Genomic and Metabolomic Characterization of Medium-Dependent Mycelial Metabolism and Bioactivities in Fulvifomes fastuosus MSU245

Metabolism in filamentous fungi is shaped by nutrient availability, but this relationship remains poorly characterized in tropical polypores. We characterized the draft genome and the untargeted metabolome of submerged mycelial cultures of Fulvifomes fastuosus MSU245 grown for 21 days in malt extract broth (MEB) or potato dextrose broth (PDB), and measured the biological activities of the mycelial and culture-filtrate fractions. Ultra-high-performance liquid chromatography coupled to Orbitrap tandem mass spectrometry (UHPLC–Orbitrap–MS/MS) detected 2822 positive- and 1792 negative-mode metabolite features—feature counts that include isotopes, adducts and in-source fragments and are therefore not compound counts—dominated by putatively annotated lipids, organic acids and organoheterocyclic compounds. Exploratory partial least squares discriminant analysis (PLS-DA) separated the two media in both modes (R2X = 0.72–0.79; R2Y = 1.00; leave-one-out Q2Y = 0.91–0.92; 0 of 6 samples misclassified); with three biological replicates per medium the model is reported as descriptive only, and the medium effect is supported primarily by univariate statistics. Of 1374 differential features, 844 were more abundant in MEB and 530 in PDB, and no pathway remained significant after multiple-testing correction. The 48.97 Mb draft genome-encoded eight biosynthetic gene clusters, six of them terpene- or terpene-precursor-related, and 332 carbohydrate-active enzyme domains consistent with a white-rot decay strategy. Bioactivity was medium- and fraction-specific: the MEB mycelial extract reduced HeLa cell viability to 51 ± 4% after 48 h at 5 mg mL−1, whereas α-glucosidase inhibition occurred only in the MEB culture filtrate (IC50 1.48 ± 0.14% v/v). The genomic and metabolomic datasets are compared rather than mechanistically coupled: no metabolite was identified to structure level and no biosynthetic cluster was linked to a product. Culture medium is therefore a major determinant of the annotated F. fastuosus metabolite profile, and the antiproliferative and α-glucosidase-inhibitory activities localize to different MEB fractions.