Bioremediation of marine environment could be the response to oil spills threats. In the present study the fungal community from a Mediterranean marine site chronically interested by oil spills was investigated. Sixty-seven taxa were isolated from water sample and 17 from sediments; for many of the identified species is the first report in seawater and sediments, respectively. The growth of 25% of the fungal isolates was stimulated by crude oil as sole carbon source. Four strains were selected to screen hydrocarbons degradation using the 2,6-dichlorophenol indophenol (DCPIP) colorimetric assay. A. terreus MUT 271, T. harzianum MUT 290 and P. citreonigrum MUT 267 displayed a high decolorization percentage (DP≥68%). A. terreus displayed also the highest decreases of hydrocarbons compounds (up to 40%) quantified by gas-chromatography analysis. These results suggest that the selected fungi could represent potential bioremediation agents with strong crude oil degradative capabilities.

The emergence of antibiotic resistance and viruses with high epidemic potential made unexplored marine environments an appealing target source for new metabolites. Marine fungi represent one of the most suitable sources for the discovery of new compounds. Thus, the aim of this work was (i) to isolate and identify fungi associated with the Atlantic sponge Grantia compressa; (ii) to study the fungal metabolites by applying the OSMAC approach (one strain; many compounds); (iii) to test fungal compounds for their antimicrobial activities. Twenty-one fungal strains (17 taxa) were isolated from G. compressa. The OSMAC approach revealed an astonishing metabolic diversity in the marine fungus Eurotium chevalieri MUT 2316, from which 10 compounds were extracted, isolated, and characterized. All metabolites were tested against viruses and bacteria (reference and multidrug-resistant strains). Dihydroauroglaucin completely inhibited the replication of influenza A virus; as for herpes simplex virus 1, total inhibition of replication was observed for both physcion and neoechinulin D. Six out of 10 compounds were active against Gram-positive bacteria with isodihydroauroglaucin being the most promising compound (minimal inhibitory concentration (MIC) 4–64 µg/mL) with bactericidal activity. Overall, G. compressa proved to be an outstanding source of fungal diversity. Marine fungi were capable of producing different metabolites; in particular, the compounds isolated from E. chevalieri showed promising bioactivity against well-known and emerging pathogens.

Covering 70 % of Earth, oceans are at the same time the most common and the environment least studied by microbiologists. Considering the large gaps in our knowledge on the presence of marine fungi in the oceans, the aim of this research was to isolate and identify the culturable fungal community within three species of sponges, namely Dysidea fragilis, Pachymatisma johnstonia and Sycon ciliatum, collected in the Atlantic Ocean and never studied for their associated mycobiota. Applying different isolation methods, incubation temperatures and media, and attempting to mimic the marine and sponge environments, were fundamental to increase the number of cultivable taxa. Fungi were identified using a polyphasic approach, by means of morpho-physiological, molecular and phylogenetic techniques. The sponges revealed an astonishing fungal diversity represented by 87 fungal taxa. Each sponge hosted a specific fungal community with more than half of the associated fungi being exclusive of each invertebrate. Several species isolated and identified in this work, already known in terrestrial environment, were first reported in marine ecosystems (21 species) and in association with sponges (49 species), including the two new species Thelebolus balaustiformis and Thelebolus spongiae, demonstrating that oceans are an untapped source of biodiversity.

Nineteen fungal strains associated with the seagrass Posidonia oceanica, with the green alga Flabellia petiolata, and the brown alga Padina pavonica were collected in the Mediterranean Sea. These strains were previously identified at the family level and hypothesised to be undescribed species. Strains were examined by deep multi-loci phylogenetic and morphological analyses. Maximum-likelihood and Bayesian phylogenies proved that Parathyridariella gen. nov. is a distinct genus in the family Thyriadriaceae. Analyses based on five genetic markers revealed seven new species: Neoroussoella lignicola sp. nov., Roussoella margidorensis sp. nov., R. mediterranea sp. nov., and R. padinae sp. nov. within the family Roussellaceae, and Parathyridaria flabelliae sp. nov., P. tyrrhenica sp. nov., and Parathyridariella dematiacea gen. nov. et sp. nov. within the family Thyridariaceae.

Fungi are widely distributed in the Oceans, interact with other organisms and play roles that range from pathogenic to mutualistic. The present work focuses on the characterization of the cultivable mycobiota associated with the seagrass Posidonia oceanica (L.) Delile collected off the Elba Island (Italy). We identified 102 taxa (mainly Ascomycota) by the mean of a polyphasic approach. Leaves, rhizomes, roots and matte were characterized by unique mycobiota revealing a “plant-part-specificity.” The comparison with the mycobiota associated with the green alga Flabellia petiolata and the brown alga Padina pavonica underlined a “substrate specificity.” Indeed, despite being part of the same phytocoenosis, these photosynthetic organisms recruit different fungal communities. The mycobiota seems to be necessary for the host’s defense and protection, playing, in this way, remarkable ecological roles. Among the 61 species detected in association with P. oceanica (including two species belonging to the newly introduced genus Paralulworthia), 37 were reported for the first time from the Mediterranean Sea.

Two fungal strains, Aspergillus terreus MUT 271 and Trichoderma harzianum MUT 290, isolated from a Mediterranean marine site chronically pervaded by oil spills, can use crude oil as sole carbon source. Herein, these strains were investigated as producers of biosurfactants, apt to solubilize organic molecules as a preliminary step to metabolize them. Both fungi secreted low molecular weight proteins identified as cerato-platanins, small, conserved, hydrophobic proteins, included among the fungal surface-active proteins. Both proteins were able to stabilize emulsions, and their capacity was comparable to that of other biosurfactant proteins and to commercially available surfactants. Moreover, the cerato-platanin from T. harzianum was able to lower the surface tension value to a larger extent than the similar protein from A. terreus and other amphiphilic proteins from fungi. Both cerato-platanins were able to make hydrophilic a hydrophobic surface, such as hydrophobins, and to form a stable layer, not removable even after surface washing. To the best of our knowledge, the ability of cerato-platanins to work both as biosurfactant and bioemulsifier is herein demonstrated for the first time.