Abstract
In the present study, a methanogenic alkane-degrading (a mixture of C9 to C12n-alkanes) culture enriched from production water of a low-temperature oil reservoir was established and assessed. Significant methane production was detected in the alkane-amended enrichment cultures compared with alkane-free controls over an incubation period of 1 year. At the end of the incubation, fumarate addition metabolites (C9 to C12 alkylsuccinates) and assA genes (encoding the alpha subunit of alkylsuccinate synthase) were detected only in the alkane-amended enrichment cultures. Microbial community analysis showed that putative syntrophic n-alkane degraders (Smithella) capable of initiating n-alkanes by fumarate addition mechanism were enriched in the alkane-amended enrichment cultures. In addition, both hydrogenotrophic (Methanocalculus) and acetoclastic (Methanothrix) methanogens were also observed. Our results provide further evidence that alkanes can be activated by addition to fumarate under methanogenic conditions.
Highlights
Methanogenic biodegradation of crude oil is a prevalent process occurring in subsurface petroleum reservoirs and has adverse effect on oil quality (Head et al 2003, 2006; Jones et al 2008)
No methane assA and mcrA genes analysis Alkylsuccinate synthase gene and methyl coenzyme-M reductase gene as the key functional genes involved in the methanogenic n-alkane degradation process were investigated
Methanogenic biodegradation of C 9 to C12 n‐alkanes initiated by addition to fumarate The detection of corresponding fumarate addition products (C9 to C12 alkylsuccinates) provides convincing evidence that the oxidation of C 9 to C 12 n-alkanes was initiated by addition to fumarate under methanogenic conditions
Summary
Methanogenic biodegradation of crude oil is a prevalent process occurring in subsurface petroleum reservoirs and has adverse effect on oil quality (Head et al 2003, 2006; Jones et al 2008). Members of genus Smithella (in the family Syntrophaceae), implicated in syntrophic alkane degradation, were frequently identified in methanogenic crude oil-degrading enrichment cultures (Gray et al 2011; Jones et al 2008; Toth and Gieg 2017). Novel members of the family Peptococcaceae were identified to be the primary degraders in several methanogenic short alkane-degrading (C5 to C 10; n-, iso- and cyclo-alkanes) enrichment cultures derived from oil sands tailings ponds (Abu Laban et al 2015; Mohamad Shahimin et al 2016; Mohamad Shahimin and Siddique 2017; Siddique et al 2015; Tan et al 2014; Tan et al 2013). A positive expression of assA gene and fumarate addition metabolites of 2-methylpentane and methylcyclopentane were detected in the methanogenic short alkane-degrading (C6 to C10; n-, iso- and cyclo-alkanes) cultures, Tan et al still failed to detect initial activation metabolites of n-alkanes (Tan et al 2015)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
