Humin Assists Reductive Acetogenesis in Absence of Other External Electron Donor
| Autor: | Takuya Kasai, Arata Katayama, Takanori Awata, Mahasweta Laskar |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Denitrification
Methanogenesis Health Toxicology and Mutagenesis lcsh:Medicine Electrons Electron donor 010501 environmental sciences 01 natural sciences Article dechlorination 03 medical and health sciences chemistry.chemical_compound Japan RNA Ribosomal 16S reductive acetogenesis Autotroph Humic Substances 030304 developmental biology 0105 earth and related environmental sciences chemistry.chemical_classification 0303 health sciences humin Chemistry lcsh:R Public Health Environmental and Occupational Health methanogenesis Electron acceptor Biodegradation Environmental CO2 reduction autotrophic Acetogenesis Environmental chemistry Humin Energy source Oxidation-Reduction |
| Zdroj: | International Journal of Environmental Research and Public Health Volume 17 Issue 12 International Journal of Environmental Research and Public Health, Vol 17, Iss 4211, p 4211 (2020) |
| ISSN: | 1660-4601 |
| Popis: | The utilization of extracellular electron transfer by microorganism is highly engaging for remediation of toxic pollutants under &ldquo energy-starved&rdquo conditions. Humin, an organo-mineral complex of soil, has been instrumental as an external electron mediator for suitable electron donors in the remediative works of reductive dehalogenation, denitrification, and so forth. Here, we report, for the first time, that humin assists microbial acetogenesis as the extracellular electron donor using the electron acceptor CO2. Humin was obtained from Kamajima paddy soil, Japan. The anaerobic acetogenic consortium in mineral medium containing CO2HCO3- as the inorganic carbon source used suspended humin as the energy source under mesophilic dark conditions. Retardation of acetogenesis under the CO2-deficient conditions demonstrated that humin did not function as the organic carbon source but as electron donor in the CO2-reducing acetogenesis. The consortium with humin also achieved anaerobic dechlorination with limited methanogenic activity. Total electron-donating capacity of humin was estimated at about 87 µ eeq/g-humin. The metagenomic sequencing of 16S rRNA genes showed the predominance of Firmicutes (71.8 ± 2.5%) in the consortium, and Lachnospiraceae and Ruminococcaceae were considered as the CO2-reducing acetogens in the consortium. Thus, microbial fixation of CO2using humin introduces new insight to the holistic approach for sustainable treatment of contaminants in environment. |
| Databáze: | OpenAIRE |
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