Rice as an Alternative to Proso Millet as a Spore Carrier for Penicillin Production by <i>Penicillium chrysogenum</i>

Abstract

Background: Penicillin remains one of the most important antibiotics in medicine, and improving its industrial production remains an active objective in biotechnology. A practical step in this process is selecting a suitable spore carrier for inoculum preparation. Objectives: This study compared rice and proso millet as solid substrates for sporulation and subsequent penicillin production by Penicillium chrysogenum. Methods: After colony selection and seed preparation, the fungus was cultivated under identical fermentation conditions on both carriers, and changes in pH, packed mycelial volume, fungal morphology, and penicillin activity were monitored during fermentation. Results: Both substrates supported fungal growth and exhibited similar pH patterns during the process. Packed mycelial volume increased in both systems, indicating robust biomass development. Microscopic observations showed comparable patterns of normal mycelial branching and fragmentation for both substrates. Final penicillin production was higher in the rice system than in the millet system, reaching an approximately 1.1-fold higher yield. Conclusions: These findings suggest that, under the tested conditions, rice can serve as a practical and accessible alternative to proso millet for penicillin production.