Amphiphilicity and thermostability modification of dipeptidyl peptidase III from aspergillus terreus HNGD-TM15 capable of simultaneously degrading aflatoxin B1 and zearalenone

Abstract

Aflatoxin B₁ (AFB₁) and Zearalenone (ZEN) are significant mycotoxins that pose serious risks to food safety and human health. This study characterized a dipeptidyl peptidase III (AsDPP III) from Aspergillus terreus HNGD-TM15, which degraded 98.25 % of AFB₁ (5.0 μg/mL) and 96.68 % of ZEN (10 μg/mL). Additionally, a self-assembling amphiphilic peptide S1 was fused to the N-terminus of AsDPP III, resulting in the amphiphilic enzyme S1-AsDPP III, which demonstrated 83.36 % and 70.08 % degradation rates for AFB₁ and ZEN in vegetable oil, respectively. Moreover, S1-AsDPP III exhibits enhanced thermostability, with its half-life at 80 °C extended 1.85-fold, and superior storage stability after seven weeks. Furthermore, the degradation products were identified as AFQ₁ for AFB₁ and DHZEN for ZEN. Zebrafish exposure assays revealed that the degradation products exhibited markedly reduced toxicity compared to the parent mycotoxins. These findings provide a promising strategy for developing efficient detoxifying enzymes for food and feed applications.