Q-199. Sphingomonas BPH, a Component of a Consortium Enriched on Bitumen, Cleaves Polyaromatic Hydrocarbon Rings

C. Milliken1, W. Jones1, C. Berry1, W. Simpson2, F. Maddox1, B. W. Smith1, R. L. Brigmon1;
1Savannah River Natl. Lab., Aiken, SC, 2South Carolina State Univ., Orangeburg, SC.

Diesel and bitumen hydrocarbons (HCs) and specifically polycyclic aromatic hydrocarbons (PAHs) are environmental pollutants that are a worldwide problem. They are organic compounds that may be carcinogenic, mutagenic, or genotoxic. HCs can be removed from sediments and groundwater through bioremediation, which uses living organisms to degrade organic contaminants into less toxic forms. A variety of microorganisms including Sphingomonas spp. can degrade PAHs and are catabolically versatile utilizing both low and high molecular weight aromatic compounds. In addition to their ability to degrade PAHs, Sphingomonas spp. are found ubiquitously in the environment_two factors that collectively make them natural candidates for use in bioremediation applications. A novel strain of Sphingomonas, BPH, isolated at Savannah River National Laboratory from an oil refinery in Katowice, Poland can convert indole to indigo and is capable of transforming the PAHs anthracene, phenanthrene, and pyrene. Byproducts from ring cleavage of indole by BPH after 4 days include 1,2-benzenedicarboxylic acid-bis(7-methyloctyl) ester, and 1,2-benzenedicarboxylic acid -butyl-8-methylnonyl ester. Products from BPH with phenanthrene after 4 days include dibenzothiophene, a ring substitution that can lead to further ring deconstruction. After 9 days most of these compounds were below detectable concentrations, by headspace analysis on GC/MS. These reactions may not be the first steps toward mineralization but to solubilization and eventual integration of supplemented aromatic hydrocarbons. This bacterium is part of a consortium, called Biotiger™, designed to loosen HCs from bitumen; and the mechanisms, like ring cleavage and surfactant production, are still being explored.

147/Q. Microbiology of Wastes and Waste Treatment - I

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