AEROBIC BACTERIAL-DEGRADATION OF SELECTED POLYAROMATIC COMPOUNDS AND N-ALKANES FOUND IN PETROLEUM

Biodegradation in vitro studies were carried out on selected aromatic and aliphatic hydrocarbons in aqueous medium. Biotic and abiotic samples were analysed by GC and/or GC-MS. It was clearly shown that abiotic losses for selected compounds were much higher than might have been expected from the literature. The experiments were undertaken using the higher-relative-molecular-mass compounds; e.g. phenanthrene, chrysene, benzo[a]pyrene and a series of n-alkanes. Although n-C-17 proved too volatile, n-C-22 and n-C-30 were shown to be extensively biodegraded, and these n-alkanes were degraded preferentially to the polyaromatic compounds. Chrysene and benzo[a]pyrene were less affected by abiotic losses but did not biodegrade significantly during a four-month incubation. A similar experiment with diesel oil confirmed the above findings.