文献类型：期刊文献

英文题名：Methanogenic Degradation of Long n-Alkanes Requires Fumarate-Dependent Activation

作者：Ji, Jia-Heng[1,2];Liu, Yi-Fan[1,2];Zhou, Lei[1,2];Mbadinga, Serge Maurice[1,2];Pan, Pan[1,2];Chen, Jing[1,2];Liu, Jin-Feng[1,2];Yang, Shi-Zhong[1,2];Sand, Wolfgang[3,4,5];Gu, Ji-Dong[6];Mu, Bo-Zhong[1,2,7]

机构：[1]East China Univ Sci & Technol, State Key Lab Bioreactor Engn, Shanghai, Peoples R China;[2]East China Univ Sci & Technol, Sch Chem & Mol Engn, Shanghai, Peoples R China;[3]Donghua Univ, Text Pollut Controlling Engn Ctr, Minist Environm Protect, Coll Environm Sci & Engn, Shanghai, Peoples R China;[4]Freiberg Univ Min & Technol, Inst Biosci, Freiberg, Germany;[5]Univ Duisburg Essen, Biofilm Ctr, Essen, Germany;[6]Univ Hong Kong, Sch Biol Sci, Hong Kong, Peoples R China;[7]East China Univ Sci & Technol, Engn Res Ctr Microbial Enhanced Oil Recovery, Shanghai, Peoples R China

年份：2019

卷号：85

期号：16

外文期刊名：APPLIED AND ENVIRONMENTAL MICROBIOLOGY

收录：;EI(收录号：20193507367120);WOS:【SCI-EXPANDED(收录号:WOS:000481577400007)】；

基金：This work was supported by the National Natural Science Foundation of China (grant no. 41530318 and 41373070), the NSFC/RGC Joint Research Fund (no. 41161160560), the Shanghai Fundamental Research Program (no. 15JC1401400), the Fundamental Research Funds for the Central Universities (no. 222201817017, 50321101917017, and 22221818014), and the Research Program of State Key Laboratory of Bioreactor Engineering.

语种：英文

外文关键词：(1-methylalkyl)succinate; biodegradation; fumarate addition; hydrocarbon; long n-alkanes; methanogenesis

摘要：Methanogenic degradation of n-alkanes is prevalent in n-alkane-impacted anoxic oil reservoirs and oil-polluted sites. However, little is known about the initial activation mechanism of the substrate, especially n-alkanes with a chain length above C-16. Here, a methanogenic C-16 to C-20 n-alkane-degrading enrichment culture was established from production water of a low-temperature oil reservoir. At the end of the incubation (364 days), C-16 to C-20 (1-methylalkyl)succinates were detected in the n-alkane-amended enrichment culture, suggesting that fumarate addition had occurred in the degradation process. This evidence is supported further by the positive amplification of the assA gene encoding the alpha subunit of alkylsuccinate synthase. A phylogenetic analysis shows these assA amplicons to be affiliated with Smithella and Desulfatibacillum clades. Together with the high abundance of these clades in the bacterial community, these two species are postulated to be the key players in the degradation of C-16 to C-20 n-alkanes in the present study. Our results provide evidence that long n-alkanes are activated via a fumarate addition mechanism under methanogenic conditions. IMPORTANCE Methanogenic hydrocarbon degradation is the major process for oil degradation in subsurface oil reservoirs and is blamed for the formation of heavy oil and oil sands. Addition of n-alkanes to fumarate yielding alkyl-substituted succinates is a well-characterized anaerobic activation mechanism for hydrocarbons and is the most common activation mechanism in the anaerobic biodegradation of n-alkanes with chain lengths less than C-16. However, the activation mechanism involved in the methanogenic biodegradation of n-alkanes longer than C-16 is still uncertain. In this study, we analyzed a methanogenic enrichment culture amended with a mixture of C-16 to C-20 n-alkanes. These n-alkanes can be activated via fumarate addition by mixed cultures containing Smithella and Desulfatibacillum species under methanogenic conditions. These observations provide a fundamental understanding of long-n-alkane metabolism under methanogenic conditions and have important applications for the remediation of oil-contaminated sites and for energy recovery from oil reservoirs.