Abstract: In the present research, 3KW7 with the highest homology to the laccase lac3 gene was selected as a template for homology modeling, and molecular docking was used to predict the binding mode of the recombinant laccase to aflatoxin B1 (AFB1). The results showed that the laccase and AFB1 could interact via hydrogen bond as the key force, indicating that it can be used for the degradation of AFB1. Using response surface methodology, the optimal conditions for degradation of AFB1 by the laccase were established as follows: substrate amount 1 μg, reaction time 15 h, temperature 34 ℃, and enzyme activity 2 U, and the maximum degradation rate of AFB1 of 91.08% was obtained under the optimized conditions. Four compounds in the degradation products of AFB1 were detected by ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS). According to their secondary mass spectrometric information and exact molecular masses, the molecular formulas of the four compounds were postulated to be C16H22O4, C14H16N2O2, C7H12N6O and C24H30O6, respectively.

Key words: aflatoxin B1, laccase, molecular docking, degradation products