Ecological and biochemical synergy in Fungal–LAB co-fermentation: From enzymatic priming to sustainable functional foods

Fungal–lactic acid bacteria (LAB) co-fermentation represents an emerging, eco-efficient biotechnology that integrates fungal enzymatic priming with bacterial metabolic refinement to generate functional and microbiologically safe foods. This review consolidates current understanding of the ecological and biochemical synergy underpinning fungal–LAB interactions, emphasizing how enzymatic hydrolysis, nutrient cross-feeding, and acidification dynamics enhance food quality, safety, and sustainability. Filamentous fungi such as Aspergillus, Rhizopus, and Penicillium initiate the process by secreting hydrolases that depolymerize complex macromolecules, thereby enriching the substrate with fermentable monomers. LAB including Lactiplantibacillus plantarum, Levilactobacillus brevis, and Weissella cibaria, subsequently convert these intermediates into organic acids, exopolysaccharides, vitamins, and bioactive peptides that stabilize the system and improve nutritional bioavailability. The resulting co-metabolism enhances protein digestibility, mineral release, and antioxidant potential while suppressing spoilage and mycotoxin formation. Recent multi-omics advances have revealed inter-kingdom signaling networks and stress-response mechanisms that enable mutual adaptation and precision control. Fungal–LAB partnerships increasingly support agro-industrial waste valorization, probiotic carrier development, and sustainable functional-food production within the circular bioeconomy. Despite clear promise, challenges remain in standardizing starter consortia, optimizing large-scale kinetics, and validating health outcomes through clinical studies. Collectively, this synergistic microbial model offers a biologically elegant and technologically versatile pathway toward next-generation functional foods and resource-efficient bioprocessing.