Soil Microfloral Interactions with Aflatoxin Synthesis and Degradation

Abstract

Levels of aflatoxin B¹ and G¹ synthesis and degradation by indigenous soil mycoflora were determined using a Psammentie paleustalf, Eufaula sand, amended with peanut meal at contrasting soil pH levels. Highest total aflatoxin levels were attained in strongly acid soilpH 5.3-5.7 and lowest in alkaline soil pH 7.2-9.1 with highly significant factorial interactions influenced by soil C:N ratio, P level, and chitin addition. Peak aflatoxin synthesis occurred with 72–96 hr incubations in saturated humidity at 30 C, with near complete degradation in non sterile soil after 144 hr. No consistent interrelationship was apparent in ratio and culture levels of aflatoxin B₁ and G₁.