Production, Purification, and Application of a Biomolecule with Herbicidal Activity Produced by Fusarium fujikuroi in Submerged Cultivation

This study investigated the production, purification, and evaluation of a microbial metabolite with herbicidal activity produced by Fusarium fujikuroi via submerged fermentation. The purified compound (PC) was obtained through organic solvent extraction and chromatographic purification, and assessed in bioassays using Raphanus sativus and Triticum aestivum as bioindicator plants. A concentration of 23 mg mL−1 completely inhibited seed germination in 96-well plate assays, while the crude extract (EXT) and cell-free broth (CFB) allowed radicle protrusion but resulted in abnormal seedlings with chlorosis and reduced growth. Mathematical models estimated that concentrations of 16.0 mg mL−1 for radish and 0.9 mg mL−1 for wheat were sufficient to suppress germination with the PC. In substrate experiments, the PC at 6.4 and 64.0 mg mL−1 did not inhibit germination but caused anomalies in radish and significantly reduced wheat seedling growth. In naturally infested soil, the PC maintained phytotoxicity symptoms for 21 days, and after 28 days, a concentration of 64.0 mg mL−1 significantly reduced radish seedling growth. The results highlight the potential of the compound as a bioherbicide.