Rhine E Danielle, Phelps Craig D, Young L Y
Biotechnology Center for Agriculture and the Environment, Cook College, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA.
Environ Microbiol. 2006 May;8(5):899-908. doi: 10.1111/j.1462-2920.2005.00977.x.
Autotrophic microorganisms have been isolated that are able to derive energy from the oxidation of arsenite [As(III)] to arsenate [As(V)] under aerobic conditions. Based on chemical energetics, microbial oxidation of As(III) can occur in the absence of oxygen, and may be relevant in some environments. Enrichment cultures were established from an arsenic contaminated industrial soil amended with As(III) as the electron donor, inorganic C as the carbon source and nitrate as the electron acceptor. In the active enrichment cultures, oxidation of As(III) was stoichiometrically coupled to the reduction of NO(3) (-). Two autotrophic As(III)-oxidizing strains were isolated that completely oxidized 5 mM As(III) within 7 days under denitrifying conditions. Based on 16S rRNA gene sequencing results, strain DAO1 was 99% related to Azoarcus and strain DAO10 was most closely related to a Sinorhizobium. The nitrous oxide reductase (nosZ) and the RuBisCO Type II (cbbM) genes were successfully amplified from both isolates underscoring their ability to denitrify and fix CO(2) while coupled to As(III) oxidation. Although limited work has been done to examine the diversity of anaerobic autotrophic oxidizers of As(III), this process may be an important component in the biological cycling of arsenic within the environment.
已分离出自养微生物，它们能够在有氧条件下通过将亚砷酸盐[As(III)]氧化为砷酸盐[As(V)]来获取能量。基于化学能量学，As(III)的微生物氧化可以在无氧条件下发生，并且可能在某些环境中具有相关性。以As(III)作为电子供体、无机碳作为碳源、硝酸盐作为电子受体，从受砷污染的工业土壤中建立了富集培养物。在活跃的富集培养物中，As(III)的氧化与NO(3)(-)的还原在化学计量上耦合。分离出了两株自养As(III)氧化菌株，它们在反硝化条件下7天内完全氧化了5 mM的As(III)。基于16S rRNA基因测序结果，菌株DAO1与食酸菌属的相似度为99%，菌株DAO10与中华根瘤菌的关系最为密切。从这两个分离株中成功扩增出了一氧化二氮还原酶(nosZ)和II型核酮糖-1,5-二磷酸羧化酶(cbbM)基因，这突出了它们在与As(III)氧化耦合时进行反硝化和固定CO(2)的能力。尽管在研究As(III)厌氧自养氧化菌的多样性方面所做的工作有限，但这一过程可能是环境中砷生物循环的一个重要组成部分。
