State Key Laboratory of Bioreactor Engineering and Institute of Applied Chemistry, East China University of Science and Technology, Shanghai, 200237, China.
Appl Microbiol Biotechnol. 2012 Oct;96(2):531-42. doi: 10.1007/s00253-011-3828-8. Epub 2012 Jan 17.
Microbial assemblage in an n-alkanes-dependent thermophilic methanogenic enrichment cultures derived from production waters of a high-temperature petroleum reservoir was investigated in this study. Substantially higher amounts of methane were generated from the enrichment cultures incubated at 55 °C for 528 days with a mixture of long-chain n-alkanes (C(15)-C(20)). Stoichiometric estimation showed that alkanes-dependent methanogenesis accounted for about 19.8% of the total amount of methane expected. Hydrogen was occasionally detected together with methane in the gas phase of the cultures. Chemical analysis of the liquid cultures resulted only in low concentrations of acetate and formate. Phylogenetic analysis of the enrichment revealed the presence of several bacterial taxa related to Firmicutes, Thermodesulfobiaceae, Thermotogaceae, Nitrospiraceae, Dictyoglomaceae, Candidate division OP8 and others without close cultured representatives, and Archaea predominantly related to uncultured members in the order Archaeoglobales and CO(2)-reducing methanogens. Screening of genomic DNA retrieved from the alkanes-amended enrichment cultures also suggested the presence of new alkylsuccinate synthase alpha-subunit (assA) homologues. These findings suggest the presence of poorly characterized (putative) anaerobic n-alkanes degraders in the thermophilic methanogenic enrichment cultures. Our results indicate that methanogenesis of alkanes under thermophilic condition is likely to proceed via syntrophic acetate and/or formate oxidation linked with hydrogenotrophic methanogenesis.
本研究调查了来自高温油藏采出水的 n-烷烃依赖型嗜热产甲烷菌富集培养物中的微生物组合。在 55°C 下用长链 n-烷烃（C(15)-C(20)）混合物培养 528 天的富集培养物产生了大量的甲烷。化学计量估计表明，烷烃依赖型产甲烷作用占预期甲烷总量的约 19.8%。在培养物的气相中偶尔会与甲烷一起检测到氢气。液体培养物的化学分析仅导致乙酸盐和甲酸盐的浓度较低。富集的系统发育分析表明存在与厚壁菌门、硫热菌科、热球菌科、硝化螺旋菌科、Dictyoglomaceae、候选分类 OP8 和其他没有密切培养代表以及古菌主要与未培养的成员在古菌目中和 CO(2)-还原产甲烷菌相关的几种细菌分类群。从烷烃添加的富集培养物中回收的基因组 DNA 的筛选也表明存在新的烷基琥珀酸合酶α亚基（assA）同源物。这些发现表明在嗜热产甲烷富集培养物中存在特征不明确（推定）的厌氧 n-烷烃降解菌。我们的结果表明，在嗜热条件下烷烃的产甲烷作用可能通过与氢营养型产甲烷作用相关的共乙酸盐和/或甲酸盐氧化进行。
