Biotechnological Potential of a Novel Strain of Fusarium proliferatum, a Terrestrial Fungus Adapted to Marine Environment

Marine habitats represent hostile environments for the majority of microorganisms. Nonetheless, in the last decades, the study of the microbial diversity of the halophylic environments has reported that fungi constitute a quantitatively relevant component. The research reports the isolation of a novel strain of Fusarium proliferatum from seawater, within a monitoring campaign conducted in the South Calabrian coasts (Regione Calabria, Italy): the microorganism presumably adapted from a terrestrial to a marine niche, potentially changing its metabolism in response to the environmental stress. The marine fungus was molecularly characterised preliminarily with Sanger Sequencing, and further employing Whole Genome Sequencing, subsequently cultivated on organic rice to stimulate the production of secondary metabolites. Chemical extraction and purification processes yielded three main compounds identified as 9-O-methylbostrycoidin (MBC), 9-O-methylfusarubin (MFR) and 3-indoleacetic acid (IAA). When tested for their antimicrobial and antioxidant potential, MBC and MFR demonstrated significant activity against Staphylococcus aureus and Listeria monocytogenes, while IAA exhibited no antimicrobial effect, but highlighted antioxidant properties with the ORAC assay. Additionally, biocompatibility assays on human keratinocyte cells (HaCaT) revealed minimal toxicity of the crude extract and MBC, while IAA displayed dose-dependent toxicity, opening to considering the purified secondary metabolites for valuable applications in environmental, industrial and pharmaceutical biotechnology.