Marine Biotechnologies for the Decontamination and Restoration of Degraded Marine Habitats
This research presents the results obtained using a bioremediation approach aiming to enhance natural remediation of the Bagnoli-Coroglio area, a post industrial site in the Gulf of Naples, Italy, characterized by the presence of several pollutants released in almost a century by the ILVA steel plant. In particular, the thesis evaluates the benthic microbial taxonomic composition of this area after ten decades of pollution. Results indicate the prevalence of the Phyla Proteobacteria, (36.7%),
... acteria, (36.7%), Planctomycetes (20.5%) and Bacteroidetes (9.6%) and the presence of a core microbiome suggesting that pollutants and other abiotic factors may have contributed to shape benthic prokaryotic communities. The thesis also evaluates the biotechnological potential of single isolates bacteria (Halomonas sp., Alcanivorax sp., Epibacterium sp., Pseudoalteromonas sp., and Virgibacillus sp.) and mixtures of these species isolated from polluted sediments collected from Bagnoli-Coroglio area and the Sarno river mouth, another polluted site in the Gulf of Naples. Laboratory tests highlighted the ability of mixed cultures and single taxa to degrade PAHs (Polyclic Aromatic Hydrocarbons) and precipitate heavy metals from culture media. Results of Sequential Selective Extraction (SSE) analysis emphasized the ability of mixed cultures to reduce the mobility of As, Cd and Zn by changing their partitioning in the geochemical fractions. Full genome sequencing of isolated strains has allowed for the genetic and molecular characterization of mechanisms underlying processes of degradation and detoxification of xenobiotics. In particular, many genes involved in hydrocarbon degradation pathways and in heavy metal detoxification systems have been identified. My results suggest a potential biotechnological application of these strains in waste-water treatment as well as decontamination of polluted sediments.