Desulfatobacillum alkenivorans AK-01
   
   
 

Photo credit: So and Young, AEM 65: 2969-76
Desulfatibacillum alkenivorans AK-01 is a mesophilic sulfate-reducer that was isolated from estuarine sediment. It utilizes C13 to C18 alkanes, 1-alkenes (C15 and C16) and 1-alkanols (C15 and C16) as growth substrates. It activates alkanes via subterminal addition of the alkane to fumarate.

Biotransformation plays an important role in the fate and transport of alkanes in the environment.  Although aerobic mechanisms and genetics are well-described, very little has been characterized for anaerobic systems.  Desulfatibacillum alkenivorans AK-01 was isolated from the Arthur Kill in New Jersey. This site has a history of contamination from the petrochemical industry.  AK-01 is a delta-proteobacterium capable of utilizing C13-C18 alkanes as growth substrates (1,2).   Analysis of labeled and fully deuterated metabolites shows that AK-01 activates alkanes via fumarate addition to the subterminal carbon (3).  Our previous work also demonstrated the presence of two gene clusters in strain AK-01, which contain genes (assA1 and assA2) with high similarity to the active subunit gene of benzylsuccinate synthase (bssA).  We have shown, using proteomic analysis, that the expression of a protein transcribed from one of these genes (assA1) correlates with growth on hexadecane (4). 

The sequencing of AK-01 was conducted in tandem with the sequencing of Desulfococcus oleovorans Hxd3, which degrades alkanes via a different mechanism than “fumarate addition” (5)  The genes involved in this pathway are unknown.  The sequencing of both strains serves to: 1) resolve the genetic differences between the two different alkane-degrading strains and provide the basis for further biochemical characterization of related strains, 2) determine and characterize the environmental diversity of genes involved in anaerobic alkane degradation to better understand the role of microorganisms in anaerobic carbon cycling,  and 3) provide additional information relevant to optimizing bioremediation strategies at contaminated sites.

Relevant Literature References

1.  So, C.M. and L.Y. Young. Isolation and characterization of a sulfate-reducing bacterium that anaerobically degrades alkanes. Appl. Environ. Microbiol. 1999 Jul;65(7):2969-76.

2.  So, C.M. and L.Y. Young. Initial reactions in anaerobic alkane degradation by a sulfate reducer, strain AK-01. Appl. Environ. Microbiol. 1999 Dec;65(12):5532-40.

3.  Callaghan, A.V., Gieg, L.M., Kropp, K.G., Suflita, J.M. and L.Y. Young. Comparison of mechanisms of alkane metabolism under sulfate-reducing conditions among two bacterial isolates and a bacterial consortium. Appl. Environ. Microbiol. 2006 Jun;72(6):4274-82.

4.  Callaghan, A.V., Wawrik, B., Ní Chadhain, S.M., Young, L.Y. and G.J. Zylstra. Anaerobic alkane-degrading strain AK-01 contains two alkylsuccinate synthase genes. Biochem. Biophys. Res. Commun. 2008 Feb 1;366(1):142-8.

5.  So, C.M., Phelps, C.D., and L.Y. Young. Anaerobic transformation of alkanes to fatty acids by a sulfate-reducing bacterium, strain Hxd3. Appl Environ Microbiol. 2003 Jul;69(7):3892-900.