Nguyen Van Khanh, Tran Huong T, Park Younghyun, Yu Jaecheul, Lee Taeho
Department of Environmental Engineering, Dong-a University, Busan, 49315, Republic of Korea.
Department of Molecular Biology, Pusan National University, Busan, 46241, Republic of Korea.
J Ind Microbiol Biotechnol. 2017 Jun;44(6):857-868. doi: 10.1007/s10295-017-1910-7. Epub 2017 Feb 9.
The purpose of this study was to identify bacteria that can perform As(III) oxidation for environmental bioremediation. Two bacterial strains, named JHS3 and JHW3, which can autotrophically oxidize As(III)-As(V) with oxygen as an electron acceptor, were isolated from soil and water samples collected in the vicinity of an arsenic-contaminated site. According to 16S ribosomal RNA sequence analysis, both strains belong to the ɤ-Proteobacteria class and share 99% sequence identity with previously described strains. JHS3 appears to be a new strain of the Acinetobacter genus, whereas JHW3 is likely to be a novel strain of the Klebsiella genus. Both strains possess the aioA gene encoding an arsenite oxidase and are capable of chemolithoautotrophic growth in the presence of As(III) up to 10 mM as a primary electron donor. Cell growth and As(III) oxidation rate of both strains were significantly enhanced during cultivation under heterotrophic conditions. Under anaerobic conditions, only strain JHW3 oxidized As(III) using nitrate or a solid-state electrode of a bioelectrochemical system as a terminal electron acceptor. Kinetic studies of As(III) oxidation under aerobic condition demonstrated a higher V and K from strain JHW3 than strain JHS3. This study indicated the potential application of strain JHW3 for remediation of subsurface environments contaminated with arsenic.
本研究的目的是鉴定能够进行砷（III）氧化以用于环境生物修复的细菌。从砷污染场地附近采集的土壤和水样中分离出两株细菌，命名为JHS3和JHW3，它们能够以氧气作为电子受体自养氧化砷（III）-砷（V）。根据16S核糖体RNA序列分析，这两株菌均属于γ-变形菌纲，与先前描述的菌株具有99%的序列同一性。JHS3似乎是不动杆菌属的一个新菌株，而JHW3可能是克雷伯菌属的一个新菌株。这两株菌都拥有编码亚砷酸盐氧化酶的aioA基因，并且能够在以高达10 mM的砷（III）作为主要电子供体的情况下进行化能无机自养生长。在异养条件下培养期间，两株菌的细胞生长和砷（III）氧化速率均显著提高。在厌氧条件下，只有JHW3菌株利用硝酸盐或生物电化学系统的固态电极作为末端电子受体氧化砷（III）。对有氧条件下砷（III）氧化的动力学研究表明，JHW3菌株的V 和K 高于JHS3菌株。本研究表明JHW3菌株在修复受砷污染的地下环境方面具有潜在应用价值。
