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| Microbial Iron Reduction as Influenced by Fermentative Dehydrogenation and Hydrogen Production |
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| KeyWord:soil microorganism; iron reduction; dehydrogenase activity; pH; hydrogen |
| Author Name | Affiliation | | JIA Rong | College of Natural Resources and Environment, Northwest A & F University, Yangling 712100, China | | QU Dong | College of Natural Resources and Environment, Northwest A & F University, Yangling 712100, China | | QIAO Sha-sha | College of Natural Resources and Environment, Northwest A & F University, Yangling 712100, China |
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| Abstract: |
| Fermentative microorganism is the major group of iron reducing bacteria in paddy soil. However, it is unclear how dehydrogenation and hydrogen production impact microbial iron reduction. In an anaerobic incubation, dehydrogenase activity, pH, partial pressure of hydrogen and iron（Ⅲ） reduction were investigated using paddy soil extract solution as microorganism source, Fe（OH）3 as electron acceptor, and glucose, pyruvate and lactate as C source. Results showed that glucose was a dominant electron donator for microorganisms in dehydrogenation, hydrogenation and iron reduction in paddy soils collected from Jilin and Guizhou provinces. With Fe（OH）3 as sole electron acceptor, the dehydrogenase activity peaked at about 4~6 d of anaerobic incubation with glucose, 15 d with pyruvate and 21~22 d with lactate. The time when the peak of dehydrogenase activity occurred was negatively correlated with the maximum iron reduction rate（Vmax）, but positively with the time to reach the max reduction rate（TVmax）. There was a negative correlation between pH and the partial pressure of hydrogen as well as iron（Ⅱ） concentrations. The change of pH caused by microbial fermentation was the major factor affecting iron reduction process. Carbon sources had a great impact on hydrogen production, with the maximum hydrogen production occurred under glucose, followed by pyruvate and the least under lactate. Addition of Fe（OH）3 increased the consumption of hydrogen in the incubation. In addition, an extremely significant positive correlation was found between the partial pressure of hydrogen and iron（Ⅱ） accumulation. |
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