Ecological Department of Water Problems Institute, Russian Academy of Sciences, 3 Gubkina str., Moscow, 119333, Russian Federation.
Antonie Van Leeuwenhoek. 2013 Feb;103(2):375-83. doi: 10.1007/s10482-012-9818-8. Epub 2012 Sep 26.
Changes in natural isotopic composition may be used to reveal metabolic pathways of substrate transformation by microbial communities (Vavilin in Ecol Model 240:84-92, 2012b). Anaerobic oxidation of methane (AOM) by sulfate has been described using a mathematical model based on chemical kinetics, microbial dynamics and equations for (13)C isotope accumulation in products as well as their redistribution between substrate and products. Experimental data for two batch cultures that originated from microbial mats covering methane seep chimneys in the Black Sea, previously obtained by Seifert et al. (Org Geochem 37:1411-1419, 2006) and Holler et al. (Env Microbiol Reports 1(5):370-376, 2009), were used to model AOM. During long-time incubation, changes of isotope signatures in CH(4) showed that in the Seifert et al. batch tests (low methane concentration), in contrast to the Holler et al. batch tests (high methane concentration), methane production occurred along with methane oxidation. In accordance with the model, apparent zero and first-order kinetics of methane oxidation were valid for the Holler et al. and Seifert et al. batch tests, respectively. The observed change of [Formula: see text] was explained by microbial kinetics reflecting that the rate is lower for heavy substrate microbial utilization when compared to light substrate microbial utilization. The model showed that small amounts of methanogenesis will change the carbon isotopic composition of methane because biogenic methane has a distinct isotopic composition and due to the large difference between the maximum specific rates of methane oxidation and production. The estimated biomass doubling time of methane-oxidizers for high and low methane concentration was 408/126 days and 4640/1160 days, respectively, depending on the value of the half-saturation constant K ( S ) (5 and 20 mM).
自然同位素组成的变化可用于揭示微生物群落中基质转化的代谢途径（Vavilin 在 Ecol Model 240：84-92，2012b）。硫酸盐厌氧氧化甲烷（AOM）已通过基于化学动力学、微生物动力学和产物中（13）C 同位素积累及其在底物和产物之间再分配的方程的数学模型进行了描述。先前由 Seifert 等人获得的源自覆盖黑海甲烷渗漏烟囱的微生物垫的两个批量培养物的实验数据（Org Geochem 37：1411-1419，2006）和 Holler 等人（Env Microbiol Reports 1（5）：370-376，2009），用于模拟 AOM。在长时间孵育过程中，CH（4）同位素特征的变化表明，在 Seifert 等人的批量测试（甲烷浓度低）中，与 Holler 等人的批量测试（甲烷浓度高）相反，甲烷生产与甲烷氧化同时发生。根据模型，Holler 等人和 Seifert 等人的批量测试分别适用于甲烷氧化的表观零级和一级动力学。观察到的 [Formula: see text] 变化通过反映重基质微生物利用时的速率比轻基质微生物利用时的速率低的微生物动力学来解释。该模型表明，少量的产甲烷作用将改变甲烷的碳同位素组成，因为生物成因甲烷具有独特的同位素组成，并且甲烷氧化和产生的最大比速率之间存在很大差异。根据 K（S）（5 和 20 mM）的值，高和低甲烷浓度下甲烷氧化菌的估计生物量倍增时间分别为 408/126 天和 4640/1160 天。
