Enzymatic transformation of aflatoxin B<inf>1</inf> by Rh_DypB peroxidase and characterization of the reaction products


Loi, M., Renaud, J.B., Rosini, E., Pollegioni, L., Vignali, E., Haidukowski, M., Sumarah, M.W., Logrieco, A.F., Mulè, G. (2020). Enzymatic transformation of aflatoxin B1 by Rh_DypB peroxidase and characterization of the reaction products. Chemosphere, [online] 250 http://dx.doi.org/10.1016/j.chemosphere.2020.126296

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Aflatoxin is the most toxic fungal metabolite that can contaminate crops such as corn and peanuts. In this study we tested an enzyme for the degradation or detoxification of aflatoxin. We determined that the enzyme worked by adding oxygen to the molecule so that it had a different form. Future work will test to determine how less toxic this new compound is and if this is a viable method for detoxifying feed.


In some environments, a number of crops, notably maize and nuts can be contaminated by aflatoxin B1 and related compounds resulting from the growth of aflatoxin-producing Aspergilli. Fungal peroxidases have been shown to degrade a number of mycotoxins, including aflatoxin B1 (AFB1). Therefore, the purpose of this study was to investigate the in vitro enzymatic degradation AFB1 by a recombinant type B dye decolorizing peroxidase (Rh_DypB). Analysis of the reaction products by HPLC-MS analysis showed that under optimized conditions AFB1 was efficiently transformed by Rh_DypB, reaching a maximum of 96% conversion after 4 days of reaction at 25 °C. Based on high resolution mass spectrometry analysis, AFB1 was demonstrated to be quantitatively converted to AFQ1, a compound with a significantly lower toxicity. A number of low molecular mass compounds were also present in the final reaction mixture in small quantities. The results presented in this study are promising for a possible application of the enzyme Rh_DypB for aflatoxin reduction in feed.

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