Polycyclic aromatic hydrocarbons (PAHs) are widespread pollutants of soil and sediment. Many are carcinogenic and are contaminants of concern at DOE sites. The health threats of PAHs are compounded by the fact that they are fat soluble and have a strong potential to accumulate in tissues and to increase in concentration over time. Thus, PAH-contaminated sediments and soils are high priorities for remediation. Bioremediation via the microbial biodegradation of PAH could be an economical means to eliminate the human health threats posed by these compounds. Unfortunately, because key processes that determine its effectiveness are either poorly understood or are simply “black boxes”, the success of PAH bioremediation has been limited at best. Making bioremediation a viable remedial technology for PAH cleanup will require improving our understanding of these ill-defined areas, one of the most important being the characteristics of the environment and of the microbes that affect the PAHs’ availability for degradation—their bioavailability.
In soil, many factors can affect PAH bioavailability, but two of the most important are diffusion into soil nanopores and uptake by organic matter. Each of the PAH-degrading soil bacteria, Burkholderia sp. strains Ch1-1 and Cs1-4, possesses unique features that may enable it to overcome these key bioavailability constraints. Sequencing the genomes of such organisms should enable researchers to determine how the degradation process works. Genome sequencing of strains Ch1-1 and Cs1-4 would also add much needed information about metabolic diversity among Burkholderia outside of the well studied B. cepacia complex. Collectively, genome sequencing of strains Ch1-1 and Cs1-4 would be valuable in providing insights into the molecular basis by which these organisms effect an environmentally important process, provide further insights into niche adaptation in Burkholderia, and expand our knowledge of speciation in less thoroughly studied strains.
Principal Investigator: William Hickey (Univ. of Wisconsin-Madison).
Program: CSP 2009