Meckenstock R U, Morasch B, Warthmann R, Schink B, Annweiler E, Michaelis W, Richnow H H
University of Konstanz, Department of Microbial Ecology, Germany. rainer.meckenstock.uni-konstanz.de
Environ Microbiol. 1999 Oct;1(5):409-14. doi: 10.1046/j.1462-2920.1999.00050.x.
The influence of microbial degradation on the 13C/12C isotope composition of aromatic hydrocarbons is presented using toluene as a model compound. Four different toluene-degrading bacterial strains grown in batch culture with oxygen, nitrate, ferric iron or sulphate as electron acceptors were studied as representatives of different environmental redox conditions potentially prevailing in contaminated aquifers. The biological degradation induced isotope shifts in the residual, non-degraded toluene fraction and the kinetic isotope fractionation factors alphaC for toluene degradation by Pseudomonas putida (1.0026 +/- 0.00017), Thauera aromatica (1.0017 +/- 0.00015), Geobacter metallireducens (1.0018 +/- 0.00029) and the sulphate-reducing strain TRM1 (1.0017 +/- 0.00016) were in the same range for all four species, although they use at least two different degradation pathways. A similar 13C/12C isotope fractionation factor (alphaC = 1.0015 +/- 0.00015) was observed in situ in a non-sterile soil column in which toluene was degraded under sulphate-reducing conditions. No carbon isotope shifts resulting from soil-hydrocarbon interactions were observed in a non-degrading soil column control with aquifer material under the same conditions. The results imply that microbial degradation of toluene can produce a 13C/12C isotope fractionation in the residual hydrocarbon fraction under different environmental conditions.
以甲苯作为模型化合物，研究了微生物降解对芳烃13C/12C同位素组成的影响。选取了四株不同的甲苯降解细菌菌株，它们在以氧气、硝酸盐、铁离子或硫酸盐作为电子受体的分批培养中生长，作为受污染含水层中可能普遍存在的不同环境氧化还原条件的代表进行研究。生物降解导致残留的未降解甲苯部分出现同位素偏移，恶臭假单胞菌（1.0026±0.00017）、芳香陶厄氏菌（1.0017±0.00015）、金属还原地杆菌（1.0018±0.00029）和硫酸盐还原菌株TRM1（1.0017±0.00016）对甲苯降解的动力学同位素分馏因子αC在所有这四个物种中处于相同范围，尽管它们至少使用两种不同的降解途径。在一个非无菌土柱中，在硫酸盐还原条件下降解甲苯时，原位观察到了类似的13C/12C同位素分馏因子（αC = 1.0015±0.00015）。在相同条件下，使用含水层材料的非降解土柱对照中未观察到由土壤 - 烃相互作用导致的碳同位素偏移。结果表明，在不同环境条件下，甲苯的微生物降解会在残留烃部分产生13C/12C同位素分馏。
