Biocontrol strategies with <i>Bacillus</i> and <i>Lactobacillus</i> : toward sustainable management of fungal pathogens

Fungal pathogens continue to pose a significant challenge to global agriculture, food security, and public health, resulting in substantial crop losses, food spoilage, and the accumulation of harmful mycotoxins. The extensive reliance on synthetic chemical fungicides raises serious concerns, including the emergence of resistant fungal strains, ecotoxicity, and adverse health effects. This review highlights the potential of Bacillus spp. and Lactobacillus (LAB) in the development of natural antifungal agents. These bacterial genera are known for the production of a wide range of bioactive metabolites, such as cell-free supernatants (CFS) with potent antifungal properties, volatile organic compounds (VOCs), phenolic acids, and lipopeptides. Lactobacillus-derived compounds, particularly phenyl lactic acid, play a dual role in inhibiting fungal growth while also improving food quality and safety. Similarly, Bacillus spp. produce lipopeptides and volatile organic compounds (VOCs) that are effective against a wide range of airborne and soilborne plant pathogens. Recent studies also highlight Bacillus-mediated green synthesis of nanoparticles (e.g. silver, zinc oxide, and selenium) with potent antifungal activity. These eco-friendly nanomaterials inhibit fungal growth, disrupt biofilms, and enhance plant defenses, offering a targeted and sustainable alternative to chemical fungicides. This review advocates the integration of bacterial antifungal strategies into sustainable agriculture and post-harvest management systems.