Enrichment and Characterization of a Psychrotolerant Consortium Degrading Crude Oil Alkanes Under Methanogenic Conditions

Abstract

Anaerobic alkane degradation via methanogenesis has been intensively studied under mesophilic and thermophilic conditions. While there is a paucity of information on the ability and composition of anaerobic alkane-degrading microbial communities under low temperature conditions. In this study, we investigated the ability of consortium Y15, enriched from Shengli oilfield, to degrade hydrocarbons under different temperature conditions (5-35 °C). The consortium could use hexadecane over a low temperature range (15-30 °C). No growth was detected below 10 °C and above 35 °C, indicating the presence of cold-tolerant species capable of alkane degradation. The preferential degradation of short chain n-alkanes from crude oil was observed by this consortium. The structure and dynamics of the microbial communities were examined using terminal restriction fragment length polymorphism (T-RFLP) fingerprinting and Sanger sequencing of 16S rRNA genes. The core archaeal communities were mainly composed of aceticlastic Methanosaeta spp. Syntrophaceae-related microorganisms were always detected during consecutive transfers and dominated the bacterial communities, sharing 94-96 % sequence similarity with Smithella propionica strain LYP(T). Phylogenetic analysis of Syntrophaceae-related clones in diverse methanogenic alkane-degrading cultures revealed that most of them were clustered into three sublineages. Syntrophaceae clones retrieved from this study were mainly clustered into sublineage I, which may represent psychrotolerant, syntrophic alkane degraders. These results indicate the wide geographic distribution and ecological function of syntrophic alkane degraders.

Metagenomic Characterization of <i>Candidatus</i> Smithella cisternae Strain M82_1, a Syntrophic Alkane-Degrading Bacteria, Enriched from the Shengli Oil Field

“…This novel hexadecane degrader ( Smithella sp.) is affiliated with Syntrophaceae sublineage II, which has been proposed as a candidate species for syntrophic alkane degradation bacteria ( 20 ). However, the metabolic potential of alkane-degrading bacteria in Syntrophaceae sublineage II ( 20 ) has not yet been examined in detail.…”

“…Members of the Syntrophaceae phylotype represent some of the most abundant syntrophic alkane-degrading bacteria and appear to play an important role in the carbon cycle in hydrocarbon-contaminated environments ( 20 ). In the present study, the combination of metagenomics and GC-MS successfully elucidated the genetic and metabolic properties of a Syntrophaceae sublineage II bacterium, which was proposed as the novel species “ Candidatus Smithella cisternae”.…”

“…Syntrophaceae members have been repeatedly detected in methanogenic alkane-degrading cultures enriched from geographically distant sites ( 10 , 14 , 28 , 72 , 73 , 85 ). These Syntrophaceae related-clones were primarily divided into three sublineages, which may represent three genera with different ecophysiological properties ( 20 ). To date, three draft genomes of uncultured syntrophic alkane degraders belonging to sublineage I have been reported ( 24 , 80 ); however, only one sublineage II genome has been published ( 87 ).…”

Reflection on Molecular Approaches Influencing State-of-the-Art Bioremediation Design: Culturing to Microbial Community Fingerprinting to Omics

“…Using T-RFLP experimental design similar to the above, diverse important bioremediation insights were developed. These include a rapid semi-quantitative understanding of microbial communities capable of degrading alkanes in cold anaerobic climates (Ding et al 2015), identifying microbes involved in uranium reduction in drinking water biostimulation strategy (Williams et al 2011), and finding favorable conditions for ammonia removal by Nitrosomonas species in a drinking water biofilter (Feng et al 2012). Knowing which microbial communities can remove pollutants under different conditions informs bioaugmentation strategies (Wang et al 2013; Zhuang et al 2012).…”

Phylogenetic Analysis of Anaerobic Co-Digestion of Animal Manure and Corn Stover Reveals Linkages between Bacterial Communities and Digestion Performance

“…Members of Ketogulonicigenium and Syntrophaceae were previously identified as fermenters with versatile metabolisms [41]- [44]. Further, the syntrophic importance of members of Syntrophaceae was linked to methane production systems using hydrocarbons as substrate [45]- [47]. It is important to note that hydrocarbons are secondary metabolites from plant material degradation.…”