Biodegradation of azaarenes and creosote in aqueous and organic liquid phase immobilized cell bioreactors by bacteria isolated from creosote contaminated soil

The biodegradation of azaarenes and coal-tar creosote was studied using aerobic bacteria isolated from creosote contaminated soil as inocula in batch cultures and in immobilized cell bioreactors. Biodegradation of quinoline, isoquinoline, and 6-methylquinoline by pure and mixed cultures yielded mono-hydroxylated metabolites as the primary products of azaarene metabolism. All azaarene degrading cultures could degrade quinoline, suggesting a common metabolic pathway based on quinoline metabolism. Mixed cultures attacking creosote degraded 2- and 3-ring polyaromatic hydrocarbons and heterocycles, but were unable to degrade 4- and 5-ring PAH. The degradation rate and loading capacity for quinoline was greatly enhanced in the bioreactors in comparison to batch cultures. The rates of isoquinoline, 6-methylquinoline degrading strain of Pseudomonas putida successfully removed 6-methylquinoline from solution in decane in a water-limited, non-aqueous liquid phase immobilized cell bioreactor. These experiments demonstrate the ability of environmental organisms to biodegrade several biologically active compounds under conditions suitable for bioremediation applications