NOVEL MODE OF MICROBIAL ENERGY-METABOLISM - ORGANIC-CARBON OXIDATION COUPLED TO DISSIMILATORY REDUCTION OF IRON OR MANGANESE
NOVEL MODE OF MICROBIAL ENERGY-METABOLISM - ORGANIC-CARBON OXIDATION COUPLED TO DISSIMILATORY REDUCTION OF IRON OR MANGANESE
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DOI：
10.1128/aem.54.6.1472-1480.1988
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发表时间：
1988-06-01
影响因子：
4.4
通讯作者：
PHILLIPS, EJP
中科院分区：
文献类型：
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作者：
LOVLEY, DR;PHILLIPS, EJP
从马里兰州波托马克河的淡水沉积物中分离到一种异化的Fe（III）和Mn（IV）还原微生物。命名为GS-15的分离物生长在限定的厌氧培养基中，乙酸盐作为唯一的电子供体，Fe（III）、Mn（IV）或硝酸盐作为唯一的电子受体。GS-15将乙酸盐氧化成二氧化碳，同时将无定形的Fe（III）氧化物还原成磁铁矿（Fe 3 O 4）。当柠檬酸铁（III）取代无定形氧化铁（III）作为电子受体时，GS-15生长更快，并将所有添加的Fe（III）还原为Fe（II）。GS-15减少了天然的无定形Fe（III）氧化物，但没有显著减少高度结晶的Fe（III）形式。Fe（III）的最佳还原条件为pH 6.7 - 7和30 - 35 ℃。C.乙醇，丁酸，丙酸也可以作为电子供体Fe（III）还原。各种其他有机化合物和氢不能。MnO 2被完全还原为Mn（II），其沉淀为菱锰矿（MnCO 3）。硝酸盐被还原成氨。氧不能作为电子受体，它抑制生长与其他电子受体。这是第一次证明，微生物可以完全氧化有机化合物与Fe（III）或Mn（IV）作为唯一的电子受体，并结合异化Fe（III）或Mn（IV）还原有机物的氧化可以产生能量的微生物生长。GS-15提供了一个模型，说明酶催化反应如何成为厌氧环境中铁和锰还原的定量重要机制。
A dissimilatory Fe(III)- and Mn(IV)-reducing microorganism was isolated from freshwater sediments of the Potomac River, Maryland. The isolate, designated GS-15, grew in defined anaerobic medium with acetate as the sole electron donor and Fe(III), Mn(IV) or nitrate as the sole electron acceptor. GS-15 oxidized acetate to carbon dioxide with the concomitant reduction of amorphic Fe(III) oxide to magnetite (Fe3O4). When Fe(III) citrate replaced amorphic Fe(III) oxide as the electron acceptor, GS-15 grew faster and reduced all of the added Fe(III) to Fe(II). GS-15 reduced a natural amorphic Fe(III) oxide but did not significantly reduce highly crystalline Fe(III) forms. Fe(III) was reduced optimally at pH 6.7 to 7 and at 30 to 35.degree. C. Ethanol, butyrate, and propionate could also serve as electron donors for Fe(III) reduction. A variety of other organic compounds and hydrogen could not. MnO2 was completely reduced to Mn(II), which precipitated as rhodochrosite (MnCO3). Nitrate was reduced to ammonia. Oxygen could not serve as an electron acceptor, and it inhibited growth with the other electron acceptors. This is the first demonstration that microorganisms can completely oxidize organic compounds with Fe(III) or Mn(IV) as the sole electron acceptor and that oxidation of organic matter coupled to dissimilatory Fe(III) or Mn(IV) reduction can yield energy for microbial growth. GS-15 provides a model for how enzymatically catalyzed reactions can be quantitatively significant mechanisms for the reduction of iron and manganese in anaerobic environments.