BIODEGRADAZIONE DEGLI IDROCARBURI: DALLE COMUNITÀ MICROBICHE MARINE AI SISTEMI READY TO USE PER IL BIORISANAMENTO

Crude oil is one of the major hazardous pollutants. A promising technology for the treatment of contaminated sites is based on biodegradation of oil pollutants by microbial populations. Several microorganisms are known to use hydrocarbons as carbon sources. In the marine environment, obligate hydrocarbonoclastic bacteria (BIC) have been defined as being ecologically important for the aerobic removal of hydrocarbons. Recent advances in microbial ecology make it possible to combine molecular and culture-dependent approaches to identify bacterial community at environmental sites. In this thesis a microbiological survey of the Priolo Bay (eastern coast of Sicily, Ionian Sea), a chronically poll…

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La Betulla dell’Etna: uno studio multidisciplinare sui fattori di deperimento della specie

La betulla dell’Etna (Betula aetnensis Rafin), è una delle specie arboree che durante le ultime glaciazioni si è spinta verso sud e dove oggi costituisce popolazioni pressoché relitte localizzate esclusivamente in Sicilia sulla sommità dell’Etna. I betulleti sono presenti sui versanti orientali ed occidentali dell’Etna, ad un’altitudine compresa tra 1.400 e 2.000 m s.l.m. Si tratta di popolamenti pionieri che colonizzano substrati vulcanici inalterati e/o poco evoluti dove costituiscono a volte dei piccoli boschi puri o misti a pino laricio. Questi boschi in passato erano sottoposti a ceduazioni, che dal 1987 non sono state più eseguite a seguito della istituzione del Parco Regionale dell’E…

Structure and composition of intertidal biofilms which enhance the settlement of the central-Mediterranean reef builder Dendropoma cristatum (Biondi 1859).

Introduction Marine biofilms are complex matrix of microorganisms and mucopolysaccharide substances which develop on all submerged surfaces, providing a variety of physical-bio-chemical cues which affect the settlement of a wide range of benthic organisms. Biofilm community composition, 3-D structure and metabolic activity vary over time. Few studies report the biological and physical changes in marine biofilm development in relationship to their effects on benthic colonisation. Biofilm maturity has been reported to enhance the settlement rate of the central-Mediterranean Dendropoma cristatum (Biondi, 1859), an intertidal vermetid gastropod which builds up ecologically relevant reefs, subje…

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Settlement performance of the Mediterranean reef-builders Dendropoma cristatum (Biondi 1859) in response to natural bacterial films

The gastropod Dendropoma cristatum is a biogenic engineer of the central Mediterranean, forming reefs along the lower rocky intertidal fringe with a remarkable ecological role. To understand whether reef-associated biofilm cultivable bacterial and biofilm ageing may trigger the settlement of the juvenile snails, a combination of laboratory techniques and field experiments was used. Reef-associated biofilm cultivable bacteria were isolated, and a settlement-choice experiment was performed in situ on artificial biofilms composed of i) a mixture of six biofilm-forming selected isolates, ii) all the cultivable bacteria, and iii) 13-, 23-, 32-day old biofilms formed under naturalconditions. Overall,sett…

Hydrocarbonoclastic bacteria from a polluted harbour in Sicily (Italy): isolation, identification and characterization of their biotechnological potential.

Metabolic specialization is a general biological principle that shapes the assembly of microbial communities. Hydrocarbonoclastic bacteria (HCB) are marine bacteria that are specialised in hydrocarbon degradation and use hydrocarbons almost exclusively as unique C and energy source. HCB become dominant in oil-­‐impacted environments and are particularly adapted for removal of hydrocarbons from contaminated sites through bioremediation treatments. The petrochemical site of Priolo-­‐Augusta-­‐Melilli (Sicily, Italy), is a Site of National Interest (SIN) due to high levels of environmental contamination of the coastline and a specific "national program of environmental remediation and restorat…

Biopolymeric porous structure for selective oil sorption and activity intensification of oil-degrading bacteria

Oil pollution is one of the environmental concerns that are currently becoming a major issue in the petroleum industry. Among the different methods for environmental cleaning, the use of sorbents to recover the spilled oils is becoming more and more attractive because of their peculiar advantages such as reusability and recoverability of the oil. In this context, bioremediation is often considered a promising and cost-effective technology that could help a more sustainable recovery of contaminated water by using oil-degrading microorganisms. In this work, it is proposed a PCL-based biodegradable and floatable oil removal sponge, able to immobilize and increase biodegradation ability of hydr…

The occurrence of mycorrhizal fungi in Betula aetnensis Raf. roots: from ecological role to conservation strategies

Betula aetnensis Raf. is an endemic tree species of particular conservation value. It only thrives in the north-eastern slopes of Mount Etna (Sicily), from 1200 to 2100 m a.s.l. This pioneer plant is able to begin primary succession on nutrient-poor and water-limited soils (C = 0.17%; N = 0.05 ‰; P2O5 = 4.1 ppm), where beneficial mycorrhizal fungi (MF) may play a crucial role. In order to investigate MF role in B. aetnensis, plant roots from natural sites and nursery grown specimens were analyzed for both ectomycorrhizal and endomycorrhizal structures. Typical structures of both symbiosis were detected by root staining and morphological observations. Ectomycorrhizae (EM) were more abundant …