Fig 5. Production of AFB₁ in the first sequential sub-culturing of A. flavus on PDB medium.

One hundred microliter of A. flavus and strain 3JW1 mixed culture was collected at the end of 96 h co-incubation on PDB, then plated on petri dishes containing PDA medium. After 4 days, a single colony of A. flavus was transferred onto a new PDA plate. Conidia of A. flavus on the new plate were collected 14 days later, and were used to inoculate into 15 ml of PDB in a 100-ml flask at a final concentration of 5×10⁵ spores/ml. After 96 h of constantly shaking (200 r/min) the above culture at 28°C in an incubator shaker, the medium filtrate was collected and the amount of AFB₁ was determined by IAC-HPLC. This study was conducted 3 times and each treatment was replicated three times. The initial conidial concentration of A. flavus in the PDB medium was 5×10⁵ spores/ml.