Degradation and detoxification of AFB₁ by Staphylocococcus warneri, Sporosarcina sp. and Lysinibacillus fusiformis

Effects associated with aflatoxins (AFs), principally aflatoxin B₁ (AFB₁) have necessitated strategies to eliminate their occurrence in commodities along the food chain. This study therefore, investigated the AFB₁ biodegradation ability of Staphylococcus warneri, Sporosarcina sp. and Lysinibacillus fusiformis liquid cultures and cell lysates (disrupted in the presence or absence of protease inhibitors to obtain lysates). These were incubated with AFB₁ (2.5 μg/mL) for 3, 6, 12, 24 and 48 h. AFB₁ degradation was subsequently monitored on high performance liquid chromatography (HPLC) and results indicated that after 48 h, % AFB₁ degradation by the liquid cultures of Lysinibacillus fusisormis, S. warneri and Sporosarcina sp. were 61.3, 47.7 and 46.9%, respectively. After 12 h of incubation, a 100% AFB₁ degradation was observed for all protease inhibited lysates tested. To establish toxicity of the AFB₁ biotransformed products, results from a cytotoxicity study against human lymphocytes demonstrated that the products exhibited significantly (p ≤ 0.05) lower cytotoxic effect compared to the parent AFB₁. From this study, it can be deduced that the mechanism of AFB₁ degradation was enzymatic and that protease inhibition of cells before disruption, could increase this enzymatic activity. Conclusively, the potential of these lysates as a biotechnological approach towards decontaminating AFB₁ is promising.