Clermont Université, Laboratoire SEESIB, Clermont-Ferrand, France.
Appl Environ Microbiol. 2010 Jan;76(1):23-9. doi: 10.1128/AEM.01127-09. Epub 2009 Oct 23.
The biodegradation of the most abundant atmospheric organic C1 to C4 compounds (formate, acetate, lactate, succinate) by five selected representative microbial strains (three Pseudomonas strains, one Sphingomonas strain, and one yeast strain) isolated from cloud water at the puy de Dôme has been studied. Experiments were first conducted under model conditions and consisted of a pure strain incubated in the presence of a single organic compound. Kinetics showed the ability of the isolates to degrade atmospheric compounds at temperatures representative of low-altitude clouds (5 degrees C and 17 degrees C). Then, to provide data that can be extrapolated to real situations, microcosm experiments were developed. A solution that chemically mimicked the composition of cloud water was used as an incubation medium for microbial strains. Under these conditions, we determined that microbial activity would significantly contribute to the degradation of formate, acetate, and succinate in cloud water at 5 degrees C and 17 degrees C, with lifetimes of 0.4 to 69.1 days. Compared with the reactivity involving free radicals, our results suggest that biological activity drives the oxidation of carbonaceous compounds during the night (90 to 99%), while its contribution accounts for 2 to 37% of the reactivity during the day, competing with photochemistry.
从法国多姆山的云水中分离出的 5 种具有代表性的微生物菌株（3 种假单胞菌、1 种鞘氨醇单胞菌和 1 种酵母）对大气中最丰富的有机 C1 到 C4 化合物（甲酸盐、乙酸盐、乳酸盐、琥珀酸盐）的生物降解进行了研究。实验首先在模型条件下进行，包括在单一有机化合物存在下培养纯菌株。动力学研究表明，这些分离株能够在代表低空云温度（5°C 和 17°C）的条件下降解大气化合物。然后，为了提供可外推到实际情况的数据，开发了微宇宙实验。一种模拟云水溶液化学成分的溶液被用作微生物菌株的孵育介质。在这些条件下，我们确定微生物的活性将显著促进云水中甲酸盐、乙酸盐和琥珀酸盐在 5°C 和 17°C 下的降解，半衰期为 0.4 到 69.1 天。与涉及自由基的反应性相比，我们的结果表明，在夜间（90%至 99%），生物活性驱动含碳化合物的氧化，而其在白天的贡献占反应性的 2%至 37%，与光化学竞争。
