Optimum Culture Conditions for Aflatoxin B₂ Production by a Human Pathogenic Strain of Aspergillus Flavus

SUMMARY

The optimum culture conditions for mycelial growth and aflatoxin production by a human pathogenic strain of Aspergillus flavus were established. On the basis of its physical and chemical properties, the toxin extracted from mycelia and culture filtrates was identified as aflatoxin B₂. The organism produced maximum amounts of toxin after the 8th da of incubation in stationary culture at 30 C in the dark. In basal medium with ammonium sulfate as the nitrogen source, at an optimum pH of 4.5, more aflatoxin was produced when sucrose rather than maltose or glucose was the carbon source. The optimum temperature for growth was 37 C. Whereas saprophytes reportedly show optimum growth at 20–32 C, the human pathogenic strain grew best at a higher temperature.