Modeling the Production of and Competition for Hydrogen in a Dechlorinating Culture
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- 作者：Donna E. Fennell and James M. Gossett
- 刊名：Environmental Science & Technology
- 出版年：1998
- 出版时间：August 15, 1998
- 年：1998
- 卷：32
- 期：16
- 页码：2450 - 2460
- 全文大小：263K
- 年卷期：v.32,no.16(August 15, 1998)
- ISSN：1520-5851
文摘
A comprehensive biokinetic model employing Michaelis-Menten-type kinetics, H2 thresholds, and thermodynamiclimitations on donor fermentation was used to describeboth fermentation of electron donors and competition forthe evolved H2 between hydrogenotrophic tetrachloroethenedechlorinators and methanogens. Model simulationscompared favorably to experimental data where deliveryof H2 to a tetrachloroethene dechlorinator was accomplishedusing the donors butyric acid, ethanol, lactic acid, andpropionic acid. Fermentations of the different donors werecharacterized by different dynamic patterns of H2generation that were captured successfully by the model.Experimental data and model simulations show that theability to use H2 at appreciable rates at low levels providesa competitive advantage to dechlorinators over methanogens. Slowly fermented substrates producing lower H2levels-kinetically accessible to dechlorinators, but toolow for significant use by methanogenic competitors-weremore effective and persistent "selective" stimulators ofdechlorination than rapidly fermented substrates producinghigher H2 levels-accessible to both dechlorinators andmethanogens. Model simulations suggest that addingexcessive levels of rapidly fermented, high H2-level-generatingdonors in an attempt to overcome competition, insteadresults in a dominant methanogen population and an eventualfailure of dechlorination. When stimulating dechlorination,the quality of the donor as well as the quantity addedmust be considered.