Sustainable waste-based fermentation for enhanced β-carotene biosynthesis by Blakeslea trispora and functional evaluation of the extracted pigment

BACKGROUND: Valorization of agri-food waste as nutrient-rich substrates provides a sustainable strategy for microbial bioprocessing. Blakeslea trispora is a well-known fungal producer of natural β-carotene; however, its performance on low-cost industrial waste streams remains underexplored. RESULTS: C-NMR analyses. Biofunctional assays revealed antimicrobial activity (MIC: 250-500 mg/mL), with greater susceptibility in Gram-positive strains. Moderate antioxidant activity was observed in the DPPH assay (38% inhibition), and cytotoxic evaluation against Caco-2 cells resulted in an IC₅₀ of 400 mg/mL, indicating potential anticancer effects. CONCLUSION: These findings demonstrate that agri-food wastes can serve as efficient substrates for fungal β-carotene production, supporting cost-effective and sustainable microbial bioprocessing. The functional properties of the extracted β-carotene further highlight its applicability as a bioactive microbial metabolite with antimicrobial, antioxidant, and anticancer potential.