Enhancement of orimulsion biodegradation through the addition of natural marine carbon substrates

Orimulsion is a bitumen-based heavy fuel that is a less expensive alternati ve to traditional fuel oils. However, because its density is intermediate b etween that of freshwater and seawater, in the event of a spill, the fuel c ould strand in the sediments. Previous work indicated that only 0.6-2.7% of the bitumen would degrade in long incubations of marine sediments. We adde d Various natural carbon substrates to stimulate the degradation of bitumen by native populations of benthic bacteria. The concentration and carbon is otopic signature of the respired carbon dioxide was measured to partition t he substrates that supported bacterial respiration. We found that the addit ion of seagrass and pinfish stimulated the degradation of bitumen by as muc h as 2-9-fold relative to incubations without these substrates. Biodegradat ion of bitumen may be enhanced by the addition of natural marine carbon sub strates and may be a useful approach for bioremediation. Preadaptation of t he bacteria to bitumin did not significantly enhance their ability to degra de it.