Department of Civil and Environmental Engineering and the Andlinger Center for Energy and the Environment , Princeton University , Princeton , New Jersey 08544 , United States.
Department of Civil, Environmental and Architectural Engineering , University of Colorado Boulder , Boulder , Colorado 80309 , United States.
Environ Sci Technol. 2020 Feb 18;54(4):2500-2509. doi: 10.1021/acs.est.9b06164. Epub 2020 Feb 7.
Bioremediation is a low-cost approach for crude oil spill remediation, but it is often limited by electron acceptor availability. In addition, the biodegradation products of crude oil contaminants are complex, and transformation pathways are difficult to decipher. This study demonstrates that bioelectrochemical systems (BESs) can be effective in crude oil degradation by integrating biological and electrochemical pathways, and more importantly, it provides the first understanding on the daughter products of bioelectrochemical hydrocarbon degradation. Using electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and two-dimensional gas chromatography (GC × GC), the results showed that the active BES reactor improved the total petroleum hydrocarbon (TPH) degradation by ∼70% than open circuit control reactors. After separating the daughter products into nine fractions (MA1-MA9) according to the molecular weight (/ 200-1000) by modified aminopropyl silica (MAPS) fractionation, we found that active BES remediation resulted in 50% more polar, oxygen-containing naphthenic (NAP) acids. The MA4 fraction (centered at ∼550 Da) increased by 47%, and MA5 and MA7 fractions with higher molucular weight increased by a maximum of ∼7- and 9-fold, respectively. These results are in accordance with the variation of bulk elemental compositions in O species, where daughter transformation products doubled relative to parent oil extract. The contribution of newly generated NAP acids was mainly from higher-order oxygen species (O-O) with increased hydrophobicity in conjunction with a decreased abundance in lower-order oxygen species (O). Overall, the study suggests that -alkane degradation occurred via β-oxidation to oxygenated transformation products with lower molecular weight, such as -alcohols in O class and subsequently to -fatty acids in O class.
生物修复是一种低成本的原油泄漏修复方法，但它通常受到电子受体可用性的限制。此外，原油污染物的生物降解产物复杂，转化途径难以破译。本研究表明，生物电化学系统（BES）可以通过整合生物和电化学途径有效地降解原油，更重要的是，它提供了对生物电化学烃降解的次级产物的首次理解。使用电喷雾电离（ESI）傅里叶变换离子回旋共振质谱（FT-ICR MS）和二维气相色谱（GC×GC），结果表明，活性 BES 反应器比开路控制反应器提高了约 70%的总石油烃（TPH）降解。将次级产物根据分子量（/ 200-1000）通过改性氨基丙基硅胶（MAPS）分级分离成九个馏分（MA1-MA9）后，我们发现活性 BES 修复导致 50%更多的极性含氧化合物环烷酸（NAP）。MA4 馏分（约 550 Da 处）增加了 47%，MA5 和 MA7 馏分的分子量更高，最大增加了约 7-9 倍。这些结果与 O 族中元素组成的变化一致，其中次级转化产物的数量是原始油提取物的两倍。新生成的 NAP 酸的贡献主要来自疏水性增加的高阶氧物种（O-O），同时降低了低阶氧物种（O）的丰度。总体而言，该研究表明，-烷烃通过β-氧化降解为低分子量的含氧转化产物，如 O 类中的-醇，随后在 O 类中转化为-脂肪酸。
