Key Katherine C, Sublette Kerry L, Duncan Kathleen, Mackay Douglas M, Scow Kate M, Ogles Dora
Department of Chemical Engineering, University of Tulsa, Tulsa, OK, USA.
Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK.
Ground Water Monit Remediat. 2013 Fall;33(4):57-68. doi: 10.1111/gwmr.12031.
Although the anaerobic biodegradation of methyl -butyl ether (MTBE) and -butyl alcohol (TBA) has been documented in the laboratory and the field, knowledge of the microorganisms and mechanisms involved is still lacking. In this study, DNA-stable isotope probing (SIP) was used to identify microorganisms involved in anaerobic fuel oxygenate biodegradation in a sulfate-reducing MTBE and TBA plume. Microorganisms were collected in the field using Bio-Sep® beads amended with C-MTBE, C-MTBE (only methoxy carbon labeled), orC-TBA. C-DNA and C-DNA extracted from the Bio-Sep beads were cloned and 16S rRNA gene sequences were used to identify the indigenous microorganisms involved in degrading the methoxy group of MTBE and the -butyl group of MTBE and TBA. Results indicated that microorganisms were actively degrading C-labeled MTBE and TBA in situ and the C was incorporated into their DNA. Several sequences related to known MTBE- and TBA-degraders in the Burkholderiales and the Sphingomonadales orders were detected in all threeC clone libraries and were likely to be primary degraders at the site. Sequences related to sulfate-reducing bacteria and iron-reducers, such as and , were only detected in the clone libraries where MTBE and TBA were fully labeled with C, suggesting that they were involved in processing carbon from the -butyl group. Sequences similar to the genus predominated in the clone library where only the methoxy carbon of MTBE was labeled with C. It is likely that members of this genus were secondary degraders cross-feeding on C-labeled metabolites such as acetate.
尽管甲基叔丁基醚（MTBE）和叔丁醇（TBA）的厌氧生物降解在实验室和现场均已得到证实，但对于其中涉及的微生物和机制仍缺乏了解。在本研究中，DNA稳定同位素探针技术（SIP）被用于识别在一个硫酸盐还原型MTBE和TBA羽流中参与厌氧燃料含氧化合物生物降解的微生物。使用添加了C-MTBE、C-MTBE（仅甲氧基碳标记）或C-TBA的Bio-Sep®珠在现场采集微生物。从Bio-Sep珠中提取的C-DNA和C-DNA被克隆，并使用16S rRNA基因序列来识别参与降解MTBE甲氧基以及MTBE和TBA丁基的本地微生物。结果表明，微生物在原位积极降解C标记的MTBE和TBA，且C被整合到它们的DNA中。在所有三个C克隆文库中均检测到了与伯克霍尔德氏菌目和鞘脂单胞菌目中已知的MTBE和TBA降解菌相关的几个序列，它们可能是该位点的主要降解菌。与硫酸盐还原菌和铁还原菌相关的序列，如 和 ，仅在MTBE和TBA被C完全标记 的克隆文库中检测到，这表明它们参与处理来自丁基的碳。在仅MTBE的甲氧基碳被C标记的克隆文库中，与 属相似的序列占主导地位。该属的成员很可能是利用C标记的代谢产物如乙酸盐进行交叉取食的次生降解菌。
