Aflatoxin B1 (AFB1) and zearalenone (ZEN) are two predominant mycotoxins ubiquitously found in corn, peanuts, and other grains, which pose a great threat to human health. Therefore, safe and effective methods for detoxification of these mycotoxins are urgently needed. To achieve simultaneous degradation of multiple mycotoxins, a fusion enzyme ZPF1 was constructed by linking zearalenone hydrolase and manganese peroxidase with a linker peptide GGGGS. This fusion enzyme was secretory expressed successfully in the newly constructed food-grade recombinant strain Kluyveromyces lactis GG799(pKLAC1-ZPF1), and was investigated with the mycotoxins degradation efficiency in two reaction systems. Results showed that both AFB1 and ZEN can be degraded by ZPF1 in reaction system 1 (70.0 mmol/L malonic buffer with 1.0 mmol/L MnSO4, 0.1 mmol/L H2O2, 5.0 µg/mL AFB1 and ZEN, respectively) with the ratios of 46.46% and 38.76%, respectively. In reaction system 2 (50.0 mmol/L Tris–HCl, with 5.0 µg/mL AFB1 and ZEN, respectively), AFB1 cannot be degraded while ZEN can be degraded with the ratio of 35.38%. To improve the degradation efficiency of these mycotoxins, optimization of the induction and degradation conditions were fulfilled subsequently. The degradation ratios of AFB1 and ZEN by ZPF1 in reaction system 1 reached 64.11% ± 2.93% and 46.21% ± 3.17%, respectively. While in reaction system 2, ZEN was degraded by ZPF1 at a ratio of 41.45% ± 3.34%. The increases of degradation ratios for AFB1 and ZEN in reaction system 1 were 17.65% and 7.45%, respectively, while that for ZEN in reaction system 2 was 6.07%, compared with the unoptimized results.

Aflatoxin B1 (AFB1) and zearalenone (ZEN) are widely distributed in corns, peanuts, and other cereals, causing serious threat to food safety and human health. As shown by our previous studies, the recombinant yeast strain Kluyveromyces lactis GG799(pKLAC1-ZPF1) had the ability of degrading AFB1 and ZEN simultaneously. In this work, the agent preparation process was optimized for K. lactis GG799(pKLAC1-ZPF1), and the storage conditions of the prepared yeast agents were investigated, for obtaining the products with high storage activities and potent mycotoxin degradation efficiency. The optimal preparation process was as follows: centrifugation at 6000 rpm for 15 min for collection of the yeast cells, spray drying with the ratio of protective compounds to yeast cells at 3:1 (w/w) and then stored at − 20 °C. Simultaneous degradation tests of AFB1 and ZEN were performed using the supernatants of reactivated yeast agents after three months of storage, and the degradation ratios for AFB1 and ZEN in reaction system 1 (70.0 mmol/L malonic buffer, pH 4.5, with 1.0 mmol/L MnSO4, 0.1 mmol/L H2O2, 5.0 μg/mL AFB1 and ZEN, respectively) were 48.2 ± 3.2% and 34.8 ± 2.8%, while that for ZEN in reaction system 2 (50.0 mmol/L Tris–HCl, pH 7.5, with 5.0 μg/mL AFB1 and ZEN, respectively) was 30.1 ± 2.7%. Besides, the supernatants of reactivated yeast agents degraded more than 80% of AFB1 and 55% of ZEN in contaminated peanuts after twice treatments. Results of this work suggested that the optimized process for K. lactis GG799(pKLAC1-ZPF1) was with high value for industrial applications.