Reductive precipitation of sulfate and soluble Fe(III) by Desulfovibrio vulgaris: Electron donor regulates intracellular electron flow and nano-FeS crystallization.
Reductive precipitation of sulfate and soluble Fe(III) by Desulfovibrio vulgaris: Electron donor regulates intracellular electron flow and nano-FeS crystallization.
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DOI：
10.1016/j.watres.2017.04.044
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发表时间：
2017-08
期刊：
影响因子：
12.8
通讯作者：
Chen Zhou;Yun Zhou;B. Rittmann
中科院分区：
文献类型：
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作者：
Chen Zhou;Yun Zhou;B. Rittmann
充分了解SRB的代谢过程，为微生物在水处理和资源回收中提供更有益的服务提供了基础。普通脱硫弧菌硫酸盐呼吸的电子传递途径已被充分研究，但仍有部分未解决。在这里，我们提供了更深入的了解，通过全面监测代谢物的变化duringD. vulgaris代谢与两个电子供体，乳酸和丙酮酸，在存在或不存在的柠檬酸螯合的可溶性FeIII作为一个额外的竞争性电子受体。H2是由乳酸氧化为丙酮酸产生的，但丙酮酸氧化主要产生甲酸。乳酸源的H2在滞后期的积累抑制丙酮酸转化为乙酸。硫酸盐还原是由乳酸来源的H2启动的，但当丙酮酸是供体时，MQ介导的去离子流启动硫酸盐还原而没有延迟。当H2诱导的电子流优先FeIII还原硫酸盐还原，硫酸盐还原前的长滞后期缩短了硫化铁微晶生长的时间，并导致较小的mackinawite（Fe 1 +xS）纳米微晶。综合所有的结果，我们提出，从乳酸或丙酮酸到SO 42 −还原为H2S的电子流至少通过三条途径，这三条途径受电子供体（乳酸或丙酮酸）和另一个电子受体（FeIIIhere）的存在或不存在的调节。这些路线不是竞争，而是互补的：例如，H2或甲酸盐的产生和氧化是亚硫酸盐和二硫/三硫还原为硫化物所必需的。我们的研究表明，电子供体提供了一个实用的工具，以调节和优化SRB占主导地位的生物修复系统。
Fully understanding the metabolism of SRB provides fundamental guidelines for allowing the microorganisms to provide more beneficial services in water treatment and resource recovery. The electron-transfer pathway of sulfate respiration by Desulfovibrio vulgaris is well studied, but still partly unresolved. Here we provide deeper insight by comprehensively monitoring metabolite changes duringD. vulgarismetabolism with two electron donors, lactate and pyruvate, in presence or absence of citrate-chelated soluble FeIIIas an additional competing electron acceptor. H2was produced from lactate oxidation to pyruvate, but pyruvate oxidation produced mostly formate. Accumulation of lactate-originated H2during lag phases inhibited pyruvate transformation to acetate. Sulfate reduction was initiated by lactate-originated H2, but MQ-mediatede−flow initiated sulfate reduction without delay when pyruvate was the donor. When H2-induced electron flow gave priority to FeIIIreduction over sulfate reduction, the long lag phase before sulfate reduction shortened the time for iron-sulfide crystallite growth and led to smaller mackinawite (Fe1+xS) nanocrystallites. Synthesizing all the results, we propose that electron flow from lactate or pyruvate towards SO42−reduction to H2S are through at least three routes that are regulated by thee−donor (lactate or pyruvate) and the presence or absence of anothere−acceptor (FeIIIhere). These routes are not competing, but complementary: e.g., H2or formate production and oxidation were necessary for sulfite and disulfide/trisulfide reduction to sulfide. Our study suggests that thee−donor provides a practical tool to regulate and optimize SRB-predominant bioremediation systems.