Evaluation of Thiobacillus denitrificans' sustainability in nitrate-reducing Fe(II) oxidation and the potential significance of Fe(II) as a growth-supporting reductant.
Stefanie Becker, Thu Trang Dang, Ran Wei, Andreas Kappler
{"title":"Evaluation of Thiobacillus denitrificans' sustainability in nitrate-reducing Fe(II) oxidation and the potential significance of Fe(II) as a growth-supporting reductant.","authors":"Stefanie Becker, Thu Trang Dang, Ran Wei, Andreas Kappler","doi":"10.1093/femsec/fiaf024","DOIUrl":null,"url":null,"abstract":"<p><p>The Betaproteobacterium Thiobacillus denitrificans (ATCC 25259) oxidizes Fe(II) while reducing nitrate, yet its capacity for autotrophic growth as a nitrate-reducing Fe(II)-oxidizer remains uncertain. This study explored this capacity through cultivation experiments across multiple transfers, using growth medium with Fe(II) and nitrate as sole electron donor and acceptor, respectively. This setup necessitated nitrate reduction coupled to Fe(II) oxidation as the primary energy-yielding mechanism and Fe(II) as the exclusive electron donor for CO2 fixation and biomass production. Thiosulfate/nitrate pre-grown T. denitrificans oxidized 42% of 10 mM Fe(II), reduced 54% of 3.5 mM nitrate, and accumulated 1.6 mM nitrite, but showed no cell growth. Subsequent transfers from this Fe(II)/nitrate culture to fresh medium with Fe(II) and nitrate showed no nitrate-reducing Fe(II) oxidation or population growth. While bacterial activity (Fe(II) oxidation, nitrate reduction) occurred in the first transfer from thiosulfate/nitrate to Fe(II)/nitrate, nitrite was produced, further reacting with Fe(II) abiotically (chemodenitrification). A kinetic model assessed enzymatic versus abiotic Fe(II) oxidation, revealing enzymatic oxidation accounted for twice as much (ca. 70%) as abiotic denitrification (ca. 30%) within 22 days. These findings suggest T. denitrificans performs the first step of denitrification with Fe(II) as an electron donor but does not achieve autotrophic growth under these conditions.</p>","PeriodicalId":12312,"journal":{"name":"FEMS microbiology ecology","volume":" ","pages":""},"PeriodicalIF":3.5000,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"FEMS microbiology ecology","FirstCategoryId":"99","ListUrlMain":"https://doi.org/10.1093/femsec/fiaf024","RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MICROBIOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
The Betaproteobacterium Thiobacillus denitrificans (ATCC 25259) oxidizes Fe(II) while reducing nitrate, yet its capacity for autotrophic growth as a nitrate-reducing Fe(II)-oxidizer remains uncertain. This study explored this capacity through cultivation experiments across multiple transfers, using growth medium with Fe(II) and nitrate as sole electron donor and acceptor, respectively. This setup necessitated nitrate reduction coupled to Fe(II) oxidation as the primary energy-yielding mechanism and Fe(II) as the exclusive electron donor for CO2 fixation and biomass production. Thiosulfate/nitrate pre-grown T. denitrificans oxidized 42% of 10 mM Fe(II), reduced 54% of 3.5 mM nitrate, and accumulated 1.6 mM nitrite, but showed no cell growth. Subsequent transfers from this Fe(II)/nitrate culture to fresh medium with Fe(II) and nitrate showed no nitrate-reducing Fe(II) oxidation or population growth. While bacterial activity (Fe(II) oxidation, nitrate reduction) occurred in the first transfer from thiosulfate/nitrate to Fe(II)/nitrate, nitrite was produced, further reacting with Fe(II) abiotically (chemodenitrification). A kinetic model assessed enzymatic versus abiotic Fe(II) oxidation, revealing enzymatic oxidation accounted for twice as much (ca. 70%) as abiotic denitrification (ca. 30%) within 22 days. These findings suggest T. denitrificans performs the first step of denitrification with Fe(II) as an electron donor but does not achieve autotrophic growth under these conditions.
期刊介绍：
FEMS Microbiology Ecology aims to ensure efficient publication of high-quality papers that are original and provide a significant contribution to the understanding of microbial ecology. The journal contains Research Articles and MiniReviews on fundamental aspects of the ecology of microorganisms in natural soil, aquatic and atmospheric habitats, including extreme environments, and in artificial or managed environments. Research papers on pure cultures and in the areas of plant pathology and medical, food or veterinary microbiology will be published where they provide valuable generic information on microbial ecology. Papers can deal with culturable and non-culturable forms of any type of microorganism: bacteria, archaea, filamentous fungi, yeasts, protozoa, cyanobacteria, algae or viruses. In addition, the journal will publish Perspectives, Current Opinion and Controversy Articles, Commentaries and Letters to the Editor on topical issues in microbial ecology.
- Application of ecological theory to microbial ecology
- Interactions and signalling between microorganisms and with plants and animals
- Interactions between microorganisms and their physicochemical enviornment
- Microbial aspects of biogeochemical cycles and processes
- Microbial community ecology
- Phylogenetic and functional diversity of microbial communities
- Evolutionary biology of microorganisms
京公网安备 11010802042870号
京ICP备2023020795号-1
分享
求助内容：
应助结果提醒方式：
扫码关注我们
