective]The research aimed to obtain bacteria with both arsenite-oxidizing and arsenate-reducing abilities.[Method]A number of arsenite-resistant bacteria were isolated from arsenic-contaminated aquifers in Hechi,Guangxi Province.Among them,a rarely reported strain named CLL-B7 with both arsenite-oxidizing and arsenate-reducing abilities was screened and identified.[Result]The phylogenetic analysis indicated that the strain belonged to the genus Microbacterium.The 16S rRNA gene sequence was deposited in the GenBank database under accession number JF975617.Strain CLL-B7 only grew in LB but couldn＇t use other organic carbon sources.And the optimal pH for its growth was 6.The strain was tolerant to 40 mmol/L arsenite and 115 mmol/L arsenate,which was able to reduce 10 mmol/L arsenate in the first three days but the oxidation of arsenite was observed on day 7.[Conclusion]The strain could reduce arsenate in aerobic conditions indicating that it used organic carbon as the electron donor.