DNA-SIP reveals that Syntrophaceae play an important role in methanogenic hexadecane degradation

• Published in: PloS one 2013-07, Vol.8 (7), p.e66784-e66784
• Main Authors: Cheng, Lei, Ding, Chen, Li, Qiang, He, Qiao, Dai, Li-Rong, Zhang, Hui
• Format: Article
• Language: English
• Subjects: Alkanes; Alkanes - metabolism; Alternative energy sources; Bacteria; Bacteriology; Biodegradation; Biogas; Biology; Chemistry; Cladistic analysis; Cloning; Comparative analysis; Consortia; Crude oil; Degradation; Deltaproteobacteria - genetics; Deltaproteobacteria - metabolism; Deoxyribonucleic acid; DNA; DNA, Bacterial - genetics; DNA, Bacterial - isolation & purification; Environmental impact; Gene polymorphism; Genes, rRNA; Hexadecane; Hydrocarbons; Laboratories; Methanogenic bacteria; Microorganisms; Nitrates; Oil and gas fields; Oil field equipment; Oil fields; Oil sands; Petroleum production; Phylogeny; Polymorphism; Relative abundance; Restriction fragment length polymorphism; RNA; RNA, Ribosomal, 16S - genetics; RNA, Ribosomal, 16S - isolation & purification; rRNA 16S; Soil contamination; Treponema; Variance analysis
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0066784

The methanogenic degradation of linear alkanes is a common process in oil-impacted environments. However, little is known about the key players involved in this process. Here, the hexadecane-degrading organisms in a methanogenic, hexadecane-degrading consortium designated M82 obtained from Shengli oilfield and maintained at 35°C for over 4 years, were identified by DNA-stable isotope probing with UL-¹³C-hexadecane, followed by density-resolved terminal restriction fragment length polymorphism (T-RFLP) analysis, cloning and phylogenetic analysis of 16S rRNA gene fragments. Compared to the fractions of the ¹²C treatment, the relative abundance of two phylotypes significantly increased in the heavy fractions of the ¹³C-hexadecane incubated microcosm. One belongs to a uncultured member of the bacterial family Syntrophaceae, which show 95-97% rRNA sequence identity with Smithella propionica, and the other is affiliated with Methanoculleus receptaculi (>99% sequence identity). The results of the present study prove the significant role of uncultured Syntrophaceae in degradation of hexadecane, probably through syntrophic interactions with hydrogenotrophic methanogens.