Rhodopseudomonas palustris TIE‐1 grows photoautotrophically with Fe(II) as an electron donor and photoheterotrophically with a variety of organic substrates. However, it is unclear whether R. palustris TIE‐1 conducts Fe(II) oxidation in conditions where organic substrates and Fe(II) are available simultaneously. In addition, the effect of organic co‐substrates on Fe(II) oxidation rates or the identity of Fe(III) minerals formed is unknown. We incubated R. palustris TIE‐1 with 2 mM Fe(II), amended with 0.6 mM organic co‐substrate, and in the presence/absence of CO2. We found that in the absence of CO2, only the organic co‐substrates acetate, lactate and pyruvate, but not Fe(II), were consumed. When CO2 was present, Fe(II) and all organic substrates were consumed. Acetate, butyrate and pyruvate were consumed before Fe(II) oxidation commenced, whereas lactate and glucose were consumed at the same time as Fe(II) oxidation proceeded. Lactate, pyruvate and glucose increased the Fe(II) oxidation rate significantly (by up to threefold in the case of lactate). 57Fe Mössbauer spectroscopy revealed that short‐range ordered Fe(III) oxyhydroxides were formed under all conditions. This study demonstrates phototrophic Fe(II) oxidation proceeds even in the presence of organic compounds, and that the simultaneous oxidation of organic substrates can stimulate Fe(II) oxidation.

中文翻译：

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沼泽红假单胞菌 TIE-1 在有机和富含 Fe(II) 的条件下光养 Fe(II) 氧化

沼泽红假单胞菌TIE-1 以 Fe(II) 作为电子供体进行光自养生长，并以各种有机底物进行光异养生长。但目前还不清楚是否沼泽红藻TIE-1 在有机底物和 Fe(II) 同时存在的条件下进行 Fe(II) 氧化。此外，有机共底物对 Fe(II) 氧化速率或形成的 Fe(III) 矿物特性的影响尚不清楚。我们孵化沼泽红藻TIE-1 含有 2 mM Fe(II)，并用 0.6 mM 有机辅助底物修正，并且存在/不存在 CO2。我们发现在没有CO的情况下2，仅消耗有机辅助底物乙酸盐、乳酸盐和丙酮酸盐，而不消耗 Fe(II)。当一氧化碳2存在时，Fe(II) 和所有有机底物都被消耗。乙酸盐、丁酸盐和丙酮酸盐在 Fe(II) 氧化开始之前被消耗，而乳酸和葡萄糖在 Fe(II) 氧化进行的同时被消耗。乳酸、丙酮酸和葡萄糖显着增加了 Fe(II) 的氧化速率（乳酸的氧化速率高达三倍）。57Fe 穆斯堡尔谱表明，在所有条件下都会形成短程有序的 Fe(III) 羟基氧化物。这项研究表明，即使在有机化合物存在的情况下，光养型 Fe(II) 氧化也会进行，并且有机底物的同时氧化可以刺激 Fe(II) 氧化。