Abstract
Aflatoxins (AFs) are secondary metabolites (toxins) primarily produced by Aspergillus flavus and Aspergillus parasiticus. Aflatoxin B1 (AFB1), a member of AFs, is the most toxic mycotoxin, responsible for numerous adverse health and economic losses. Despite several physical and chemical means aimed at reducing or inactivating AFs, they still persist along the food chain. This has necessitated the need for efficient ways of reducing or at best eliminating them from foods and feeds. Bacterial degradation of AFs presents an effective, cost efficient and feasible way in doing so. This study thus, investigated AFB1 degradation by protease inhibited and uninhibited bacterial lysates. Aflatoxin B1 (2.5 μg/mL) was incubated with each of seven different bacterial lysates for 3, 6, 12, 24 and 48 hrs. As monitored on high performance liquid chromatography (HPLC), significant (p˂0.05) AFB1 degradation by all the lysates was recorded. After 48 hrs of incubation, the highest percentage degradation obtained for the lysates was 60.9% while the lowest was 31.7% corresponding to lysates of Lysinibacillus fusiformis and Sporosarcina sp. respectively. Conversely, a drastic increase in AFB1 degradation was observed after bacterial cells were treated with protease inhibitors prior to lysis. Following 12 hrs of incubation, a 100% detoxification was detected for all the protease inhibited lysates. Cytotoxicity studies on human lymphocytes following the MTT assay also indicated that the toxicity of AFB1 degraded samples were considerably reduced when compared to the parent AFB1. Results obtained from this study suggest that AFB1 degradation by these bacterial lysates is potentially enzymatic and the consequent decrease in fluorescence intensity based on HPLC indicates the cleavage of the furan ring of the AFB1 molecule. The successful degradation of AFB1 by these lysates could be an important bio-control measure in safeguarding the quality of agricultural commodities that may have a huge potential for industrial applications.
M.Tech. (Food Technology)