Degradation of Aflatoxin B1 by the Armillariella tabescens-derived aldo-keto reductase AtAKR

Aflatoxin B1 (AFB1) is one of the most toxic mycotoxins discovered to date and is prevalent in various geographical regions. Armillaria tabescens has been substantiated to be capable of degrading AFB1, with the degradation process potentially attributable to aldo-keto reductases. Therefore, this study aimed at assessing the AFB1-degrading efficacy of the aldo-keto reductase AtAKR through its cloning and recombinant expression in A. tabescens. The entire AtAKR open reading frame spans a length of 954 bp, which corresponds to 317 encoded amino acids. The in vitro analysis of the interaction between AtAKR and AFB1 revealed that AtAKR exhibits direct degradation of AFB1 (100 ppb) in the presence of NADPH. The degradation rates observed were 24.3% and 34.06% within 12-h and 36-h periods, respectively. Liquid chromatography-mass spectrometry was employed for the identification of the degradation products, and the results indicated that AFB1 can undergo direct degradation to Aflatoxicol, which is considerably less toxic compared to AFB1. These findings present AtAKR as a promising candidate for a potential application in the degradation of AFB1 present in food and feed.