The bioremediation potential of the Priolo Harbour (SR, Italy): isolation, identification and catabolic ability of hydrocarbonoclastic bacteria

The petrochemical site of Priolo-Augusta-Melilli (Sicily, Italy), is a Site of National Interest (SIN) due to high levels of contamination of the coastline and its remediation is urgently needed. Successful remediation strategies relying on the catabolic potential of marine hydrocarbonoclastic bacteria (HCB) have been described. HCB are specialised hydrocarbon (HC)-degrading marine bacteria that use HC almost exclusively as unique carbon and energy source and become dominant in oil-impacted environments. In order to identify the key hydrocarbon degraders and explore the natural bioremediation potential of the contaminated area, sediment cores and sea water were collected inside the Priolo Harbour (SR, Italy) and used to set enrichment cultures on mineral broth containing different mixtures of linear (C14, C16, C24) and aromatic (phenatrene, pyrene, biphenyl and dibenzothiophene) hydrocarbons and crude oil. The collection of HC degrading bacteria is composed of about 100 isolates that are mainly obligate hydrocarbonoclastic bacteria of the genera Alcanivorax, Marinobacter, Thalassospira, Oleibacter and other HC-degraders of the genera Maribacter, Alteromonas, Methylophaga and as yet uncharacterized Rhodospirillales and Oceanospirillales. Assays of HC biodegradation efficiency of some representative isolates revealed their high potential of application in bioremediation. The analysis of the key catabolic genes involved in HC degradation is in progress.