Abstract

The objective of the present work was to evaluate the capacity of two isolates ofAspergillus flavus from sugar cane (SC), SC-3 and SC-5 to produce aflatoxin under different culture conditions. Aflatoxin B₁ (AFB₁) production was determined in four different media and culture conditions (temperature and pH) were varied to achieve maximal toxin production. AFB₁ was extracted directly from the cultures with chloroform. Thin layer chromatography (TLC) and high performance liquid chromatography (HPLC) were used to identify AFB₁. It was observed that A. flavus cultures SC-3 and SC-5 produced highest AFB₁ when grown in potato dextrose medium (PD) and maximum mycelium production in sabauroud dextrose medium (SD). Supplementation of potato dextrose medium with peptone (PD+P) and sodium nitrate (PD+SN), AFB₁ production increased by 27 and 20% respectively when compared to the control. The effect of pH and temperature on aflatoxin production by A. flavus was examined in peptone containing PD medium. The results concluded that AFB₁ production and mycelial growth was maximum at pH 5.6 when incubated at 27°C in potato dextrose medium supplemented with peptone.

Key words: Aflatoxin B₁, Aspergillus flavus, mycotoxins